An integrated pipe string and process for coordinated oil production using water injection and steam injection huff and puff

Abstract

The present invention discloses an integrated pipe string and process method for coordinated oil production with water injection and steam injection huff and puff. A water injection pipe string and a steam injection heat insulation pipe are installed in parallel in a casing. A bell mouth is installed at the bottom of the water injection pipe string. A tubing centralizer is provided between the water injection pipe string and the outer wall of the steam injection heat insulation pipe. A double-pipe packer is provided between the inner wall of the casing, the outer wall of the water injection pipe string, and the outer wall of the steam injection heat insulation pipe. An eccentric packer is provided between the outer wall of the steam injection heat insulation pipe and the inner wall of the casing. A rod pump seat is connected to the bottom of the steam injection heat insulation pipe, and a pen tip is installed at the bottom of the rod pump seat. A sucker rod is installed in the steam injection heat insulation pipe, and the bottom of the sucker rod is connected to a rod pump, which is installed on the rod pump seat. The method realizes water injection for thin oil layers and steam huff and puff for thick oil layers, followed by pumping for production, thereby reducing the number of wells and improving the oil production rate of the block. At the same time, the pipe string also has negative pressure oil production and tubing straightening functions, which can increase oil well fluid production and prevent tubing entanglement.

Description

Technical Field

[0001] The present invention relates to an integrated pipe string and process method for coordinated oil production by water injection and steam injection, in particular to an integrated pipe string and process method for coordinated oil production by water injection and steam injection for multiple oil reservoirs with large oil layer spans and large differences in crude oil viscosity, which require multiple different development methods. Background Art

[0002] For multiple reservoirs with large spans and widely varying crude oil viscosities, requiring diverse development methods, the current approach is to develop separate layers separately. Light oil reservoirs are primarily developed through waterflooding, while heavy oil reservoirs are primarily developed through steam stimulation. These two layers are produced separately at different stages, making simultaneous production impossible. Therefore, a new integrated string and process for coordinated oil production using waterflooding and steam stimulation has been designed. Waterflooding is performed on the light oil layer, while steam stimulation is performed on the heavy oil layer, followed by pumping. This allows two different development layers to be simultaneously utilized in a single well, reducing the number of wells deployed and increasing oil production rates in the block.

[0003] After reviewing the "Application of Integrated Injection and Production Strings in Super Heavy Oil Wells" published in "Oil and Gas·Petroleum and Natural Gas Science" in 2021, an integrated steam injection and production string process emerged. This string only shortens the operation time from steam injection to pumping of super heavy oil, and reduces the cold damage to the oil layer caused by well washing operations, but still cannot solve problems such as the simultaneous development and production of thin oil and heavy oil layers.

[0004] After checking the CN201910044009.5 patent "A horizontal well water injection and oil production integrated tubing string and process method", an integrated water injection and oil production tubing string appeared. However, this tubing string only realizes general water injection and combined layer oil production, and is only suitable for light oil water injection development. It still cannot solve the problems of steam injection and huff and puff in heavy oil layers and the simultaneous production of light oil and heavy oil according to different development methods.

[0005] After checking the CN201520211846.X patent "A pipe string for an integrated oil production and water injection process", an integrated oil production and water injection process pipe string appeared. However, this pipe string only combines the oil production pipe string and the water injection pipe string into one, and this pipe string is only suitable for light oil water injection development. It still cannot solve the problems of steam injection and huff and puff in heavy oil layers and the simultaneous development of light oil and heavy oil according to different development methods. Summary of the Invention

[0006] In order to solve the problem that multiple layers cannot be simultaneously utilized according to different development methods, the present invention designs an integrated pipe string and process method for coordinated oil production with water injection and steam injection. Water injection is implemented in the thin oil layer, and steam injection and steam injection are performed in the heavy oil layer before switching to production. In this way, two different development layers can be simultaneously utilized in one oil well, reducing the number of wells and increasing the oil production rate of the block.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: an integrated pipe string for coordinated oil production with water injection and steam injection, comprising a casing, a water injection pipe string and a steam injection insulation pipe are installed in parallel in the casing, a bell mouth is installed at the bottom of the water injection pipe string, an oil pipe straightener is provided between the water injection pipe string and the outer wall of the steam injection insulation pipe, a double-tube packer is provided between the inner wall of the casing, the outer wall of the water injection pipe string and the outer wall of the steam injection insulation pipe, an eccentric packer is provided between the outer wall of the steam injection insulation pipe and the inner wall of the casing, the bottom of the steam injection insulation pipe is connected to a rod pump seat, and a pen tip is installed at the bottom of the rod pump seat; a sucker rod is installed in the steam injection insulation pipe, the bottom of the sucker rod is connected to a rod pump, and the rod pump is installed on the rod pump seat.

[0008] Furthermore, the tubing centralizer and the dual-tube packer are located above the water injection layer.

[0009] Furthermore, the tubing centralizer is located above the dual tubing packer.

[0010] Furthermore, the eccentric packer is located between the water injection layer and the oil production layer.

[0011] Furthermore, the eccentric packer is located below the dual-tube packer.

[0012] Furthermore, there are two tubing centralizers.

[0013] A water injection and steam injection huff-and-puff coordinated oil recovery process method, having an integrated tubing string, comprises the following steps:

[0014] A. Separately run the steam injection insulation pipe with eccentric packer and rod pump seat and the water injection string with double pipe packer into the predetermined position. Straighten the water injection string and steam injection insulation pipe with the tubing centralizer.

[0015] B. Set the eccentric packer to isolate the thin oil layer and the heavy oil layer, and set the double-tube packer to protect the casing;

[0016] C. Inject water into the thin oil layer through the water injection string;

[0017] D. Carry out steam injection and huff-and-puff in the heavy oil layer through the steam injection insulation pipe;

[0018] E. After the steam injection is completed, lower the sucker rod assembly with the rod pump into the steam injection insulation pipe, and start the well and pump out the oil.

[0019] Furthermore, the sucker rod assembly with the rod pump is lowered into the steam injection insulation pipe, and the well is opened for production; due to the presence of the eccentric packer, when the sucker rod assembly with the rod pump pumps up and down, negative pressure is formed near the rod pump seat, thereby improving the fluid supply capacity of the oil-producing layer.

[0020] This invention integrates a water injection and steam injection huff-and-puff string for coordinated oil production. This allows for separate water injection into thin oil reservoirs and steam huff-and-puff into thick oil reservoirs, followed by transition to pump-out production. This allows for simultaneous activation of two distinct development zones within a single well, reducing the number of wells deployed and increasing oil production rates. Furthermore, the string also features negative pressure production and tubing straightening, increasing well fluid production and preventing tubing entanglement. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the water injection-steam injection string;

[0022] Figure 2 It is a schematic diagram of the water injection-oil production string.

[0023] Among them: 1. Casing; 2. Sucker rod; 3. Water injection string; 4. Tubing centralizer; 5. Double tube packer; 6. Steam injection insulation tube; 7. Eccentric packer; 8. Rod pump seat; 9. Pen tip. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1 、 2 The specific embodiments of the present invention are further described.

[0025] A tubing string for coordinated water and steam injection huff-and-puff oil production includes a casing 1, within which a water injection string 3 and a steam injection insulation pipe 6 are installed in parallel. A bellmouth is installed at the bottom of the water injection string 3. Two tubing centralizers 4 are installed between the water injection string 3 and the outer walls of the steam injection insulation pipe 6. A double-tube packer 5 is installed between the inner wall of the casing 1, the outer walls of the water injection string 3, and the outer walls of the steam injection insulation pipe 6. An eccentric packer 7 is installed between the outer wall of the steam injection insulation pipe 6 and the inner wall of the casing 1. A rod pump seat 8 is connected to the bottom of the steam injection insulation pipe 6, and a pen tip 9 is installed at the bottom of the rod pump seat 8. A sucker rod 2 is installed within the steam injection insulation pipe 6, and the bottom of the sucker rod 2 is connected to a rod pump, which is installed on the rod pump seat 8. The tubing centralizers 4 and double-tube packers 5 are located above the water injection layer, with the tubing centralizer 4 located above the double-tube packers 5. The eccentric packer 7 is located between the water injection layer and the oil production layer, and the eccentric packer 7 is located below the double-tube packer 5.

[0026] A water injection and steam injection huff-and-puff coordinated oil recovery process method, having an integrated tubing string, comprises the following steps:

[0027] A. Separately lower the steam injection insulation pipe 6 with the eccentric packer 7 and the rod pump seat 8 and the water injection string 3 with the double tube packer 5 into the predetermined positions. The water injection string 3 and the steam injection insulation pipe 6 are straightened by the tubing straightener 4.

[0028] B. Setting the eccentric packer 7 to isolate the thin oil layer and the heavy oil layer, and setting the dual-tube packer 5 to protect the casing 1;

[0029] C. Inject water into the thin oil layer through the water injection string 3;

[0030] D. injecting steam into the heavy oil layer through the steam injection insulation pipe 6;

[0031] E. After the steam injection is completed, the sucker rod 2 with the rod pump is lowered into the steam injection insulation pipe 6, and the well is opened for production.

[0032] The sucker rod 2 with rod pump is lowered into the steam injection insulation pipe 6, and the well is started for production. Due to the presence of the eccentric packer 7, the sucker rod 2 with rod pump pumps up and down, creating a negative pressure near the rod pump seat 8, thus improving the fluid supply capacity of the oil-producing layer.

[0033] The present invention employs a dual-tubing structure for water and steam injection into thin oil and heavy oil reservoirs, respectively. The water injection string 3 utilizes conventional tubing, while the steam injection heat-insulated pipe 6 utilizes insulated tubing. A rod pump seat 8 is pre-installed beneath the steam injection heat-insulated pipe 6. Tubing centralizers 4 are run between the two pipes every 50 meters for centralization. Eccentric packers 7 are used to isolate the thin oil and heavy oil reservoirs. A dual-tubing packer 5 is run into the top of the thin oil reservoir to protect the casing 1. After steam injection into the heavy oil reservoir, the system transitions to production, directly using a rod pump and sucker rod 2. This allows for simultaneous development of both water injection into the thin oil reservoir and steam injection into the heavy oil reservoir.

[0034] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed in the present invention, and they should be covered by the scope of protection of the present invention.

Claims

1. An integrated string for water injection and steam injection huff and puff coordinated oil production, characterized in that: The invention comprises a casing (1), wherein a water injection pipe column (3) and a steam injection heat insulation pipe (6) are installed in parallel in the casing (1), a bell mouth is installed at the bottom of the water injection pipe column (3), an oil pipe centralizer (4) is provided between the water injection pipe column (3) and the outer wall of the steam injection heat insulation pipe (6), a double pipe packer (5) is provided between the inner wall of the casing (1), the outer wall of the water injection pipe column (3) and the outer wall of the steam injection heat insulation pipe (6), an eccentric packer (7) is provided between the outer wall of the steam injection heat insulation pipe (6) and the inner wall of the casing (1), a rod pump seat (8) is connected to the bottom of the steam injection heat insulation pipe (6), and a pen tip (9) is installed at the bottom of the rod pump seat (8); a sucker rod (2) is installed in the steam injection heat insulation pipe (6), the bottom of the sucker rod (2) is connected to a rod pump, and the rod pump is installed on the rod pump seat (8).

2. The integrated pipe string for water injection and steam injection huff-and-puff coordinated oil production according to claim 1, characterized in that: The oil pipe centralizer (4) and the double-pipe packer (5) are located above the water injection layer.

3. The integrated pipe string for water injection and steam injection huff-and-puff coordinated oil production according to claim 1, characterized in that: The oil pipe centralizer (4) is located above the double-pipe packer (5).

4. The integrated pipe string for coordinated oil production with water injection and steam injection huff and puff according to claim 1 is characterized in that: The eccentric packer (7) is located between the water injection layer and the oil production layer.

5. The integrated pipe string for water injection and steam injection huff-and-puff coordinated oil production according to claim 1, characterized in that: The eccentric packer (7) is located below the double-tube packer (5).

6. The integrated pipe string for coordinated oil production with water injection and steam injection huff and puff according to claim 1, characterized in that: There are two oil pipe centralizers (4).

7. A water injection and steam injection huff-and-puff coordinated oil recovery process, characterized in that: The integrated tubing string according to any one of claims 1 to 6 comprises the following steps: A. The steam injection heat insulation pipe (6) with the eccentric packer (7) and the rod pump seat (8) and the water injection string (3) with the double pipe packer (5) are respectively lowered into predetermined positions, and the water injection string (3) and the steam injection heat insulation pipe (6) are straightened by the tubing straightener (4); B. Setting the eccentric packer (7) to isolate the thin oil layer and the heavy oil layer, and setting the double-tube packer (5) to protect the casing (1); C. injecting water into the thin oil layer through the water injection string (3); D. injecting steam into the heavy oil layer through the steam injection insulation pipe (6); E. After the steam injection is completed, the sucker rod (2) with the rod pump is lowered into the steam injection insulation pipe (6) and the well is opened for production.

8. The water injection and steam injection huff-and-puff coordinated oil recovery process according to claim 7, characterized in that: In the step E, the sucker rod (2) assembly with the rod pump is lowered into the steam injection insulation pipe (6) to start the well and pump out the oil; due to the presence of the eccentric packer (7), when the sucker rod (2) assembly with the rod pump pumps up and down, a negative pressure is formed near the rod pump seat (8), thereby improving the liquid supply capacity of the oil-producing layer.

Images