The White Tiger field is the largest on the southern shelf of Vietnam and is located 120 km from the port city of Vung Tau, which is the main production and technical base of the enterprise.

The sea depth within the field is about 50 m, which makes it possible to use jack-up rigs (jack-up rigs) for drilling. According to the data of engineering and geological surveys on the characteristics of soils, the upper, bottom part of the section is favorable for the construction of oil field facilities. The seismicity of the area does not exceed 6 points on the Richter scale.

The climate in the area of ​​the deposit is tropical, monsoon, with rainy summers, at an air temperature of 25-35 ° and a dry season in winter, at a temperature of 24-30 ° C. The season of the southwestern summer monsoon lasts from June to September. At this time, there are heavy, intermittent rains with a squall wind up to 25 m / s. Air humidity rises to 87 - 89%. In winter, from November to March, the northeastern monsoon prevails, with strong winds up to 20 m / s, forming waves up to 10 m high.

Favorable for work at sea is the period of the southwestern monsoons: June-September, as well as transition periods: April-May and November, when the direction of the monsoons changes. Sea currents are associated with the regime of monsoon winds and tidal processes. The speed of currents at a depth of 15-20 m reaches 85 cm / sec, and in the bottom layer it ranges from 20 to 30 cm / sec. The water temperature varies throughout the year from 25 to 30 ° C. The salinity of sea water ranges from 33 to 35 g / l.

The first commercial oil inflow at the White Tiger field was obtained from the Lower Miocene deposits by the Mobil company in 1975 from the Bat'kho-1 well. In 1983, the oil-bearing capacity of the Lower Miocene was confirmed by testing well 5, drilled by JV Vietsovpetro. In 1984, in well 4 for the first time in the field, and in general in Southeast Asia, the commercial oil-bearing capacity of the Lower Oligocene sediments was established. In 1986, as a result of deepening into the foundation and testing of well 6, a unique in geological structure, large in reserves, highly productive deposit in the basement was discovered, confined to an array of fractured granitoid rocks.

Oil production at the White Tiger field has been going on since 1986. To date, 10 offshore fixed platforms (MSP), the Central Technological Platform (TsTP-2), 7 conductor blocks (BC) have been built at the White Tiger field, two installations for free oil loading into the sea (UBN) have been equipped, subsea oil pipelines and gas pipelines have been laid for gas supply to the shore and compressor gas lift systems, water pipelines for the needs of reservoir pressure maintenance.

The power source for offshore installations is internal combustion engines.

The industrial base of JV "Vietsovpetro" is located in the city of Vung Tau and is supplied with electricity via power lines from power plants in Ho Chi Minh City, Baria, Fumi.

The basement deposit is confined to a large three-domed horst-anticlinal uplift of submeridional strike complicated by tectonic faults. The uplift is more than 25 km long and up to 7 km wide.

Longitudinal faults of northeastern strike determined the formation of a three-domed uplift. The most studied is the central vault (with the highest hypsometric elevation of the basement surface, minus 3050 m), as well as the northern vault. The southern arch requires additional exploration and additional study to assess the oil content.

In addition to the indicated structure-forming faults of large amplitude, there are also less significant tectonic faults within the uplift, which determine its block structure. Thus, the basement deposit can be defined as massive-block.

The upper and lower Oligocene clayey-argillic rocks are the cover.

According to the data of lithological and petrophysical studies, granitoid rocks of the basement reservoirs differ in chemical composition and high heterogeneity of the composition of rock-forming minerals. The rocks are represented: acidic (mainly granites), moderately acidic (granodiorites) and medium (monzodiorites, diorites.). They have significant petrographic zonal heterogeneity. The central arch is composed mainly of granites, and its southwestern framing is composed of medium rocks, mainly quartz diorites. The northern arch is characterized by a variegated composition of rocks, including leucocratic granodiorites, granites, adamellites, quartz monzonites, quartz monzodiorites, quartz and quartz-bearing diorites. The southern arch is represented by granites, granodiorites and quartz monzodiorites

The basement rocks were affected by secondary processes that formed a void space in them and turned them into porous and cavernous-fractured reservoirs. The main of these processes are tectonic activity and the action of hydrothermal solutions. Tectonic activity was expressed in the formation of faults, which are associated with increased fracturing of rocks.

The development map of the basement deposit with a network of tectonic faults is shown in Figure 25.

Cracks are observed in the cores of the basement rocks. Their width ranges from 0.1 mm to 3-4 mm, sometimes reaching 2-3 cm. They, as a rule, are partially or completely healed by secondary minerals, mainly calcite and zeolite. The cracks are usually steep - 60 - 70 °, although the angles of incidence can vary from several degrees to 80 - 90 °. They often intersect or form a system of parallel cracks spaced 1-3 cm apart.

Figure 25 - Development map of the basement deposit with a network of tectonic faults.

The void space of rocks, under the microscope, is represented by caverns, pores and leaching cracks, thin meandering cracks at the contacts of xenomorphic grains and larger crushing cracks. With depth, the void space in the rocks decreases markedly. This is especially noticeable from a depth of 500 m from the surface of the foundation.

Reservoir oil is characterized by a significant content of paraffin (24.1%), asphaltene-resinous substances (3.3%) and a high pour point (+33 0 C).

Oil reservoir performance characteristics.

Reservoir permeability decreases with depth.

At the top of the foundation, the permeability coefficient is 0.4-0.2 μm 2, in the withdrawal zone (a.o. minus 3500-3600 m) - 0.05 μm 2, in the injection zone (below a.o. minus 4000 m) - 0.02 μm 2.

High oil production rates are obtained in wells from highly fractured intervals, the permeability of which exceeds 1-2 µm 2.

The oil-bearing capacity of the basement has been proved by direct tests and studies to the hypsometric mark of minus 4350 m. The lower boundary of the deposit is taken conditionally at the hypsometric mark of minus 4650 m, according to the last closed isohypse of the foundation surface. Produced water was not encountered even in the deepest vertical well 905 with a hypsometric bottomhole mark of minus 5014 m.

Features of lithological composition and reservoir properties of horizonsVII + VIIILower Oligocene age in the White Tiger oil field (Vietnam)

Bui Khak Hung

National Research Tomsk Polytechnic University, Tomsk

Scientific adviser associate professor

The White Tiger field is a unique oil field in Vietnam in terms of oil reserves. It is located offshore in southern Vietnam, 120 km southeast of the coastline. The geological section of the deposit is represented by Pre-Cenozoic crystalline basement rocks and Cenozoic terrigenous rocks of the sedimentary cover, in which sandy-silty and clayey rocks of the Oligocene, Neogene and Quaternary age are distinguished. The basal Lower Oligocene sediments, which pinch out on the slopes of the basement blocks, which occupy a high hypsometric position, are characterized by the greatest variability in thickness and composition. Among the Lower Oligocene sediments, horizons VII + VIII are the most oil-saturated and refer to oil deposits of industrial importance. Therefore, the study of the features of the lithological composition and reservoir properties of horizons VII + VIII is of great importance.

Using the Surfer program, a structural map was built for the roof of the VII + VIII horizons of the Lower Oligocene and modeled it in 2D (Fig. 1A).

(A) (B)

top - well / bottom - elevation (m) top - borehole / bottom - thickness (m)

Rice. 1.Structural map (A) and isopach map (B) of horizons VII + VIII of the lower

Oligocene deposits White Tiger

Figure 1A shows that the drawing of the structural maps of the northern area (horizons VII + VIII of the Lower Oligocene) of the White Tigr field changes greatly. Well 1013 drilled through the lowest elevation of -4161 m at the top and -4225 m at the bottom, that is, there is a depression zone in the eastern direction. And the highest elevation is -3336 m at the top and -3381 m at the bottom in the north-west in well 4, in the area of ​​which the structure arch is confidently distinguished. The amplitude of the dome is 470 meters along the contouring isohypse - 3850 m. For a visual representation of the distribution of capacities, an isopach map was built. (Figure 1B)

Figure 1B shows a northeastern strike of disjunctive faults. It can be seen that the maximum thickness reaches 94 m in well 10 and is represented by sandstones of continental genesis. And the minimum thickness is 22m and 17m in wells 64 and 83, in the western part of the site.

The formation of the thickness of the deposits is possible in two directions of the conditions of sedimentation. The reduction in the thickness of sediments in the roof and its increase on the wings of the uplifts is due to the erosion of this upland and the filling of the depressions with products of destruction.

An increase in the thickness of sediments on the slopes of paleo-uplifts indicates the accumulation of sediments in the shallow water zone during wave activity.

According to the methodology developed and logging data from wells, maps of lithological composition and sandiness were built (Fig. 2).

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( A) (B)

upper - well upper - well

lower - net-to-gross ratio (%) lower - αPS value

right - clasticity coefficient (%) right - thickness (m)

Rice. 2. Map of net-to-gross and clasticity coefficients (A) and a map of lithological composition (B) horizonsVII + VIIILower Oligocene (0-0.2: clays and silty-clayey rocks; 0.2-0.4: siltstone and clay-silty rocks; 0.4-0.6: mixed sandy-silty-clayey rocks; 0.6 -0.8: Fine-grained sandstone; 0.8-1: Coarse-medium-grained non-clayey sandstone)

Figure 2A shows the distribution of type A reservoirs (PS value in the interval 1-0.8) in the zone of wells 83, 64, 4, 14, 602, 1014, 1003. The distribution zone of type B reservoirs (PS value in the interval 0.6- 0.4) in wells 10, 1013. The zone of distribution of type B (0.6-0.8) reservoirs in wells 114, 116, 907. The zone of distribution of non-reservoirs is identified in the east, northeast (well 9), in the south ( wells 1106, 12).

In Fig. 2B, we see that the zone of high distribution of sand bodies is located in the area of ​​wells 14; 116 and 1014 with an average thickness of 23 m. The maximum net-to-gross ratio is in well 1014 and corresponds to 70.2%. The maximum value of the coefficient of clasticity is also observed in the well, 1.3%). A decrease in the net-to-gross ratio at the crest and an increase in it on the slopes and at the foot of the uplifts is due to the activity of streams that erode the upland and form cones of removal of erosion products.

A geological profile of the VII + VIII horizons of the Lower Oligocene was built along the line of wells 16-9 (Fig. 3).

Rice. 3. Geological profileVII + VIIIhorizons of the Lower Oligocene in the White Tiger oil field (Vietnam) along the line of wells 10 - 14 - 145 - 116 - 9

Horizons VII + VIII represent an anticlinal fold complicated by ruptured faults. On the profile, we can see the change in the thickness of the horizons by wells. In well 10, the thickness of the sediments reaches 94 m. And in well 14, the thickness of the sediment decreases to 33 m. A break is noted between wells 14 and 145. And between wells 116 and 9, 2 faults were identified, differing in a significant width of the rock crushing zone. The lithological composition of the deposits is heterogeneous. In well 10, we see an alternation of clay and sandy-silty rocks. The thickness of the clay is 40 m. The clay deposits wedge out and completely disappear in well 14. In well 14, only sandy-alveritic rocks with a thickness of 33 m are observed. horizon as a layer. The thickness is insignificant in comparison with the thickness of sandstones and amounts to 6-7 m. In well 9, the thickness of the clay layer is doubled. On the profile, we mark the zones of the highest reservoir properties in wells 14, 145, 116, in which the porosity coefficient varies from 12% to 14% and the oil saturation coefficient is 0.6-0.66 unit fractions. Of all the studied wells, the highest oil production rate was obtained in the well m3 / day. With such low values ​​of porosity (practically non-reservoir), high oil production rates can be explained by the proximity of the zones of two tectonic faults.

Thus, a complex type of rock reservoir of porous-fractured horizons VII + VIII in the northern block of the White Tigr field has been identified. In the wells drilled close to the zones of tectonic faults, high oil production rates were obtained. In wells that have only a porous reservoir type and are far from zones of disjunctive disturbances, much less oil production rates are obtained.

Bibliography:

1. P, G, et al. Geology and oil and gas content of the Sunda shelf basement. M., Oil and Gas, 1988, 285s.

2. Ezhova interpretation of geophysical data; Tomsk Polytechnic University. - 3rd ed. - Tomsk: TPU Publishing House, 200p.

3. Pospelov foundation: geological and geophysical methods for studying reservoir potential and oil and gas potential - Moscow 2005.

UDC 550.84: 551.8

OIL GENESIS OF THE WHITE TIGER FIELD (VIETNAM) ACCORDING TO THE DATA ON THE COMPOSITION OF SATURATED ACYCLIC HYDROCARBONS

O.V. Serebrennikova *, Wu Wang Hai, Yu.V. Savinykh *, N.A. Krasnoyarova *

Tomsk Polytechnic University * Institute of Petroleum Chemistry SB RAS, Tomsk E-mail: [email protected]

The general characteristics of the composition of the dispersed organic matter of the Miocene and Oligocene rocks within the White Tigris field (Vietnam) and its comparison with the corresponding characteristics of oils are described.

Keywords:

Metalloporphyrins; dispersed organic matter; porphyrins; catagenesis; phytoplankton.

Metalloporphyrins, dispersed organic matter, porphyrin, catagenesis, phytoplankton.

The White Tigr (Bach Ho) field is located on the southern shelf of Vietnam's SR in Block 09-1, 120 km southeast of the port city of Vung Tau, the main production, technical and supply base of JV Vietsovpetro (Fig. 1). Oil deposits were found in the Lower Miocene and Oligocene sandy-silt deposits, as well as, contrary to preliminary expectations, in fractured granitoid basement reservoirs. The not common case of the discovery of industrial accumulations of oil in crystalline rocks attracts special attention. The White Tiger field has become the largest oil-bearing province, confined to the central uplift of the Kyulong depression.

To restore the history of the formation of hydrocarbon accumulations in the Earth's interior, to reconstruct the conditions of naphthydogenesis, it is necessary to study in detail the composition of organic matter dispersed in the rocks, in particular, the distribution of chemofossils in it, which inherited their structural features from biological predecessors. The composition of these structures is determined, first of all, by the initial biomass and the subsequent stages of its transformation.

The complex of chemofossils (the individual composition of isoprenoid and normal alkanes, the content of metalloporphyrins and perylene), as well as the composition of phenatrenes that we selected for research, allow us to judge the facies-genetic nature of the organic matter present in the rocks. Thus, the presence of complexes of porphyrins with vanadyl (VO-p) in organic matter indicates a predominantly marine genesis of organic matter and reducing conditions during sedimentation. The presence of nickel porphyrins (Ni-p) indicates the absence of hydrogen sulfide contamination of natural waters during sedimentation and early diagenesis of organic matter. Prilene, widespread in lakes, is also found in coastal areas of the seas and is absent in deep-water facies. Isoprenoid hydrocarbon ratio

pristane (P) and fritana (F) can be used to assess the oxidation-reduction conditions in the sedimentation basin. However, it should be taken into account that, along with the oxidizing environment, the increased content of pristane in sediments may be due to a significant contribution to the organic matter of zooplankton and bacterial biomass. The composition of n-alkanes characterizes the participation of certain groups of bioproducers in the formation of the composition of organic matter. The main hydrocarbons of phytoplankton are C15 and C17 n-alkanes. Terrestrial vegetation is characterized by the predominance of C27, C29 and C31 n-alkanes. In coastal algae, C21, C23 and C25 homologues predominate.

To determine the degree of thermal maturity of organic matter, we used CPI - the ratio of the concentration of n-alkanes with an odd number of carbon atoms in the molecule to “even” n-alkanes, as well as the calculated reflectivity of vitrinite (Rc), based on the difference in the thermal stability of individual methylphenatrenes isomers ... Rc correlates well with the reflectance of vitrinite (% Rm) in the range of its values ​​corresponding to the main zone of formation of oil from kerogen.

The material accumulated to date on the features of the composition of dispersed organic matter and oils from the White Tigr field has shown that the geochemical parameters of hydrocarbons-biomarkers for dispersed organic matter of rocks and base oils are very different. The data obtained indicate that the basement rocks have nothing to do with the generation of oil filling the caverns in the basement. The rocks of the Lower Oligocene and Upper Oligocene and the Lower Miocene and Eocene play an important role for oil formation in the White Tigr field. Analysis of the composition of oils from the White Tiger field showed the presence of two groups of oils of different genesis. The first is oils from the basement and the Olinocene, and the second is from the Miocene.

The aim of this study was to characterize the composition of the dispersed organic matter of the Miocene and Oligocene rocks within the White Tigris field (Vietnam) and compare it with the corresponding characteristics of oils.

Characteristics of objects and research methods

The bitumen was extracted with a 7% solution of methanol in chloroform using a Tesa-101 Coxies NT-system. Phenanthrenes, perylene, and metalloporphyrins were concentrated by chromatographic separation of bitumen on alumina columns. The content of metalloporphyrins and perylene in chromatographic fractions was determined by electron spectroscopy from the intensity of absorption bands at R = 550 nm (for M-p), 570 nm (for VO-p), and 435 nm (for rerimelene) using extinction coefficients in the calculations 2.7-104, 2.9-104, 4-104 l / (mol cm), respectively. The composition and distribution of alkanes and phenatrenes were investigated by gas-liquid chromatography (GLC) using a 8E-54 stationary phase and a flame ionization detector. Compounds were identified by retention time

by comparing with already available as well as published data. The maxima of the molecular weight distribution of n-alkanes were determined from the chromatograms of gas-liquid chromatography, the parameters of the composition of alkanes were calculated: the ratio of P / F, P / n-C17, F / n-C18 and CPI, for the composition of phenatrenes - the methiphenatrene index MPI = 1.5 (2MP + 3MP) / (P + 1MP + 9MP) and Кс - calculated reflectivity of vitrinite (Rc = 0.6MPI + 0.4).

Results and its discussion

Characteristics of potential oil source rocks of the White Tiger field. In the overwhelming majority of rock samples (except for the Miocene-1 core), VO-p was found in low concentrations (from 3 to 31 nmol / g), Ni-p is absent in the Miocene-1 samples (Table 1). At the same time, the rocks of the Miocene and Oligocene-3 contain chlorine pigments, the preservation of which in sediments is facilitated by hydrogen sulfide contamination. This may be the reason for the absence of porphyrin complexes with nickel in them. The organic matter of such rocks, as a rule, is enriched in vanadium, vanadyl porphyrins, and organosulfur compounds.

Symbols

e- * U - Prospective structures - Gas fields

Щ - Oil fields - Oil and gas fields

| Dragon | - Developed by | lantai | - Prepared for development

Rice. 1. Overview map of the region on the shelf of the south of Vietnam

Table 1. The content of metalloporphyrins and perylene in the rocks of the White Tiger deposit

Kern Vietnam

Miocene 1 Miocene 2 Oligocene 1 Oligocene 2

Depth, m 2822.75 2992.75 4098.5 4142.5

P / F 1.24 3.31 1.16 1.58

P / n-S17 0.28 0.53 0.44 0.37

F / n-S18 0.41 0.33 0.41 0.36

CPI-1 / (C20-C28) 1.05 1.11 1.09 1.02

CPI-2 / (C22-C30) 1.13 1.21 1.08 1.10

CPI-2 / (C24-C32) 1.06 1.35 1.12 1.14

CPI (C12-C34) 1.01 1.07 1.06 1.07

MPI 0.61 0.62 0.83 0.66

Rc 0.76 0.77 0.89 0.79

The distribution of paraffinic hydrocarbons in the organic matter of the White Tigr field is shown in Fig. 2. In the majority of n-alkanes, hydrocarbons of the composition C10-C20 predominate, while the concentration of n-alkanes of the C21-C35 composition is noticeably lower. The nature of the molecular weight distribution of n-alkanes in the OM of the rocks of the lower interval of the Oligocene (4142.5 m) indicates the mixed nature of the initial organic matter produced by phytoplankton, coastal and terrestrial plants in a close ratio (Fig. 2). The organic material was deposited under suboxidizing (P / F = 1.58) conditions, apparently in the coastal sea basin. Higher in the section (4098.5 m), the contribution of coastal algae decreased, and the main bioproducers were phytoplankton and woody plants that accumulated in the reducing environment (P / F = 1.16). In the Miocene (2992.75 m), the sedimentation environment changed to oxidative (P / F = 3.31), flora representatives practically disappeared among bioproducers, and microbial lipids predominated. The presence of perylene in organic matter indicates the shallowness of the sedimentation basin. Over time (rocks from a depth of 2822.75 m), the conditions of sedimentation changed to reducing conditions, and bioproducers to phytoplankton and, to a lesser extent, coastal algae.

In all core samples, CPI is close to unity (1.01 ... 1.07). predominance of fatty acids with an even number of carbon atoms. J. Hunt and M. Calvin note that this ratio of LF / h is 1.01.1.07 for algae. In general, the CPI values ​​in the studied samples correspond to organic matter that is sufficiently mature for oil formation.

Name of n-alkanes

Rice. 2. Molecular weight distribution of n-alkanes in scattered organic matter of the White Tiger deposit

Thus, in the Oligocene-Miocene section of the White Tigr deposit, there are rock varieties that differ significantly in sedimentogenesis and the composition of bioproducers that supplied organic matter to the sediment. By its thermal transformation of organic matter, the White Tiger field can be characterized as mature, capable of generating oil. This is evidenced by the values ​​of the calculated reflectivity of vitrinite corresponding to the stage of MK2-MK3 catagenesis, the CPI values, and the ratio of isoprenoid and n-alkanes.

Characteristics of oils from the White Tigr field. The oil from this field is highly paraffinic (18.25.3%), with a very low sulfur content. In depth, the density and viscosity of oil, the content of resins and asphaltenes in it decrease. The content of VO-p and Ni-p, found by us in very low concentrations, also decreases with depth (Table 2). This tendency to change the parameters of the composition of oil can be associated with an increase in reservoir temperature with an increase in the depth of the reservoir and the partial decomposition of complex high molecular weight molecules.

Table 2. The content of metalloporphyrins in oil from the White Tiger field

Oil Miocene Oligocene Foundation

P / F 1.28 2.04 2.84

P / n-S17 0.24 0.46 0.51

F / n-S18 0.24 0.24 0.23

CPI-1 (C20-C28) 1.0 1.1 1.1

CPI-2 (C22-C30) 1.0 1.1 1.1

CPI-3 (C24-C32) 1.1 1.1 1.1

CPI (C12-C34) 1.2 1.1 1.2

MPI 0.61 0.78 0.51

Rc 0.77 0.87 0.71

The distribution of paraffinic hydrocarbons in oils is shown in Fig. 2. Among n-alkanes, C10-C20 predominates. By the nature of their molecular weight distribution, oils are similar to each other and to the scattered organic matter of the Miocene rocks. At the same time, the P / F ratio in oils varies widely (1.28.2.84). This indicates a difference in the conditions of accumulation of their initial oil source substance. Comparison of oils and dispersed organic matter of rocks in terms of the ratio of pristane to phytane, taking into account the nature of the molecular weight distribution of n-alkanes, shows that Miocene oil could have been generated by sediments of the same age (Miocene-1). The values ​​of the genetic parameter P / F for dispersed organic matter of the Oligocene rocks (P / F = 1.16 ... 1.58) are significantly lower than for oil lying in these sediments (P / F = 2.04), which indicates a different source of oil. The complex geological structure of the territory on which the White Tiger field is located could lead to the filling of the trap in the Oligocene reservoirs with younger oil generated by the Miocene strata (Miocene-1 and Miocene-2), which contains rocks with dispersed organic matter characterized by P / Ф from 1.2 to 3.3 .. Oil, which occurs in the basement rocks, is closest to the dispersed organic matter of the Miocene-2 ​​rocks.

Name of n-alkanes

Rice. 3. Molecular weight distribution of n-alkanes of oils from the White Tiger field

Thus, gas-liquid chromatography analysis of oil samples and core samples from the White Tigr field shows that the source material for all oils was composed mainly of phytoplankton with an admixture of bottom algae and an insignificant proportion of terrestrial plants. Miocene oil is generated by organic matter of sediments that accumulated in a reducing environment, and oil from Oligocene reservoirs and basement - in weakly oxidizing and oxidizing environments. The most probable source of oils from the White Tiger field are polyfacial deposits of the Miocene, which have reached the main phase of oil formation and are capable of generating oil.

BIBLIOGRAPHY

1. Krasnoyarova N.A., Serebrennikova O.V., Zaitsev S.P. Conditions of sedimentation and catagenesis of dispersed organic matter of the Lower Jurassic of western Siberia // Geology, geophysics and development of oil and gas fields. - 2009. -№3. - S. 11-17.

2. Serebrennikova O.V., Belokon T.V. Geochemistry of porphyrins. -Novosibirsk: Nauka, 1984 .-- 86 p.

3. Savinykh Yu.V., Luong Z.Kh., Drowned V.K. OM of the rocks of the crystalline basement of the White Tiger field // New ideas in geology and geochemistry of oil and gas: Proceedings of VIII Mezh-dunar. conf. - M., 2005 .-- S. 231-236.

4. Savinykh Yu.V. Comparative characteristics of the molecular composition of oils from the Dragon and White Tiger deposits // Chemistry of oil and gas: Proceedings of the VII Intern. conf. - Tomsk, 2009. -S. 157-160.

5. Ilninskaya V.V. Genetic relationship of hydrocarbons of organic matter of rocks and oils. - M .: Nedra, 1985 .-- 157 p.

6. Goncherov I.V. Geochemistry of oils from western Siberia. - M .: Nedra, 1987 .-- 179 p.

7. Petrov Al.A., Arefiev O.A. Biomarkers and geochemistry of oil formation processes // Geochemistry. - 1990. - No. 5. -S. 704-714.

8. Golovko A.K., Peneva G.S., Gorbunova L.V., Dong Ch.L., Ngia N.Ch., Savilykh Yu.V., Kamyanov V.F. Hydrocarbon composition of oils on the shelf fields of Vietnam // Neftekhimiya. - 2003. - T. 42. - No. 1. - S. 13-22.

9. Petrov Al.A. Petroleum hydrocarbons. - Moscow: Nauka, 1984 .-- 262 p.

10. Hoàng Binh Tiên, Hô Trung Chat, Nguyên Ng (jc Dung, Nguyên Ng (jc Ânh. So sành d | c diêm dia hoa dà me và dâu, khi o hai bê tram tich Cenozoi Cuu Long và Nam Côn Son // Tor chi khoa hçic và ki thuât. - 2008. - T. 11. - No. 11. - T. 15-23.

The uniqueness of the Vietnamese shelf is the discovery of large deposits in granites.

Vietnam's oil and gas industry is very young. Even before the Civil War, some American companies, for example Mobil, tried unsuccessfully to find oil in Vietnam. For the first time, Soviet oilmen applied here the practice of drilling not at 500-600 m, as was usually done, but at 3,000 m, trying to discover oil and gas reserves in deep rocks.

In 1983, with the direct assistance of the Soviet Union, the first significant oil field, Bakhkho ( White Tiger- "White Tiger"). Its commercial operation began in 1986.The first gas well was drilled in the same area and produced results in 1994.As a result of intensive geological exploration over the next 12 years, it was established that the subsoil of Vietnam has a sufficiently high potential to provide the country with energy resources and allow it to enter the world oil market as an exporter. According to BP Amoco Statistical Review of World Energy for 2001, the proven oil reserves on the continental and shelf parts of the SRV are estimated at 100 million tons, and natural gas at 190 billion cubic meters (Fig. 1).

At present, only the oil and gas industry exists in the SRV, and the country's leadership is persistently pursuing a policy of creating refining enterprises. International tenders are announced for each proposed project. The winner enters into a Production Sharing Agreement (PSA). Vietnam provides its land and resources, a foreign partner - equipment and technology for a specific project. After that, the production is divided in percentage according to the signed agreement, and if earlier the foreign partner was allowed to have at its disposal no more than 15-20% of the shares of the joint venture, now it is allowed to own a 50% stake. It is also possible to pay off the cost of depreciation of equipment owned by a partner company, produced by oil.

Rice. 1. Map of the Vietnam shelf with the location of hydrocarbon deposits (Areshev, 2003): 1 – spreading zones; 2 - isobaths of the seabed, m;

So, a state company PetroVietnam has already signed more than 30 contracts for a total amount of over $ 2 billion with leading foreign firms: Unocal, Mobil, Conoco, British Gas, British petroleum, Statoil(Norway), Petronas(Malaysia), Anzoil(Australia - New Zealand), Idemizu(Japan) and Shell.

Soviet-Russian-Vietnamese cooperation

There are two joint ventures operating in the Vietnamese market: VietSovpetro(50/50) and VietRoss... With their direct participation, the construction of a large oil refinery and an 800-kilometer oil pipeline in the Dungkuat region (Quang Ngai province) has begun, the project cost is $ 1.3 billion. diesel and aviation fuel. The agreement is valid for 25 years. The actual monopoly on the Vietnamese oil market is the Russian-Vietnamese joint venture VietSovpetro- it accounts for 90% of the oil produced in the country. The Vietnamese made no attempts to curtail cooperation; on the contrary, they intend to expand it.

VietSovpetro was created 20 years ago, when an agreement was signed between Zarubezhneft and a state-owned company PetroVietnam on the beginning of the development with the assistance of the Soviet side of oil fields on the shelf off the coast of South Vietnam. In 1986, the field with the exotic name "White Tiger" gave the first oil. Now the average annual oil production is 13 million tons, the growth rate is 15% per year. According to the plans of the JV management, in the next decade this figure will increase to 20-22 million tons. VietSovpetro today it is the largest and most successful joint venture in the country with foreign participation. When the joint venture was created in 1981, its authorized capital was set at $ 1.5 billion, and at present the fixed capital is $ 2.8 billion. The total proceeds from the sale of crude oil in 1991–1998. exceeded 7.5 billion dollars, a significant part of which replenished the state budgets of the Socialist Republic of Vietnam and Russia.

To work on the shelf, the Soviet Union specially built a base for the construction of drilling platforms in Vietnam (all of them have VietSovpetro twelve). A typical project of socialist management turned out to be profitable in market conditions as well. If foreign companies are forced to transport their platforms over distances of thousands of kilometers, then VietSovpetro collects them on the spot, and for other countries in the region, for example, Malaysia, and even on orders from American and British companies. Not without the mediation of Zarubezhneft, OJSC Gazprom appeared in Vietnam. We are talking about plans to develop a gas field on the shelf of Central and North Vietnam with reserves, according to preliminary estimates, at 700 billion cubic meters. The work of the Russian gas monopoly in Vietnam begins, as in the case of VietSovpetro, with the creation of a joint venture. The new company will primarily deal with the supply of gas to Vietnamese consumers, but its further export to neighboring countries, such as China, is not excluded.

Undoubtedly, not only Russia is interested in the Vietnamese oil and gas potential. Recently British British Petroleum, Indian ONGC and Norwegian Statoil signed an agreement with the Vietnamese government to develop a natural gas field on the country's shelf. Over the course of 20 years, the companies undertake to supply gas to three Vietnamese power plants and invest about $ 1.5 billion in its production and transportation. However, the Russian side does not believe that its interests may be infringed upon. Russia's position in Vietnam is very strong. Nevertheless, the current situation suggests that the Russian side must pursue an active and reasonable policy. Moreover, without updating the resource base in five years, production VietSovpetro can be significantly reduced.

Another fact gives Russia confidence. Recently, the parties signed documents according to which Vietnam must pay Russia (on the principles of the Paris Club of creditors) $ 1.7 billion over 23 years. At the same time, the parties agreed that Vietnam's debt should be repaid by investments in large interstate projects, including oil and gas projects.

Oil and gas fields and their use

To date, 10 main hydrocarbon deposits have been explored in the country, four of them have confirmed the presence of oil and gas (the deltas of the Krasnaya, Mekong, South Konshon, Tkhotyu rivers). Particular attention is paid to the development of gas fields on the shelves of the Gulf of Tonkin and Siam. Vietnam's shelf zone is 327.9 thousand km 2 and five main oil fields are currently being developed on it: Bakhho ( White Tiger) - since 1986, 150 km southeast of the city of Vung Tau, production volumes - 7 million tons per year with the prospect of increasing productivity to 8.5 million tons in 2000 and up to 13 million tons by 2005; Dayhung - since 1994, with a capacity of 565 thousand tons per year; Rong - since 1994, with a capacity of 475 thousand tons per year; Bungkekwa - 755 thousand tons per year; Rangdong - with a prospect of up to 12.1 million tons per year.

However, so far there are contradictions (mutual claims) with China regarding the ownership of the Paracel Islands, Spratly Islands and adjacent shelf areas, as well as the shelf of the northern part of Bakbo Gulf (Tonkin) and the disputed water area in the Gulf of Thailand, which Malaysia claims , exploration and industrial development of about half of the promising oil and gas area remains highly problematic.

The first Bakhho gas field began producing returns in 1994 (joint venture PetroVietnam – Hyundai), followed by the Tienhai field discovered in 1970 (with a productivity of 110 million cubic meters per year) and Namkonshon. The total proven reserves of natural gas are 190 billion cubic meters, and the projected reserves are 325 billion cubic meters (according to US Energy InformationAdministration December 1998). By the end of 2000, Vietnam increased gas production to 3-4 bcm. With the assistance of an American concern Mobil a master plan for the development of the gas industry for the period up to 2010 was developed.

The growth in gas production is associated with the further development of the country's power grid. The largest gas-fired power plant, Fumu, is under construction, with a total capacity of 3,600 MW by 2010. The possibility of building a number of chemical plants using natural gas as a feedstock is being considered.

As you know, earlier, Korean companies, in cooperation with foreign partners, discovered an oil field off the coast of Vietnam. This field, located at a depth of 47 meters, 180 kilometers northeast of Ho Chi Minh City, is believed to have oil reserves of 570 million barrels. It was planned that the net income of Korean companies will be at least $ 800 million, including all investment costs. In the consortium set up to search for and develop Vietnamese oil fields, the Korea National Petroleum Corporation and SK Corporation have, respectively, 14.25 and 9% of shares, an American company Conoco- 23.25% of shares. The rest of the shares are controlled by PetroVietnam- 50% and Geopetrol- 3.5%. The first drilling in the area of ​​the discovered field was carried out in August 2000, and additional, testing - in May 2001. Thanks to the participation of Korean firms in this project, Korea will be able to receive about 28.6 thousand tons per day, or 10% of the crude it needs. oil from Vietnam, which will greatly reduce its dependence on oil supplies from the Middle East. Korea is now forced to import 77% of its crude oil from the Persian Gulf region.

Geology and exploration

The water area of ​​the shelf in the south of SRV, where the JV Vietsovpetro conducted geological exploration, is confined to the Kyulong and South Konshon depressions, separated by the Konshon uplift. This is an area of ​​young trough, characterized by the accumulation of a thick stratum of terrigenous and chemogenic-terrigenous deposits of the Oligocene-Pliocene age. Among them, bodies of effusive rocks are quite widespread. In the most submerged parts of the depressions, the presence of more ancient Paleogene deposits is assumed. The deposits lie on the erosional surface of a heterogeneous crystalline basement composed of granitoids of various compositions. The age of the basement rocks, according to the limited data available, is Late Triassic - Early Cretaceous.

Geological exploration of the shelf of South Vietnam began in the late 1960s. firms Mandrel,Shell, Mobil Oil, Marathon, Pecten and later Deminex, Agip, Bow Walley etc. Within the water area of ​​JV Vietsovpetro, aeromagnetic surveys were carried out, about 30 thousand km of regional and detailed seismic profiles were worked out, and nine prospecting wells were drilled.

Systematic work on the development of oil and gas resources on the continental shelf in the south of SRV began in 1981 after the establishment of JV Vietsovpetro. The water area of ​​the JV's activities covered seven blocks of the shelf with a total area of ​​about 50 thousand km 2. It included almost the entire Kyulong depression and the northern part of the South Konshon. According to preliminary estimates, the potential geological resources of hydrocarbons in this area along the sedimentary section in the volume of the Lower Oligocene and Lower Miocene amounted to 6,200 million tons of standard fuel (recoverable - about 1,800 million tons). Subsequently, the area of ​​activity of the joint venture was focused on accelerated exploration and development of the White Tiger field. It was an exceptional site with the presence of oil in the granite basement beneath the Paleogene sediments. Such a discovery in the practice of oil and gas works is considered revolutionary. After that, water areas containing almost 60% of the initial resources in the Kyulong depression and completely along the South Konshonskaya basin were excluded from the scope of the JV work. Nevertheless, by 1996 the joint venture had completed 63.4 thousand km of seismic studies, including 15 thousand km - spatial (three-dimensional). 34 prospecting and exploratory wells were drilled, of 28 oil and gas inflows were obtained. 7 deposits were discovered, of which three: White Tiger, Dragon and Daihung belong to the category of large ones. A large amount of research work has been carried out to study the geological structure and oil and gas content of the region.

The main area of ​​the JV is the Kyulong depression with an area of ​​about 30 thousand km 2. On the mainland side, it is limited by the Chatan monocline, in the southeast - by the Konshon Rise. Within the depression, the Central Kyulong and South Kyulong troughs are distinguished, separated by the Central uplift. In the troughs, the basement surface is at a depth of 6.5–8 km, in the most elevated blocks of the Central Rise - at a depth of 2.5–3 km. A characteristic feature of the geological structure of the depression is the presence of large, several tens of kilometers long and with an amplitude of up to 1,500–1,600 m of consedimentation faults and faults-strike-slip faults, as well as numerous smaller faults. Northeastern faults caused the formation of the high-amplitude horst structure White Tiger, the main element of the Central Rise. Within the Kyulong depression, a significant number of anticlinal structures have been identified, formed as a result of multidirectional movements of basement blocks. Non-anticlinal structures are widespread, associated with lithological replacements, wedging out, adjacent to the basement of sandy-siltstone horizons, as well as with intraformational erosion.

In the South Konshonskaya depression, Vietsovpetro carried out work only within the northern part, at the Daikhung and Thanlong structures. The first corresponds to a high-rise block of the basement (its surface is at a depth of 2,600 m), in the second, crystalline formations are assumed at a depth of more than 6,000-7,000 m.

In accordance with the existing ideas about the geological structure and oil-bearing capacity of the Kyulong and South Konshonskaya depressions, the first prospecting wells were drilled in the crests of the largest and most elevated anticlinal structures. Initially, the main objects of search were terrigenous deposits of the Lower Oligocene and Lower Miocene. Formations of the crystalline basement were not considered promising. Prospecting drilling successively involved the structures of the Central Rise, the Chatan monoclines, the South Konshonskaya depression and the Prikonshonskaya monoclines. This made it possible to reasonably assess the industrial potential of a significant part of the water area of ​​JV Vietsovpetro.

The first exploratory wells produced various oil inflows and discovered the White Tiger (1984), Dragon (1985), Tamdao and Daihung (1988), Bavi and Baden (1989), Volk (1990) fields. ... At all deposits, except for the Tamdao deposit, the deposits of the Lower Oligocene and Lower Miocene proved to be productive; in the Tamdao field, a minor inflow of oil was obtained from the basement.

In connection with the discovery in 1988 at the White Tiger field of a unique deposit in the basement, the directions of prospecting and exploration have objectively changed.

The main discovery of JV Vietsovpetro is the White Tiger field, which is large in terms of reserves and unique in terms of geological structure and oil and gas content. About 70% of the initial geological reserves of categories C 1 + C 2 are concentrated here. It is characterized by a large volume of oil-saturated granitoids, a basement depth of at least 1,300 m, and a large accumulated production of anhydrous oil. Wells were drilled here to a depth of 5,014 m, however, even at these elevations, bottom water was not found. Deposits of the Lower and Upper Oligocene and Lower Miocene are also productive. The White Tigr structure is a large horst-anticlinal uplift formed by longitudinal northeastern consedimentary faults. Their amplitude along the surface of the basement reaches 1,500–1,600 m. The White Tigr deposit has already been explored quite well.

The Dragon deposit is located close to the White Tiger deposit and joins with it en-echelon. The field is confined to a complex structure and consists of two separate parts that do not have a common oil-bearing contour for any of the deposits. Conventionally, the Dragon deposit includes small local structures associated with uplifted basement blocks on the Prikonshon monocline.

Despite the fact that the Dragon structure, like the White Tiger, is located within the Central Rise, their structure is significantly different - the Dragon structure is not a horst, there are no longitudinal breaks. The structure of the sedimentary strata in both deposits is approximately the same. At the Drakon deposit, the stratigraphic range of productivity is the same as at the White Tigr deposit, but its reserves are much lower. Most of them are concentrated in the central area (wells 16–109) and are confined to the deposits of the Lower Miocene. Deposits are complex bodies, consisting of interbedded thin permeable sandy-siltstone and clay layers. The formations of the foundation are water-bearing to the very surface.

In the northeastern section (wells 3–7), commercial oil and gas flows were obtained from the Lower Miocene, Upper and Lower Oligocene deposits, a minor oil inflow from the basement formations, where the oil reservoir is underlain by water.

The near-drive part of the Dragon deposit is well explored, its potential has been reliably estimated. The main prospects for prospecting for new deposits are associated here with the deposits of the Lower Oligocene, developed within the vast eastern limb of the structure. According to the available geological and geophysical data, their thickness is much greater than in the areas studied by drilling. Numerous traps of the non-anticlinal type are developed here, tectonically and lithologically screened, adjacent to the basement surface, under the surfaces of erosion (unconformities).

On other local structures (blocks) of the Prikonshonskaya monocline, one or two wells were drilled. In well. 11 high-rate oil inflows were obtained from granitoids of the basement and sediments of the Lower Oligocene, in well. 14 - from the formations of the foundation; Lower Oligocene sediments in the roof of the structure are eroded.

The exploration of resources in JV Vietsovpetro as a whole is quite high - reserves of category C 1 make up 61.5%, and category C 3 - only 18.1%. Taking into account this indicator, as well as the limited area of ​​the enterprise's activities and the geological and geophysical information available on it, it can be stated that there are no grounds for predicting the discovery of new deposits here, significant in terms of reserves. At the same time, the available non-localized prospective resources of category C 3 at the Dragon field allow us to hope for the discovery of several fields (deposits) - satellites, possibly profitable for development. The real basis for increasing industrial reserves are reserves of category C 2.

JV Vietsovpetro has developed a geological exploration program. It is determined by the actual results of geological exploration work to study the oil-bearing capacity of individual areas and productive complexes of fields; the size and structure of undiscovered reserves and resources of categories C 2 and C 3; technical and economic capabilities of the enterprise. In accordance with these factors, two main directions of exploration work have been formulated.

1. Additional exploration of already discovered oil deposits and searches for new ones at the most promising objects (areas, blocks) of the Dragon field (area). To implement this direction, it is planned to drill several wells in the peripheral sections of the Dragon structure. This will make it possible to transfer to category C 1 at least 50% of reserves in category C 2 and about 30% of resources in category C 3.

2. Additional exploration of the southern arch of the White Tiger field and the search for new deposits in the Oligocene sediments and basement formations in its individual blocks. For its implementation, it is planned to drill additional wells.

The implementation of this program will help to strengthen the resource base of oil production in the coming years. Providing a more distant perspective for the joint venture requires fundamentally new solutions.

Concepts for the formation of unique deposits in granitoids

The initial geological reserves of the basement deposit of the White Tiger field were previously estimated at 600 million tons, and the Oligocene deposits - 150 million tons, which in total is more than 750 million tons of oil. Calculations showed that when the generation potential of Oligocene sediments was realized within the oil-gathering area around the White Tiger field, oil deposits could have formed only in the Oligocene complex itself.

The data obtained refute the well-established traditional ideas about the mechanism of formation of oil deposits in the basement of the White Tiger field only due to the resources of Oligocene deposits. Apparently, the granite basement contains its own additional hydrocarbon sources for the accumulation of oil deposits in real parameters.

Many researchers note that the formation of HC accumulations in the basement of platform areas could occur both due to the influx of hydrocarbons from the adjacent sedimentary strata, and due to the basement's own hydrocarbon potential. Most of the granitoids that make up the basement of the platform areas, as well as the entire "granite" layer of the earth's crust, are not so much magmatic as metamorphic in origin. The formation of granite rocks could occur in subduction zones when an oceanic plate plunged under an island arc or under an active continental margin. The basaltic crust of the oceans, together with pelagic sediments, falls to considerable depths with increasing temperature and pressure. Under the influence of these factors, the rocks of the basement and sedimentary cover gradually lose bound water, excess silica, alkalis, and lithophilic elements. There is a process of dehydration of the oceanic crust in a complex multistage reaction. The released water is water vapor with a very high alkaline reserve.

Thus, on the one hand, the hot water-mineral flow carries out excess heat from the subduction zones, and on the other hand, it saturates the rocks of the lithosphere with fluids rich in silica and alkalis. As a result, the earth's crust is enriched with oxides of potassium, sodium, aluminum, silicon and other compounds typical of the "granite" layer. As a result, this leads to the processes of granitization and the appearance of andesite magmatism.

The mechanism of saturation of crystalline basement rocks with naphthide fluid is closely related to the proposed model of the genesis of granitoids. The primary sedimentary complexes (Jurassic, Cretaceous and Early Paleogene age), which participated in the processes of accretion, granitization and the formation of the "granite" crust of the Sunda shelf, also contained dispersed organic matter. The thermal water-mineral flow exerted a temperature and metasomatic effect on the overlying sedimentary strata. At the same time, partially organic matter (OM) was remelted in submagmatic foci, but its large mass could well have been preserved and become the basis for the formation of various types of naphthide-generating systems:

- hard-carbon, anthraxolite-like accumulations;

- dispersed-dispersed, sorbed, light;

- encapsulated gas-liquid hydrocarbons (C 2 - C 6), etc.

Thus, almost simultaneously with the formation of the "granite" layer of the Sunda shelf crust, hydrocarbon fluids also appear, which are included in the general water-mineral flow, together with which they enter the sedimentary rocks of the island arc.

An important argument in favor of the proposed idea is the detection of HC gases in bubbles encapsulated in the granites of this region. Special studies carried out at VNIIgeoinformsystem have identified and analyzed gas-liquid fluids that form inclusions in basement samples from the White Tigr and Dragon deposits. Only the fluids of closed voids were isolated and analyzed, which could be obtained only by mechanical destruction of the sample under high vacuum conditions. These fluids are encapsulated in capillaries, mineral growth channels, voids of specific mineral structures in the form of isolated inclusions (vacuoles).

In the inclusions, a relatively high content of hydrocarbon gases C 2 - C 6 and higher is observed. Thus, in granite raised from a depth of 4584.1 m (well 442 White Tiger), the content of C 4 H 10 reached 11.6 cm 3 / kg, C 5 H 12 - 11.2, C 6 H 14 - 11, 9 cm 3 / kg of breed. This indicates, in the opinion of Moscow researchers, that the primary source of hydrocarbons could be sedimentary rocks, both involved in recrystallization and granitization, and drawn into subduction zones. A kind of water-mineral flow, saturated with hydrocarbon gases, arose. The latter could be captured and encapsulated in vacuoles of granitized rocks.

If we assume that the average content of HC gases is 15 cm 3 / kg, then in the 10-km "granite" layer of the crust only the Kyulong depression with an area of ​​20 thousand km 2 contains about 10 trillion m3 of hydrocarbon gases, mainly methane, in dispersed form.

The participation of a hydrocarbon fluid in the “gas respiration” of the earth's interior and, as a consequence, the encapsulation of hydrocarbon gases in the form of inclusions in rock microcracks, basement minerals, was noted by a number of researchers for other regions of ancient and young platforms.

As a result of the movement of the hydrocarbon flow from the bottom up in the White Tiger field, there is a pronounced vertical zoning in the distribution of oils: light oils in the basement and lower Oligocene sediments, heavier ones in the Upper Oligocene and Lower Miocene rocks. This zoning is explained by the fact that the process of oil formation is taking place in the basement at the present time. The arrival of new, fresh portions "dilutes" the oil, makes them relatively light, while those located higher in the oil section of the Upper Oligocene - Lower Miocene, not associated with this source, have lost some of their light fractions.

Summarizing the above arguments, it can be assumed that during the formation of the "granite" layer due to the granitization of primary sedimentary strata, the process of transformation of dispersed OM into hydrocarbons of the oil series took place. Under the conditions of a severe thermobaric regime, light HC fractions were generated, which formed the basis of the oil reservoir in the basement of the White Tiger and Dragon fields. In addition, HC fluids rising from the underthrust zones together with the water-mineral flow were deposited in igneous and sedimentary rocks when the temperature and pressure conditions changed. Through cracks and other channels, basement liquid hydrocarbons could penetrate into the Lower Oligocene sediments.

If we accept the stated idea of ​​the formation of oil in the basement rocks of the Sunda shelf, then the potential oil resources of the White Tiger field will significantly increase. In addition, the proposed mechanism of oil and gas formation can be extended to neighboring structures located in the area of ​​action of rifts or underthrust zones and having geological conditions similar to the White Tiger field.

As already mentioned, in 1988, in the fractured granitoids of the Mesozoic basement of the Kyulong depression, the unique White Tigr oil field was discovered. It has a proven thickness of over 1,600 m and a volume of oil-saturated granitoids of 88.2 billion m 3. This discovery has intensified prospecting and exploration work on the formation of a magmatogenic basement on the shelf of Vietnam and in the region as a whole, and in other parts of the world.

Despite the presence in the world of several hundred deposits confined to igneous and metamorphic rocks of the basement, the White Tiger deposit is unique both in terms of reserves and production levels. For 13 years of exploration and development of oil deposits in the basement of the field, about 100 million tons have already been produced.

The Mekong oil and gas basin (especially the Kyulong depression) is the first area on the shelf of Vietnam, where powerful gushers of oil were obtained from fractured granitoid protrusions of the basement. At the White Tigr field, from a depth of 3,150 m, an oil gusher was obtained with a flow rate of about 2,830 tons / day.

Recall that the basement of the White Tiger is a large horst-anticlinal uplift of a complex structure, 22 × 9 km in size. It consists of three vaults - South, Central and North. The structure is broken by a series of faults, mainly submeridional striking and subordinate sublatitudinal faults. Currently, more than 120 exploration, production and injection wells have been drilled to the foundation, which account for more than 90% of the total oil production at the field (Fig. 2).

Rice. 2. Geological profile of the Vietnam shelf (Areshev, 2003):
1 - geological profile of the Vietnamese shelf, illustrating the granitoid basement overhangs; 2 - schematic profile of the White Tiger deposit

Most of the wells on the White Tigr, drilled to the foundation, are high-rate wells (flow rates over 1,000 tons / day). Revealed thickness of igneous rocks of the basement reaches 2,000 m. The lower boundary of the deposit is conditionally established to an absolute depth of 5,014 m. Oil-bearing reservoirs are fractured-cavernous reservoirs, the voidness of which is represented by macro- and microcracks, isometric caverns and matrix voids. The uniqueness of the White Tigr field lies, first of all, in the large thickness of the productive section, in which young Late Cretaceous granitoids are primarily oil-bearing.

In terms of mineral composition, the section of the White Tigr intrusive massif is represented by granites, granodiorites, quartz diorites, monzodiorites, amphibole leukodiorites (diorites), the transition between which is not always quite clear. In addition, the massif is dissected by numerous dikes of comagmates of Oligocene effusive rocks, represented by diabases, basalts, trachybasaltic porphyrites, which form lava sheets over the basement.

It seems possible to generalize these phenomena using mathematical models. The main problem that arises along this path is that these fluid processes are multifactorial and multivariate. It is difficult to single out only one dominant factor among them, which can be simplified and schematized.

Geological exploration of the shelf of South Vietnam began in the late 1960s. (by Mandrel, Shell, Mobil Oil, Marathon, Pecten, and later Deminex, Agip, Bow Walley, etc.)

Systematic work on the development of oil and gas resources on the continental shelf in the south of SRV began in 1981 after the establishment of JV Vietsovpetro.

The Zarubezhneft project is the Vietsovpetro joint venture established in 1981 on the basis of an Intergovernmental Agreement on a parity basis with the Petrovietnam Oil and Gas Corporation

JV VietSovpetro is a de facto monopoly on the Vietnamese oil market, accounting for 90% of the oil produced in the country)

The main discovery of JV Vietsovpetro is the White Tiger field, which is large in terms of reserves and unique in terms of geological structure and oil and gas content.

For the first time, Soviet oilmen applied here the practice of drilling not at 500-600 m, as was usually done, but at 3,000 m, trying to discover oil and gas reserves in deep rocks.

It was an exceptional site with the presence of oil in the granite basement beneath the Paleogene sediments. Such a discovery in the practice of oil and gas works is considered revolutionary.

The field is located within the Mekong (Kyulong) depression of the Sunda shelf. Tectonically, the Sunda shelf is part of the Indo-Sunda intercontinental region, the formation of which can be traced back to the end of the Paleozoic era.

The geological section of the White Tigr deposit is represented by pre-Cenozoic crystalline basement rocks and terrigenous rocks of the sedimentary cover. The maximum exposed thickness of the basement reaches 1700 m, the thickness of the sedimentary cover exceeds 4300 m.

The basement of the deposit is composed of granitoid formations ((granites, granodiorites, diorites) of the Late Cretaceous-Early Jurassic age, broken by dikes of diabase and andesite-basaltic porphyrites. Granitoid rocks are represented by almost all transitional varieties - plagiogranites, adamellites, various granodiorites, leucodiorites.)

Basement rocks have been altered to varying degrees by secondary processes. Among the secondary minerals, the most widespread are zeolite and calcite. According to radiological data, the absolute age of crystalline basement rocks ranges from 245 (Late Triassic) to 89 (Late Cretaceous) Ma.

The granitoids of the White Tiger field contain a gigantic deposit of oil.

The sedimentary cover of the White Tigr deposit is represented by terrigenous rocks of the Paleogene (Oligocene), Neogene (Miocene, Pliocene) and Quaternary systems. The Oligocene and Lower Miocene reservoirs are associated with industrial oil deposits in

The basement surface was formed under the influence of tectonic and erosion processes. The ledge is bounded on all sides by faults. The most important (structure-forming) disturbances are considered to be traced not only in the sedimentary cover, but also in the basement, presumably of Oligocene age. They are assigned a leading role in the formation of both the structure itself and the fracturing in the basement rocks. The main faults have a NE strike, significant length and large amplitude (1.0-1.5 km).

Neogene faults are few in number, have a submeridional strike, their amplitude does not exceed 100 m, and their length is 3-5 km. In the section of the cover, the faults form tectonically screened deposits.

The White Tigr field is located within the Kyulong Depression on the shelf of South Vietnam. The depression is 450–500 km long and 75–110 km wide.

The basement of the sedimentary cover is a horstlike batholith of a complex structure, 30 x 6–8 km in size. Batholith consists of three vaults - South, Central, North, which are broken by a series of faults.

The productivity of the field was established in the basement rocks, deposits of the Oligocene and Lower Miocene age. There are 4 development targets - basement rocks, deposits of the Lower Oligocene, Upper Oligocene and Lower Miocene (BT). The foundation is the main facility providing high productivity and basic reserves - 90%.

The results of the study of the core of the basement rocks indicate that the rocks have significant petrographic heterogeneity.

The initial geological reserves of the basement deposit of the White Tiger field were previously estimated at 600 million tons, and the Oligocene deposits - 150 million tons, which in total is more than 750 million tons of oil.

researchers and for other regions of ancient and young platforms.

As a result of the movement of the hydrocarbon flow from the bottom up in the White Tiger field, there is a pronounced vertical zoning in the distribution of oils: light oils in the basement and lower Oligocene sediments, heavier ones in the Upper Oligocene and Lower Miocene rocks.

The office is located within the Kyulong depression, its length is 450-500 km, width is 75-110 km.

Most of the wells drilled to the foundation are high-rate wells.

The maximum exposed thickness of the basement reaches 1700 m, the thickness of the sedimentary cover exceeds 4300 m.

The lower boundary of the reservoir is set conditionally, the well BT-905, drilled to an absolute depth of 5014 m, did not open the oil-water contact.

ESSENCE: The volume of oil production at the "White Tiger" field on the sea shelf of Vietnam has surpassed the most optimistic forecasts of geologists and inspired many oilmen with the hope that huge reserves of "black gold" are stored at great depths

From the very beginning of oil production, "black gold" was extracted exclusively from sedimentary strata, here the sedimentary stratum (about 3 km) was drilled through, entered the foundation of the earth's crust, and the well was gushed. Moreover, according to the calculations of geologists, it was possible to extract about 120 million tons from the well, but even after this volume was produced, oil continued to flow from the bowels with good pressure. The field has posed a new question for geologists: does oil accumulate only in sedimentary rocks, or can it be stored in basement rocks? If the foundation also contains oil, then the world reserves of oil and gas may turn out to be much larger than we assume.

More than 120 exploration wells, production and injection wells have been drilled into the field.

On the Central Arch, more wells have been drilled to depths of 4500-4760 m.

On the Northern Arch - 4457 m.

The deepest well BT-905 was drilled to a depth of 5014 m.

In 1988, the first million oil was recovered.

2005 - 150 million tons of oil.

2008 - 170 million tons of oil.

By the end of 2009, cumulative production was 183 million tonnes.

2012 - 200 million tons of crude oil - White Tiger and Dragon fields.

In 2012, Vietsovpetro's production amounted to 6,110 thousand tons, including White Tiger - 4,398 thousand tons, Dragon - 1,504 thousand tons.

The oils from the Vietnamese fields Bach Ho, Rong, Nam Rong - Doi Moi have a common characteristic in terms of their rheological properties: high viscosity and high wax content. The pumping and transportation of such oils indicate that in oil pipelines laid under water, intense heat exchange between the flow of the pumped oil and the environment leads to a sharp change in the thermohydrodynamic regime in the flow along the pipeline. The drop in oil temperature along the movement causes a change in its rheological properties and is accompanied by phase transitions, as a result of saturation of the flow with heavy hydrocarbons (a number of hydrocarbons that affect the process of phase transitions, from C 6 and above), as well as the formation of wall oil deposits on the inner surface of the pipeline. These factors, under certain technological conditions, turn out to be the cause of a gradual spontaneous decrease in the throughput of the pipeline, which, first of all, increases the energy consumption for pumping, therefore, increases the cost of pipeline transport.

Oil produced in the country's fields is characterized by a low sulfur content (0.035-0.14%)

while in Brent it is 0.2-1%, and in Urals it is 1.2-1.3%.

If, in this case, special measures are not taken in a timely manner, then this can lead to a complete stop of pumping, followed by solidification (freezing) of the pipeline, the restart of which, as is known, is always associated with great technological difficulties.

In terms of its rheological properties, the oil from these Vietnamese fields can be attributed to the Bingham model. To improve the rheological properties of these oils, various methods have been proposed, in particular, the method of thermomagnetic treatment, the use of depressants, etc.

The following were built at the White Tiger and Dragon deposits:

13 offshore fixed platforms

22 block conductors

2 technological platforms - maximum productivity: for oil 38 thousand tons per day, for gas-liquid mixture 46 thousand tons per day.

3 compressor stations with a capacity of 9.8 million cubic meters per day.

The unified low-pressure gas gathering system ensures the normal functioning of the entire technological process for collecting and transporting gas to the shore, preparing gas-lift gas and using it for mechanized oil production at the JV Vietsovpetro fields, and also makes it possible to utilize up to 97% of the produced gas.
JV Vietsovpetro has created one of the best onshore bases in Southeast Asia for the construction and installation of offshore technological and satellite platforms for drilling wells and oil and gas production.
JV Vietsovpetro has four jack-up rigs, more than 20 fleet units, including crane-assembly, fire-fighting, diving and transport-tug vessels, and four free-loading units.

Stationary platforms are interconnected by a network of underwater pipelines. Production platforms provide simultaneous drilling and oil production from 16 cluster wells. The topside structure consists of 23 block-modules, in which, according to the principle of functional autonomy, life support equipment, drilling, operational and power complex are mounted. The platforms from which the mining takes place operate in an autonomous mode.

The produced oil is pumped to two central technological platforms, where it is cleaned of water and gas. Then, the processed oil goes to storage tankers, from which the oil is shipped to the buyer. Associated gas, separated from oil, enters the mainland through a pipeline. Several power plants in Vietnam operate on the blue fuel of the White Tiger.

All platforms built are capable of withstanding typhoons up to 12 points and waves of water 7-8 meters high.

The Tam Dao jack-up drilling rig stands on three supports that go under the water to a depth of 50 meters. Form-type support columns perform drilling on the shelf from 10 to 120 meters. Each supporting leg has 12 electric motors. The electric motors are turned on when the platform has been positioned with centimeter precision at the drilling point. In half an hour, the support reaches the bottom, and then for several minutes the entire floating structure, weighing more than 25,000 tons, rises above sea level. To prevent the wave from overturning "There Tao", the platform is raised 20 meters. All that remains is to lower the drilling rig onto the previously prepared jig and start work.

The only operating oil refinery in the country is the Zung Kuat Refinery. Currently, the construction of an oil refinery is starting in the north of the country and construction is planned in the south. The Zung Kuat oil refinery was built in three years (from November 2005 to January 2009), launched in February 2009. The total investment in construction amounted to $ 3.053 billion.

The Ngi Son refinery was planned for construction in the north of the country, its capacity, according to the basic design, is 10 million tons per year. Commissioning was scheduled for 2013–2014. Participants of the Ngi Son refinery project: PetroVietnam (25.1%), Idemitsu (Japan, 35.1%), Kuwait Petroleum (Kuwait, 35.1%), Mitsui Chemicals (Japan, 4.7%).

The Long Son refinery will be located in the south of the country; its design capacity is also 10 million tons per year. The project is at an early stage of development, partners and investors have not been identified. Commissioning is scheduled for 2016–2020. Most of the demand for petroleum products is concentrated in the southern part of Vietnam. The volume of demand for petroleum products in the central part where Zung Kuat is located is small, but the convenience of transporting petroleum products by sea provides effective access to the entire Vietnamese market for the sale of the products of the Zung Kuat plant.

Oil field "White Tiger" (Bat Ho) is located on the shelf of the South China Sea in the economic zone of Vietnam at a distance of 120 km from the coast (Vung Tau). The operator of the field is the Russian-Vietnamese JV Vietsovpetro.

The field was discovered in 1975. Commercial mining began in 1986. Initial oil reserves were estimated at 191.1 million tons.

The geological section "White Tiger" of the deposit is represented by crystalline basement rocks on top of which there are terrigenous rocks of the sedimentary cover. The maximum thickness of the sedimentary cover exceeds 4300 meters, the exposed thickness of the basement reaches 1700 meters.

Development of the White Tiger field began with the commissioning of the Lower Miocene deposits. Now the deposits of the Lower Miocene, Upper Oligocene, as well as the basement are under development.

The basement deposit was discovered in 1988 and is confined to an array of fractured granitoid rocks (granites, diorites). The size of the deposit in the plan is 28x7 km. The permeability of the basement reservoir is very high and reaches 20 Darcy.

There are a total of 296 wells at the field, including 219 producing wells, 45 injection wells, 20 wells abandoned, 8 are in conservation and 4 are observation wells.

The maximum oil production in the field as a whole was reached in 2002 and amounted to 12.9 million tons, with the overwhelming amount of 12.1 million tons produced from the basement.

As of 2012, cumulative oil production amounted to 187 million tons, cumulative water injection reached 270 million m3. The current oil recovery factor is 0.33.

The initial reservoir pressure of the basement deposit at an elevation of 3650 m (the conditional middle of the deposit) was 41.7 MPa. The initial period of reservoir operation is characterized by a significant drop in reservoir pressure and the manifestation of a closed-elastic development mode. At the time of the decision to implement waterflooding, the reservoir pressure decreased by 13.7 MPa to 28 MPa.

Since 1995, two years after the start of water injection, the rate of decrease in reservoir pressure has significantly decreased, the mode of operation of the reservoir has changed from elastic to elastic-water pressure. In the period from 2005 to 2008, the drop in reservoir pressure was 0.9 MPa and then stabilized at the level of 23 MPa.

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