Geology of the Priobskoye deposit (Priobka). Priobskoye field Priobsky region
The Priobskoye field is located in the central part of the West Siberian Plain. Administratively, it is located in the Khanty-Mansiysk region, 65 km east of the city of Khanty-Mansiysk and 100 km west of the city of Khanty-Mansiysk. Nefteyugansk.
In the period 1978-1979. as a result of detailed seismic surveys of CDP MOV, the Priobskoe uplift was identified. From this moment, a detailed study of the geological structure of the territory begins: the widespread development of seismic surveys in combination with deep drilling.
The discovery of the Priobskoye field took place in 1982 as a result of drilling and testing of well 151, when a commercial inflow was obtained oil with a flow rate of 14.2 m 3 /day on a 4 mm choke from the intervals of 2885-2977 m (Tyumen suite YUS 2) and 2463-2467 m (formation AS 11 1) - 5.9 m 3 /day at a dynamic level of 1023 m.
The Ob structure, according to the tectonic map of the Meso-Cenozoic platform cover.
The West Siberian geosyneclise is located in the junction zone of the Khanty-Mansiysk depression, the Lyaminsky megatrough, the Salym and West Lyaminsky uplift groups.
The structures of the first order are complicated by swell-like and dome-shaped uplifts of the second order and separate local anticlinal structures, which are the objects of prospecting and exploration work on oil and gas.
Productive formations in the Priobskoye field are formations of the "AS" group: AS 7, AS 9, AS 10, AS 11, AS 12. In stratigraphic terms, these layers belong to the Cretaceous deposits of the Upper Vartovskaya suite. Lithologically, the Upper Vartovskaya Formation is composed of frequent and uneven intercalation of mudstones with sandstones and siltstones. Mudstones are dark gray, gray with a greenish tint, silty, micaceous. Sandstones and siltstones are gray, clayey, micaceous, fine-grained. Among mudstones and sandstones there are interlayers of argillaceous limestones and siderite concretions.
The rocks contain charred plant detritus, rarely bivalves (inocerams) of poor and moderate preservation.
Permeable rocks of productive formations have a northeastern and submeridial strike. Almost all reservoirs are characterized by an increase in total effective thicknesses, net-to-gross ratio, mainly towards the central parts of reservoir development zones, as reservoir properties increase and, accordingly, clastic material is strengthened in the eastern (for layers of the AC 12 horizon) and north-eastern directions (for horizon AC 11).
Horizon AS 12 is a thick sand body elongated from southwest to northeast in the form of a wide band with maximum effective thicknesses up to 42 m in the central part (well 237). Three objects are distinguished in this horizon: the layers AC 12 3 , AC 12 1-2 , AC 12 0 .
The deposits of the AC 12 3 formation are presented as a chain of sandy lenticular bodies with a northeast strike. Effective thicknesses vary from 0.4 m to 12.8 m, with higher values associated with the main deposit.
The main deposit AS 12 3 was discovered at depths of -2620 and -2755 m and is lithologically shielded from all sides. The dimensions of the deposit are 34 x 7.5 km, and the height is 126 m.
Deposit AS 12 3 in the area of the well. 241 was discovered at depths of -2640-2707 m and is confined to the Khanty-Mansiysk local uplift. The reservoir is controlled from all sides by reservoir replacement zones. The size of the deposit is 18 x 8.5 km, height - 76 m.
Deposit AS 12 3 in the area of the well. 234 was uncovered at depths of 2632-2672 m and represents a sandstone lens at the western subsidence of the Priobskaya structure. The size of the deposit is 8.5 x 4 km, and the height is 40 m, the type is lithologically shielded.
Deposit AS 12 3 in the area of the well. 15-C was discovered at depths of 2664-2689 m within the Selyarovsky structural ledge. The dimensions of the lithologically screened deposit are 11.5 x 5.5 km, and the height is 28 m.
The AS 12 1-2 deposit is the main one, it is the largest in the field. It is confined to a monocline complicated by local uplifts of small amplitude (boreholes 246, 400) with transition zones between them. On three sides it is limited by lithological screens, and only in the south (towards the Vostochno-Frolovskaya area) do reservoirs tend to develop. However, given the considerable distances, the boundary of the deposit is still conditionally limited to a line passing 2 km south of the well. 271 and 259. Oil-saturated thickness varies in a wide range from 0.8 m (well 407) to 40.6 m (well 237) tributaries oil up to 26 m 3 /day on a 6 mm choke (well 235). The size of the deposit is 45 x 25 km, height - 176 m.
Deposit AS 12 1-2 in the area of the well. 4-KhM was discovered at depths of 2659-2728 m and is associated with a sandy lens on the northwestern slope of the Khanty-Mansiysk local uplift. Oil-saturated thickness varies from 0.4 to 1.2 m. The size of the deposit is 7.5 x 7 km, height - 71 m.
Deposit AS 12 1-2 in the area of the well. 330 opened at depths of 2734-2753m Oil-saturated thickness varies from 2.2 to 2.8 m. The size of the deposit is 11 x 4.5 km, height - 9 m. Type - lithologically screened.
The deposits of the AC 12 0 formation - the main one - were discovered at depths of 2421-2533 m. It is a lenticular body oriented from the southwest to the northeast. Oil-saturated thicknesses vary from 0.6 (well 172) to 27 m (well 262). tributaries oil up to 48 m 3 / day on an 8 mm fitting. The dimensions of the lithologically screened deposit are 41 x 14 km, the height is 187 m. 331 was discovered at depths of 2691-2713 m and is a lens of sandy rocks. oil-saturated thickness in this well is 10 m. Dimensions 5 x 4.2 km, height - 21 m. Debit oil- 2.5 m 3 / day per Hd \u003d 1932 m.
The deposit of the AS 11 2-4 formation is of lithologically shielded type, there are 8 in total, discovered by 1-2 wells. In terms of area, the deposits are located in the form of 2 chains of lenses in the eastern part (the most elevated) and in the west in the more submerged part of the monoclinal structure. Oil-saturated thicknesses in the east increase by 2 or more times compared to western wells. The overall range of change is from 0.4 to 11 m.
The deposit of the AS 11 2-4 formation in the area of well 246 was discovered at a depth of 2513-2555 m. The dimensions of the deposit are 7 x 4.6 km, the height is 43 m.
The deposit of the AS 11 2-4 formation in the area of the well 247 was discovered at a depth of 2469-2490 m. The size of the deposit is 5 x 4.2 km, the height is 21 m.
The deposit of the AS 11 2-4 formation in the area of the well 251 was discovered at a depth of 2552-2613 m. The size of the deposit is 7 x 3.6 km, the height is 60 m.
The deposit of the AS 11 2-4 formation in the area of the well 232 was discovered at a depth of 2532-2673m. The size of the deposit is 11.5 x 5 km, the height is 140 m.
The deposit of the AS 11 2-4 formation in the area of the well 262 was discovered at a depth of 2491-2501m. The size of the deposit is 4.5 x 4 km, height - 10 m.
The deposit of the AS 11 2-4 formation in the area of well 271 was discovered at a depth of 2550-2667m. The size of the deposit is 14 x 5 km.
The deposit of the AS 11 2-4 formation in the area of the well 151 was discovered at a depth of 2464-2501m. The size of the deposit is 5.1 x 3 km, height - 37 m.
The deposit of the AS 11 2-4 formation in the area of the well 293 was discovered at a depth of 2612-2652 m. The size of the deposit is 6.2 x 3.6 km, the height is 40 m.
The deposits of the AC 11 1 formation are confined mainly to the crest part in the form of a wide strip of northeast strike, limited on three sides by clay zones.
The main deposit AS 11 1 is the second in value within the Priobskoye field, it was discovered at depths of 2421-2533 m. 259. Debits oil vary from 2.46 m 3 /day at a dynamic level of 1195 m (well 243) to 118 m 3 /day through an 8 mm choke (well 246). Oil-saturated thicknesses vary from 0.4 m (well 172) to 41.6 (well 246). The size of the deposit is 48 x 15 km, the height is up to 112 m, the type is lithologically shielded.
Deposits of the AC 11 0 formation. The AS 11 0 formation has a very small zone of reservoir development in the form of lenticular bodies confined to the submerged sections of the crest.
Deposit AS 11 0 in the area of the well. 408 was discovered at a depth of 2432-2501 m. The size of the deposit is 10.8 x 5.5 km, the height is 59 m, the type is lithologically shielded. Debit oil from well 252 amounted to 14.2 m3/day for Hd = 1410 m.
Deposit AS 11 0 in the area of the well. 172 was opened by one well at a depth of 2442-2446 m and has dimensions of 4.7 x 4.1 km, height - 3 m. Debit oil amounted to 4.8 m 3 / day for Hd \u003d 1150 m.
Deposit AS 11 0 in the area of the well. 461 measures 16 x 6 km. oil-saturated thickness varies from 1.6 to 4.8 m. Deposit type - lithologically shielded. Debit oil from well 461 amounted to 15.5 m 3 / day, Nd = 1145 m.
Deposit AS 11 0 in the area of the well. 425 opened by one well. oil-saturated power - 3.6 m. Debit oil amounted to 6.1 m 3 / day per Hd \u003d 1260 m.
The AC 10 horizon was exposed within the central zone of the Priobskoye field, where it is confined to more submerged places near the crest, as well as to the southwestern flank of the structure. The division of the horizon into layers AS 10 1, AS 10 2-3 (in the central and eastern parts) and AS 10 2-3 (in the western part) is to a certain extent conditional and is determined by the conditions of occurrence, formation of these deposits, taking into account the lithological composition of the rocks and the physical chemical characterization oils.
The main deposit AS 10 2-3 was discovered at depths of 2427-2721 m and is located in the southern part of the deposit. Debits oil are in the range from 1.5 m 3 /day on an 8 mm choke (well 181) to 10 m 3 /day on Hd = 1633 m (well 421). Oil-saturated thicknesses range from 0.8 m (well 180) to 15.6 m (well 181). The size of the deposit is 31 x 11 km, the height is up to 292 m, the deposit is lithologically shielded.
Deposit AS 10 2-3 in the area of the well. 243 was discovered at depths of 2393-2433 m. Debit oil is 8.4 m 3 /day at Hd = 1248 m (well 237). Oil-saturated thickness - 4.2 - 5 m. Dimensions 8 x 3.5 km, height up to 40 m. Deposit type - lithologically shielded.
Deposit AS 10 2-3 in the area of the well. 295 was opened at depths of 2500-2566 m and is controlled by clay formation zones. Oil-saturated thicknesses vary from 1.6 to 8.4 m. 295, 3.75 m 3 /day was obtained at Hd = 1100 m. The size of the deposit is 9.7 x 4 km, the height is 59 m.
The main deposit AS 10 1 was discovered at depths of 2374-2492 m. 259 and 271. Oil-saturated thicknesses vary from 0.4 (well 237) to 11.8 m (well 265). Debits oil: from 2.9 m 3 / day at Hd = 1064 m (well 236) to 6.4 m 3 / day on a 2 mm choke. The size of the deposit is 38 x 13 km, the height is up to 120 m, the deposit type is lithologically shielded.
Deposit AS 10 1 in the area of the well. 420 was discovered at depths of 2480-2496 m. The size of the deposit is 4.5 x 4 km, the height is 16 m.
Deposit AS 10 1 in the area of the well. 330 was discovered at depths of 2499-2528 m. The size of the deposit is 6 x 4 km, the height is 29 m.
Deposit AS 10 1 in the area of the well. 255 was discovered at depths of 2468-2469 m. The size of the deposit is 4 x 3.2 km.
The section of the AS 10 formation is completed by the productive formation AS 10 0 . Within which three deposits were identified, located in the form of a chain of submeridian strike.
Deposit AC 10 0 in the area of the well. 242 was uncovered at depths of 2356-2427 m and is lithologically shielded. Debits oil are 4.9 - 9 m 3 / day at Hd-1261-1312 m. Oil-saturated the thickness is 2.8 - 4 m. The dimensions of the deposit are 15 x 4.5 km, the height is up to 58 m.
Deposit AC 10 0 in the area of the well. 239 was discovered at depths of 2370-2433 m. Flow rates oil are 2.2 - 6.5 m 3 / day at Hd-1244-1275 m. Oil-saturated the thickness is 1.6 -2.4 m. The size of the deposit is 9 x 5 km, the height is up to 63 m.
Deposit AC 10 0 in the area of the well. 180 was exposed at depths of 2388-2391 m and is lithologically shielded. oil-saturated thickness - 2.6m. tributary oil amounted to 25.9 m 3 / day at Hd-1070 m.
The cap above the AC 10 horizon is represented by a pack of clayey rocks varying from 10 to 60 m from east to west.
Sandy-silty rocks of the AS 9 formation have a limited distribution and are presented in the form of facies windows, tending mainly to the northeastern and eastern parts of the structure, as well as to the southwestern subsidence.
The deposit of the AS 9 formation in the area of the well. 290 was discovered at depths of 2473-2548 m and is confined to the western part of the deposit. Oil-saturated thicknesses range from 3.2 to 7.2 m. oil are 1.2 - 4.75 m 3 / day with Hd - 1382-1184 m. The size of the deposit is 16.1 x 6 km, the height is up to 88 m.
Two small deposits (6 x 3 km) were discovered in the east of the deposit. Oil-saturated thickness varies from 0.4 to 6.8 m. Tributaries oil 6 and 5.6 m 3 /day at Hd =1300-1258 m. The deposits are lithologically shielded.
The Neocomian productive deposits are completed by the AC 7 layer, which has a very mosaic pattern in placement. oil-bearing and aquifers.
The largest in area eastern deposit of formation AS 7 was discovered at depths of 2291-2382 m. It is contoured on three sides by reservoir replacement zones, and in the south its boundary is conditional and drawn along a line passing 2 km from wells 271 and 259. The deposit is oriented from the south -west to northeast. tributaries oil: 4.9 - 6.7 m 3 / day per Hd \u003d 1359-875 m. Oil-saturated thickness varies from 0.8 to 7.8 m. The dimensions of the lithologically screened deposit are 46 x 8.5 km, height up to 91 m.
Deposit AS 7 in the area of the well. 290 was discovered at a depth of 2302-2328 m. Oil-bearing thicknesses are 1.6 - 3 m. In the well. 290 received 5.3 m 3 / day oil at P = 15MPA. The size of the deposit is 10 x 3.6 km, the height is 24 m.
Deposit AS 7 in the area of the well. 331 was uncovered at a depth of 2316-2345 m and is a lenticular body of an arcuate shape. Oil-saturated thicknesses vary from 3 to 6 m. 331 inflow received oil 1.5 m 3 /day at Hd = 1511 m. The dimensions of the lithologically screened deposit are 17 x 6.5 km, height - 27 m.
Deposit AS 7 in the area of the well. 243 was discovered at a depth of 2254-2304 m. Oil-saturated thickness 2.2-3.6 m. Dimensions 11.5 x 2.8 km, height - 51 m. In the well 243 received oil 1.84 m 3 / day on Nd-1362 m.
Deposit AS 7 in the area of the well. 259 was uncovered at a depth of 2300 m; it is a lens of sandstones. oil-saturated thickness 5.0 m. Dimensions 4 x 3 km.
Priobskoye field
|
Name indicators |
Category |
AC 12 3 |
AC 12 1-2 |
AC 12 0 |
AC 11 2-4 |
AC 11 1 |
AC 11 0 |
AC 10 2-3 |
AC 10 1 |
AC 10 0 |
AC 9 |
AC 7 |
|
Initial recoverable reserves, thousand tons |
Sun 1 From 2 |
7737 3502 |
230392 39058 |
26231 1908 |
3725 |
266919 4143 |
1377 |
40981 4484 |
33247 2643 |
1879 5672 |
||
|
Accumulated booty, thousand tons |
1006 |
|||||||||||
|
Annual booty, thousand tons |
||||||||||||
|
Well fund mining injection |
||||||||||||
|
Scheme drilling out |
3-row |
3-row |
3-row |
3-row |
3-row |
3-row |
3-row |
3-row |
3-row |
|||
|
Grid size |
500*500 |
500*500 |
500*500 |
500*500 |
500*500 |
500*500 |
500*500 |
500*500 |
500*500 |
|||
|
Density wells |
Brief geological and field characteristics of the reservoirs
Priobskoye field
|
Options |
Index |
reservoir |
|||||||||||||
|
Productive layer |
AC 12 3 |
AC 12 1-2 |
AC 12 0 |
AC 11 2-4 |
AC 11 1 |
AC 11 0 |
AC 10 2-3 |
AC 10 1 |
AC 10 0 |
AC 9 |
AC 7 |
||||
|
Seam roof depth, m |
2620-2802 |
2536-2753 |
2495-2713 |
2464-2667 |
2421-2533 |
2442-2501 |
2393-2721 |
2374-2528 |
2356-2433 |
2393-2548 |
2254-2382 |
||||
|
Absolute elevation of the seam top, m |
2587-2750 |
2504-2685 |
2460-2680 |
2423-2618 |
2388-2500 |
2400-2459 |
2360-2686 |
2340-2460 |
2322-2400 |
2357-2514 |
2220-2348 |
||||
|
Absolute mark of VNK, m |
|||||||||||||||
|
Total seam thickness, m |
18.8 |
||||||||||||||
|
Effective thickness, m |
11.3 |
10.6 |
|||||||||||||
|
oil-saturated thickness, m |
2.88 |
4.68 |
1.69 |
1.52 |
4.72 |
3.25 |
1.72 |
2.41 |
2.47 |
||||||
|
Net-to-gross ratio, shares, units |
0.49 |
0.40 |
0.45 |
0.28 |
0.53 |
0.63 |
0.47 |
0.48 |
0.51 |
0.42 |
0.54 |
||||
Petrophysical characterization of reservoirs
|
Options |
Index |
reservoir |
|||||||||||||
|
Productive layer |
AC 12 3 |
AC 12 1-2 |
AC 12 0 |
AC 11 2-4 |
AC 11 1 |
AC 11 0 |
AC 10 2-3 |
AC 10 1 |
AC 10 0 |
AC 9 |
AC 7 |
||||
|
Carbonate,% |
min-mac average |
3.05 3.05 |
1.9-5.1 |
2.2-5.6 |
1.6-4.6 |
1.3-2.1 |
|||||||||
|
With grain size, 0.5-0.25mm |
min-mac average |
1.75 |
|||||||||||||
|
with a grain size of 0.25-0.1 mm |
min-mac average |
35.45 |
35.9 |
38.5 |
42.4 |
41.4 |
28.7 |
||||||||
|
with a grain size of 0.1-0.01 mm |
min-mac average |
53.2 |
51.3 |
48.3 |
46.3 |
42.3 |
60.7 |
||||||||
|
with a grain size of 0.01 mm |
min-mac average |
11.0 |
10.3 |
15.3 |
|||||||||||
|
sorting factor, |
min-mac average |
1.814 |
1.755 |
1.660 |
1.692 |
||||||||||
|
Median grain size, mm |
min-mac average |
0.086 |
0.089 |
0.095 |
0.073 |
||||||||||
|
Clay content,% |
|||||||||||||||
|
type of cement |
clayey, carbonate-clayey, film-porous. |
||||||||||||||
|
Coeff. Open porosity. by core, fractions of a unit |
Ming-mak average |
0.17 0.16-0.18 |
0.18 0.17-0.19 |
0.18 0.17-0.20 |
0.19 0.18-0.19 |
0.20 0.18-0.22 |
0.18 0.18 |
0.20 0.20-0.22 |
0.17 0.17 |
||||||
|
Coeff. core permeability, 10 -3 µm 2 |
min-mac average |
1.04 1.0-1.05 |
5.41 0.59-20.2 |
4.76 0.57-13.0 |
15.9 4.3-27.0 |
47.0 2.2-87.6 |
2.2 2.2-23.1 |
||||||||
|
Water holding capacity,% |
min-mac average |
||||||||||||||
|
Coeff. Open porosity according to logging, USD |
|||||||||||||||
|
Coeff. Well logging permeability, 10 -3 µm 2 |
|||||||||||||||
|
Coeff. oil saturation according to GIS, shares of units |
0.41 |
0.44 |
0.45 |
0.71 |
0.62 |
0.73 |
|||||||||
|
Initial reservoir pressure, MPa |
25.73 |
25.0 |
25.0 |
25.54 |
26.3 |
||||||||||
|
Reservoir temperature, С |
|||||||||||||||
|
Debit oil according to the results of the reconnaissance test. well m3/day |
Ming-mak average |
1.0-7.5 |
0.1-26.0 |
2.5-21.6 |
0.4-25.5 |
2.5-118 |
5.94-14.2 |
1.5-58 |
1.64-6.4 |
9-25.9 |
1.2-4.8 |
1.5-6.7 |
|||
|
Productivity, m3/day MPa |
min-mac average |
2.67 |
2.12 |
4.42 |
1.39 |
||||||||||
|
Hydraulic conductivity, 10 -11 m -3 / Pa * sec. |
min-mac average |
58.9 |
55.8 |
55.1 |
28.9 |
38.0 |
34.6 |
||||||||
Physico-chemical characteristics oil and gas
|
Options |
Index |
reservoir |
|
|
Productive layer |
AC 12 3 |
AC 11 2-4 |
AC 10 1 |
|
Density oil in the surface conditions,kg/m3 |
886.0 |
884.0 |
|
|
Density oil in reservoir conditions |
|||
|
Viscosity in surface conditions, mPa.s |
32.26 |
32.8 |
29.10 |
|
Viscosity in reservoir conditions |
1.57 |
1.41 |
1.75 |
|
Silica gel resins |
7.35 |
7.31 |
|
|
asphaltenes |
2.70 |
2.44 |
2.48 |
|
Sulfur |
1.19 |
1.26 |
1.30 |
|
Paraffin |
2.54 |
2.51 |
2.73 |
|
pour point oil, С 0 |
|||
|
Temperature saturation oil paraffin, С 0 |
|||
|
Fraction yield,% |
|||
|
up to 100 С 0 |
|||
|
up to 150 С 0 |
66.8 |
||
|
up to 200 С 0 |
15.1 |
17.0 |
17.5 |
|
up to 250 С 0 |
24.7 |
25.9 |
26.6 |
|
up to 300 С 0 |
38.2 |
39.2 |
|
|
Component composition oil(molar Concentration,%) |
|||
|
Carbonic gas |
0.49 |
0.52 |
0.41 |
|
Nitrogen |
0.25 |
0.32 |
0.22 |
|
Methane |
22.97 |
23.67 |
18.27 |
|
Ethane |
4.07 |
4.21 |
5.18 |
|
Propane |
6.16 |
6.83 |
7.58 |
|
Isobutane |
1.10 |
1.08 |
1.13 |
|
normal butane |
3.65 |
3.86 |
4.37 |
|
Isopentane |
1.19 |
1.58 |
1.25 |
|
normal pentane |
2.18 |
2.15 |
2.29 |
|
С6+higher |
57.94 |
55.78 |
59.30 |
|
Molecular weight, kg/mol |
161.3 |
||
|
Saturation pressure, mPa |
6.01 |
||
|
Volume ratio |
1.198 |
1.238 |
1.209 |
|
Gas factor under conditional separation m 3 / t |
|||
|
Density gas,kg/m3 |
1.242 |
1.279 |
1.275 |
|
Type of gas |
|||
|
Component composition petroleum gas (molar concentration,%) |
|||
|
Nitrogen |
1.43 |
1.45 |
1.26 |
|
Carbonic gas |
0.74 |
0.90 |
0.69 |
|
Methane |
68.46 |
66.79 |
57.79 |
|
Ethane |
11.17 |
1.06 |
15.24 |
|
Propane |
11.90 |
13.01 |
16.42 |
|
Isobutane |
1.26 |
1.26 |
1.54 |
|
normal butane |
3.24 |
3.50 |
4.72 |
|
Isopentane |
0.49 |
0.67 |
0.65 |
|
Pentane |
0.71 |
0.73 |
0.95 |
|
С6+higher |
0.60 |
0.63 |
0.74 |
Composition and properties of formation waters
|
aquifer complex |
|||
|
Productive layer |
AC 12 0 |
AC 11 0 |
AC 10 1 |
|
Density of water in surface conditions, t/m3 |
|||
|
Mineralization, g/l |
|||
|
Water type |
chlorine-ka- |
oblique |
|
|
Chlorine |
9217 |
||
|
Sodium+Potassium |
5667 |
||
|
Calliy |
|||
|
Magnesium |
|||
|
Bicarbonate |
11.38 |
||
|
iodine |
47.67 |
||
|
Bromine |
|||
|
Bor |
|||
|
Amonius |
40.0 |
||
New technologies and a competent policy of Yuganskneftegaz have improved the condition of the Priobskoye oil field, whose geological reserves are at the level of 5 billion tons of oil.
Priobskoye NM is a giant oil field in Russia. This hard-to-reach and remote field is located 70 km from the city of Khanty-Mansiysk and 200 kilometers from the city of Nefteyugansk. It is included in the West Siberian oil and gas province. About 80% of the Priobsky NM is located directly in the floodplain of the Ob River and is divided by water into two parts. A feature of Priobskoye is flooding during periods of floods.
Main geological and physical characteristics of the deposit
A distinctive feature of the Priobskoye is a complicated geological structure, characterized by multi-strata and a low degree of productivity. Reservoirs of the main productive formations are characterized by low permeability, low net-to-gross ratio, high level of clay content and high dissection. These factors suggest the use of hydraulic fracturing technologies in the development process.
The location of the deposits is not deeper than 2.6 km. Oil density indicators are 0.86–0.87 tons per m³. The amount of paraffins is moderate and does not exceed 2.6%, the amount of sulfur is about 1.35%.
The field is classified as sour and has class II oil in accordance with GOST for refineries.The deposits are lithologically screened and have the elasticity and isolation of the natural regime. The reservoir thickness indicators range from 0.02 to 0.04 km. The formation pressure has initial values of 23.5–25 MPa. The temperature regime of the reservoirs remains in the range of 88–90°C. The reservoir type of oil has stable viscosity parameters and has a dynamic coefficient of 1.6 MPa s, as well as the effect of oil saturation at a pressure of 11 MPa.
The presence of paraffin content and low resin content of the naphthenic series are characteristic. The initial daily volume of operating oil wells varies from 35 to 180 tons. The type of wells is based on the cluster location, and the maximum recovery factor is 0.35 units. The Priobskoye oilfield produces crude oil with a significant amount of light hydrocarbons, which entails the need to stabilize or separate APG.
Start of development and stocks
Priobskoe NM was opened in 1982. In 1988, the development of the left-bank part of the field began, and eleven years later, the development of the right bank began.
The amount of geological reserves is 5 billion tons, and the proven and recoverable amount is estimated at almost 2.5 billion tons.
Features of production at the field
The duration of development under the terms of the Production Sharing Agreement was assumed to be no more than 58 years. The maximum level of oil production is almost 20 million tons in 16 years from the moment of development.
Financing at the initial stage was planned at the level of $1.3 billion. The capital expenditure item accounted for $28 billion, and the cost of operational work amounted to $27.28 billion. It was planned to attract the Latvian city of Ventspils, Odessa, Novorossiysk.
According to 2005 data, the field has 954 production wells and 376 injection wells.Companies developing the field
In 1991, Yuganskneftegaz and Amoso began discussing the prospects of joint developments in the northern 
the bank of the NM Priobskoye.
In 1993, the Amoso company won the competition and received the exclusive right to develop the Priobskoye oilfield together with Yuganskneftegaz. A year later, the companies prepared and submitted to the government a project agreement on the distribution of products, as well as an environmental and feasibility study of the developed project.
In 1995, the government got acquainted with an additional feasibility study, which reflected new data on the Priobskoye field. By order of the Prime Minister, a government delegation was formed, including representatives of the Khanty-Mansi Autonomous Okrug, as well as some ministries and departments, in order to negotiate a Production Sharing Agreement in the context of the development of the northern segment of the Priobskoye field.
In the middle of 1996, a statement was heard in Moscow by a joint Russian-American commission on the priority of design innovations in the energy industry, including on the territory of the Priobskoye oilfield.
In 1998, the partner of Yuganskneftegaz in the development of NM Priobskoye, the American company Amoso, was taken over by the British company British Petroleum, and an official statement was received from BP / Amoso about the termination of participation in the project for the development of the Priobskoye field.
Then a subsidiary of the state company Rosneft, which received control over the central asset of Yukos, Yuganskneftegaz, LLC RN-Yuganskneftegaz, was involved in the development of the field.
In 2006, specialists from NM Priobskoye and Newco Well Service performed the largest hydraulic fracturing of an oil reservoir in the Russian Federation, into which 864 tons of proppant were pumped. The operation lasted seven hours, the live broadcast could be watched through the Internet office of Yuganskneftegaz.Now RN-Yuganskneftegaz LLC is working steadily on the development of the northern part of the Priobskoye oil field, and Gazpromneft-Khantos LLC, which belongs to Gazpromneft, is developing the southern segment of the field. The southern segment of the Priobskoye NM has license areas that are insignificant in area. The development of the Sredne-Shapshinskiy and Verkhne-Shapshinskiy segments has been carried out since 2008 by NAK AKI OTYR, which belongs to OAO Russneft.
Prospects for the Priobsky NM
A year ago, Gazpromneft-Khantos became the owner of a license to conduct a geological study of parameters related to deep oil-saturated horizons. The southern part of the NM Priobskoe, including the Bazhenov and Achimov formations, is subject to study.
Last year was marked by the analysis of geographical data on the territory of the Bazheno-Abalaksky complex of the Yuzhno-Priobsky oilfield. The combination of specialized core analysis and evaluation of this class of reserves involves the drilling of four deviated prospecting and appraisal wells.
Horizontal wells will be drilled in 2016. To estimate the volume of recoverable reserves, a multi-stage hydraulic fracturing is envisaged.
The impact of the deposit on the ecology of the area
The main factors affecting the environmental situation in the area of the deposit are the presence of emissions into the atmosphere. 
layers. These emissions are petroleum gas, products of combustion of oil, components of evaporation from light hydrocarbon fractions. In addition, spills of oil products and components onto the soil are observed.
The unique territorial feature of the deposit is due to its location on floodplain river landscapes and within the water protection zone. Making special demands on development is based on high value. In this situation, floodplain lands are considered, with characteristic high dynamism and complex hydrological regime. This territory was chosen for nesting by migratory birds of semiaquatic species, many of which are included in the Red Book. The deposit is located on the territory of migration routes and wintering grounds for many rare representatives of the ichthyofauna.
Even 20 years ago, the Central Commission for the development of NM and NGM under the Ministry of Fuel and Energy of Russia, as well as the Ministry for Environmental Protection and Natural Resources of Russia, approved the exact scheme for the development of NM Priobskoye and the environmental part of all preliminary design documentation.
The Priobskoye deposit is cut into two parts by the Ob River. It is swampy and during the flood most of it is flooded. It was these conditions that contributed to the formation of fish spawning grounds on the territory of the NM. The Ministry of Fuel and Energy of Russia submitted materials to the State Duma, on the basis of which a conclusion was made about the complication of the development of the Priobskoye oilfield due to the existing natural factors. Such documents confirm the need for additional financial resources in order to use only the latest and environmentally friendly technologies in the field, which will allow highly efficient implementation of environmental protection measures.
The Priobskoye field appeared on the map of Khanty-Mansiysk Autonomous Okrug in 1985, when its left-bank part was discovered by well number 181. Geologists received an oil fountain with a volume of 58 cubic meters per day. Four years later, drilling began on the left bank, and commercial operation of the first well on the right bank of the river began 10 years later.
Priobskoye field characteristics
The Priobskoye field lies close to the borders of the Salym and Lyaminsky oil and gas regions.
The characteristics of oil from the Priobskoye field make it possible to classify it as low-resinous (paraffins at the level of 2.4-2.5 percent), but at the same time with a high sulfur content (1.2-1.3 percent), which requires additional purification and reduces profitability. The viscosity of reservoir oil is at the level of 1.4-1.6 mPa*s, and the thickness of the reservoirs reaches from 2 to 40 meters.
The Priobskoye field, whose characteristics are unique, has geologically justified reserves of five billion tons. Of these, 2.4 billion are proven and recoverable. As of 2013, the estimate of recoverable reserves at the Priobskoye field was over 820 million tons.
By 2005, daily production reached high figures - 60.2 thousand tons per day. In 2007, over 40 million tons were mined.
To date, about a thousand production and almost 400 injection wells have been drilled in the field. The reservoir deposits of the Priobskoye oil field are located at a depth of 2.3.2.6 kilometers.
In 2007, the annual volume of production of liquid hydrocarbons at the Priobskoye field reached 33.6 million tons (or more than 7% of the total production in Russia).
Priobskoye oil field: features of development
The peculiarity of drilling is that the bushes of the Priobskoye field are located on both sides of the Ob River and most of them are located in the river floodplain. On this basis, the Priobskoye field is divided into South and North Priobskoye. In the spring-autumn period, the territory of the deposit is regularly flooded with flood waters.
This arrangement was the reason that its parts have different owners.
From the northern bank of the river, Yuganskneftegaz (a structure that passed to Rosneft after Yukos) is developing, and from the south there are areas that are being developed by the Khantos company, the structure of Gazpromneft (except for Priobskoye, it also deals with the Palyanov project). In the southern part of the Priobskoye field, a subsidiary of Russneft, the company Aki Otyr, has been allocated insignificant license areas for the Verkhne- and Sredne Shapshinskiy blocks.
These factors, along with the complex geological structure (multiple reservoirs and low productivity), make it possible to characterize the Priobskoye field as difficult to access.
But modern technologies of hydraulic fracturing, by pumping a large amount of water mixture underground, make it possible to overcome this difficulty. Therefore, all newly drilled pads of the Priobskoye field are being operated only with hydraulic fracturing, which significantly reduces the cost of operation and capital investment.
At the same time, three oil reservoirs are being fractured. In addition, the bulk of the wells are laid using the progressive cluster method, when lateral wells are directed at different angles. In cross section, it resembles a bush with branches pointing down. This method saves the arrangement of land sites for drilling.
The cluster drilling technique has become widespread, since it allows you to preserve the fertile soil layer and only slightly affects the environment.
Priobskoye field on the map
The Priobskoye field on the map of Khanty-Mansiysk Autonomous Okrug is determined using the following coordinates:
- 61°20′00″ north latitude,
- 70°18′50″ East.
The Priobskoye oil field is located just 65 km from the capital of the Autonomous Okrug - Khanty-Mansiysk and 200 km from the city of Nefteyugansk. In the area of development of the deposit there are areas with settlements of indigenous small nationalities:
- Khanty (about half of the population),
- Nenets,
- Mansi,
- Selkups.
Several nature reserves have been formed in the region, including Elizarovskiy (of republican significance), Vaspuholskiy, Shapshinskiy cedar forest. Since 2008, in the Khanty-Mansi Autonomous Okrug - Yugra (the historical name of the area with the center in Samarovo), a natural monument "Lugovskie Mammoths" with an area of 161.2 hectares was established, on the site of which fossil remains of mammoths and hunting tools dating from 10 to 15 thousand years were repeatedly found. back.
Priobskoye oil field
§1.Priobskoye oil field.
Priobskoye- the largest field in Western Siberia is administratively located in the Khanty-Mansiysk region at a distance of 65 km from Khanty-Mansiysk and 200 km from Nefteyugansk. It is divided by the Ob River into two parts - left and right bank. The development of the left bank began in 1988, the right bank - in 1999. Geological reserves are estimated at 5 billion tons. Proved and recoverable reserves are estimated at 2.4 billion tons. Opened in 1982. Deposits at a depth of 2.3-2.6 km. The density of the oil is 863-868 kg/m3 (the type of oil is medium, because it falls in the range of 851-885 kg/m 3 ), the content of paraffins is moderate (2.4-2.5%) and the sulfur content is 1.2-1 ,3% (belongs to the class of sulphurous, class 2 oil supplied to the refinery in accordance with GOST 9965-76). As of the end of 2005, there were 954 producing and 376 injection wells in the field. Oil production at the Priobskoye field in 2007 amounted to 40.2 million tons, of which Rosneft - 32.77, and Gazprom Neft - 7.43 million tons. The microelement composition of oil is an important characteristic of this type of raw material and carries various geochemical information about the age of oil, conditions of formation, origin and migration routes and is widely used for identifying oil fields, optimizing the search strategy for deposits, separating the production of jointly operated wells.
Table 1. Range and average value of microelement content of Priobskaya oil (mg/kg)
The initial flow rate of operating oil wells is from 35 tons / day. up to 180 t/day. The location of the wells is clustered. Oil recovery factor 0.35.
A cluster of wells is such an arrangement when the mouths are close to each other on the same technological platform, and the bottoms of the wells are in the nodes of the reservoir development grid.
Currently, most production wells are drilled in clusters. This is explained by the fact that cluster drilling of deposits can significantly reduce the size of the areas occupied by drilling and then production wells, roads, power lines, and pipelines.
This advantage is of particular importance during the construction and operation of wells on fertile lands, in reserves, in the tundra, where the disturbed surface layer of the earth is restored after several decades, in swampy areas, which complicate and greatly increase the cost of construction and installation work of drilling and operational facilities. Pad drilling is also necessary when it is required to open oil deposits under industrial and civil structures, under the bottom of rivers and lakes, under the shelf zone from the shore and overpasses. A special place is occupied by cluster construction of wells on the territory of the Tyumen, Tomsk and other regions of Western Siberia, which made it possible to successfully carry out the construction of oil and gas wells on backfill islands in a remote, swampy and populated region.
The location of the wells in the well pad depends on the terrain conditions and the proposed means of communication between the well pad and the base. Bushes that are not connected by permanent roads to the base are considered local. In some cases, bushes can be basic when they are located on highways. On local well pads, as a rule, they are arranged in the form of a fan in all directions, which makes it possible to have the maximum number of wells on a well pad.
Drilling and auxiliary equipment is mounted in such a way that when the drilling rig is moved from one well to another, the drilling pumps, receiving pits and part of the equipment for cleaning, chemical treatment and preparation of flushing fluid remain stationary until the completion of the construction of all (or part) of the wells on this well pad.
The number of wells in a cluster can vary from 2 to 20-30 or more. Moreover, the more wells in the pad, the greater the deviation of the bottoms from the wellheads, the length of the wellbore increases, the length of the wellbore increases, which leads to an increase in the cost of well drilling. In addition, there is a danger of meeting trunks. Therefore, it becomes necessary to calculate the required number of wells in a cluster.
A deep-pumping method of oil production is a method in which liquid is lifted from a well to the surface using various types of rod and rodless pumping units.
At the Priobskoye field, electric centrifugal pumps are used - a rodless deep-well pump, consisting of a multi-stage (50-600 stages) centrifugal pump located vertically on a common shaft, an electric motor (an asynchronous electric motor filled with dielectric oil) and a protector that serves to protect the electric motor from liquid ingress. The motor is powered by an armored cable, which is lowered along with the pump pipes. The frequency of rotation of the motor shaft is about 3000 rpm. The pump is controlled at the surface by means of a control station. The performance of the electric centrifugal pump varies from 10 to 1000 m3 of liquid per day with an efficiency of 30-50%.
The installation of an electric centrifugal pump includes underground and surface equipment.
The installation of a downhole electric centrifugal pump (ESP) has only a control station with a power transformer on the surface of the well and is characterized by the presence of high voltage in the power cable lowered into the well along with tubing. Highly productive wells with high reservoir pressure are operated by electric centrifugal pump units.
The field is remote, difficult to access, 80% of the territory is located in the floodplain of the Ob River and is flooded during the flood period. The field is characterized by a complex geological structure - a complex structure of sand bodies in terms of area and section, the layers are hydrodynamically weakly connected. Reservoirs of productive formations are characterized by:
Low permeability;
Low grit;
Increased clay content;
High dissection.
The Priobskoye field is characterized by a complex structure of productive horizons both in terms of area and section. The reservoirs of horizons AC10 and AC11 are medium and low productive, and AC12 are anomalously low productive. The geological and physical characteristics of the productive strata of the field indicate the impossibility of developing the field without actively influencing its productive strata and without using methods of production stimulation. This confirms the experience of developing the operational section of the left-bank part.
The main geological and physical characteristics of the Priobskoye field for assessing the applicability of various impact methods are:
1) depth of productive layers - 2400-2600 m,
2) deposits are lithologically shielded, the natural regime is elastic, closed,
3) the thickness of the layers AC 10, AC 11 and AC 12, respectively, up to 20.6, 42.6 and 40.6 m.
4) initial reservoir pressure - 23.5-25 MPa,
5) formation temperature - 88-90°С,
6) low permeability of reservoirs, average values according to the results
7) high lateral and vertical heterogeneity of formations,
8) reservoir oil viscosity - 1.4-1.6 mPa*s,
9) saturation pressure of oil 9-11 MPa,
10) oil of the naphthenic series, paraffinic and low-resinous.
Comparing the presented data with the known criteria for the effective use of reservoir stimulation methods, it can be noted that, even without a detailed analysis, thermal methods and polymer flooding (as a method of oil displacement from reservoirs) can be excluded from the above methods for the Priobskoye field. Thermal methods are used for deposits with high-viscosity oils and at depths up to 1500-1700 m. higher temperatures, expensive, special polymers are used).
