Novel two-stroke type gravel layered filling device

Abstract

The invention designs a novel two-stroke type gravel layered filling device, and relates to the technical field of oil exploitation downhole tools. The device comprises a double-piston driving hydraulic compensation cavity, a phase compensation piston assembly, a spring pre-tightening type two-way locking bolt set and a composite drainage system. The double-piston-driven hydraulic compensation chamber realizes reciprocating switching of filling / drainage actions through a reciprocating gear, and a built-in synchronous piston accurately controls the displacement through a stroke limiting regulator. The phase compensation piston assembly is integrated with an infrared positioning instrument to monitor the thickness of a filling layer in real time, and a plunger type pressure balancing valve is linked to dynamically adjust the sectional area of a water flow slideway. The first filling sliding sleeve and the second filling sliding sleeve are alternately locked through a spring pre-tightening mechanism and are matched with a parallel water path formed by the sand control screen pipe and the built-in drainage pipe to achieve layered operation. The stirring turbine fan generates rotational flow to prevent gravel deposition, and the stroke buffer device cooperates with the composite drainage channel to improve the stability of the system.

Description

Technical Field

[0001] The invention relates to the technical field of downhole tools for oil production, and in particular to a novel two-stroke gravel layered filling device. Background Art

[0002] In the gravel filling operation in the field of oil extraction, conventional filling devices generally use a single piston drive with a fixed sleeve structure for layered construction. Such devices usually rely on a one-way hydraulic cylinder to provide power, and switch the filling channel through a mechanical connecting rod. Its stroke motion trajectory is limited by the piston stroke and the gear transmission ratio, and a single operation can only complete the filling operation of a single layer. Due to the lack of a multi-stroke linkage mechanism, the equipment needs to be frequently reset and restarted during the operation, resulting in less than 40% of the effective working time, which seriously restricts the completion efficiency of deep oil and gas wells. More importantly, the layered control of the traditional device mainly relies on the preset mechanical limit device, which cannot perceive the actual formation state of the gravel filling layer in the well in real time. When encountering a sudden change in formation permeability or a fluctuation in the rheology of the filling mortar, it is very easy to have problems such as layer dislocation and uneven thickness. The measured data show that the layering error of conventional devices generally exceeds ±15mm, resulting in an invalid filling area between the sand screen and the formation, which directly affects the effective period of sand control in oil and gas wells.

[0003] In addition, the drainage system of existing filling devices mostly adopts a single-channel open design. The return water generated during the filling process is directly discharged through the gaps in the screen tube, lacking an effective solid phase separation and pressure regulation mechanism. In long-term operations, fine sand particles with a particle size of less than 0.3 mm are prone to accumulate on the inner wall of the drainage channel, forming a dense filter cake that blocks the flow channel. According to on-site statistics from the oil field, the drainage efficiency of the traditional device can drop by more than 60% after 8 hours of continuous operation, forcing the operator to interrupt the construction for manual well cleaning. What is more serious is that there is physical interference between the conventional drainage path and the filling channel. When the drainage flow rate exceeds 2m / s, a negative pressure siphon effect will occur, resulting in local backflow damage to the filled gravel layer. This phenomenon occurs as high as 32% in inclined well operations. Although some improved devices have tried to add auxiliary flushing pipelines, the failure to establish an intelligent control system that links pressure compensation with flow often leads to a surge in energy consumption in the hydraulic system, which in turn exacerbates the instability of equipment operation.

[0004] In response to the above-mentioned technical pain points, the industry has proposed a variety of solutions, such as using electro-hydraulic proportional valves to control the filling pressure and adding ultrasonic thickness gauges to improve stratification accuracy, but these improvement plans often have new problems such as high system complexity and poor downhole adaptability. Taking a certain type of electronically controlled filling device as an example, although it improves the stratification accuracy to ±8mm, the failure rate of electronic components under high temperature and high pressure well conditions exceeds 25%, and additional ground control cabinets and data cables are required, which greatly increases operating costs and operational risks. Therefore, how to achieve high-efficiency and high-precision stratified filling while ensuring the reliability of the device, and at the same time build an intelligent drainage system with self-cleaning capabilities, has always been the core problem restricting the development of gravel filling technology. Therefore, it is necessary to design a new two-stroke gravel stratified filling device. Summary of the invention

[0005] In order to improve the sand prevention ability and operation efficiency during the gravel filling process, the technical problem to be solved by the present invention is to provide a new type of two-stroke layered filling device and method. The hydraulic compensation chamber is driven by a double piston to provide a two-way power output. The phase compensation piston assembly dynamically adjusts the opening of the plunger pressure equalization valve according to the real-time layer thickness detection data of the infrared locator; the spring pre-tightened two-way locking bolt group alternately locks the first filling sleeve and the second filling sleeve, so that the water flow slideway is docked with the target filling layer in turn; the stirring turbine fan generates a 1500rpm vortex field during the filling process to prevent gravel deposition, and the built-in drainage pipe and sand prevention screen pipe form a composite drainage channel.

[0006] After filling is completed, the stroke buffer device cooperates with the limit adjuster to return the double pistons to the middle position, and the spring preload mechanism re-locks the sliding sleeve to reset the device status and prepare for the next operation cycle.

[0007] The technical solution provided by the present invention is: A novel two-stroke gravel layered filling device comprises a double-piston driven hydraulic compensation chamber, a compression chamber fixing bracket, a spring preloaded two-way locking bolt group, a reciprocating gear, a plunger pressure equalizing valve, a stroke buffer device, a stroke limit regulator, a water flow slide, a stirring turbine fan, a first drainage sleeve, a second filling sleeve, a built-in drainage pipe, a second drainage sleeve, a drainage head, a sand control screen pipe, a phase compensation piston assembly, an infrared locator and a first filling sleeve.

[0008] The double-piston driven hydraulic compensation chamber is connected to the spring preloaded two-way locking bolt group through the compression chamber fixing bracket, and its bottom is meshed with the reciprocating gear. The plunger pressure equalization valve runs through the water flow slide and is connected to the phase compensation piston assembly. The stirring turbine fan is symmetrically distributed on both sides of the water flow slide. The sand screen forms a parallel waterway with the first drainage sleeve and the second drainage sleeve through the built-in drainage pipe. The infrared locator is integrated at the end of the phase compensation piston assembly. The double-piston driven hydraulic compensation chamber is equipped with a two-way synchronous piston. The piston rod controls the displacement through the stroke limit regulator and forms a transmission pair with the reciprocating gear to realize the reciprocating switching of the filling / draining action. The first filling sleeve and the second filling sleeve are alternately locked by the spring preloaded two-way locking bolt group. The opening and closing state is triggered by the displacement of the phase compensation piston assembly, and an adjustable throttle valve is provided between the sand screen and the built-in drainage pipe. The first filling sleeve and the second filling sleeve are alternately locked by a spring pre-tightened two-way locking bolt group, and their opening and closing states are triggered by the displacement of the phase compensation piston assembly, and an adjustable throttle valve is provided between the sand control screen pipe and the built-in drainage pipe.

[0009] A novel two-stroke gravel layered filling device, the method comprises the following steps: The reciprocating gear drives the double piston to drive the left piston of the hydraulic compensation chamber to advance, and transmits the axial thrust through the compression chamber fixed bracket.

[0010] The displacement of the left piston is controlled by the stroke limit regulator, which pushes the first filling sleeve to align with the upper opening of the sand screen pipe. The filling mortar is injected into the target layer through the water flow slide, and the stirring turbine fan is started synchronously to prevent gravel deposition. After the infrared locator detects that the filling thickness meets the standard, the spring-preloaded two-way locking bolt group releases the first filling sleeve, and the built-in drainage pipe and the second drainage sleeve form a composite drainage channel to implement drainage. The reciprocating gear rotates in the opposite direction to drive the right piston to push the second filling sleeve to the middle opening of the sand screen pipe.

[0011] When the phase compensation piston assembly detects abnormal pressure, the plunger pressure equalizing valve forces the first filling channel to close, and the phase compensation piston assembly directly pushes the second filling sleeve to establish an independent filling path. The built-in drain pipe simultaneously opens the auxiliary drainage function, and the lateral holes of the sand control screen maintain the main drainage path. After the filling is completed, the stroke buffer device absorbs the residual kinetic energy, and the spring preload mechanism re-locks the sleeve position.

[0012] After adopting the above technical scheme, the patent of the present invention has the following beneficial effects: the present invention is a new type of two-stroke gravel layered filling device and method, which drives the first filling sleeve and the second filling sleeve to accurately align with the layered opening of the sand control screen through the coordinated control of the double-piston driven hydraulic compensation chamber and the phase compensation piston assembly; the discharged water forms a dual-channel drainage system through the built-in drainage pipe and the second drainage sleeve, and the plunger-type pressure equalizing valve dynamically adjusts the fluid pressure; after the filling is completed, the stroke buffer device cooperates with the spring-preloaded two-way locking bolt group to realize the reset of the device, providing a stable foundation for continuous operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0014] In the figure, 1. double-piston driven hydraulic compensation chamber, 2. compression chamber fixing bracket, 3. spring pre-tightened two-way locking bolt group, 4. reciprocating gear, 5. plunger type pressure equalizing valve, 6. stroke buffer device, 7. stroke limit regulator, 8. water flow slide, 9. stirring turbine fan, 10. first drainage sleeve, 11. second filling sleeve, 12. built-in drainage pipe, 13. second drainage sleeve, 14. drainage head, 15. sand control screen, 16. phase compensation piston assembly, 17. infrared locator, 18. first filling sleeve. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings: The present invention comprises a double-piston driven hydraulic compensation chamber 1, a compression chamber fixing bracket 2, a spring pre-tightened bidirectional locking bolt group 3, a reciprocating gear 4, a plunger pressure equalizing valve 5, a stroke buffer device 6, a stroke limit regulator 7, a water flow slide 8, a stirring turbine fan 9, a first drainage sleeve 10, a second filling sleeve 11, a built-in drainage pipe 12, a second drainage sleeve 13, a drainage head 14, a sand control screen 15, a phase compensation piston assembly 16, an infrared locator 17, and a first filling sleeve 18. Combination Figure 1As shown, a new type of two-stroke gravel layered filling device has a double piston driven hydraulic compensation chamber 1 fixed vertically by a compression chamber fixing bracket 2, and its internal bidirectional piston is in the axial middle position; the spring preloaded bidirectional locking bolt group 3 locks the first filling sleeve 18 at the upper opening position of the sand screen 15, and the phase compensation piston assembly 16 and the infrared locator 17 form a closed-loop monitoring system. The plunger pressure equalizing valve 5 forms a pressure buffer system with the stroke buffer device 6 in the water flow slide 8. The reciprocating gear 4 receives the external motor drive to drive the left piston of the double piston driven hydraulic compensation chamber 1 to move to the outside of the wellbore, and the displacement of the left piston is monitored in real time by the stroke limit regulator 7. The filling mortar enters the first filling sleeve 18 through the water flow slide 8, and the stirring turbine fan 9 rotates to break the material agglomeration; the phase compensation piston assembly 16 dynamically adjusts the plunger pressure equalizing valve according to the filling layer density data fed back by the infrared locator 17. The built-in drainage pipe 15 maintains a 10% flow area during the filling process to prevent hydraulic shock from damaging the sand screen 15. The second drainage sleeve 13 is in a normally closed state and is sealed by the drainage head 14. The first drainage sleeve 10 is opened, and the water flow carries impurities and is discharged laterally through the sand screen 15. The flow area of ​​the built-in drainage pipe 12 is expanded, and the second drainage sleeve 13 is opened synchronously to form a siphon effect.

[0016] The reciprocating gear 4 rotates in the opposite direction, driving the right piston of the double piston driving hydraulic compensation chamber 1 to push the second filling sleeve 11. The stroke buffer device 6 absorbs the kinetic energy of the piston reversing impact.

[0017] The characteristics and advantages of the novel two-stroke gravel layered filling device of the present invention are: 1. Highly integrated process: Simply start the dual-piston driven hydraulic compensation chamber to automatically complete the entire process of filling-draining-resetting through the phase compensation piston assembly without manual segmented operation.

[0018] 2. Flexible mode switching: The device can fill the sand screen layer by layer according to its hierarchical structure, or directly drive the second filling sleeve of the target layer through the transmission push rod to achieve precise operation at a specific layer.

[0019] 3. Energy recycling: The hydraulic energy of the filling fluid provides the main driving force for the reciprocating gears. The water flow pressure in the drainage stage is converted into auxiliary power through the plunger-type pressure equalizing valve. The dual energy synergistically improves operating efficiency.

[0020] 4. Operation cycle optimization: The dual-piston alternating working mode and the composite drainage channel operate in parallel, and the single filling-drainage cycle is shortened by 50% compared with the traditional process, significantly reducing manpower and equipment investment.

Claims

1. A novel two-stroke gravel layered filling device, comprising a double-piston driven hydraulic compensation chamber (1), a compression chamber fixing bracket (2), a spring preloaded two-way locking bolt group (3), a reciprocating gear (4), a plunger pressure equalizing valve (5), a stroke buffer device (6), a stroke limit regulator (7), a water flow slide (8), a stirring turbine fan (9), a first drainage sleeve (10), a second filling sleeve (11), a built-in drainage pipe (12), a second drainage sleeve (13), a drainage head (14), a sand control screen (15), a phase compensation piston assembly (16), an infrared locator (17) and a first filling sleeve (18); characterized in that: The dual-piston driven hydraulic compensation chamber (1) is connected to a spring preloaded bidirectional locking bolt group (3) through a compression chamber fixing bracket (2), and its bottom is meshed with a reciprocating gear (4). The plunger type pressure equalizing valve (5) passes through the water flow slide (8) and is connected to the phase compensation piston assembly (16). The stirring turbine fan (9) is symmetrically distributed on both sides of the water flow slide (8). The first filling sleeve (18) is located on the upper side of the first drainage sleeve (10). The sand control screen pipe (15) forms a parallel waterway with the first drainage sleeve (10) and the second drainage sleeve (13) through a built-in drainage pipe (12). The infrared locator (17) is integrated at the end of the phase compensation piston assembly (16).

2. A novel two-stroke gravel layer filling device according to claim 1, characterized in that: The dual-piston driven hydraulic compensation chamber (1) has a built-in bidirectional synchronous piston, the displacement of which is controlled by a stroke limit regulator (7) and forms a transmission pair with the reciprocating gear (4) to achieve reciprocating switching of the filling / draining action.

3. A novel two-stroke gravel layer filling device according to claim 1, characterized in that: The first filling sleeve and the second filling sleeve (11) are alternately locked by a spring pre-tightened two-way locking bolt group (3), and their open and closed states are triggered by the displacement of the phase compensation piston assembly (16), and an adjustable throttle valve is provided between the sand control screen pipe (15) and the built-in drainage pipe (12).

4. A novel two-stroke gravel layered filling device according to claim 1, characterized in that: The phase compensation piston assembly (16) comprises a pressure feedback module, which monitors the thickness of the filling layer in real time through an infrared locator (17) and links the plunger-type pressure equalizing valve (5) to adjust the flow cross-sectional area of ​​the water flow slide (8).

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