RU2603867C1 - Method for development of inhomogeneous oil deposit - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the petroleum industry. Method for development of inhomogeneous oil deposit comprises selecting on a deposit zones with different permeability, recovery of products through production wells, pumping working agent through injection wells and down-spacing. Zones of high and low permeability are selected. Injection wells are arranged on one side, and production wells - on other side from zone of low permeability. Down-spacing is performed by drilling an additional injection well near and opposite central part of low-permeability zone on side of producers. Working fluid is pumped through additional injection well in a continuous mode, producer, nearest to additional injection well, is stopped until formation pressure increases. Additional injection well is stopped, stopped production well is put into operation, and other production wells along zone of low permeability are stopped. Method then comprises waiting for recovery of formation pressure in section of high permeability by pumping injection wells, stopped producers are launched.

EFFECT: higher oil recovery of deposit.

1 cl, 1 dwg

Description

The invention relates to the oil industry and may find application in the development of a heterogeneous oil field.

A known method of developing oil deposits with layer-by-layer heterogeneity, including drilling along any of the known grids of vertical, horizontal and deviated wells, determining the boundaries of zones with different permeabilities, installing a packer in the wells at the boundary of the zones, injecting the displacing fluid into each zone through injection wells and producing products formation from each zone through injection wells. The thickness of the effective oil saturation for the reservoir is determined, the grid of wells is compacted with additional wells up to 1-4 ha / well. Moreover, additional wells are drilled obliquely with a length of the reservoir equal to 2-3 thicknesses of the effective oil saturation, and the units for simultaneous-separate are lowered into production wells together with the packer operation, and injection - for simultaneous-separate injection, above or below the boundary of zones with different permeability in the zone of deposits with lower permeability carry out acid treatment, injection of liquid they are injected through injection wells above and below the boundaries of zones with different permeability using installations for simultaneous-separate injection, and production through production wells is carried out using installations for simultaneous-separate operation (RF patent No. 2443855, class E21B 43/20, 43 / 14, published on February 27, 2012).

The disadvantage of this method is the impossibility of regulating the selection of products and injection of the displacing agent depending on the permeability of the zones of the reservoir, and also due to the intensive selection of products from low-permeability sections, the inability to achieve a high coefficient of oil recovery from the reservoir.

Closest to the proposed invention in technical essence is a method of developing a heterogeneous oil reservoir, including drilling along any of the known grids of vertical, horizontal and deviated wells, determining the boundaries of zones with different permeability, compaction of the grid of wells no more than 4 ha / well, injection of displacing fluid to each zone through injection wells and production of formation products from each zone through injection wells. Zones with different permeability are divided into low permeability, medium permeability and high permeability, well grids are compacted only in low permeability zones, while in high permeability zones the ratio of injection and production wells is chosen at least 1: 5, medium permeability - from 1: 3 to 1: 5, low permeability - from 1: 1 to 1: 3, after reducing the flow rate in one of the sections of the zones below the cost-effective in this section, hydraulic fracturing is carried out, then the permeability in this section is determined, it is assigned to the corresponding zone and from this predelyayut number of injection and production wells at the site (RF patent №2517674, Cl E21B 43/30, E21B 43/26, E21B 43/20, published 27.05.2014 -.. prototype).

The disadvantage of the prototype is the low oil recovery of the reservoir, caused by compaction of the grid of producing wells only in the low-permeability zone.

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

The problem is solved in that in the method of developing a heterogeneous oil field, including the allocation of zones with different permeability to the deposits, the selection of reservoir products through production wells, pumping a working agent through injection wells and sealing the grid of production wells, according to the invention, zones of high and low permeability are distinguished, injection wells are placed on one side, and production wells are located on the other side of the low permeability zone, well mesh compaction is performed by drilling, and a flare injection well near and opposite the central part of the low permeability zone from the side of producing wells, the working agent is pumped through an additional injection well in a constant mode, the producing well closest to the additional injection well is stopped until the reservoir pressure rises, the additional injection well is stopped, and commissioned stopped production well, and other production wells along the zone of low permeability stop, wait until the formation pressure is restored in the area with high permeability due to injection wells, start production wells stopped.

SUMMARY OF THE INVENTION

When developing a heterogeneous oil field, part of the reserves remains undeveloped due to the lack of exposure to parts of the field with lower permeability than in the main part of the reservoir. As a result, oil recovery remains at a low level. The proposed invention solves the problem of increasing oil recovery. The problem is solved as follows.

When developing a heterogeneous oil field in the main zone of high permeability, a zone of low permeability is distinguished. Injection wells are placed on one side, and production wells on the other side of the low permeability zone. The working agent is pumped through injection wells and reservoir products are taken through production wells. The densification of the grid of wells is performed by drilling an additional injection well near and opposite the central part of the low permeability zone from the side of producing wells. With all working wells, the working agent is pumped through an additional injection well in a constant mode. Stop the production well closest to the additional injection well. Downhole and formation pressure is monitored in a stopped well. When the reservoir pressure is higher than the average in the highly permeable zone, an additional injection well is stopped. A stopped production well is put into operation, and other production wells along the low permeability zone are stopped. Waiting for the restoration of reservoir pressure in the area with high permeability due to injection of injection wells and start production wells stopped.

Due to the displacement of oil along the low permeability zone and the selection of displaced oil by producing wells, it is possible to involve the stagnant zone in the area of the additional injection well and thereby increase the oil recovery of the field.

Concrete example

An oil field is being developed with the following characteristics: depth 1700 m, reservoir pressure 15 MPa, reservoir temperature 30 ° C, porosity 20%, permeability 400 mD, oil saturation 78%, reservoir thickness 4.5 m, reservoir sandstone, oil viscosity 7 MPa · S, the oil density of 0.86 g / cm ³ .

A low permeability zone with a permeability of 80 mD and a size of 800 × 300 m is distinguished at the field.

In FIG. 1 shows a low permeability zone. In FIG. 1 the following designations are adopted: 1 - zone of high permeability, 2 - zone of low permeability, 3, 4, 5 - injection wells in the zone of high permeability, 6, 7, 8 - production wells in the zone of high permeability, 9 - injection well in the zone of high permeability permeability.

A heterogeneous oil field is being developed. Areas of high 1 and low 2 permeability are distinguished in the field. Selected reservoir products are taken through production wells 6, 7, 8, a working agent is pumped - produced water through injection wells 3, 4, 5. Injection wells 3, 4, 5 are placed on one side, and production wells 6, 7, 8 on the other side of the zone of low permeability 2. Compaction of the grid of wells is performed by drilling an additional injection well 9 in the zone of high permeability 1 near and opposite the central part of the zone of low permeability 2 from the side of producing wells 6, 7, 8. This zone is stagnant. The working agent does not reach this zone from injection wells 3, 4, 5. The working agent is pumped through an additional injection well 9 in a constant mode and the oil is displaced from the stagnant zone to production wells. The producing well 7 closest to the additional injection well 9 is stopped until the reservoir pressure is increased to 15 MPa. The additional injection well 9 is stopped, the stopped producing well 7 is put into operation, and the other producing wells 6 and 8 along the low permeability zone 2 are stopped. Waiting for the restoration of reservoir pressure in the area with high permeability up to 15 MPa due to injection of injection wells, start stopped production wells 6 and 8.

As a result, it is possible to displace oil from the stagnant zone along the low permeability zone and to select the displaced oil by producing wells. It is possible to involve in the development a stagnant zone in the area of an additional injection well and thereby increase the oil recovery of the field. Oil recovery is increased by 3% and reaches 50%.

Application of the proposed method will improve oil recovery.

Claims (1)

A method of developing a heterogeneous oil field, including the allocation of zones with different permeability to the deposits, the selection of reservoir products through production wells, the injection of a working agent through injection wells and the sealing of the production well network, characterized in that high and low permeability zones are distinguished, injection wells are placed one at a time side, and production wells - on the other side of the zone of low permeability, compaction of the grid of wells is performed by drilling an additional injection well in near and opposite to the central part of the low-permeability zone from the side of production wells, the working agent is pumped through an additional injection well in a constant mode, the production well closest to the additional injection well is stopped until the reservoir pressure rises, the additional injection well is stopped, and the stopped production well is put into operation well, and other production wells along the low permeability zone are stopped, and reservoir recovery is waiting Lenia on an area with a high permeability due to the injection of injection wells, production wells run stopped.

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