RU2530005C1 - Multipay oil deposit development method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: the method includes drilling of inclined wells penetrating several pays, completion of productive pays, equipment of the well for dualing of the completed pays, extraction of product through producers and injection of a working agent through injectors. Penetration of the pays by inclined wells is made with permanent zenith and azimuth angles in order to receive a crew-shaped well. Before completion oil-bearing sections of the well in the productive strata are identified. At that in the wells equipped with devices for dualing isolation is performed between the penetrated sections of the well by means of feed-through packers.

EFFECT: improving oil recovery of the deposit.

2 dwg

Description

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

A known method of developing an oil reservoir (patent RU No. 2439299, IPC E21B 43/20, published January 10, 2012), comprising drilling a reservoir with horizontal and vertical wells along a square grid and forming elements by drilling in the center of a vertical and / or directionally directed injection element wells, by drilling multilateral wells at the sides of the elements, pumping a working agent through injection wells cyclically and taking products through production wells, measuring oil, water and injected liquid, idrodinamicheskih research and maintain reservoir pressure at the level of the original selection area. Before drilling the deposits, areas with total oil-saturated thicknesses of more than 13 m in carbonate reservoirs and / or areas with effective oil-saturated thicknesses of at least 5 m in the water-oil zone in terrigenous reservoirs are distinguished, drill a vertical and / or directional injection well in the center of each element, the sides of each the element is closed with multilateral wells with a horizontal end in the form of semicircles, each of which covers half of the element, with one ascending branch in the middle of the semicircle and directed in an angle member for generating a prikrovelnoy oil producing formation portion, replacing the element in two or three horizontal, vertical and / or extended reach wells on the sides and corners of the elements. The displacing working reagent is pumped through the injection well into the lower part of the production interval cyclically. The optimal injection period is determined at which the maximum pressure recovery in the selection zone and the oil is displaced from the matrix.

The disadvantages of this method are the difficulty in drilling and placing wells in the field, increasing the cost of drilling wells, the likelihood of a breakthrough of pumped water to the trunks of producing wells, the inability to produce small thickness formations.

Closest to the proposed invention in technical essence is a method of developing a multi-site oil field (patent RU No. 3459935, IPC E21B 43/14, 43/30, 43/20, publ. 08/27/2012), including drilling a top object with a rare exploration grid wells, production selection through production wells and injection of a working agent through injection wells. They make optimal placement of the project fund of production and injection wells on the plan of the upper object within the framework of economically sound cost-effective isopachy of at least two meters. At least one horizontal well is drilled with an entrance to the upper productive object, pass the upper productive object to a length of 30-70 m at an zenith angle of 82-86 °, pass a jumper between the objects to stabilize the zenith angle, enter the lower object by 10-12 m along the well, casing the well with a column, installing the shoe of the column 10-12 m along the trunk from the roof of the lower productive object, isolate annular space, continue drilling in the interval of the second lower productive object by 50-100 m with access to the zenith angle of 88-90 °. Install a controlled filter with two curtains above and below the clay interval, close the curtains and isolate the upper and lower objects from each other. The production casing is lowered with the entrance to the lower object, the oil-saturated part of the upper object in the casing is perforated, the well is mastered as the production one, if it is located in the vaulted and / or near-water, and / or inclined parts of the structures controlling the oil reservoir, with the introduction of equipment simultaneously well operation and operation of facilities at different design depressions that prevent premature flooding of produced products. A well is developed as an injection well if it is located in lower parts of structures. The equipment of simultaneous-separate injection is being introduced and the displacing agent is injected under different design pressures for each object, which ensure optimal injectivity.

The disadvantages of this method are low oil recovery, the difficulty in selecting the zenith angle when drilling a horizontal wellbore, significant capital costs for drilling wells, insufficient coverage by production over the area, difficulties in wiring a horizontal well in small thicknesses and installing equipment for simultaneous and separate operation (WEM )

The technical objectives of the proposed method are to increase oil recovery, reduce capital expenditures for oil production by reducing the drilling of additional production wells, the ability to operate several productive facilities using the WEM technology and to develop oil reserves from productive formations of small thickness.

Technical problems are solved by the method of developing a multi-field oil field, including drilling deviated wells that open several objects, re-opening productive objects, equipping wells with devices for open-end gas distribution of opened objects, selecting products through production wells and injecting a working agent through injection wells.

The new fact is that the opening of objects with deviated wells is carried out with constant zenith and azimuth angles to obtain a helical well, before the second opening, oil-saturated sections of the well located in productive objects are determined, while in wells equipped with devices for the electric power distribution unit, isolation is made between the opened sections of the well using through packers.

SUMMARY OF THE INVENTION

When developing a multi-field oil field, productive formations of the field are not fully developed. The main task is to achieve the maximum oil recovery coefficient with maximum reservoir coverage. The proposed method solves the problem of increasing the oil recovery of a multilayer object due to the possibility of producing at small thicknesses of the reservoir, maximum contact area with the reservoir, simultaneous development of several productive objects, without leaving the reserves of one of them in long-term preservation, while significantly reducing capital investments for drilling and operation multi-layer object, developing several objects with one grid.

Figure 1 presents the implementation diagram of the proposed method for the development of a multi-site oil field, where 1 is a section of a multi-site oil field; 2 - deviated well; 3, 4 and 5 - sections of well 2, revealing the corresponding oil-saturated parts 6, 7 and 8 of field 1 with the corresponding oil-saturated thicknesses h1, h2 and h3, while section 5 of the wellbore 2 may be left open when posting in dense rocks; α ₁ - zenith angle of inclination of the wellbore.

Figure 2 presents the layout of the wellbore when implementing the proposed method for the development of multi-site oil field 1 (top view), where 3, 4 and 5 are sections of the wellbore 2; 9 - entry point into the production interval of field 1; 10 - feedthrough packers; 11 - perforation intervals, α ₂ - azimuthal angle of deviation of the wellbore.

The method is carried out in the following sequence.

Field 1 (Fig. 1) is drilled by exploration wells (not shown) according to the design grid, the type of field 1 and the type of structure of parts 6, 7 and 8 of field 1 are determined. Based on the drilling results, the geological structure of field 1 is also determined and the capacitance-filtration properties are determined ( permeability, porosity) of oil-saturated sections 6, 7 and 8, structural plans of productive objects, make correlation schemes of sections of drilled wells, build maps of oil-saturated thicknesses h1, h2, h3, identify several zones of productive parts 6 th, 7 and 8, in terms of matching. Optimum placement of the project fund of producing 2 and injection wells (not shown) is performed. Production deviated wells 2 are drilled in the allocated zones 6, 7 and 8, secondary parts are opened 6, 7 and 8 at perforation intervals 11, production is taken through wells 2 and the working agent is injected through injection wells that open the corresponding parts 6, 7 and 8 of field 1 . Moreover inclined drilled hole 2 to the entrance to the design point 9 in the production intervals field 1. in this opening of the productive parts 6, 7 and 8 produced under constant zenith angle α ₁ and the azimuth angle α ₂ (Figure 2) for obtaining helical profile with important 2. Due to the helical profile of well 2, the maximum contact area of all oil-saturated parts 6, 7 and 8 with the corresponding sections 3, 4 and 5 of well 2 is obtained. Next, studies are carried out on the wellbore 2 (Fig. 1) and productive parts 6, 7 are determined and 8 with corresponding thicknesses h1, h2 and h3. Carry out a secondary opening at intervals of perforation 11 (figure 2) in sections 3, 4 and 5 (in the presence of a casing) to communicate with the corresponding parts 6, 7 and 8 of the field. Then, the well 2 is equipped with a device for the WEM with the installation of passage packers 10 between sections 3, 4 and 5. The products are selected through the wells 2, and the working agent is injected through the injection wells (not shown), revealing the corresponding parts 6, 7 and 8 of the field 1.

An example of a specific implementation.

A multi-field oil field 1 is being developed with the following characteristics: reservoir temperature - 25.4 ° C, permeability - 811 · 10 ^-3 μm ² , porosity - 24%, oil saturation - 82%, oil viscosity - 145.1 mPa · s, oil density - 0.904 t / m ³ .

The project fund of wells was placed on a square grid. Structural maps were constructed on the roof of all objects and maps of oil-saturated thicknesses h1 (Fig. 1), h2, h3, three zones of the corresponding productive parts 6, 7 and 8 were identified.

The upper object - part 6 of field 1 - is represented by terrigenous deposits of the Tula horizon with the following characteristics: occurrence depth - 1350 m, reservoir thickness - 1.9 m, reservoir pressure -13.2 MPa, reservoir temperature - 25.4 ° C, permeability - 812 · 10 ^-3 μm ² , porosity - 25%, oil saturation - 81%, oil viscosity - 145.1 MPa · s, oil density - 0.904 t / m ³ .

The middle object - part 7 - is represented by terrigenous deposits of the Bobrikov horizon with the following characteristics: occurrence depth - 1353 m, reservoir thickness - 2.9 m, reservoir pressure - 13.5 MPa, reservoir temperature - 25.4 ° C, permeability - 810 · 10 ^-3 μm ² , porosity - 23%, oil saturation - 82%, oil viscosity - 145.1 MPa · s, oil density - 0.904 t / m ³ .

The lower object - part 8 - is represented by carbonate rocks of a massive type of the Tournaisian layer with the following characteristics: occurrence depth - 1367.2 m, reservoir thickness - 5 m, reservoir pressure - 13.5 MPa, reservoir temperature - 26 ° C, permeability - 31 · 10 ^-3 μm ² , porosity - 11%, oil saturation - 61%, oil viscosity - 86 MPa · s, oil density - 0.897 t / m ³ .

Drilled an inclined well 2 with an entrance to the upper productive object - part 6 of the Tula horizon at - design point 9 with a constant zenith angle α ₁ = 45 ° and a constant set of azimuth angle α ₂ = 68 ° (Fig. 2) after entering the reservoir , i.e. without changing the zenith and azimuth angles, we obtain the profile of a helical well (figures 1 and 2). The effective oil-saturated thickness h1 (Fig. 1) of the upper object - part 6 of the Tula horizon was 1.9 m.

Then, under the constant zenithal α ₁ and azimuthal α ₂ angles, we went through the productive interval and entered the middle object - part 7 of the Bobrikov horizon, 2.9 m thick, after which the productive lower object - part 8 of the Tournaisian layer - 5 m thick was opened. In this case, wellbore 2 in terrigenous sediments — parts 6 and 7 — was cased with column 5, and in carbonate low-permeability sediments of the Tournaisian stage — part 8 — wellbore 3 was left open.

We performed a second opening of oil-saturated parts 6, 7, and 8 at perforation intervals 11 in the corresponding sections 3, 4, 5, after which we performed geophysical surveys (GIS) over the entire wellbore 2 and determined oil-saturated sections of the wellbore 3, 4, 5 in oil-saturated parts 6 , 7, 8 deposits 1.

Further, in the well 2 (Fig. 2), the WEM equipment was installed with installation between sections 3, 4, 5 of the passage packers 10 (see patents RU No. 2470144, 2449114, etc.).

Well 2 was mastered and put into operation, and the injection of the working agent was carried out through injection wells, revealing the corresponding parts 6, 7 and 8 of field 1.

Due to the application of the proposed method, the oil production rate from the carbonate terrigenous deposits of the Bobrikov horizon was 21 tons / day with a production rate of surrounding wells of 3.7 tons / day; in the Tournaisian stage, the oil production rate was 14 tons / day, while the production rate of the neighboring well was 4 tons / day. The daily total effect is 35 tons / day. Taking into account the fall, annual production will amount to 7776 tons of oil. There is no longer a need to drill additional production wells to extract residual reserves in this area.

Application of the proposed method will increase oil recovery in a multi-site oil field, reduce the volume of drilling an independent grid of wells at the lower object, ensuring uniform production of reserves in all productive facilities, reduce the cost of drilling additional wells, and develop residual reserves from productive formations of small thickness.

Claims (1)

A method for developing a multi-site oil field, including drilling deviated wells that open several objects, re-opening productive objects, equipping wells with devices for simultaneous and separate operation — open-hole production of open-cut objects, selecting products through production wells and injecting a working agent through injection wells, characterized in that the opening of objects with deviated wells is carried out with constant zenith and azimuth angles to obtain a helical well, before toricity they define opening portions oil saturated wells located in production facilities, while in wells equipped with devices for WEM produce insulation between the unopened portions of the well by means of feedthrough packers.

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