RU2334097C1 - Method of high-viscosity oil pool development - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: method involves positioning injection wells between production wells at the distance of 30-250 m between wells. Injection well bottom is positioned at 5-7 m distance from productive formation bottom. Production well bottom is positioned at 0.5-1.5 m distance from productive formation bottom. The wells are perforated at 0.6-1.0 m interval from the bottom. Steam alternated with air is used as heat carrier. Heat carrier is pumped over injection wells, and oil is withdrawn over production wells.

EFFECT: increased oil yield of a pool.

1 ex, 1 dwg

Description

The invention relates to the oil industry and may find application in the development of deposits of high viscosity oil.

A known method of developing a reservoir of high viscosity oil, according to which vertical injection and horizontal and vertical wells are drilled on a reservoir of high viscosity oil. The coolant is pumped through the injection wells and at the same time periodically through horizontal wells until the coolant breaks through to the vertical production wells. After the coolant breakthrough, a displacing agent is pumped through the injection wells, and sand and formation fluid are taken through horizontal wells (RF Patent No. 2062865, published. 1996.06).

The known method does not allow to develop an oil reservoir with the achievement of high oil recovery.

Closest to the proposed invention in technical essence is a method of developing deposits of high viscosity oil, according to which rows of vertical injection and production wells are drilled. Horizontal rows are drilled along rows of vertical wells. The coolant is periodically pumped into horizontal wells. Oil is taken from vertical producing and vertical injection wells. During the termination of steam injection, oil is taken from horizontal wells, which are a source of steam breakthrough into vertical wells. After the development of the reservoir in the area of the bottom-hole zones of all the wells, they transfer to areal injection of a displacing agent, for example water, into vertical injection wells. At the same time, oil is taken from the remaining wells. Before areal injection of the displacing agent, horizontal wells located near vertical injection wells are filled with an insulating composition, for example, a gel-forming one (RF Patent No. 2199656, published. 2003.02.27 - prototype).

The known method allows you to perform coverage by exposure to a large area of the reservoir, however, in this case, undeveloped zones remain in the interwell space, which reduces the oil recovery of the reservoir.

The proposed invention solves the problem of increasing oil recovery deposits.

The problem is solved in that in the method of developing a highly viscous oil deposit, including drilling vertical injection and production wells, pumping coolant through injection wells and oil extraction through production wells, according to the invention, injection wells are placed between production wells with a distance between wells of 30-250 m, the bottom of injection wells are placed at a distance of 5-7 m from the bottom of the reservoir, the bottom of production wells are placed at a distance of 0.5-1.5 m from the bottom of the reservoir, perforation wells ruyut ranging from bottom, equal to 0.6-1.0 m, and in use steam as a coolant in alternation with air.

The features of the invention are:

1) drilling of vertical injection and production wells;

2) coolant injection through injection wells;

3) oil extraction through production wells;

4) placement of injection wells between producing wells with a distance between wells of 30-250 m;

5) the placement of the bottom of the injection wells at a distance of 5-7 m from the bottom of the reservoir;

6) placement of the bottom of production wells at a distance of 0.5-1.5 m from the bottom of the reservoir;

7) perforation of wells in the interval from the bottom, equal to 0.6-1.0 m;

8) the use of steam as a coolant in alternation with air.

Signs 1-3 are common with the prototype, signs 4-8 are the salient features of the invention.

SUMMARY OF THE INVENTION

When developing a reservoir of high-viscosity oil (with a viscosity of more than 300 mPa · s), especially in carbonate reservoirs of small (up to 15 m) thickness, as a rule, the oil recovery of the reservoir remains low even with the most advanced technologies. This is due to irrational distances between the wells and the location of the wells themselves. At the same time, a significant part of the oil reserves is buried in the reservoir. Oil recovery remains low. The proposed invention solves the problem of increasing oil recovery deposits. The problem is solved as follows.

When developing high-viscosity oil deposits, vertical injection and production wells are drilled. The drawing shows a layout of wells. Steam is pumped in alternation with air through vertical injection wells 1, oil is withdrawn through vertical production wells 2. Injection wells 1 are placed between production wells 2 with a distance L between wells of 30-250 m. The bottom of injection wells 1 is placed at a distance of h ₁ from the bottom 3 productive formation 4, equal to 5-7 m. The bottom of production wells 2 is placed at a distance of h ₂ from the bottom 3 of the productive formation 4, equal to 0.5-1.5 m. Wells are perforated in the interval h ₃ from the bottom, equal to 0.6- 1,0 m. As the heat carrier using steam in alternation with air.

Steam is injected until a deposit zone is developed near injection well 1, as evidenced by a sharp decrease in the production rate of production well 2. After that, air is pumped, which occupies the upper part of the formation, forcing oil down. Then steam is injected again, which heats the formation. Heated oil flows down to production well 2.

Concrete example

A highly viscous oil reservoir is developed with the following characteristics: depth 90 m, reservoir thickness 8-30 m, reservoir temperature 8 ° C, reservoir pressure 0.5 MPa, oil saturation 0.70 ged units, porosity 30%, permeability 0.265 μm ² , oil density 956 kg / m ³ , viscosity 500 mPa · s.

When developing high-viscosity oil deposits, vertical injection and production wells are drilled according to the drawing. Steam is pumped in alternation with air through vertical injection wells 1, oil is taken through vertical production wells. The injection wells 1 are placed between the production wells 2 with a distance L between the wells of 50 m. The bottom of the injection wells 1 is placed at a distance h ₁ from the bottom 3 of the reservoir 4, equal to 6 m. The bottom of the production wells 2 is placed at a distance h ₂ from the bottom 3 of the reservoir 3 4, equal to 1 m. Wells are perforated in the interval h ₃ from the bottom, equal to 0.8 m. Steam is used as a heat carrier in alternation with air.

As a result, it is possible to achieve oil recovery of a deposit of 50%, while known methods can achieve oil recovery of the order of 25-30%.

The application of the proposed method will improve oil recovery deposits.

Claims (1)

A method of developing a highly viscous oil deposit, including drilling vertical injection and production wells, pumping coolant through injection wells and extracting oil through production wells, characterized in that the injection wells are placed between production wells with a distance between wells of 30-250 m, the bottom of injection wells is placed at a distance 5-7 m from the bottom of the reservoir, the bottom of the producing wells is placed at a distance of 0.5-1.5 m from the bottom of the reservoir, the wells are perforated in the interval from the bottom, p vnom 0.6-1.0 m, and in use steam as a coolant in alternation with air.