Multi-packer tubular column jam releasing processing method

Abstract

The invention provides a multi-packer string jam releasing treatment method, which comprises the following steps of: detecting the thickness of a pipe wall of a multi-packer string by using an electromagnetic flaw detection logging instrument to judge whether a hydraulic anchor is not shrunk or a stuck point position of a sand-buried packer, then tripping in a hydraulic cutter, cutting an oil pipe in sections, cutting off the oil pipe, fishing out the oil pipe at the upper part, and releasing the oil pipe at the lower part of the multi-packer string. The casing milling barrel is put down to mill the position of the sticking point, the oil pipe on the lower portion is fished out after casing milling, if fishing does not move, step-by-step jam releasing treatment is conducted on the multi-packer stuck pipe column in a segmented cutting and segmented fishing mode, and the problem that the multi-packer stuck pipe column cannot be pulled out is solved. And a new means is provided for production recovery of a multi-packer stuck tubular column well.

Description

Technical Field

[0001] The invention belongs to the technical field of gas field production management, and in particular relates to a method for unblocking a multi-packer pipe string. Background Art

[0002] At present, there are many multi-packer pressure-dividing pipe strings in use in oil fields. The hydraulic anchors of many pressure-dividing pipe strings do not shrink after pressure. At the same time, some packers are buried in sand, resulting in the phenomenon that the pipe string is stuck and cannot be pulled out during the later salvage, which seriously affects the normal production of oil (gas) wells. The traditional method is to use the process of reversed oil pipes, reversed step by step, reversed to the stuck point, then milled and salvaged, and then all the oil pipes are pulled out. For example, the utility model with announcement number CN 210685904U discloses an integrated milling and salvaging device that is easy to unblock. The delivery pipe string is lowered so that the milling teeth at the bottom of the milling shoe contact the upper surface of the outer part of the center pipe of the bridge plug or packer to be salvaged, and a certain drilling pressure is applied to the pipe string to mill the outer part of the center pipe of the bridge plug or packer to be salvaged. However, this unblocking method has the problems of long operation cycle, large operation workload and high operation cost. Summary of the invention

[0003] The present invention aims to provide a method for unstuck multi-packer pipe strings to overcome the above technical defects.

[0004] In order to solve the above technical problems, the present invention provides a method for unstuck multi-packer string, comprising the following steps:

[0005] Obtain the stuck point position of the multi-packer string;

[0006] Lowering the hydraulic cutter to the position above the stuck point and cutting the oil pipe, the oil pipe is cut into two sections, the upper section, and the upper section is salvaged first;

[0007] Lowering the milling barrel to the clamping point to perform milling;

[0008] Then salvage the lower oil pipe;

[0009] Repeat the above steps to gradually release the stuck points of multiple packers to achieve full-well tubing release and salvage.

[0010] Obtain the stuck point position of the multi-packer string, including:

[0011] An electromagnetic flaw detection and logging instrument is lowered into the multi-packer string to detect the hydraulic anchor non-retracted position and / or the sand-buried packer position of the multi-packer string. The hydraulic anchor non-retracted position and / or the sand-buried packer position are used as the stuck point position.

[0012] Insert the milling barrel to the clamping point to implement milling, including:

[0013] Assemble a sleeve milling tool string, which includes a tool oil pipe and a sleeve milling barrel connected to each other.

[0014] Lower the hydraulic cutter to the top of the stuck point and cut the oil pipe, including:

[0015] Assemble the cutting tool string, install the hydraulic cutter at the tail of the cutting tool string, lower the cutting tool string until the hydraulic cutter is above the stuck point, and start the cutting tool string to make the hydraulic cutter rotate and cut the oil pipe.

[0016] The cutting tool string includes a coiled tubing, a safety joint, a hydraulic motor and a hydraulic cutter connected in sequence. The pump truck located at the wellhead pressurizes the coiled tubing to drive the hydraulic motor to rotate, thereby driving the hydraulic cutter to rotate.

[0017] Repeat the above steps to gradually release the stuck points of multiple packers to achieve full well string release and salvage, including:

[0018] Obtain the stuck points of the multi-packer string, which are numbered K1, K2, K3, etc. from top to bottom;

[0019] Lower the hydraulic cutter to the upper part of the stuck point K1 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvaging the oil pipe above the stuck point, then lowering the milling barrel to the stuck point K1 to perform milling, and finally salvaging the lower part of the oil pipe below the stuck point K1;

[0020] If the lower oil pipe cannot be salvaged, continue to lower the hydraulic cutter to the upper part of the stuck point K2 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvage the oil pipe above the stuck point, then lower the milling barrel to the stuck point K2 again and perform milling to salvage the lower oil pipe below the stuck point K2.

[0021] If the lower oil pipe cannot be salvaged, lower the hydraulic cutter to the upper part of the stuck point K3 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvage the oil pipe above the stuck point, then lower the milling barrel to the stuck point K3 again and perform milling to salvage the lower oil pipe below the stuck point K3.

[0022] Repeat this process continuously to release all stuck points of the Kado packer step by step from top to bottom.

[0023] The tools used to salvage the oil pipe are overshot or spear.

[0024] The beneficial effects of the present invention are as follows:

[0025] First, the wall thickness of the multi-packer string is detected by an electromagnetic flaw detection logging instrument to determine the stuck point position of the hydraulic anchor or the sand-buried packer, and then a milling barrel is lowered to mill the stuck point position, and finally a hydraulic cutter is lowered to cut the oil pipe in sections. After the oil pipe is cut, the stuck pipe string of the multi-packer is gradually unstuck by means of segmented salvage, which solves the problem that the stuck pipe string of the multi-packer cannot be removed, and provides a new means for resuming production of wells with stuck pipe strings of the multi-packer.

[0026] In order to make the above contents of the present invention more clearly understood, preferred embodiments are specifically described in detail below. DETAILED DESCRIPTION

[0027] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0028] The present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0029] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0030] This embodiment relates to a method for unstuck multiple packer strings, comprising the following steps:

[0031] Obtain the stuck point position of the multi-packer string;

[0032] Lowering the hydraulic cutter to the position above the stuck point and cutting the oil pipe, the oil pipe is cut into two sections, the upper section, and the upper section is salvaged first;

[0033] Lowering the milling barrel to the clamping point to perform milling;

[0034] Then salvage the lower oil pipe;

[0035] Repeat the above steps to gradually release the stuck points of multiple packers to achieve full-well tubing release and salvage.

[0036] The method of obtaining the stuck point position of the multi-packer string specifically includes:

[0037] An electromagnetic flaw detection and logging instrument is lowered into the multi-packer string to detect the hydraulic anchor non-retracted position and / or the sand-buried packer position of the multi-packer string. The hydraulic anchor non-retracted position and / or the sand-buried packer position are used as the stuck point position.

[0038] That is to say, in this embodiment, the electromagnetic flaw detection logging instrument is used to detect the thickness of the pipe wall. The electromagnetic flaw detection logging can detect the damage of the oil pipe and casing inside the oil pipe, and detect the damage of the casing and surface casing inside the casing, saving the cost and time of lifting and lowering the oil pipe when checking the casing condition. This feature makes it possible to conduct a census of the wellbore structure of oil and water wells.

[0039] The structure of electromagnetic flaw detection logging tool is:

[0040] It consists of multiple probes, upper and lower centralizers and circuits. The multiple probes include temperature probe, natural gamma probe, longitudinal long axis probe A, transverse probe B, and longitudinal short axis probe C. The temperature probe is used to detect the change of the temperature field of the fluid in the well and determine the location of the outlet; the natural gamma probe detects the natural gamma intensity around the wellbore for depth calibration; probes A, B, and C are used to detect casing damage.

[0041] This embodiment mainly uses electromagnetic flaw detection and logging instruments to detect pipe wall thickness and depth of packer distribution positions to determine the hydraulic anchor non-retracted position and / or sand-buried packer position, which are the stuck points.

[0042] Insert the milling barrel to the clamping point to implement milling, including:

[0043] Assemble a sleeve milling tool string, which includes a tool oil pipe and a sleeve milling barrel connected to each other.

[0044] The milling process requires the selection of different milling shoes, and different milling shoes are used in conjunction with the milling of different parts of multiple packers to achieve the unblocking of the packers without damaging the fish top, thereby successfully achieving salvage.

[0045] To mill a packer, one must first understand the structure of the packer and select a suitable milling shoe based on the structure and size of the packer. The shape of the bottom teeth and the inner diameter of the milling teeth of the selected milling shoe must meet the following requirements: (1) The shape of the milling teeth must be suitable for the milling of the packer body (high-strength steel), rubber, and tooth plate, and must be able to ensure a high milling speed; (2) The inner diameter of the milling teeth must be able to effectively destroy the packer's slips or slip locking mechanisms with a relatively small amount of cutting, thereby releasing the packer; and (3) The inner diameter of the milling shoe must be sufficient to prevent the packer from being loosened, thereby avoiding difficulties in subsequent salvage.

[0046] The following example illustrates the milling operation:

[0047] During the milling process, first use the flat-bottomed milling shoe with an inner diameter of 6-3 / 4″--7″, the advance is slow, and the 24-hour milling advance is 80-120mm. The torque increment is about 7KN.m when the pressure is increased to 10 tons. The advance is faster when the milling reaches the rubber position. It only takes 12 hours to mill through the rubber 170mm. The torque increment of this section reaches 7KN.m at a drilling pressure of 5-6 tons, and there is a torque retention phenomenon. When replacing the 6-1 / 2″ flat-bottomed milling shoe to trim the outer diameter of the milled section, the advance is faster, reaching 100mm per hour, but the torque increment is obvious, and the pressure cannot exceed 2 tons, otherwise it will cause serious torque retention.

[0048] Milling and salvaging special packers requires a detailed understanding of the structure of the packers in advance in order to formulate a reasonable milling and salvaging plan; usually the drilling pressure for milling is controlled at 3 tons, and the maximum does not exceed 5 tons. However, when milling the packer, if the torque is stable, the drilling pressure can be appropriately increased to 12 tons, and the torque increment is controlled at 80% of the torque on the milling pipe; the milling footage of the packer is very slow, so accurate milling footage is of great significance to reducing the milling time. Usually, the packer can be successfully released by milling off the support mechanism of the slip.

[0049] Lower the hydraulic cutter to the top of the stuck point and cut the oil pipe, including:

[0050] Assemble the cutting tool string, install the hydraulic cutter at the tail of the cutting tool string, lower the cutting tool string until the hydraulic cutter is above the stuck point, and start the cutting tool string to make the hydraulic cutter rotate and cut the oil pipe.

[0051] The cutting tool string includes a coiled tubing, a safety joint, a hydraulic motor and a hydraulic cutter connected in sequence. During the cutting process, the coiled tubing is connected to the safety joint, and the pump truck located at the wellhead pressurizes the coiled tubing to drive the hydraulic motor to rotate, thereby driving the hydraulic cutter to rotate, generating a lateral cutting impact force on the tubing wall. When the cutting impact force reaches a certain value, the tubing is cut off.

[0052] The working principle of hydraulic cutter is:

[0053] When the cutter is lowered to the predetermined cutting position, the pump is turned on to circulate and the displacement is gradually increased. The well fluid passes through the nozzles of the upper and lower sliding valves, causing a pressure difference between the upper and lower sliding valves. This pressure difference causes the sliding valve to overcome the spring resistance and move downward, pushing the cutter head to rotate outward and enter the cutting state. At this time, the rotary cutter can cut. After cutting, stop the pump, and the pressure difference between the upper and lower sliding valves disappears. The sliding valve moves upward and resets under the action of the compressed spring. The cutter head rotates inward and resets under the action of the spring pressure plate, and the cutter can be taken out of the well.

[0054] Conventional tubing cutting tools mainly include mechanical cutters and hydraulic cutters. Mechanical cutters have the advantages of good centering and less risk of cutting 9-5 / 8" casing compared to hydraulic cutters, but the disadvantages are that they require delicate operation and are difficult to control, and mechanical cutters have low strength and low cutting efficiency. Considering the different characteristics of the cutters, it is recommended to use hydraulic cutters with higher cutting efficiency and simpler operation in highly inclined ultra-deep wells, and add a centralizer to the cutting drill to reduce the risk of cutting 9-5 / 8" casing.

[0055] For example, a 5-3 / 4" hydraulic cutter is used to cut a 7" oil pipe. Its parameters are: the maximum outer diameter of the inner cutter is 146mm, the joint buckle type is 331, the tensile strength is 150t, the torsional strength is 26kN·m, the body water hole diameter is 38mm, the piston water hole diameter is 8mm, and the maximum diameter of the cutter when fully opened is 188mm.

[0056] Repeat the above steps to gradually release the stuck points of multiple packers to achieve full well string release and salvage, including:

[0057] Obtain the stuck points of the multi-packer string, which are numbered K1, K2, K3, etc. from top to bottom;

[0058] Lower the hydraulic cutter to the upper part of the stuck point K1 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvaging the oil pipe above the stuck point, then lowering the milling barrel to the stuck point K1 to perform milling, and finally salvaging the lower part of the oil pipe below the stuck point K1;

[0059] If the lower oil pipe cannot be salvaged, continue to lower the hydraulic cutter to the upper part of the stuck point K2 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvage the oil pipe above the stuck point, then lower the milling barrel to the stuck point K2 again and perform milling to salvage the lower oil pipe below the stuck point K2.

[0060] If the lower oil pipe cannot be salvaged, lower the hydraulic cutter to the upper part of the stuck point K3 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvage the oil pipe above the stuck point, then lower the milling barrel to the stuck point K3 again and perform milling to salvage the lower oil pipe below the stuck point K3.

[0061] Repeat this process continuously to release all stuck points of the Kado packer step by step from top to bottom.

[0062] It should be noted that the tool used to salvage the oil pipe is a salvage tube or a salvage spear.

[0063] In general, the principle of the multi-packer string unstuck treatment method is:

[0064] First, the instrument detects the position where the hydraulic anchor does not shrink (or the sand-buried packer), and then the hydraulic motor and hydraulic cutter are lowered to the upper part of the stuck point with the continuous tubing. The pump truck is used to pressurize the continuous tubing to drive the hydraulic motor to rotate. The hydraulic motor drives the hydraulic cutter to rotate and cut the tubing. After the tubing is cut, the upper tubing is first salvaged, and then the milling barrel is lowered to the stuck point for milling. Finally, after the tubing is cut, the upper tubing is first salvaged, and then the salvage barrel (or salvage spear) is lowered to salvage the lower tubing. After the first-stage packer is salvaged, if the lower packer also has the problem of hydraulic anchor not shrinking (or sand-buried packer), the salvage steps of the first-stage packer are repeated to achieve the unstuck salvage of the entire well string.

[0065] The function of the milling barrel is to ensure good milling performance and thorough milling.

[0066] The function of the hydraulic motor is to function well and provide sufficient power for the water cutter.

[0067] The overall unblocking operation is to first use the detection instrument to detect, then lower the hydraulic cutter to cut the oil pipe. After the oil pipe is cut, the upper oil pipe is salvaged first, and then the milling barrel is lowered to mill the stuck point. After the oil pipe is cut, the upper oil pipe is salvaged first, and then the salvage barrel (or salvage spear) is lowered to salvage the lower oil pipe, realizing the unblocking and salvage of the entire well string.

[0068] That is, this embodiment proposes instrument detection + milling + coiled tubing supporting related tools to perform segmented cutting and segmented salvage, and finally achieve the purpose of unblocking and salvaging the entire well string. Among them, milling is achieved by process string 1, which is composed of tool tubing + milling barrel; the related tools supporting coiled tubing refer to process string 2, which is composed of coiled tubing + hydraulic motor + hydraulic cutter.

[0069] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A method for unblocking a multi-packer string, characterized in that: The following steps are involved: Obtain the stuck point position of the multi-packer string; Lowering the hydraulic cutter to the position above the stuck point and cutting the oil pipe, the oil pipe is cut into two sections, the upper section, and the upper section is salvaged first; Lowering the milling barrel to the clamping point to perform milling; Then salvage the lower oil pipe; Repeat the above steps to gradually release the stuck points of multiple packers to achieve full-well tubing release and salvage.

2. The method for unblocking a multi-packer pipe string according to claim 1, characterized in that: Obtain the stuck point position of the multi-packer string, including: An electromagnetic flaw detection and logging instrument is lowered into the multi-packer string to detect the hydraulic anchor unretracted position and / or the sand-buried packer position of the multi-packer string, and the hydraulic anchor unretracted position and / or the sand-buried packer position are used as the stuck point position.

3. The method for unstuck multiple packer strings according to claim 1, characterized in that: The milling barrel is lowered to the position of the clamping point to implement the milling, which specifically includes: Assemble a milling tool string, the milling tool string comprising a tool oil pipe and a milling barrel connected to each other.

4. The method for unstuck multiple packer strings according to claim 1, characterized in that: Lowering the hydraulic cutter to the position above the stuck point and cutting the oil pipe specifically includes: Assemble the cutting tool string, install the hydraulic cutter at the tail of the cutting tool string, lower the cutting tool string until the hydraulic cutter is above the stuck point, and start the cutting tool string to make the hydraulic cutter rotate and cut the oil pipe.

5. The method for unblocking a multi-packer pipe string according to claim 4, characterized in that: The cutting tool string includes a coiled tubing, a safety joint, a hydraulic motor and a hydraulic cutter connected in sequence. A pump truck located at the wellhead pressurizes the coiled tubing to drive the hydraulic motor to rotate, thereby driving the hydraulic cutter to rotate.

6. The method for unstuck multiple packer strings according to claim 1, characterized in that: Repeat the above steps to gradually release the stuck points of multiple packers to achieve full well string release and salvage, including: Obtain the stuck points of the multi-packer string, which are numbered K1, K2, K3, etc. from top to bottom; Lower the hydraulic cutter to the upper part of the stuck point K1 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvaging the oil pipe above the stuck point, then lowering the milling barrel to the stuck point K1 to perform milling, and finally salvaging the lower part of the oil pipe below the stuck point K1; If the lower oil pipe cannot be salvaged, continue to lower the hydraulic cutter to the upper part of the stuck point K2 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvage the oil pipe above the stuck point, then lower the milling barrel to the stuck point K2 again and perform milling to salvage the lower oil pipe below the stuck point K2. If the lower oil pipe cannot be salvaged, lower the hydraulic cutter to the upper part of the stuck point K3 and cut the oil pipe in sections. Cutting the oil pipe in sections means cutting the oil pipe into two sections, first salvage the oil pipe above the stuck point, then lower the milling barrel to the stuck point K3 again and perform milling to salvage the lower oil pipe below the stuck point K3. Repeat this process continuously to release all stuck points of the Kado packer step by step from top to bottom.

7. The method for unstuck multiple packer strings according to claim 6, characterized in that: The tools used to salvage the oil pipe are overshot or spear.