Hydraulic slotting device and plug removal slotting method

Abstract

The invention discloses a hydraulic slotting device and a plug removal slotting method, and relates to the technical field of oil exploitation, the hydraulic slotting device comprises an out-well water supply unit and an in-well water supply unit, and the in-well water supply unit comprises an oil pipe connector, a centralizer, a data collector used for positioning position information and a perforating gun which are connected in sequence; the inner cavities of the oil pipe connector, the centralizer and the data collector are communicated to form a water supply channel for supplying water to the perforating gun; according to the method, blockage removal of the blocked position is achieved in the mode that water flow is sprayed out of the perforating gun, a sleeve and a cement sheath can be better protected, a water layer is prevented from being sprayed by mistake, the applicability in an oil well is high, the method is suitable for an extremely deep well or a super-hard stratum, the application range is wide, meanwhile, self-cleaning in a seam can be achieved, and no compacted zone exists; in addition, through the centralizing effect of the centralizer and the positioning effect of the data collector, the position of the perforating gun can be more accurately positioned, and the hydraulic slotting accuracy is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil extraction, in particular to a hydraulic cutting device and a cutting method for unblocking. Background Art

[0002] During the construction process, oil wells often experience near-well pollution blockage. After near-well pollution blockage, the formation energy cannot be effectively released, and the problem of insufficient fluid supply in a single well will occur. At this time, it is necessary to carry out reservoir unblocking to improve the fluid supply capacity. At present, shaped energy perforating bullets are commonly used to perforate near-well pollution to achieve unblocking, improve the stress around the well, increase the oil leakage area, and improve the permeability of the near-well zone. However, the following problems were found during the operation: 1. When the metal jet generated by conventional perforation passes through the casing, it will cause serious damage to the casing, reduce the production capacity of the perforated well, and greatly reduce the service life of the casing; 2. The manufacturing cost and technical complexity of shaped energy perforating bullets and their supporting equipment are high. Although shaped energy perforating has good penetration, the energy attenuation of the jet may affect the penetration effect in extremely deep wells or ultra-hard formations, limiting its application range; 3. There is a perforation depth error in the perforation of shaped energy perforating bullets, which affects the perforation degree of the oil layer, and even misfires the water layer, causing oil well flooding and damaging oilfield development.

[0003] Therefore, people are in urgent need of a hydraulic cutting device with wide application range and strong applicability. Summary of the invention

[0004] The purpose of the present invention is to provide a hydraulic cutting device and a cutting method for unblocking, so as to solve the problems existing in the above-mentioned prior art. The unblocking is completed by hydraulic cutting, which can reduce the damage to the casing and facilitate the control of the hydraulic cutting strength. The invention has strong applicability and a wide range of applications.

[0005] To achieve the above-mentioned purpose, the present invention provides the following scheme: The present invention provides a hydraulic cutting device, including an off-hole water supply unit and an in-hole water supply unit, the in-hole liquid supply unit includes an oil pipe connector, a centralizer, a data collector for positioning position information and a perforating gun connected in sequence, the oil pipe connector, the centralizer and the data collector are all hollow, the inner cavities of the oil pipe connector, the centralizer and the data collector are connected to form a water supply channel, one end of the water supply channel is connected to the off-hole water supply unit, and the other end is connected to the water inlet of the perforating gun.

[0006] Preferably, a blowout-prevention check valve is provided between the oil pipe connector and the centralizer, and a flow channel of the blowout-prevention check valve is connected to the water supply channel.

[0007] Preferably, a safety release handle is provided between the blowout-prevention check valve and the centralizer, and an inner cavity of the safety release handle is communicated with the water supply channel.

[0008] Preferably, a power assembly for providing power for water flow is provided between the perforating gun and the data collector. Preferably, a bridge plug setting tool and a bridge plug are sequentially connected to one end of the perforating gun away from the data collector.

[0009] Preferably, along the water supply direction of the water supply channel, the data collector is sequentially connected to a plurality of the perforating guns.

[0010] Preferably, the data collector includes a locator for acquiring position information, a pressure sensor for acquiring target layer pressure information, a signal sending unit for sending the acquired information to a remote terminal, and a battery pack; the locator, the pressure sensor and the signal sending unit are all electrically connected to the battery pack.

[0011] Preferably, the off-hole water supply unit includes a pump truck, a sand mixing skid, a water tank and ground data processing and monitoring equipment. The sand mixing skid and the water tank are connected to the oil pipe connector through the pump truck and the oil pipe, and the ground data processing and monitoring equipment is remotely connected to the data acquisition device via electrical signals.

[0012] Preferably, the off-hole water supply unit further comprises a sand adding tank, and the sand adding tank is connected to the feed port of the sand mixing skid.

[0013] The present invention also provides a method for unblocking and cutting seams using the hydraulic cutting device, comprising the following steps:

[0014] S1: Connect the water supply unit above the well and the water delivery unit below the well;

[0015] S2: Lower the downhole water supply unit to the position to be unblocked, and the data collector locates the current position;

[0016] S3: According to the position information located in step S2, the position of the downhole water supply unit is adjusted so that the perforating gun is directly at the position to be unblocked;

[0017] S4: Start the water supply unit on the well and start the hydraulic cutting operation.

[0018] Compared with the prior art, the present invention mainly achieves the following technical effects:

[0019] The blockage is unblocked by spraying water from the perforating gun. The slow and uniform cutting can better protect the casing and cement ring than the explosive cutting of the focused energy perforating, and the cutting strength can be controlled by controlling the water pressure to avoid mis-shooting of the water layer. It has strong applicability in oil wells and is suitable for extremely deep wells or ultra-hard formations, with a wide range of applications. During the hydraulic cutting process, debris and pollutants are returned to the ground, and the seam is self-cleaning and has no compaction zone. Compared with the oil leakage area generated by the focused energy perforating, the risk of bottom water intrusion is reduced in small well sections. For side drilling wells, deep penetration can be achieved in small wellbores to open the oil and gas layers and fully release the formation energy. In addition, the position of the perforating gun can be more accurately located through the straightening effect of the straightener and the positioning effect of the data collector, thereby improving the accuracy of the hydraulic cutting. Compared with the traditional process of fracturing after focused energy perforating, the hydraulic cutting method has a short overall operation cycle, less equipment investment, and lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 An exploded view of a downhole water delivery unit in an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of water flow during the hole formation process of the present invention;

[0023] Among them, 1. tubing connector; 2. blowout prevention check valve; 3. safety release; 4. stabilizer; 5. data collector; 6. power assembly; 7. perforating gun; 8. bridge plug setting tool; 9. bridge plug; 10. nozzle; 11. casing; 12. cement ring; 13. rock; 14. hole; 15. abrasive jet; 16. return fluid. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The purpose of the present invention is to provide a hydraulic cutting device and a cutting method for unblocking, so as to solve the problems existing in the prior art. The unblocking is completed by hydraulic cutting, which can reduce the damage to the casing and facilitate the control of the hydraulic cutting strength. The invention has strong applicability and a wide range of applications.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Please refer to Figure 1 , Figure 2 As shown, a hydraulic cutting device is provided, including an off-hole water supply unit and an in-hole water supply unit, the in-hole liquid supply unit includes a tubing connector 1, a centralizer 4, a data collector 5 for positioning position information and a perforating gun 7 which are connected in sequence, the tubing connector 1, the centralizer 4 and the data collector 5 are all hollow, the inner cavities of the tubing connector 1, the centralizer 4 and the data collector 5 are connected to form a water supply channel, the tubing connector 1 at one end of the water supply channel is connected to the off-hole water supply unit through the tubing, and the other end is connected to the water inlet of the perforating gun 7, the nozzle 10 of the perforating gun 7 is arranged radially toward the water supply channel to spray toward the blocked position; in this device, the blocked position is unblocked by spraying water from the perforating gun 7, and the slow and uniform cutting can better protect the casing 11 and the cement ring 12 compared with the explosive cutting of the energy-gathering perforating, and will not cause damage to the casing 11 and the cement ring 12 due to the explosive impact, and can be The water pressure is controlled to control the cutting strength, and then the cutting depth, to avoid mis-shooting of water layers. Compared with energy-gathering perforating, it has stronger applicability in oil wells and is suitable for extremely deep wells or super-hard formations, with a wide range of applications. Hydraulic cutting has other advantages: during hydraulic cutting, the movement of water flow will discharge debris and pollutants out of the cutting and return them to the ground through the oil well, so that the seam is self-cleaned without a compaction zone, avoiding affecting the oil output. Compared with energy-gathering perforating, the oil leakage area generated by hydraulic cutting is larger, and the risk of bottom water intrusion is reduced in small well sections. For side drilling wells, deep penetration can be achieved in small wellbores to open oil and gas layers and fully release formation energy. In addition, through the straightening effect of the straightener 4 and the positioning effect of the data collector 5, the position of the perforating gun 7 can be more accurately positioned, thereby improving the accuracy of hydraulic cutting. Compared with the traditional process of fracturing after energy-gathering perforating, the hydraulic cutting method has a short overall operation cycle, less equipment investment, and lower cost.

[0028] The principle of self-cleaning is as follows: the abrasive jet 15 ejected from the nozzle 10 of the perforating gun 7 cuts the casing 11, cement ring 12 and rock 13 in sequence, and forms a hole 14 in the rock 13 that first gradually expands and then gradually shrinks. The abrasive jet 15 returns at the end of the hole 14 and flows out of the hole 14 to form a return fluid 16, and the return fluid 16 is discharged back to the ground from the wellhead of the oil well.

[0029] The stabilizer 4 uses elastic legs or rigid legs on its outer side. The elastic legs are generally made of spring steel, and the rigid legs are generally made of hard plastic. The legs contact the well wall to generate a reaction force, forcing the downhole water supply unit to maintain the center position of the wellbore. In this embodiment, the legs are elastic legs, which rely on their own elasticity to adapt to the irregular shape of the wellbore and provide sufficient supporting force.

[0030] A blowout preventer check valve 2 is provided between the tubing connector 1 and the centralizer 4. The flow channel of the blowout preventer check valve 2 is connected to the water supply channel. It is used to prevent the formation pressure from pushing the well fluid to spray upward along the drill string water hole when the formation pressure exceeds the well fluid column pressure. It is used to close the water supply channel to prevent internal blowout. In this embodiment, a blowout preventer is provided at the inlet of the oil well for use with the blowout preventer check valve 2.

[0031] Since the underground environment is unpredictable, a safety release 3 is provided between the blowout preventer check valve 2 and the centralizer 4. The inner cavity of the safety release 3 is connected with the water supply channel. The safety release 3 can be mechanically, hydraulically or electrically controlled. When encountering abnormally high pressure, drill stuck, etc., it allows the upper equipment to quickly and safely detach from the underground operating part to avoid equipment damage or well control accidents and ensure operation safety.

[0032] In order to provide power for hydraulic cutting and ensure that the cutting operation is completed, a power assembly 6 for providing power for water flow is arranged between the perforating gun 7 and the data collector 5. The power assembly 6 selected in this embodiment can refer to the hydraulic power assembly in patent CN112127837A.

[0033] In this embodiment, a bridge plug setting tool 8 and a bridge plug 9 are sequentially connected to the end of the perforating gun 7 away from the data collector 5, which are used to seal the formation or pipeline below the slot position to prevent oil leakage from the area. Since the thickness of the blocking layer is different in different blocking environments, for a thicker blocking layer, a data collector 5 can be sequentially connected to multiple perforating guns 7 along the water supply direction of the water supply channel, and the number of perforating guns 7 is determined according to actual needs.

[0034] The data collector 5 includes a locator for acquiring position information, a pressure sensor for acquiring target layer pressure information, a signal sending unit, and a battery pack. The locator, the pressure sensor, and the signal sending unit are all electrically connected to the battery pack. The locator is used to acquire position information, the pressure sensor is used to acquire pressure information of the underground target layer, and the information sending unit is used to send the acquired information to a remote terminal.

[0035] In this embodiment, the locator is a magnetic locator, which is used to determine the precise position and direction of the drilling tool in the well and obtain position information. It has a built-in high-sensitivity magnetic sensor that can detect the direction and strength of the earth's magnetic field; wherein the magnetic sensor can be a magnetoresistive sensor or a fluxgate sensor. By measuring the magnetic field components in three dimensions (north component, east component and vertical downward component), the inclination angle (i.e., well inclination angle) and tool face angle (i.e., magnetic azimuth angle) of the drilling tool in space are determined, so as to achieve the positioning of the position, and the position information collected by the locator includes well inclination angle and tool face angle. Well inclination angle refers to the angle at which the drilling tool deviates from the vertical direction, and tool face angle is the deviation angle of the drilling tool from the true north direction. In a specific example, the raw magnetic field data collected by the locator is converted into actual well inclination and azimuth information through algorithm analysis. This algorithm analysis process includes correcting the local magnetic field interference, that is, correcting the actually measured magnetic field data to obtain the magnetic field data with interference removed (including the actual well inclination angle and tool face angle after filtering) to improve the measurement accuracy.

[0036] The off-hole water supply unit includes a pump truck, a sand mixing skid, a water tank and ground data processing and monitoring equipment. The sand mixing skid and the water tank are connected to the oil pipe and the oil pipe connector 1 through the pump truck and the oil pipe. The ground data processing and monitoring equipment is remotely connected to the data collector 5 by electrical signals. During the hydraulic cutting operation, the water in the water pipe is transported to the well through the pump truck. The pump truck provides the necessary liquid pressure for the cutting operation. The sand mixing skid is used to work in coordination with the pump truck. After the hydraulic cutting is completed, the sand-carrying liquid mixed with a certain amount of sand in the sand mixing skid is supplied to the hole 14 position through the pump truck to support the oil layer and optimize the oil production effect after perforation.

[0037] In order to realize the continuous supply of the sand mixing skid, an additional sand adding tank is provided, which is connected with the feeding port of the sand mixing skid and is used for storing and preliminarily mixing the proppant and the sand. The proppant is a common material, such as ceramsite proppant: bauxite is used as the raw material, and the powder is granulated and sintered into spherical particles.

[0038] The present invention also provides a method for unblocking and cutting seams using the hydraulic cutting device, comprising the following steps:

[0039] S1: Connect the water supply unit on the well and the water delivery unit downhole. Specifically, connect the output port of the pump truck to one end of the oil pipe, and connect the other end of the oil pipe to the oil pipe connector 1 of the downhole water delivery unit;

[0040] S2: Lower the downhole water delivery unit below the position to be unblocked, and the data collector 5 locates the current position. Specifically, the magnetic field data (i.e., the position information measured by the locator) and the pressure data collected by the data collector 5 are transmitted to the ground data processing and monitoring equipment. The ground data processing and monitoring equipment removes the inhomogeneity and local interference of the geomagnetic field on the magnetic field data. In a specific example, the Kalman filter algorithm is used to correct the magnetic field data actually measured by the locator. The specific process of correcting the original magnetic field data is as follows: Establish a system model:

[0041] State equation: A mathematical model that defines the evolution of system states (such as well inclination angle, tool face angle and their rate of change) over time. Assuming the state variables are [x_k = [well inclination angle, tool face angle, well inclination angle change rate, tool face angle change rate]^T], establish a state equation that represents how these state variables change over time.

[0042] Observation equation: describes how the observed value (i.e. the actual measured magnetic field data) is composed of the true state and possible observation noise. The observed value usually includes the raw data obtained from the magnetometer and gyroscope, and the preliminary well inclination and azimuth calculated from these data are used as the observed value.

[0043] Initialize the Kalman filter: set the initial state estimate and covariance matrix to reflect the uncertainty of the initial state.

[0044] Iteration process: Based on the state estimate and system dynamic model of the previous moment, the state estimate and its covariance matrix of the next moment are predicted. The new state estimate and covariance matrix are calculated by Kalman gain using the observation data of the current moment and the predicted value. Kalman gain reflects the degree of trust in the state estimate of the observation data, and changes with the change of observation noise and prediction error covariance.

[0045] Application results: The final state estimation value is the actual well inclination angle and tool face angle after filtering. These values ​​will be more accurate than the original data, removing a lot of random noise and deviation.

[0046] S3: According to the position information located in step S2, the position of the downhole water supply unit is adjusted by ground lengthening or dragging the oil pipe, so that the perforating gun 7 is directly at the position to be unblocked, and then the bridge plug 9 is pressed and sealed;

[0047] S4: Start the pump truck of the water supply unit on the well and start the hydraulic cutting operation.

[0048] If there are multiple positions to be unblocked, it is necessary to complete the unblocking of different positions to be unblocked from bottom to top in sequence. After the unblocking of the lower position to be unblocked is completed, the coiled tubing or oil pipe is lifted to the upper position to be unblocked, and the S4 operation is repeated; when all the positions to be unblocked are unblocked, the coiled tubing or oil pipe can be pulled out.

[0049] After step S4 is completed, a sand-carrying liquid is sprayed into the cut holes 14 to support the cracks.

[0050] Before step S2, it is necessary to check the wellhead, blowout preventer and other components, tighten them, and conduct a pressure stabilization test. The specific pressure stabilization test is as follows: start the pump truck, conduct a clean water overall pressure test to the rated working pressure of the blowout preventer, and the pressure stabilization time is not less than 30 minutes. There is no leakage in the sealing part, and the pressure drop does not exceed 0.5MPa to be qualified.

[0051] When lowering the underground water supply unit, it should be lowered at 5 m / min when passing the wellhead and other reduced diameter parts, and at 20 m / min after passing the wellhead. When lowering, it should be circulated and flushed at the minimum displacement to the position to be unblocked.

[0052] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0053] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0054] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A hydraulic cutting device, characterized in that: It comprises an off-hole water supply unit and an in-hole water delivery unit, wherein the in-hole liquid delivery unit comprises an oil pipe connector, a centralizer, a data collector for locating position information and a perforating gun connected in sequence, wherein the oil pipe connector, the centralizer and the data collector are all hollow, and the inner cavities of the oil pipe connector, the centralizer and the data collector are connected to form a water delivery channel, wherein one end of the water delivery channel is connected to the off-hole water supply unit, and the other end is connected to the water inlet of the perforating gun.

2. The hydraulic cutting device according to claim 1, characterized in that: A blowout-prevention check valve is arranged between the oil pipe connector and the centralizer, and a flow channel of the blowout-prevention check valve is connected to the water supply channel.

3. The hydraulic cutting device according to claim 2, characterized in that: A safety release handle is arranged between the blowout prevention check valve and the centralizer, and the inner cavity of the safety release handle is communicated with the water supply channel.

4. The hydraulic cutting device according to claim 1, characterized in that: A power assembly for providing power for water flow is arranged between the perforating gun and the data collector.

5. The hydraulic cutting device according to claim 1, characterized in that: One end of the perforating gun away from the data collector is connected in sequence with a bridge plug setting tool and a bridge plug.

6. The hydraulic cutting device according to any one of claims 1 to 5, characterized in that: Along the water supply direction of the water supply channel, the data collector is sequentially connected to a plurality of the perforating guns.

7. The hydraulic cutting device according to claim 1, characterized in that: The data collector includes a locator for acquiring position information, a pressure sensor for acquiring target layer pressure information, a signal sending unit for sending the acquired information to a remote terminal, and a battery pack. The locator, the pressure sensor, and the signal sending unit are all electrically connected to the battery pack.

8. The hydraulic cutting device according to claim 1, characterized in that: The off-hole water supply unit includes a pump truck, a sand mixing skid, a water tank and ground data processing and monitoring equipment. The sand mixing skid and the water tank are connected to the oil pipe connector through the pump truck and the oil pipe. The ground data processing and monitoring equipment is remotely connected to the data collector by electrical signals.

9. The hydraulic cutting device according to claim 8, characterized in that: The off-hole water supply unit also includes a sand adding tank, which is connected to the feed port of the sand mixing skid.

10. A method for unblocking a cutting seam, characterized in that: The use of the hydraulic cutting device according to any one of claims 1 to 9 comprises the following steps: S1: Connect the water supply unit above the well and the water delivery unit below the well; S2: Lower the downhole water supply unit to the position to be unblocked, and the data collector locates the current position; S3: According to the position information located in step S2, the position of the downhole water supply unit is adjusted so that the perforating gun is directly at the position to be unblocked; S4: Start the water supply unit on the well and start the hydraulic cutting operation.

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