Method for developing oil deposit controlled by non-contrasting uplifts of massive and reservoir types

Abstract

FIELD: oil industry.SUBSTANCE: invention relates to methods for developing oil deposits controlled by non-contrasting uplifts of massive and reservoir types. The method includes determining the area of oil deposits in carbonate reservoirs with an oil-bearing level of 9 meters or more. A triangular row development system is formed with sides of 190-340 m in length, then vertical injection wells are placed along a series of triangle vertices every two rows of producing branched horizontal wells. At the bases of the nearest and next rows, producing branched horizontal wells are located, and they are drilled from one vertex to the right and left along the bases of two triangles touching at the bases, not reaching the corners of the triangle by more than 40 m. The upper horizontal shaft in the section is located no more than 2-3 m from the roof of the productive object with the bottomhole lowered vertically to a possible depth depending on the oil-bearing level and 4-5 m from the base of the object with branches drilled from it every 50 m to the left and the next to the right at an angle to the plane of the main shaft of 40-60° and with a smooth descent of the faces down by 2.5-3 m. The second shaft is drilled 4.5-6.5 m below the first, up to the position of the face of the first, going around it and then with the face going up in the direction of the roof behind the face of the first with a distance to the roof of 2.5-3.5 m with drilling branches from it every 50 m to the left and the next one to the right with an angle to the plane of the main shaft of 40-60° and with a smooth rise of the faces of each branch upwards towards the roof 3-4 m vertically. Perforated casing strings are installed in intervals in horizontal wells with shut-off valves 6-7 m from the branch locations, which allows for the interval shut-off of flooded areas during further operation. The same thing is done in the same sequence with a branched horizontal trunk, built in the opposite direction along the adjacent base of the neighboring triangle, and so on in rows. Two rows of production branched wells are formed. Wells are developed and put into operation, injection wells are initially used as production wells, and only after up to 85% of the wells have been flooded they are converted to injection wells. Their research is used to adjust the geological and hydrodynamic model, structural maps, and maps of oil-saturated thicknesses necessary for determining the position of horizontal wells and their branches in the section.EFFECT: maximum displacement of products from a heterogeneous carbonate reservoir and the most complete development of oil reserves by area and section.1 cl, 1 dwg

Description

[0001] The invention relates to the oil producing industry, in particular to methods for developing oil deposits controlled by non-contrasting uplifts of massive and reservoir types, represented by a heterogeneous productive carbonate reservoir with an oil-bearing level of 9 m or more, using vertical injection, horizontal and branched horizontal production wells, and can be used both in the early and late stages of development.

[0002] A method for developing an oil deposit is known (RU patent no. 2823943, IPC E21B 43 / 16, published 30.07.2024, bulletin no. 22), including drilling one or more horizontal production wells in a formation with a thickness of at least 10 m above the base of the deposit at least 3 m, and a vertical injection well - at a distance of 1 / 3 of the approved interwell space of the producing vertical well stock on the deposit from the bottom of the horizontal production well, secondary opening of the deposit in a vertical injection well above the hypsometric mark of the base of the deposit, but not above the position of the horizontal borehole of the production well, opening the lower aquifer, pumping by downhole pumping in a vertical injection well from the lower aquifer formation with a pressure 10% higher than the initial formation pressure and an injection cycle of 7 days of injection and 5 days of downtime.

[0003] The disadvantages of this method are uneven development of oil reserves, insufficient development of residual oil reserves and low oil recovery in the oil deposit area.

[0004] The closest technical solution to the proposed invention is a method for developing an oil deposit using horizontal wells (RU patent no. 2474677, IPC E21B 43 / 16, published 10.02.2013, bulletin no. 4), which provides for the placement of horizontal production wells in parallel, wherein from the horizontal sections, branches ascending to the roof of the formation are drilled sequentially in different directions in more permeable sections, between the horizontal sections, rows of vertical wells are located with the distance between the wells in the rows 1.2-1.4 times greater than the distance to the horizontal section of the nearest horizontal production well, wherein one vertical well in each row is an injection well, and the rest are production wells, and as the vertical production wells become flooded to 90%, they are converted into injection wells.

[0005] The known method does not allow for the full development of the reserves of a deposit area and requires drilling a large number of wells and branches.

[0006] The technical objectives of the proposed method are to achieve maximum displacement of products from a heterogeneous carbonate reservoir and to achieve the most complete development of oil reserves by area and section, to reduce the number of wells drilled and to achieve a high oil recovery factor.

[0007] Technical objectives are achieved by developing oil deposits controlled by non-contrasting uplifts of massive and reservoir types, which involves the placement of horizontal production wells and vertical injection wells.

[0008] What is new is that in the oil deposits in carbonate reservoirs, a section with an oil-bearing level of 9 meters or more is allocated and a triangular row development system with a side length of 190-340 m is formed, where vertical injection wells are located along a row of triangle vertices every two rows of producing branched horizontal wells, and branched horizontal wells are located along the bases of the nearest and next rows, and they are drilled from one vertex to the right and left along the bases of two triangles touching at the bases, not reaching the corners of the triangle by more than 40 m, and the upper horizontal trunk in the section is located no more than 2-3 m from the roof of the productive object with the bottomhole lowered vertically to a possible depth depending on the oil-bearing level, the bottomholes are located at 4-5 m from the base of the object,branches are drilled from the shaft every 50 meters to the left and the next to the right at an angle to the plane of the main shaft of 40-60° and with a smooth descent of the faces downwards by 2.5-3 m, the second shaft is drilled 4.5-6.5 m below the first, moreover, to the position of the face of the first, bending around it and then with the exit of the face upwards in the direction of the roof behind the face of the first and a distance to the roof of 2.5-3.5 m with drilling branches from it every 50 m to the left and the next to the right at an angle to the plane of the main shaft of 40-60° and with a smooth rise of the faces of each branch upwards in the direction of the roof 3-4 m vertically, then interval perforated casing columns are installed in horizontal shafts with shut-off valves at 6-7 m from the locations of branches, allowing for interval shutdown in the future during operation waterlogged areas, in the same sequence they do it with a branched horizontal trunk,built in the opposite direction along the adjacent base of the neighboring triangle and so on in rows, form two rows of producing branched horizontal wells, develop the wells and put them into operation, use injection wells initially as producing wells and only after up to 85% of the water is flooded are they converted to injection, based on their research they adjust the geological-hydrodynamic model, structural maps and maps of oil-saturated thicknesses necessary to determine the position in the plan and section of the horizontal trunks and their branches.

[0009] The drawing shows a diagram of the method implementation, where 1 is a triangular row development system, 2 is a row of production branched horizontal wells, 3 are injection vertical wells.

[0010] The method is carried out in the following sequence.

[0011] Development of oil deposits in carbonate reservoirs with an oil-bearing level of 9 m or more. Formation of a triangular row development system 1 (drawing) with side lengths of 190-340 m, then, along a series of triangle vertices, every two rows of production branched horizontal wells 2, injection vertical wells 3 are located.

[0012] At the bases of the nearest and next rows, production branched horizontal wells 2 are located, and they are drilled from one vertex to the right and left along the bases of two triangles touching at the bases, not reaching the corners of the triangle by more than 40 m.

[0013] In this case, the upper horizontal shaft in the section is located no more than 2-3 m from the roof of the productive object with a vertical bottomhole descent to a possible depth depending on the oil-bearing level and 4-5 m from the base of the object with drilling branches from it every 50 m to the left and the next to the right at an angle to the plane of the main shaft of 40-60° and with a smooth descent of the bottomholes down by 2.5-3 m.

[0014] The second shaft is drilled 4.5-6.5 m below the first, up to the position of the face of the first, going around it and then with the face going up in the direction of the roof behind the face of the first with a distance to the roof of 2.5-3.5 m with drilling branches from it every 50 m to the left and the next one to the right with an angle to the plane of the main shaft of 40-60° and with a smooth rise of the faces of each branch upward in the direction of the roof 3-4 m vertically.

[0015] Next, perforated casing strings are installed in intervals in horizontal wells with shutoff valves 6-7 meters from the branch locations, allowing for interval shutoff of flooded sections during future operation. The same sequence is followed with a branched horizontal well built in the opposite direction along the adjacent base of the adjacent triangle, and so on in rows.

[0016] Thus, two rows of production branched wells are formed.

[0017] Wells are developed and put into operation, injection wells are initially used as production wells (only after up to 85% of the wells have been flooded are they converted to injection) and, based on their research, the geological and hydrodynamic model, structural maps and maps of oil-saturated thicknesses are adjusted, which are necessary for determining the position of horizontal wells and their branches in the section.

[0018] Specific Application Example

[0019] An oil deposit in the Bashkirian formation is being developed. The average depth to the top of the productive deposits is 795.4 meters. The effective oil-saturated thickness is 12 meters. The total thickness is 16 meters.

[0020] At the designated site, a triangular row development system with sides 190 m long is formed. Eight vertical injection wells are located along the vertices of the triangles, every two rows of production branched horizontal wells, and four production branched horizontal wells are located along the bases of the nearest and next rows.

[0021] Moreover, production branched horizontal wells are drilled from one vertex to the right and left along the bases of two triangles touching at the bases, not reaching the corners of the triangle by 40 m.

[0022] In this case, the upper horizontal shaft in the section is located at a depth of 798.4 m with a bottom hole descending to a depth of 806.4 m. From the horizontal shaft, three branches are drilled every 50 m to the left and the next one to the right at an angle of 40° to the plane of the main shaft and with a smooth descent of the bottom holes down by 2.5 m.

[0023] The second shaft is drilled 5 m below the first, up to the position of the face of the first, going around it and then with the face going up in the direction of the roof behind the face of the first to a depth of 798 m, three branches are drilled from it every 50 m to the left and the next one to the right at an angle to the plane of the main shaft of 50° and with a smooth rise of the faces of each branch upward in the direction of the roof 3 m vertically.

[0024] Install interval-perforated casing columns in horizontal wells with shut-off valves 6 m from branch locations, which will allow for interval shut-off of flooded areas during operation.

[0025] The same thing is done in the same sequence with a branched horizontal trunk, built in the opposite direction along the adjacent base of the neighboring triangle, and so on in rows.

[0026] Thus, two rows of production branched wells are formed.

[0027] Wells are developed and put into operation. Injection wells are initially used as producers and, when water cuts reach 85%, are converted to injection. Research is conducted and, if necessary, the geological and hydrodynamic model, structural maps, and oil-saturated thickness maps are adjusted to determine the position of horizontal wells and their branches.

[0028] The method helps to achieve maximum displacement of products from a heterogeneous carbonate reservoir and the most complete development of oil reserves by area and section, as well as a reduction in the number of wells drilled and a high oil recovery factor.

Claims

A method for developing an oil deposit controlled by non-contrasting uplifts of the massive and reservoir types, which involves placing horizontal production wells and vertical injection wells, characterized in that an area with an oil-bearing level of 9 meters or more is allocated in an oil deposit in carbonate reservoirs and a triangular row development system with a side length of 190-340 m is formed, where vertical injection wells are placed along a row of triangle vertices every two rows of branched production horizontal wells, and branched horizontal wells are placed along the bases of the nearest and next rows, and they are drilled from one vertex to the right and left along the bases of two triangles touching at the bases, not reaching the corners of the triangle by more than 40 m, and the upper horizontal wellbore in the section is placed no more than 2-3 m from the roof of the productive object with the bottomhole lowered vertically to a possible depth depending on the oil-bearing level,the faces are located at 4-5 m from the base of the object, branches are drilled from the shaft every 50 meters to the left and the next one to the right at an angle to the plane of the main shaft of 40-60° and with a smooth descent of the faces down by 2.5-3 m, the second shaft is drilled 4.5-6.5 m below the first, and up to the position of the face of the first, bending around it and then with the exit of the face upward in the direction of the roof behind the face of the first and a distance to the roof of 2.5-3.5 m with drilling branches from it every 50 m to the left and the next one to the right at an angle to the plane of the main shaft of 40-60° and with a smooth rise of the faces of each branch upward in the direction of the roof 3-4 m vertically, then interval perforated casing columns are installed in horizontal shafts with cut-offs at 6-7 m from the places branches, which allow for the interval shut-off of flooded sections during further operation, are carried out in the same sequence with a branched horizontal trunk,built in the opposite direction along the adjacent base of the neighboring triangle and so on in rows, form two rows of producing branched horizontal wells, develop the wells and put them into operation, use injection wells initially as producing wells and only after up to 85% of the water is flooded are they converted to injection, based on their research they adjust the geological-hydrodynamic model, structural maps and maps of oil-saturated thicknesses necessary to determine the position in the plan and section of the horizontal trunks and their branches.

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