RU2463444C1 - Method to develop oil pool - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: proposed method comprises oil withdrawal via production wells and injecting working agent via injection wells in cyclic manner: 10 to 20 days - injection, 10 to 20 days - break. Note here that all injection wells are communicated via ground system of air ducts to allow working agent cross-flows. In compliance with this invention, mean arithmetic magnitude of bed pressure in injection wells and water cut in production wells is determined. Injection wells with bed pressure lower than average one is related to decreased pressure zones while injection wells with bed pressure exceeding mean bed pressure is related to increased pressure zones. Production wells with water cut exceeding mean value are relates to increased water cut zones while those with water cut smaller than mean value are related to lower water cut zones. Injection wells are grouped by parts. Part of injection and/or production wells with high water cut located in zone of increased bed pressure, nearby oil content outline, is equipped with downhole electrically driven rotary pumps set to boost fluid pumping. Fluid extracted from said wells is injected via existing water ducts into injection wells located in lower bed pressure zone inside oil content outline. Besides, production wells in higher water cut zone is grouped, nearby water content outline. Said wells are set to boost oil production. Oil production volume is decreased in production wells in lower water cut zone inside oil content outline.

EFFECT: higher oil recovery efficiency.

1 dwg

Description

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

A known method of developing an oil reservoir (RF patent No. 2061179, IPC 8 E21B 43/20, published in Bulletin No. 15 of 05/27/1996), including the selection of oil through production wells to reduce reservoir pressure by 20-25% of the initial , the injection of the working agent through injection wells in a cyclic mode: 10-20 days injection, 10-20 days stop.

The disadvantages of this method is that due to the reduction of reservoir pressure does not allow the interaction of injection wells when injection is stopped, because all pumped working agent is absorbed by the formation, which makes it impossible to redistribute the volumes of pumped working agent.

Also known is a method of developing a sophisticated oil reservoir in a late stage (patent RU No. 2077663, IPC 8 E21B 43/20, published in Bulletin No. 11 of 04/20/1997, including drilling it with producing and injection wells, establishing residual reserves by determining the displacement characteristics , injection of the displacing agent and selection of well products, while the displacement characteristics for each well and the reservoir as a whole are determined at a water cut of the produced product of 50-60%, then the predicted values of the volumes of produced water and FTI, on the basis of which the predicted estimated oil and water factor is calculated with the subsequent construction of maps of equal characteristics of the oil and water factor by area, after which zones with high and low values of the oil and water factor are allocated to deposits, measures are taken to increase fluid withdrawal, and in areas with high values to reduce fluid sampling, while as measures to increase fluid withdrawal use forced sampling or injection of surfactants, and as measures to reduce fluid withdrawal use use cyclic selection and injection with a change in filtration flows or injection of a polymer solution.

The disadvantages of this method are:

- firstly, the complexity of the method and the high probability of erroneous calculation of the oil-water factor with the subsequent construction of maps of equal characteristics of the oil-water factor by area;

- secondly, the development is carried out only taking into account the oil and water factor, but without taking into account reservoir pressures of injection wells, which reduces the effectiveness of this method.

The closest in technical essence is the method of developing an oil reservoir (patent No. 2303126, IPC 8 E21B 43/20, published in Bulletin No. 20 of July 20, 2007), including the selection of oil through production wells and injection of the working agent through injection wells in a cyclic mode, in this case, the arithmetic mean injectivity of injection wells is determined, wells with injectivity of less than average are classified as low-acceptivity, wells with injectivity of more than medium are classified as highly receptive, group in pairs located geographically nearest highly-responsive and low-responsive injection wells, all injection wells communicate hydrodynamically with each other through a surface water conduit system with the possibility of overflow of a working agent from a low-acceptivity well to a highly-responsive well, with cyclic pumping of a working agent, grouped in pairs highly-responsive and low-responsive wells stop and start the next, and the cycle is started and the cycle is started simultaneously : 10-20 days - injection, 10-20 days - stop.

The disadvantages of this method are:

firstly, as a working agent for maintaining reservoir pressure, loop (waste) water, which has a higher density than fresh water and has a better displacing ability, is therefore not used; therefore, the oil recovery coefficient (CIN) is low;

- secondly, in the selection of oil (products) from production wells, watering of production wells is not taken into account, therefore, in some cases, with high volumes of production from production wells, premature flooding of produced products may occur, and in others this allows the extraction of additional oil;

- thirdly, not high efficiency and uneven displacement of residual oil reserves from the oil reservoir due to the fact that reservoir pressures in injection wells and watering of production wells in one oil reservoir have a large difference in values.

The objective of the invention is to increase the efficiency and uniformity of the displacement of residual oil reserves from an oil reservoir due to the equalization of reservoir pressure in injection wells and the selection of products from producing wells of an oil reservoir, taking into account their water cut, as well as an increase in oil recovery factor due to the use of marginal wastewater of the same oil deposits, with the possibility of changing the volume of production from production wells of oil deposits, depending on their water cut.

The problem is solved by the method of developing an oil deposit, including the selection of oil through production wells and the injection of a working agent through injection wells in a cyclic mode: 10-20 days - injection, 10-20 days - shutdown, and all injection wells are interconnected hydrodynamically through a ground system water conduits with the possibility of overflow of a working agent.

What is new is that the arithmetic mean values of the reservoir pressure in the injection and water cut in the producing wells of the oil reservoir are determined, while the injection wells with a reservoir pressure of less than average are attributed to the zones of reduced pressure, and the injection wells with reservoir pressure of a higher average are classified as the zones of increased pressure, and production wells with a water cut of more than average are attributed to areas of increased water cut, and production wells with a water cut of less than average are attributed to zones of reduced water cut, group injection wells in parts, and some of the injection wells and / or part of production wells with high water cut located in the zone of high reservoir pressure near the oil content circuit are equipped with electric submersible centrifugal pumps ESP and transfer them to the forced selection of fluid produced from these wells the fluid is pumped through the system of existing water pipelines into injection wells located in the zone of low reservoir pressure inside the oil circuit, also production wells located in the zone of high water cut near the oil circuit are guarded, transferred to forced production sampling, and in production wells located in the zone of low water content inside the oil circuit, production volumes are reduced.

In FIG. shows a diagram of the implementation of the proposed method.

Oil reservoir 1 is developed by a grid of injection 2; 2 '; 2 ''; ... 2 ⁿ and extractive 3; 3 '; 3 ''; ... 3 ⁿ wells. In injection wells 2; 2 '; 2 ''; ... 2 ⁿ inject the working agent (for example, water) in a cyclic mode: 10-20 days - injection, 10-20 days - stop, and from production wells 3; 3 '; 3 ''; ... 3 '' select products.

As the development of oil reservoir 1, its reserves are depleted, produced products are irrigated, reservoir pressures in injection wells change, moreover, on one oil reservoir 1, the run-up of reservoir pressures of injection wells 2; 2 '; 2 ''; ... 2 ⁿ can be significant, for example, from 8 MPa to 27 MPa, therefore, its further development becomes economically inexpedient, therefore, to develop residual oil reserves in the oil reservoir, its development is carried out as follows.

The arithmetic mean values (P _cf ) of the reservoir pressure of all injection wells 2 are determined; 2 '; 2 ''; ... 2 ⁿ located on the oil reservoir 1, including near the contour 4 of the oil content. For example, the arithmetic mean value of reservoir pressure of injection wells 2; 2 '; 2 ''; ... 2 ⁿ is (P _sr = 15 MPa) of oil reservoir 1.

The arithmetic mean value (Q _cp ) of the water cut of all producers 3 is determined; 3 '; 3 ''; ... 3 ⁿ wells located in the oil reservoir 1. For example, the arithmetic mean of the water cut of producing wells 3; 3 '; 3 ''; ... 3 ⁿ is (Q _cp = 75%) of oil reservoir 1.

Injection wells 2; 2 '; 2 ''; ... 2 ⁿ with reservoir pressure less than average (P _av.n. = 15 MPa), the values are attributed to low pressure zones (P _n ), and injection wells with reservoir pressure of more than average (P _av.n = 15 MPa) are assigned to zones high pressure (P _in ).

Production wells 3; 3 '; 3 ''; ... 3 ⁿ with a water cut of more than average (Q _cp = 75%) are attributed to zones of increased water cut (Q _c ), and production wells with a water cut of less than average (Q _cp = 75%) are attributed to zones of reduced water cut (Q _n ).

Group injection 2; 2 '; 2 ''; ... 2 ⁿ and extractive 3; 3 '; 3 ''; ... 3 ⁿ wells in parts as follows.

Part of injection wells, for example, injection wells: 2 'and 2'', and / or part of production wells with high water cut, for example, production wells 3' and 3 '', water cut of which is 98% and higher, located near oil circuit 4 in the zone of increased reservoir pressure (P _in ), for example, the reservoir pressure of these wells is P _in = 20-25 MPa, equipped with electric submersible centrifugal pumps (ESP) (not shown in Fig.) and these wells are transferred: 2 '; 2 '' and 3 '; 3 '' for forced fluid withdrawal.

Extracted from these wells: 2 '; 2 '' and 3 '; 3 "liquid, for example waste water from injection wells 2"; 2 '' with density ρ = 1100 kg / m ³ according to the system of existing water pipelines 5, pumped into 2 '''injectionwells; 2 ''''; 2 ″ ″ ″ located inside the oil circuit 4 in the zone of reduced reservoir pressure (P _n ), for example reservoir pressures of injection wells 2 ″ ″; 2 ''''; 2 '''''are P _in = 8-12 MPa.

Thus, the redistribution of the volumes of injection of the working agent (wastewater) from zones with high reservoir pressure (P _in ) to the zone of low reservoir pressure (P _n ) located inside the circuit 4 of the oil content of oil reservoir 1. This is done in order to uniformly displace the residual reserves oil (pillars of oil) located in oil reservoir 1. As a result, a more even reservoir pressure is achieved in oil reservoir 1, i.e. decreases the interval of changes in reservoir pressure up or down.

3 '' production wells; 3 '''', located near the oil content circuit 4 in the zone of increased water cut (Q _in ), for example with a water cut: Q _in = 85-95%, they are transferred under forced production (oil) extraction, and in production wells 3 '''''; 3 '''''', located inside the oil content circuit in the zone of low water cut Q _n , for example with water cut: Q _n = 60-70% reduce production volumes (oil), i.e. transfer production wells 3 '''''; 3 '''''''to a lower flow rate (ESP is replaced by a sucker-rod sucker rod pump (SHG) (not shown in Fig.). This allows additional oil to be extracted in production wells in the zone of high water cut (Q _в ), and with a decrease in withdrawal in the zone of low water cut (Q _in ) to exclude premature flooding of the extracted products from the oil deposits.

The proposed method for the development of an oil reservoir makes it possible to equalize reservoir pressures in injection wells and thereby efficiently and uniformly displace residual oil reserves from the oil reservoir by redistributing the wastewater of injection wells from areas with reduced reservoir pressure to areas of increased reservoir pressure, as well as increasing (CIN) ) due to the use of near-surface sewage as the working agent of the same oil reservoir, which has a better displacing ability than fresh water ode pumped cluster pumping stations.

In addition, the implementation of the proposed method allows you to change the volume of production from production wells of an oil deposit, depending on their water cut, which, in turn, allows you to extract additional oil and exclude premature flooding of produced products from the oil reservoir.

Claims (1)

A method for developing an oil reservoir, including oil extraction through production wells and pumping a working agent through injection wells in a cyclic mode: 10-20 days - injection, 10-20 days - shutdown, and all injection wells communicate with each other hydrodynamically through a surface water conduit system with the possibility the flow of the working agent, characterized in that they determine the arithmetic mean values of reservoir pressure in the injection and water cut in the producing wells of the oil deposits, while the injection wells less than average reservoir pressure is attributed to reduced pressure zones, and injection wells with a more average reservoir pressure are classified as increased pressure zones, production wells with a water cut of more than average are classified as high water cut zones, and production wells with less than average water cut are classified as reduced water content, group injection wells in parts, with part of the injection wells and / or part of the production wells with high water cut in the area of increased flooding pressure gauge near the oil content circuit, they are supplied with electric submersible centrifugal pumps - ESP and transfer them to forced fluid extraction, the fluid extracted from these wells is pumped into the injection wells located in the zone of low reservoir pressure inside the oil circuit by the system of existing water pipelines, and production wells located in the oil well are also grouped in the zone of high water cut near the oil contour, they are transferred under forced production selection, and in production wells located in the zone of low water cut inside the oil circuit, reduce production volumes.

Images