Offshore oilfield hollow integrated pulsating water injection tool and method without moving string

Abstract

The present application provides a pulsating water injection tool and method based on offshore oilfield hollow integrated technology without moving pipe column, comprising a pulsating water injection tool based on offshore oilfield hollow integrated technology without moving pipe column, which comprises a hollow integrated separate injection technology pipe column, a water injection working barrel and a pulsating water injection tool, one to multiple water injection working barrels are arranged in the hollow integrated separate injection technology pipe column, a water nozzle is arranged on the side wall of the water injection working barrel, the pulsating water injection tool is detachably arranged in the water injection working barrel, a nozzle is arranged on the pulsating water injection tool, and an amplitude adjusting mechanism is arranged in the pulsating water injection tool to control the pulsating pressurized injection of water flow into the water injection working barrel. The present application has the beneficial effect that the original hollow integrated separate injection technology pipe column does not need to be moved, the wellhead equipment does not need to be changed, and only the pulsating water injection tool needs to be put into the downhole for setting, the process is simple, and the adaptability is good. The size of the pulsating water injection tool and the original water injection working barrel core is the same, and the amplitude can be arbitrarily adjusted in the downhole in the form of pressure wave.

Description

Technical Field

[0001] This invention relates to the field of offshore oilfield water injection tools, and more specifically to a water injection tool and method based on a stationary tubing string using a hollow integrated offshore oilfield process. Background Technology

[0002] Pulsed water injection differs from traditional constant-pressure water injection; it is variable-pressure water injection with a specific frequency and amplitude. Pulsed water injection utilizes the pulsating switching characteristics of downhole pulsed water injection tools. By transforming the conventional, stable fluid injection method into a periodic, pulsating fluid injection method, it achieves pulsed water injection, thereby reducing pressure and increasing injection in the injection well, improving the formation's water absorption profile. It is applicable to high- and low-permeability injection wells in offshore oilfields and features low operating costs, environmental friendliness, and zero pollution, meeting the low-cost, green development needs of offshore oilfields.

[0003] Currently, the pulsed water injection method based on hollow integrated technology in offshore oilfields has achieved certain results in reducing water pressure and increasing injection in injection wells, as well as improving formation water absorption profiles. However, it still requires the amplitude of the pulsed water injection tool to be adjusted in advance on the surface. If the effect is not obvious after the tubing string is inserted, wireline operation is required to remove it and readjust the amplitude. It is not possible to perform pulsed water injection adjustment effectively in a single long period of time. Summary of the Invention

[0004] This invention overcomes the shortcomings of the prior art and provides a tool and method for pulsating water injection with a stationary tubing string based on the hollow integrated process in offshore oil fields.

[0005] The objective of this invention is achieved through the following technical solution.

[0006] The hollow integrated process for offshore oilfields includes a stationary tubing system with a pulsating water injection tool. The system comprises a hollow integrated sub-injection process tubing, a water injection working cylinder, and a pulsating water injection tool. The hollow integrated sub-injection process tubing contains one or more water injection working cylinders. A water nozzle is provided on the side wall of the water injection working cylinder. The pulsating water injection tool is detachably installed inside the water injection working cylinder. The pulsating water injection tool is equipped with a nozzle and has an amplitude adjustment mechanism inside to control the pulsating pressurization of water flow into the water injection working cylinder.

[0007] The pulsating water injection tool is equipped with a main piston, a secondary piston, and an amplitude adjustment mechanism. The main piston has a water inlet passage that is connected to a water source. The main piston and the secondary piston are movably connected to an adjustment rod inside the sleeve of the pulsating water injection tool. The adjustment rod at the top of the secondary piston is equipped with a first elastic element. The bottom end of the secondary piston is sealed to the water inlet passage on the main piston. The main piston is connected to the amplitude adjustment mechanism.

[0008] The adjusting rod is a fixed column, and the main piston and the auxiliary piston are nested on the fixed column.

[0009] The pulsating water injection tool is a sealed cylinder, which includes a top end and a bottom end. The top end of the cylinder is provided with a retrieval head, and the bottom end of the cylinder is provided with a first opening. The main piston is matched with the first opening.

[0010] The main piston is provided with a limiting cylinder, the outer diameter of which is larger than the outer diameter of the first opening.

[0011] The top of the pulsating water injection tool is provided with a second opening. The outer opening of the second opening is connected to the water inlet end of the main piston water inlet passage. The inner opening of the second opening is provided with a sealing ball. The sealing ball is movably mounted on the adjusting rod. The adjusting rod is provided with a second elastic element to push the sealing ball against the inner opening of the second opening.

[0012] The amplitude adjustment mechanism includes a main control circuit, a battery, and a motor. The battery provides power to the main control circuit and the motor. The main control circuit includes a signal sensing module and an action module. The signal sensing module receives action signals in the form of pressure waves and transmits the information to the action module. The motor drives the action module to move and change the position of the main piston to adjust the pulsation amplitude.

[0013] The water injection working cylinder is equipped with a built-in retrieving core.

[0014] The hollow integrated sub-injection process string includes a Christmas tree, tubing hanger, tubing, sliding sleeve, positioning seal, packer, water injection working cylinder, pulsating water injection tool, and blind plug. The Christmas tree is equipped with a tubing hanger, the tubing hanger is equipped with tubing, the tubing hanger is equipped with tubing, the tubing is equipped with a sliding sleeve, the tubing is sealed to the packer at the top, the positioning seal is connected to the packer at the top, the water injection working cylinder is set in the packer at a preset layer to form a seal, and the bottom end of the tubing string is connected to the blind plug to form the hollow integrated sub-injection process string.

[0015] The specific steps for using a stationary tubing pulsating water injection tool based on the hollow integrated process in offshore oilfields are as follows:

[0016] S1. Amplitude adjustment: The pulsating water injection tool set in the water injection working cylinder at the specified layer is adjusted by different pressure wave signals. The amplitude adjustment mechanism is sent to the amplitude adjustment mechanism in the pulsating water injection tool at different layers through a specific pressure wave signal. The amplitude adjustment mechanism will adjust the amplitude according to the received signal.

[0017] S2. The pulsating water injection tool pressurizes. In the initial state, the main piston presses against the auxiliary piston to close the water inlet passage and achieve a seal. The water pressure in the cavity of the pulsating water injection tool gradually increases due to the closure of the water injection channel, creating a pressure difference between the two chambers of the main piston. When the pressure difference increases to the point that it can balance the pressure applied by the elastic element, the elastic element is compressed, and the water flow in the main piston pushes the auxiliary piston upward.

[0018] S3. The pulsating water injection tool oscillates and injects water. When the main piston moves to the limited position of the limiting cylinder, the main piston stops moving. The water flow in the cavity pushes the auxiliary piston to continue moving upward, creating a gap between the auxiliary piston and the main piston. The two ends of the water inlet passage of the main piston are connected. High-pressure water is injected into the formation through the nozzle in an oscillating manner. When the pressure in the two chambers of the main piston reaches equilibrium, the auxiliary piston moves back under the compressive force of the elastic element. The auxiliary piston resets and contacts the end of the water inlet passage of the main piston again to seal the two chambers. The above reciprocating motion between the auxiliary piston and the main piston is repeated, periodically forming pressure rise and oscillating water injection, thus realizing the periodic pulsating water injection of the water injection well.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. No need to modify the original hollow integrated injection process tubing or change the wellhead equipment. Only the pulsating water injection tool needs to be inserted downhole for setup. The process is simple and has good adaptability.

[0021] 2. The pulsating water injection tool has the same core size and running process as the original water injection working cylinder. The amplitude can be adjusted arbitrarily downhole through pressure waves. It can selectively unblock under-injected layers without repeatedly dropping and retrieving to adjust the amplitude. The tool can also be reused, greatly reducing operating costs.

[0022] 3. When the booster function fails, the regular backup water injection channel can be activated for regular water injection, without affecting the normal water injection needs of the tubing string, thus providing good emergency response capability. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the pulsating water injection tool;

[0024] Figure 2 This is a schematic diagram of the hollow integrated injection tubing column;

[0025] Figure 3 This is a schematic diagram of the amplitude adjustment mechanism;

[0026] In the diagram: 1. Salvage head; 2. Sealing ball; 3. Second elastic element; 4. Nozzle; 5. First elastic element; 6. Water nozzle; 7. Secondary piston; 8. Main piston; 9. Limiting cylinder; 10. Amplitude adjustment mechanism; 110. Christmas tree; 120. Tubing hanger; 130. Sliding sleeve; 140. Tubing; 150. Positioning seal; 160. Packer; 170. Water injection working cylinder; 180. Pulsating water injection tool; 190. Blind plug; 210. Motor; 220. Main control circuit; 230. Battery; 310. Signal sensing module; 320. Action module. Detailed Implementation

[0027] The technical solution of the present invention will be further described below through specific embodiments.

[0028] Example 1

[0029] like Figure 1-3 As shown, a pulsating water injection tool based on a hollow integrated process stationary tubing in offshore oilfields includes a hollow integrated sub-injection process tubing, a water injection working cylinder 170, and a pulsating water injection tool 180. The hollow integrated sub-injection process tubing is provided with one or more water injection working cylinders 170. A water nozzle 6 is provided on the side wall of the water injection working cylinder 170. The pulsating water injection tool 180 is detachably installed inside the water injection working cylinder 170. The pulsating water injection tool 180 is provided with a nozzle 4. The pulsating water injection tool 180 is provided with an amplitude adjustment mechanism 10 to control the pulsating pressurization of water flow into the water injection working cylinder 170.

[0030] The pulsating water injection tool 180 is equipped with a main piston 8, a secondary piston 7, and an amplitude adjustment mechanism 10. The main piston 8 has a water inlet passage that is connected to a water source. The main piston 8 and the secondary piston 7 are movably connected to an adjustment rod inside the sleeve of the pulsating water injection tool 180. The adjustment rod at the top of the secondary piston 7 is equipped with a first elastic element 5. The bottom end of the secondary piston 7 is sealed to the water inlet passage on the main piston 8. The main piston 8 is connected to the amplitude adjustment mechanism 10.

[0031] The adjusting rod is a fixed column, and the main piston 8 and the auxiliary piston 7 are nested on the fixed column.

[0032] In this embodiment, water is introduced via a main piston 8. The position of the main piston 8 is adjusted by an amplitude adjustment mechanism 10 to coordinate with the auxiliary piston 7, achieving pulsating water injection. The main piston 8 is connected to the adjusting rod via a threaded connection. A motor 220 drives an action module 320 to move the main piston 8 axially up and down. The auxiliary piston 7 is sleeved onto the adjusting rod, and its engagement with the main piston is achieved through stress provided by a first elastic element 5. The first elastic element 5 is a rectangular compression spring.

[0033] The amplitude of the pulsating water injection tool 180 is determined by the distance between the main piston 8 and the limited position. The farther the main piston 8 is from the limited position, the larger the amplitude. The main piston 8 moves axially up and down on the adjusting rod through a threaded connection to adjust the amplitude. The action module 320 is connected to the adjusting rod. The motor 220 drives the action module 320 to make the main piston 8 move axially on the adjusting rod. The pulsating amplitude is adjusted by the change in the position of the main piston 8.

[0034] Example 2

[0035] Based on Embodiment 1, a retrieval head 1 is provided to better coordinate with the steel wire for retrieval and setup. In this embodiment, the pulsating water injection tool adopts a cylindrical structure, and to facilitate setup and reduce interference, the retrieval head 1 is located at the opposite end of the main piston 8.

[0036] Example 3

[0037] Based on Embodiments 1 and 2, in order to enable the main piston 8 to move more smoothly and reduce interference, a limiting cylinder 9 is provided on the main piston 8. The outer diameter of the limiting cylinder 9 is larger than the outer diameter of the first opening. Through the cooperation with the limiting cylinder 9, the main piston 8 can move back and forth more smoothly.

[0038] Example 4

[0039] Based on the above embodiments, to avoid the problem of water flow not being able to be discharged and affecting normal production due to the main piston 8 getting stuck or unable to move, the top of the pulsating water injection tool 180 is provided with a second opening. The outer opening of the second opening is connected to the water inlet end of the water inlet passage of the main piston 8. The inner opening of the second opening is provided with a sealing ball 2, which is movably mounted on an adjusting rod. The adjusting rod is provided with a second elastic element 3 to push the sealing ball 2 against the inner opening of the second opening.

[0040] In this embodiment, the second opening is connected to the main piston 8 via a bridge structure, and the sealing ball 2 is made of steel. Pressure is provided by the second elastic element 3, which in this embodiment is a compression spring. When the pressure in the water inlet passage of the main piston 8 exceeds a set value, the sealing ball 2 is pushed open from the outside, and water flows from the second opening into the tool cavity and is sprayed into the water injection working cylinder 170 by the nozzle 4, and then sprayed into the bottom layer by the nozzle 4 for normal water injection.

[0041] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A water injection tool based on the hollow integrated process for offshore oilfields with stationary tubing, characterized in that: The system includes a hollow integrated sub-injection process tubing, a water injection working cylinder, and a pulsating water injection tool. The hollow integrated sub-injection process tubing is equipped with one or more water injection working cylinders. Water nozzles are provided on the side walls of the water injection working cylinders. A pulsating water injection tool is detachably installed inside the water injection working cylinders. The pulsating water injection tool is equipped with a nozzle and has an amplitude adjustment mechanism inside to control the pulsating pressurization of water flow into the water injection working cylinders. The pulsating water injection tool is equipped with a main piston, a secondary piston, and an amplitude adjustment mechanism. The main piston has a water inlet passage that is connected to a water source. The main piston and the secondary piston are movably mounted on an adjustment rod inside the sleeve of the pulsating water injection tool. The adjustment rod at the top of the secondary piston is equipped with a first elastic element. The bottom end of the secondary piston is sealed and matched with the water inlet passage on the main piston. The main piston is connected to the amplitude adjustment mechanism. The amplitude adjustment mechanism is equipped with a main control circuit, a battery and a motor. The battery provides power to the main control circuit and the motor. The main control circuit includes a signal sensing module and an action module. The signal sensing module is used to receive action signals in the form of pressure waves and transmit the information to the action module. The main piston (8) is connected to the adjustment rod by a thread. The action module (320) is connected to the adjustment rod. The motor drives the action module to move and change the position of the main piston to adjust the pulsation amplitude.

2. The water injection tool based on the hollow integrated process for offshore oilfields with stationary tubing and pulsating injection as described in claim 1, characterized in that: The adjusting rod is a fixed column, and the main piston and the auxiliary piston are nested on the fixed column.

3. The water injection tool based on the hollow integrated process for offshore oilfields with stationary tubing and pulsating injection as described in claim 2, characterized in that: The pulsating water injection tool is a sealed cylinder, which includes a top end and a bottom end. The top end of the cylinder is provided with a retrieval head, and the bottom end of the cylinder is provided with a first opening. The main piston is matched with the first opening.

4. The pulsating water injection tool based on the hollow integrated process for offshore oilfields with stationary tubing as described in claim 3, characterized in that: The main piston is provided with a limiting cylinder, the outer diameter of which is larger than the outer diameter of the first opening.

5. The pulsating water injection tool based on the hollow integrated process for offshore oilfields with stationary tubing as described in claim 3, characterized in that: The top of the pulsating water injection tool is provided with a second opening. The outer opening of the second opening is connected to the water inlet end of the main piston water inlet passage. The inner opening of the second opening is provided with a sealing ball. The sealing ball is movably mounted on the adjusting rod. The adjusting rod is provided with a second elastic element to push the sealing ball against the inner opening of the second opening.

6. The water injection tool based on the hollow integrated process for offshore oilfields with stationary tubing and pulsating injection as described in claim 1, characterized in that: The water injection working cylinder is equipped with a built-in retrieving core.

7. The pulsating water injection tool based on the hollow integrated process for offshore oilfields using stationary tubing, as described in any one of claims 1-6, is characterized in that: The hollow integrated sub-injection process string includes a Christmas tree, tubing hanger, tubing, sliding sleeve, positioning seal, packer, water injection working cylinder, pulsating water injection tool, and blind plug. The Christmas tree is equipped with a tubing hanger, the tubing hanger is equipped with tubing, the tubing hanger is equipped with tubing, the tubing is equipped with a sliding sleeve, the tubing is sealed to the packer at the top, the positioning seal is connected to the packer at the top, the water injection working cylinder is set in the packer at a preset layer to form a seal, and the bottom end of the tubing string is connected to the blind plug to form the hollow integrated sub-injection process string.

8. A method for using a stationary tubing pulsating water injection tool based on the hollow integrated process for offshore oilfields, for use with the stationary tubing pulsating water injection tool as described in any one of claims 1-7, characterized in that... The specific steps are as follows: S1. Amplitude Adjustment: Different pressure wave signals are used to adjust the pulsating water injection tool installed in the water injection working cylinder at a designated layer. Commands are sent to the amplitude adjustment mechanism inside the pulsating water injection tool at different layers through a specific pressure wave signal. The amplitude adjustment mechanism adjusts the amplitude based on the received signal; S2. The pulsating water injection tool pressurizes. In the initial state, the main piston presses against the auxiliary piston to close the water inlet passage and achieve a seal. The water pressure in the cavity of the pulsating water injection tool gradually increases due to the closure of the water injection channel, creating a pressure difference between the two chambers of the main piston. When the pressure difference increases to the point that it can balance the pressure applied by the elastic element, the elastic element is compressed, and the water flow in the main piston pushes the auxiliary piston upward. S3. The pulsating water injection tool oscillates and injects water. When the main piston moves to the limited position of the limiting cylinder, the main piston stops moving. The water flow in the cavity pushes the auxiliary piston to continue moving upward, creating a gap between the auxiliary piston and the main piston. The two ends of the water inlet passage of the main piston are connected. High-pressure water is injected into the formation through the nozzle in an oscillating manner. When the pressure in the two chambers of the main piston reaches equilibrium, the auxiliary piston moves back under the compressive force of the elastic element. The auxiliary piston resets and contacts the end of the water inlet passage of the main piston again to seal the two chambers. The above reciprocating motion between the auxiliary piston and the main piston is repeated, periodically forming pressure rise and oscillating water injection, thus realizing the periodic pulsating water injection of the water injection well.

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