Continuous acid liquid distribution and injection system for offshore oil and gas field

Abstract

The invention discloses a continuous acid liquor injection allocation system for an offshore oil and gas field. The system comprises an acid liquor mixing mechanism, a clear water input mechanism and an acid liquor input mechanism, the clear water input mechanism comprises a high-pressure water input assembly, a pressure gauge, a flow regulating valve II and a clear water flow meter assembly which are communicated in sequence; the acid liquor input mechanism comprises two acid liquor input branches, and outlets of the acid liquor input branches are communicated with the acid liquor mixing mechanism; the acid liquid mixing mechanism comprises a cyclone mixer, a stirring tank, a liquid storage tank and a conveyor which are communicated in sequence. Flow meter passages are changed into parallel connection, redundancy design is added, and the reliability of the system is improved; an acid liquor passage is changed into two branches, so that different types of acid liquor can be conveniently added; the acid liquid diaphragm pump adopts an electric mode and a pneumatic mode so as to cope with severe weather of the offshore platform; the cyclone mixer is additionally arranged in front of the stirring tank, so that liquid is mixed more sufficiently; due to the design of the double-layer stirring liquid storage tank and the double-layer acid tank, the occupied area is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of acid injection in offshore oil fields, and in particular relates to a system for continuous acid injection in offshore oil and gas fields. Background Art

[0002] As a major energy source and important chemical raw material, oil and natural gas play an important role in the economic development of human society. my country has abundant offshore oil and gas reserves, but the utilization of low-permeability reserves is low. With the development of offshore oil and gas fields, horizontal well development has become the mainstream, and the corresponding acid injection system and supporting processes are becoming increasingly mature. However, the on-site implementation of offshore acid injection is still limited by realistic conditions. Continuous preparation and injection of acid are two important links in the on-site construction of fracturing. The traditional preparation and supply methods are not only slow, but also have uncertain factors. During the exploitation of offshore oil and gas fields, the wellbore near the wellbore area often becomes blocked, causing the oil production and water injection to decrease, and the number of oil and water wells unblocking increases year by year. In addition, the deck space of offshore oilfield platforms is limited, and other operations are also increasing year by year, resulting in a serious shortage of platform space resources, consuming a lot of manpower, affecting the construction of oil and water well acidification operations, and then affecting the completion of production and water injection tasks. Acidification can be completed with the help of tugboats, but the cost is high and it is easily affected by climatic factors, and efficient completion cannot be guaranteed.

[0003] Therefore, how to reduce the number of acid tanks at the acid injection site, reduce the labor intensity of the staff, reduce the loss of acid, reduce the cost of tank transportation, improve production efficiency, and meet the ever-changing acidizing process requirements are issues that must be considered in the current acid injection construction. Carrying out research on the process technology of continuous acid injection in offshore oil fields and proposing solutions require improving the capacity of offshore acidizing equipment and having good adaptability. At the same time, it requires the construction quality of acidizing operations to be continuously improved, so that the detection and control of the process are automated, which is of great significance to ensure the development effect of oilfield production increase measures. Realizing the automation of the offshore platform acid injection process and reducing the volume of the injection system are issues that must be solved for offshore oilfield unblocking. It can effectively reduce the total scale of the injection system and improve the liquid injection efficiency of the offshore platform, which is of great significance to increasing the production of oil wells and the injection volume of water injection wells. Therefore, in order to solve the problems existing in the existing offshore acid injection platform, it is urgent to design a process flow for automatic acid injection. Summary of the invention

[0004] The present invention is proposed to solve the problems of complicated process and large space occupied in offshore acid solution configuration in the prior art, and its purpose is to provide an offshore oil and gas field continuous acid solution configuration system.

[0005] The present invention is achieved through the following technical solutions:

[0006] A system for continuous acid injection in offshore oil and gas fields comprises an acid mixing mechanism and a clean water input mechanism and an acid input mechanism respectively connected to the acid mixing mechanism; the clean water input mechanism comprises a high-pressure water input component, a pressure gauge, a No. II flow regulating valve and a clean water flow meter component connected in sequence; the acid input mechanism comprises two acid input branches, and the outlets of the acid input branches are both connected to the acid mixing mechanism; the acid input branch comprises an acid tank component, a diaphragm pump component and an acid flow meter component connected in sequence; the acid mixing mechanism comprises a cyclone mixer, a stirring tank, a liquid storage tank and a conveyor connected in sequence.

[0007] In the above technical solution, the high-pressure water input component includes two high-pressure water input branches, the inlet of one high-pressure water input branch is connected to the high-pressure water inlet of platform No. 1, and the inlet of the other high-pressure water input branch is connected to the high-pressure water inlet of platform No. 2, and the outlets of the two high-pressure water input branches are connected to each other.

[0008] In the above technical solution, the high-pressure water input branch includes a No. 1 pressure transmitter and a No. 1 flow regulating valve which are interconnected; the clean water flow meter assembly includes two clean water flow meter branches connected in parallel, and the clean water flow meter branch includes a No. 1 stop valve, a No. 1 flow meter and a No. 1 check valve which are connected in sequence.

[0009] In the above technical scheme, the acid tank assembly includes two acid tank branches connected in parallel, and the acid tank branch includes an acid tank and a No. II stop valve connected in sequence; the diaphragm pump assembly includes a pneumatic pump branch and an electric pump branch connected in parallel; the pneumatic pump branch includes a No. II stop valve, a pneumatic diaphragm pump and a No. II check valve connected in sequence; the pneumatic diaphragm pump is connected to the platform air source, and an air source flow regulating valve is arranged on the connecting pipeline; the electric pump branch includes a No. III stop valve, an electric diaphragm pump and a No. III check valve connected in sequence; the electric diaphragm pump is connected to the acid pump motor, and the acid pump motor is connected to the frequency converter; the acid liquid flowmeter assembly includes two acid liquid flowmeter branches connected in parallel, and the acid liquid flowmeter branch includes a No. IV stop valve, a No. II flowmeter and a No. IV check valve connected in sequence.

[0010] In the above technical solution, the inlet of the cyclone mixer is connected to the outlets of the clean water input mechanism and the acid liquid input mechanism respectively; a No. V stop valve is arranged between the stirring tank and the liquid storage tank; a No. VI stop valve is arranged between the liquid storage tank and the conveyor; a pH detector and a No. II pressure transmitter are respectively arranged on the pipelines before and after the No. VI stop valve.

[0011] In the above technical solution, a No. Ⅰ liquid level gauge and a mechanical float are arranged in the mixing tank.

[0012] In the above technical solution, a No. II liquid level gauge is arranged in the liquid storage tank.

[0013] In the above technical scheme, it also includes an acid tank cleaning mechanism, which includes two cleaning main pipes respectively connected to the high-pressure water inlet of platform No. Ⅰ and the high-pressure water inlet of platform No. Ⅱ, each cleaning main pipe is connected to two cleaning branch pipes, and the cleaning branch pipes are connected to the upper part of the acid tank. An electric control valve is arranged on the cleaning main pipe.

[0014] In the above technical scheme, the acid tank is a double-layer acid tank, which includes an acid tank frame and an upper acid tank and a lower acid tank which are overlapped and placed in the acid tank frame; the upper acid tank and the lower acid tank are connected through an acid tank stop valve; and No. II stop valves are provided at the outlets of the upper acid tank and the lower acid tank.

[0015] In the above technical solution, the liquid storage tank is a double-layer stirring liquid storage tank, which includes a liquid storage tank frame, an upper liquid storage tank and a lower liquid storage tank which are overlapped and placed in the liquid storage tank frame, and the upper liquid storage tank and the lower liquid storage tank are connected through a liquid storage tank stop valve.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides an offshore oil and gas field continuous acid injection system. The flow meter passage is changed to parallel connection, and the redundant design is increased to increase the reliability of the system. The acid passage is changed to two branches to facilitate the addition of different types of acid. The acid diaphragm pump adopts electric and pneumatic methods to cope with the severe weather of the offshore platform. A cyclone mixer is added in front of the stirring tank to make the liquid mixing more complete. The design of the double-layer stirring liquid storage tank and the double-layer acid tank saves floor space. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the acid tank in the present invention;

[0020] Figure 3 It is a structural schematic diagram of the liquid storage tank in the present invention.

[0021] in:

[0022] 1. Clean water input mechanism; 11. No. Ⅰ pressure transmitter; 12. No. Ⅰ flow control valve; 13. Pressure gauge; 14. No. Ⅱ flow control valve; 15. No. Ⅰ stop valve; 16. No. Ⅰ flow meter; 17. No. Ⅰ check valve;

[0023] 2. Acid liquid input mechanism; 21. Acid tank; 2101. Acid tank frame; 2102. Upper acid tank; 2103. Lower acid tank; 2104. Acid tank stop valve; 22. Stop valve No. Ⅱ; 23. Stop valve No. Ⅱ; 24. Pneumatic diaphragm pump; 25. Check valve No. Ⅱ; 26. Air source flow regulating valve; 27. Stop valve No. Ⅲ; 28. Electric diaphragm pump; 29. ​​Check valve No. Ⅲ; 210. Acid pump motor; 211. Frequency converter; 212. Stop valve No. Ⅳ; 213. No. Ⅱ Flow meter; 214, No. IV check valve; 3, acid liquid mixing mechanism; 31, cyclone mixer; 32, stirring tank; 33, liquid storage tank; 3301, liquid storage tank frame; 3302, upper liquid storage tank; 3303, lower liquid storage tank; 3304, liquid storage tank stop valve; 34, conveyor; 35, No. V stop valve; 36, VI stop valve; 37, pH detector; 38, No. II pressure transmitter; 39, No. I liquid level gauge; 310, mechanical float; 311, No. II liquid level gauge.

[0024] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0026] like Figure 1 As shown, an offshore oil and gas field continuous acid injection system includes a clean water input mechanism 1, an acid liquid input mechanism 2 and an acid liquid mixing mechanism 3; the clean water input mechanism 1 and the acid liquid input mechanism 2 are respectively connected to the acid liquid mixing mechanism 3;

[0027] The clean water input mechanism 1 includes a high-pressure water input component, a pressure gauge 13, a No. II flow regulating valve 14 and a clean water flow meter component which are connected in sequence;

[0028] The high-pressure water input assembly comprises two high-pressure water input branches, one high-pressure water input branch inlet is connected to the high-pressure water inlet of platform I, the other high-pressure water input branch inlet is connected to the high-pressure water inlet of platform II, and the outlets of the two high-pressure water input branches are connected to each other;

[0029] The high-pressure water input branch includes a No. 1 pressure transmitter 11 and a No. 1 flow regulating valve 12 which are interconnected;

[0030] The clean water flow meter assembly comprises two clean water flow meter branches connected in parallel, and the clean water flow meter branches comprise a No. I stop valve 15, a No. I flow meter 16 and a No. I check valve 17 which are connected in sequence;

[0031] The pressure transmitter in the clean water input mechanism adjusts the overall water pressure. The flow meter branch is selected through two parallel stop valves. The flow meter cooperates with the regulating valve to adjust the water flow. A check valve is designed before the acid water is mixed to prevent the clean water from flowing back.

[0032] The acid liquid input mechanism 2 comprises two acid liquid input branches, and the outlets of the acid liquid input branches are both connected to the acid liquid mixing mechanism 3;

[0033] The acid liquid input branch comprises an acid tank assembly, a diaphragm pump assembly and an acid liquid flow meter assembly which are connected in sequence;

[0034] The acid tank assembly comprises two acid tank branches connected in parallel, and the acid tank branches comprise an acid tank 21 and a No. II stop valve 22 connected in sequence;

[0035] The diaphragm pump assembly includes a pneumatic pump branch and an electric pump branch connected in parallel; in order to adapt to the harsh conditions of the offshore platform, the acid pump adopts the design of both a pneumatic diaphragm pump and an electric diaphragm pump, so the power source of the pump includes both electricity and platform air source;

[0036] The pneumatic pump branch includes a No. II stop valve 23, a pneumatic diaphragm pump 24 and a No. II check valve 25 which are connected in sequence; the pneumatic diaphragm pump 24 is connected to the platform air source, and an air source flow regulating valve 26 is arranged on the connecting pipeline;

[0037] The electric pump branch includes a No. III stop valve 27, an electric diaphragm pump 28 and a No. III check valve 29 which are connected in sequence; the electric diaphragm pump 28 is connected to an acid pump motor 210, and the acid pump motor 210 is connected to a frequency converter 211;

[0038] The acid flow meter assembly comprises two parallel connected acid flow meter branches, wherein the acid flow meter branches comprise a No. IV stop valve 212, a No. II flow meter 213 and a No. IV check valve which are connected in sequence;

[0039] The acid input mechanism 2 is equipped with 4 acid tanks, and every 2 acid tanks are one acid input. The acid tank output port is connected through a redundant stop valve to select the type of acid pump. The pneumatic pump is driven by the platform air source, and the electric pump is driven by the motor. The flow meter branch is selected through two parallel stop valves. The flow meter in the pipeline can measure the flow continuously; a check valve is designed before the acid and water are mixed to prevent the acid from flowing back.

[0040] The acid liquid mixing mechanism 3 includes a cyclone mixer 31, a stirring tank 32, a liquid storage tank 33 and a conveyor 34 which are connected in sequence;

[0041] The inlet of the cyclone mixer 31 is connected to the outlets of the clean water input mechanism 1 and the acid liquid input mechanism 2 respectively;

[0042] A No. V stop valve 35 is provided between the mixing tank 32 and the liquid storage tank 33; a No. VI stop valve 36 is provided between the liquid storage tank 33 and the conveyor 34; a pH detector 37 and a No. II pressure transmitter 38 are provided on the pipelines before and after the No. VI stop valve 36; the No. VI stop valve 36 realizes the output and cutoff of the mixed liquid; the No. II pressure transmitter 38 detects the outlet pressure;

[0043] A No. I liquid level gauge 39 and a mechanical float 310 are provided in the mixing tank 32;

[0044] A No. II liquid level gauge 311 is arranged in the liquid storage tank 33 to detect the pH in the discharge pipeline of the liquid storage tank 33 .

[0045] The acid liquid mixing mechanism 3 is designed with three mixing processes: the first mixing of acid and water is completed in the cyclone mixer, the acid liquid after the first mixing is transported to the stirring tank, the motor drives the stirrer to achieve the second mixing, and a conveyor is installed at the acid liquid discharge port to achieve the third mixing to prevent the mixed liquid from settling in the pipeline;

[0046] The offshore oil and gas field continuous acid injection system also includes an acid tank cleaning mechanism, which includes two cleaning main pipes respectively connected to the high-pressure water inlet of the No. Ⅰ platform and the high-pressure water inlet of the No. Ⅱ platform, each cleaning main pipe is connected to two cleaning branch pipes, and the cleaning branch pipes are connected to the upper part of the acid tank 21, and an electric control valve is arranged on the cleaning main pipe;

[0047] After the fracturing acidizing operation is completed, the acid tank cleaning mechanism should flush the acid tank to prevent the acid from corroding the equipment and process pipelines. The design of the electronically controlled valve can achieve controllable cleaning of the acid line.

[0048] In this embodiment, the acid tank 21 is a double-layer acid tank.

[0049] like Figure 2 As shown, the acid tank 21 includes an acid tank frame 2101 and an upper acid tank 2102 and a lower acid tank 2103 which are overlapped and placed in the acid tank frame 2101; the upper acid tank 2102 and the lower acid tank 2103 are connected through an acid tank stop valve 2104; and the outlets of the upper acid tank 2102 and the lower acid tank 2103 are both provided with a No. II stop valve 22;

[0050] The upper and lower layers of the acid tank are overlapped to save space; the design of the acid tank stop valve realizes the communication between the upper and lower acid tanks; the acid tank frame is used to stabilize the acid tank and prevent the acid tank from tipping over. At the same time, the acid tank frame is convenient for hoisting the acid tank.

[0051] In this embodiment, the liquid storage tank 33 is a double-layer stirring liquid storage tank.

[0052] like Figure 3As shown, the liquid storage tank 33 includes a liquid storage tank frame 3301, an upper liquid storage tank 3302 and a lower liquid storage tank 3330 which are overlapped and placed in the liquid storage tank frame 3301, and the upper liquid storage tank 3302 and the lower liquid storage tank 3330 are connected through a liquid storage tank stop valve 3304; the structure of the liquid tank frame 331 is the same as that of the acid tank frame.

[0053] The present invention aims at solving the problems that the wellbore near the offshore oil and gas field is often blocked, the deck space of the platform is limited, a large amount of manpower is consumed, and the acidizing operation of the oil and water wells is affected. Compared with the conventional acid liquid configuration process, the present invention realizes the full mixing of the acid liquid and the clean water, and the redundant design increases the reliability of the system; in addition, the design of the double-layer stirring liquid storage tank and the double-layer acid tank saves the floor space of the offshore acid injection platform; it is conducive to reducing the total scale of the injection system and improving the liquid configuration efficiency of the offshore platform, which is of great significance to increasing the production of oil wells and the injection volume of water injection wells.

[0054] The continuous acid preparation system of the present application adopts a skid-mounted miniaturized design, and the platform water delivery area, acid liquid input area and liquid mixing area of ​​the device are reasonably designed inside the skid body, so that it can be installed as a whole on the offshore platform, which is convenient for installation and maintenance;

[0055] Redundant design: In order to improve the reliability of the control system, a redundant design is adopted. Two flow meters are connected in parallel in both the acid injection pipeline and the water injection pipeline; the pneumatic diaphragm pump and the electric diaphragm pump are connected in parallel in the acid injection pipeline to achieve redundancy of the acid pump.

[0056] Large displacement acid pump optimization: In order to cope with the severe weather at sea, the pneumatic diaphragm pump and the electric diaphragm pump are designed to be connected in parallel, and the pump type is switched by two stop valves. Under normal circumstances, the platform air source is used as the power source of the pneumatic diaphragm pump, and the electric diaphragm pump driven by the motor is used as a backup pump; since strong acid is corrosion-resistant, both acid pumps have strong corrosion resistance.

[0057] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A continuous acid injection system for offshore oil and gas fields, characterized by: It comprises an acid liquid mixing mechanism (3) and a clean water input mechanism (1) and an acid liquid input mechanism (2) respectively connected to the acid liquid mixing mechanism (3); The clean water input mechanism (1) comprises a high-pressure water input component, a pressure gauge (13), a No. II flow regulating valve (14) and a clean water flow meter component which are connected in sequence; The acid liquid input mechanism (2) comprises two acid liquid input branches, the outlets of which are both connected to the acid liquid mixing mechanism (3); the acid liquid input branch comprises an acid tank assembly, a diaphragm pump assembly and an acid liquid flow meter assembly which are connected in sequence; The acid liquid mixing mechanism (3) comprises a cyclone mixer (31), a stirring tank (32), a liquid storage tank (33) and a conveyor (34) which are connected in sequence.

2. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: The high-pressure water input component includes two high-pressure water input branches, one high-pressure water input branch inlet is connected to the high-pressure water inlet of platform No. 1, and the other high-pressure water input branch inlet is connected to the high-pressure water inlet of platform No. 2, and the outlets of the two high-pressure water input branches are connected to each other.

3. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: The high-pressure water input branch comprises a No. 1 pressure transmitter (11) and a No. 1 flow regulating valve (12) which are interconnected; the clean water flow meter assembly comprises two clean water flow meter branches which are connected in parallel, and the clean water flow meter branches comprise a No. 1 stop valve (15), a No. 1 flow meter (16) and a No. 1 check valve (17) which are interconnected in sequence.

4. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: The acid tank assembly comprises two acid tank branches connected in parallel, and the acid tank branches comprise an acid tank (21) and a No. II stop valve (22) connected in sequence; The diaphragm pump assembly comprises a pneumatic pump branch and an electric pump branch connected in parallel; the pneumatic pump branch comprises a No. II stop valve (23), a pneumatic diaphragm pump (24) and a No. II check valve (25) which are connected in sequence; the pneumatic diaphragm pump (24) is connected to a platform gas source, and a gas source flow regulating valve (26) is arranged on the connecting pipeline; the electric pump branch comprises a No. III stop valve (27), an electric diaphragm pump (28) and a No. III check valve (29) which are connected in sequence; the electric diaphragm pump (28) is connected to an acid pump motor (210), and the acid pump motor (210) is connected to a frequency converter (211); The acid liquid flow meter assembly comprises two acid liquid flow meter branches connected in parallel, and the acid liquid flow meter branches comprise a No. IV stop valve (212), a No. II flow meter (213) and a No. IV check valve which are connected in sequence.

5. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: The inlet of the cyclone mixer (31) is connected to the outlets of the clean water input mechanism (1) and the acid liquid input mechanism (2) respectively; a No. V stop valve (35) is arranged between the stirring tank (32) and the liquid storage tank (33); a No. VI stop valve (36) is arranged between the liquid storage tank (33) and the conveyor (34); and a pH detector (37) and a No. II pressure transmitter (38) are respectively arranged on the pipelines before and after the No. VI stop valve (36).

6. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: A No. I liquid level gauge (39) and a mechanical float (310) are arranged in the stirring tank (32).

7. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: A No. II liquid level gauge (311) is arranged in the liquid storage tank (33).

8. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: The acid tank cleaning mechanism also includes two cleaning main pipes respectively connected to the high-pressure water inlet of the No. I platform and the high-pressure water inlet of the No. II platform, each cleaning main pipe is connected to two cleaning branch pipes, and the cleaning branch pipes are connected to the upper part of the acid tank (21). The cleaning main pipes are provided with electric control valves.

9. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: The acid tank (21) is a double-layer acid tank, which comprises an acid tank frame (2101) and an upper acid tank (2102) and a lower acid tank (2103) which are overlapped and placed in the acid tank frame (2101); the upper acid tank (2102) and the lower acid tank (2103) are connected through an acid tank stop valve (2104); and a No. II stop valve (22) is provided at the outlets of the upper acid tank (2102) and the lower acid tank (2103).

10. The offshore oil and gas field continuous acid injection system according to claim 1, characterized in that: The liquid storage tank (33) is a double-layer stirring liquid storage tank, which includes a liquid storage tank frame (3301), an upper liquid storage tank (3302) and a lower liquid storage tank (3330) which are overlapped and placed in the liquid storage tank frame (3301), and the upper liquid storage tank (3302) and the lower liquid storage tank (3330) are connected via a liquid storage tank stop valve (3304).

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