In technical terms, a fish can be any object which has been lost or stuck in a borehole, and has a serious negative impact on well operations. Fishes can be anything, whether that is a drill string that has come away, a bit cone, or even a hand tool that has been inadvertently dropped into the well. To solve this issue, fishing involves the use of special tools and procedures to recover the fish and allow drilling to continue. While this article will deal solely with regular fishing, there is also an alternative method, which involves using through-tubing processes that make use of tools on a wireline or coiled tubing.
Fishing tools and crafts
During drilling and completion and workover operations, drill rods, drill collars, casings, tubing strings are stuck or broken, drill bit cones are dropped, logging tools or cables are stuck, cable wire ropes are broken, packers are broken Interruption of normal drilling, workover, and completion operations due to stuck, sand, serious leaks, well collapse, blowout, etc., need to use fishing tools or take special measures to remove leaks, collapse, stuck, spray to resume normal operations. The operation and process of removing leaks, collapses, jams, and sprays is called "fishing."
实践经验告诉我们，打捞作业不可避免。据国内过去统计，每打五口井就可能有一口，每修五口井可能就有四口井需要进行打捞作业。因此准备常用的打捞工具及了解掌握常用的打捞技术是必要的。Practical experience tells us that salvage operations are inevitable. According to past statistics in China, there may be one for every five wells, and for every five wells repaired, four wells may need to be salvaged. Therefore, it is necessary to prepare common fishing tools and understand the common fishing techniques.
Classification of fishing tools:
Fishing: Retractable fishing barrel, pin tap, three-ball fishing device, etc.
Inward fishing: box tap, retractable fishing spear, casing fishing spear, inverted fishing spear
Removal of small objects: Recycling basket, salvage cup, multi-round salvage device
Grinding tools: grinding shoes, milling shoes
Cutting tools: mechanical hydraulic inner cutters, forging and milling tools
Dressing tool: casing subsidy
Fishing tools: fishing tools
Retractable slip overshot(S-150)
1.Uses: It is used for externally fishing drill collars, drill pipes, tubing and other special fishing tools for fishing in drilling and workover projects. It is designed based on the outer diameter of drill collars, drill pipes, tubing, joints, couplings and other well tubing. When the fish is caught and cannot be removed, the fishing rod can be pulled out of the fish and lifted back to the ground.
Overshot can carry out mud circulation after catching fish. It also has milling shoes which can effectively repair the fish top crack and flash. It is convenient for falling fish to enter the fishing barrel smoothly. If you need to increase the fishing area, you can connect to increase the boot shoes. When the fish top leans against the well wall, you can use wall hooks.
Structure: Consisting of upper joint, cylinder and guide shoes. Inside are equipped with catch slips, packing and milling shoes or control rings.
1、Retractable slip overshot （S-150)
Spiral slips: Spiral slips are shaped like springs, with wide serrated left-handed threads on the outside, which are matched with the internal threads of the barrel, the pitch is the same, but the thread surface is much narrower than the barrel. The inside is a multi-headed left-handed zigzag screw with sharp and hard teeth. Finger keys are welded on the lower end of the spiral slip, and the spiral slip is prevented from rotating in the barrel after cooperating with the control card. This type of spiral slip is usually designed in three fishing sizes. The total catch size range is 9-12MM. Considering the wear of the pipe, the catch size of each slip is within the range of 3MM below the standard catch size.
Basket slip: It is cylindrical and looks like a flower basket. The outer part is the same as the spiral slip, but it is a complete wide serrated left-handed thread. The internal fishing teeth are also multiple left-handed zigzag-shaped teeth. There is a key slot at the lower end and an equal expansion and contraction slot in the vertical direction. It is like a spring chuck. . Taking into account the wear of the tube, the salvage size of each slip is within the range of 3MM below the standard salvage size.
Clamping and withdrawal Principle: The fishing part-type spiral slips and basket slips of the fishing barrel are left-handed due to the wide serrated threads on the outside and the catch teeth on the inner side. The gap with the barrel is relatively large. In this way, the slip can expand and contract in a certain stroke in the cylinder. When the falling fish is introduced into the fishing barrel, as long as an axial pressure is applied, the slips travel upward in the barrel. Due to the axial pressure, the falling fish enters the slip, and at this time, the slip is moving upward and swells. Using its hard and sharp slip, the falling fish bites and catches the catch. When the lifting column is lifted, the slip moves relatively downward in the barrel lift. Because the longitudinal section of the wide zigzag thread is a conical bevel, the kava will inevitably move the fish towards the small end of the cone with a heavy drop.
Function of accessories:
Increasing shoes: increasing catch area
Wall hook: Used when the fish head leans against the wall of the well.
Extended length and short section: Use when the fishing part is too far from the top of the fish.
1.Connect the fishing cylinder to the fishing column. The tongs must not be caught on the cylinder to avoid damaging the cylinder. The tightening torque is equal to the fishing column.
2. Fishing to 0.3 ~ 0.5m from the fish top to open the pump cycle, and flush the sediment around the fish top.
3 .Stop the circulation and slowly rotate the lower fishing rod to introduce the falling fish into the fishing rod. If the jumping phenomenon occurs, the cause should be analyzed and measures taken, or it can be lifted by lifting the fishing column.
4.It is estimated that the falling fish enters the fishing bucket, that is, the rotation is stopped and a certain axial pressure is applied to make the falling fish enter the slip.
5.Raise the fishing column, if the hanging weight increases, it proves to catch the falling fish.
Turn on the pump to fully circulate the mud, and pay attention to the change in pump pressure.
Connect the fishing cylinder to the fishing column. The tongs must not be caught on the cylinder to avoid damaging the cylinder. The tightening torque is equal to the fishing column.
Fishing to 0.3 ~ 0.5m from the fish top to open the pump cycle, and flush the sediment around the fish top.
Stop the circulation and slowly rotate the lower fishing rod to introduce the falling fish into the fishing rod. If the jumping phenomenon occurs, the cause should be analyzed and measures taken, or it can be lifted by lifting the fishing column.
It is estimated that the falling fish enters the fishing bucket, that is, the rotation is stopped and a certain axial pressure is applied to make the falling fish enter the slip.
Raise the fishing column, if the hanging weight increases, it proves to catch the falling fish.
Turn on the pump to fully circulate the mud, and pay attention to the change in pump pressure.
Before starting drilling, lift the falling fish 0.5 ～ 0.8m from the bottom of the well and slam the brake 2 or 3 times.
When lifting and disassembling the pipe string, you cannot use the turntable to shackle. You can use a rope twister, a chain rope twister, or an automatic pliers shackle to avoid turning the fishing column under the turntable.
9 .When the falling fish is taken out of the wellhead, wash it with clean water. Do not rush to release it at the wellhead, let alone loosen the fishing rod at the wellhead. When possible, loosen the fishing rod on the drill floor.
Hang down the fishing platform to catch the fishing rod, and then continue drilling.
Use a chain clamp to clamp the fishing tube, and another chain clamp to clamp the fish to rotate clockwise, and the fish can be released from the fishing teeth.
Lower the fishing pole so that the slip is at the large cone end of the wide serrated thread of the cylinder. At this time, the slip has a large swelling.
Rotate the drill string clockwise and slowly raise it until it exits the bucket.
If the falling fish is not released, it cannot be slammed. This is prone to accidents, and the cause should be identified and measures taken.
If the fishing bucket cannot be taken out, use a jar to conduct multiple low-tonnage shocks.
2、Short fish head retractable slip overshot
Uses: used to catch fish with a short fishing path
Structure: It consists of upper joint and cylinder. It is fitted with slips, packing and milling shoes or control rings.
Wide fishing range: single basket / spiral tile fishing range: 9mm.
2、Structure: It consists of upper joint and cylinder. It is fitted with slips, packing and milling shoes or control rings.
4、pin tap fishing Principle
The pin tap is made of high-strength alloy steel forging and is heat-treated. There are two types of fishing thread: zigzag and triangle. Thread surface hardness HRC60 ~ 65. The pin tap fishing Principle is to squeeze the buckle on the outside of the fish head.
pin taps are divided into: positive and negative pin taps
Identification of positive and negative pin taps: marking grooves, identification grooves.
The pin tap is made of high-strength alloy steel forging and is heat-treated. There are two types of fishing threads: zigzag and triangle. Thread surface hardness HRC60 ~ 65. The pin tap fishing Principle is to squeeze the buckle on the outside of the fish head.
The pin tap can be divided into positive pin tap and reverse pin tap.
Identification of positive and negative fpin tap: marking grooves, identification grooves.
1、Retrievable slip spear
Use: It is a tool for fishing from the inner hole of the falling fish. It is mainly used for fishing drill rods, tubing, casings, etc. It can be used in conjunction with tools such as internal cutters, jars, etc. When it comes out, you can withdraw the spear and raise the drill.
Structure: The fishing spear is composed of a mandrel, a slip, a release ring, a pilot cone, etc. Each type of fishing spear is equipped with different sizes of slips for use during salvage.
When the fishing spear was introduced into the falling fish, it was pressurized, the kava entered the falling fish, the kava shrank, and the outer teeth of the kava tightened the falling fish by the elastic force. The longitudinal section of the wide zigzag thread is a tapered bevel. When it is lifted up, the slip moves toward the end of the large cone, and the falling fish is caught more tightly.
Use: enter the fish (you can catch it by lifting it;
Press down (while turning right, lift 5 to 10kN until it comes off.
Fishing spear specifications: 1 3/4 "--- 13 3/8"
Instructions:Choosing slips: There are many slips of different sizes for each type of fishing spear. The slips should be selected according to the size of the fish and according to the technical parameter table of the fishing spear.
Well platform operation process:
Calculate the top of fish and salvage before drilling
If there is an inward burr on the top of the fish, it should be ground away.
Depending on the situation, the pump can be stopped for salvage or opened for salvage.
Slowly lower the drilling tool until the fishing spear reaches the expected depth of the falling fish, then turn the drilling tool left to make the fishing spear turn left 1 turn, and then raise the drilling tool to lift the fishing fish. If the fish gets stuck, it must be raised gradually after fishing. If the activity is not effective, you can use shock to release the card.
The method of exiting the fishing spear in the well: first use the weight of the drilling tool to slam down, loosen the engagement between the slip and the wide sawtooth thread bevel of the spear rod, and then lift the drilling tool above the fishing spear by 1 to 2 tons of right-handed rotation. As you spin, lift slowly and carefully until the fishing spear escapes from the falling fish.
Slider fishing spear
Drilling Buckle Spear
The upper part of the spear body is an anti-drilling drill pipe joint thread, and the lower part is provided with a guide cone to facilitate the buckle between the tool and the fish-fishing joint. After the tools are buckled, raise the drill, and the expansion buckle sleeve can firmly support the falling fish, and then the buckle operation can be performed. ZDM fishing spear upper joint thread also has a positive buckle form, when ordering must be marked "double positive buckle".
Fishing pin tap
1、Uses: It is a tool specifically used to make buckle and salvage from the inner hole of the hole falling object such as drill pipe and tubing. It has a high salvage success rate for pipe-type objects with couplings. The pin tap is used in conjunction with forward and reverse drill rods and other tools, which can be used for different salvage processes. The pin tap is made of high-strength alloy steel forging and is heat-treated. In order to facilitate the buckle, the pin tap has a cutting groove.
4、Fishing pin tap
Uses: It is a tool specifically used to make buckle and salvage from the inner hole of the hole falling object such as drill pipe and tubing. It has a high salvage success rate for pipe-type objects with couplings. The pin tap is used in conjunction with forward and reverse drill rods and other tools, which can be used for different salvage processes. The pin tap is made of high-strength alloy steel forging and is heat-treated. In order to facilitate the buckle, the pin tap has a cutting groove.
Select the size of the pin tap according to the size of the fish's water eye. Measure the size of each part and draw a working sketch. Calculate the depth of the fish head and the fishing angle.
3.Generally, when a pin tap goes down, it should be equipped with a jar and a safety joint.
4.When drilling down to 1 to 2 meters above the depth of the fish head, turn on the pump to flush, then circulate with a small displacement and explore the fish head. Determine whether the pin tap has reached the top of the fish according to the changes in the lowering depth, pump pressure, and suspension weight. The hand feels the hook of the kelly. The increase in pump pressure and the decrease in suspended weight indicate that the pin tap has entered the top
5.When the buckle is made, the size of the fish drop is different, and the pressure of the buckle is also different. The size of the fish drop is large, and the drill pressure is also large. Attention should be paid to the change of torque and weight while drilling
6.Before fishing, the drill should be lifted and then lowered to 2-3 meters away from the bottom of the well to slam the brakes to check whether the fishing is reliable. The lifting operation requires smooth operation. It is forbidden to use the drill plate to shackle.
Purpose: mainly used to catch heavy cuttings or metal chips which can not be brought out by normal mud circulation during drilling. It plays an important role in keeping the bottom of the well clean, improving the service life of the bottom of the bit, reducing and preventing unexpected damage of the bit
Structure and working principle
Structure: it is composed of three parts: spindle, centralizer block and cup cylinder. There are three types of fishing cup with the same size and specification: standard type (s type), long type (L type) and extra long type (ex type)
2.2 Working principle: because the outer diameter of fishing cup is large, the annular gap between fishing cup and wellbore is small, while the diameter of bottom mandrel at cup mouth is small, and the annular gap between fishing cup and wellbore is large
method of application
The fishing cup is attached to the drill bit, grinding head, flat head milling shoe, pipe scraper or fishing basket
Generally, no special operation is required, and fishing can be carried out along with the bottom drilling. If it is specially used for fishing, it can rotate at the bottom of the well and change the displacement to wash for several minutes after the bottom of the well is cleaned, then it can trip out
2、Pay attention to prevent the cup mouth from scraping the casing shoe during tripping out
Reverse circulation fishing basket
Application: mainly used for fishing small objects at the bottom of the well, such as bit cone, teeth, hand tools and scrap iron. When fishing, it can cause local reverse circulation at the bottom of the well
Structure: the outer part is composed of upper joint, barrel, milling shoe, etc. the inner part is composed of valve cup, steel ball, valve seat, fishing claw body assembly, etc.
There is a recyclable space between the outer cylinder and the inner cylinder. The water hole on the outer cylinder is 45 degrees upward, which is not connected with the middle of the two cylinders, but it is connected with the inner cavity of the inner cylinder, while the water hole is 15 degrees downward, which is connected with the middle of the two cylinders. Tungsten carbide particles are welded on the lower milling shoe teeth, which has high wear resistance and is easy to repair. The valve cup is used to guide the steel ball to fall into the valve seat correctly. In order to form a reverse cycle.
After tripping in, circulate the mud with large displacement for 10 minutes, and clean the mud in the barrel
2. Discharge the wellhead drill pipe and put the steel ball (Note: all drilling tools, joints, etc. can ensure that the steel ball passes) and open the pump to circulate mud and send the steel ball to the valve seat. At this time, pay attention to the change of the pump pressure. When the steel ball falls into the valve seat, the pump pressure will suddenly rise by 1-2mpa.
3. When RIH the drilling tool to the bottom of the well, circulate the mud while rotating, and flush the falling object into the bailing basket. After reaching the bottom of the well, lift up 0.1-0.2m to move up and down for 10-20 minutes
3、Reverse circulation strong magnetic fishing tool
Application: it is a tool for fishing small downhole objects in petroleum and geological exploration. It uses its permanent magnet to magnetize the small tool falling objects such as teeth, tong teeth and so on, so as to effectively salvage the small tool falling objects and purify the bottom of the well
Structure: composed of upper joint, centralizer sleeve, permanent magnetic core, steel sleeve, steel ball and flat bottom guide shoe, etc
According to the characteristics of well diameter and falling objects, choose a strong magnetic fishing tool with suitable guide shoes
Multi wheel catcher
1.A circulation channel is arranged in the semicircle barrel to the bottom of the well, which increases the power of the roller entering the barrel.
2. The magnets are arranged in multiple layers in the half cylinder, which increases the magnetic field strength and the contact area with the teeth
The magnet is in the protection of the overshot shell and is not easy to break
During fishing, the fishing tool slides down the wall of the well and inserts into the gap of the landing cone. At the same time, the cone is attracted to the magnet by the impact of the drilling fluid. Lift the drilling tool and press it down in a different direction, and the other teeth at the bottom of the well push the teeth already absorbed on the magnet, and at the same time, they are also attracted by the magnet. According to this principle, the landing cone is captured by the fishing tool one by one, and then salvaged in series.
Milling shoe is used to grind metal objects at the bottom of the well and trim the fish crown.
Trim and grind the top of the fish; grind stuck pipes, rods, and downhole tools. It has obvious effect on the repair and grinding of the fractured casing fractured well.
三、Fishing tools: Milling fishing tools
Shoe milling is a tool for over-milling operations and milling falling objects. It is used for drilling and removing rock, sand, cement, and other deposits around the falling fish during well milling operations. It can also be used to trim the fish roof.
Its own advantages: It is used for annulus milling, sleeve milling, and flushing of stuck process pipe strings and downhole tools to remove jamming and open channels, creating necessary conditions for fishing.
Types of milling shoes are: A, B, C, D, E, F, G, H, I, J, K, L, M, N types.
1、Hydraulic Casing cutter
Uses: It is a tool that uses hydraulic power to drive mechanical rotation to cut in the tube.
2、Working principle: When the cutting knife is lowered into the predetermined cutting position, the pump is circulated and the displacement is gradually increased. The drilling fluid passes through the nozzles of the upper and lower valves to cause a pressure difference between the upper and lower sliders. The valve moves downward against the resistance of the spring and pushes the cutter head to rotate outward into the cutting state. At this time, the rotary cutter can cut. After the fish is cut off, the pressure difference between the stop of the pump and the down valve disappears. The slide valve is reset by the upward movement of the compressed spring. The cutter head rotates inward to reset under the action of the spring pressing piece. The cutter can be removed from the well.
2、Forging and milling tools
Working principle: The TDX series casing section mill adopts a hydraulic piston structure, which relies on water to push the piston to support the blade, expands the cutting and milling of the casing, stops the pump when the construction requirements are met, the piston relies on spring force to reset, and the blade depends on its own weight and external force Received inside the blade slot.
The external cement of the section milling casing is well cemented to ensure that the lower casing does not shake and the upper casing does not trip.
2.Try to avoid casing couplings and start cutting 3 ~ 4m below the couplings. Minimize casing couplings within 20-30 meters of the forging and milling section. Avoid cutting the casing centralizer to ensure the milling speed and the section milling length of a single blade.
Use a pipe scraper to connect the well to the well and to mill the section to 80m to ensure that the wellbore is unobstructed.
The specific viscosity of the mud depends on the condition of the iron chips, which can guarantee the smooth ejection of iron chips from the well.
During forging and milling, the operation must be stable, the drill is evenly fed, and the weight is pressurized according to the regulations. The brake lever can only be operated by the driller or the assistant driller.
2.After lowering the tool to the predetermined position, start the turntable slowly. After the drill string rotates normally without obvious torque and skipping, the mud pump can be started slowly, and the displacement can be cut from small to the designed displacement at a fixed speed of 30 ～ 50r / min Casing (Note: Do not lower the drilling tool at this time); after the pump pressure drops 1 ~ 3Mpa, the casing is cut off, and then continue to rotate the tool for 30 ~ 45 minutes to trim the cutting section
3.During the section milling process, iron filings may form a “sand bridge” around the drill string, causing the pump to move the drilling tool regularly (the drilling tool is moved up and down once every 0.5 to 1 m of milling, and the upper and lower windows cannot be exceeded during the movement). Destroy the "sand bridge" so that iron filings return in time.
If you need to repair the equipment during drilling, you must stop the pump first, idle for a few minutes, and then stop the turntable to lift the drilling tool from the bottom of the well to the upper window (it cannot exceed the upper window). When continuing to drill, first turn on the turntable to idle, and then turn on the pump after the torque is normal.
Because there are too many iron filings or insufficient displacement, a large amount of iron filings are entangled in the tool. When the tool cannot lift the window, do not rush to raise the drilling tool to avoid damaging the blade or even jamming. It can be solved by moving up and down drilling tools and inverted eye, and slowly lift the tool out of the window
Before starting drilling, the mud should be fully circulated (twice as late as possible) to remove all iron filings from the ground, then stop the pump to start drilling. During the drilling process, the speed of the lifting tool should be controlled before the tool enters the casing to prevent window hanging.
The patch connector is composed of an upper joint, an outer cylinder, an inner cylinder, a shoe, a spiral slip, a control ring, a seal assembly, and a shoe mill.
Use: Casing adapter is a repair tool used to connect new and old casings and seal when the casing is damaged downhole. In addition to the primary seal which is compressed and deformed by a lead ring, it can also be cemented. Well, secondary sealed with cement.
一、Construction operation method
Pass the well, scrape the inner wall of the casing, and grind the casing when the casing is seriously damaged
Logging to find casing coupling depth to determine cutting position
Under sleeve milling tube, sleeve milling to about 10m below the cutting position
According to the damage of the casing, choose a cutting tool and cut it at the designed depth. The cutting casing must not have burrs, and the upper casing is raised.
The steps of the lower connector to connect the sleeve are as follows
1.Check the adapter, connect it to the bottom of the casing and run it into the well
2.The tool is lowered to 3-5m above the casing, the suspended weight is recorded, and the pump is circulated to wash the well until the pump pressure and the outlet are stable.3.
Slowly lift the tubing string so that the tool is at the neutral point, so that the tubing string eliminates the elastic torque
4.Lifting column 18-19mm, compressed lead seal
Reduce the setting pressure to a quarter of the original, open the pump to test the pressure, the test pressure value is 3.5-7.5Mpa6.After passing the pressure test, slowly lower the pipe string so that the connector can withstand a load of 70-90KN to open the watertight circulation channel.
Cement injection reaches design height
Lift the pipe string and keep the specified setting load until the cement is solidified.
Role: One of the shaping tools for repairing small deformation of downhole casing. Not only can it provide downward impact force to wedge the tool into the deformed casing part to expand and restore its inner diameter, but it can also provide upward impact force to make the tool overcome the elastic deformation of the casing to achieve bidirectional shaping.
Structure and principle
The mating end faces of the inner sleeve and the upper and lower cones correspond to a cam mechanism. When the mandrel is pressed down and rotated right, a downward impact force is generated due to the action of the cam mechanism, and when the mandrel is lifted and rotated right, an upward impact force is generated.
1、Mechanical jar while drilling
It is connected to the drilling tool to perform drilling operation along with the drill string. When a stuck accident occurs in the well, the jar can be activated in time according to need, and continuous up or down strike can be made to quickly release the card to resume normal drilling. It is essential for directional wells, complex wells, and deep wells. tool
The seal-while-drilling performance is good. The service life of the drill-drill is about 500 hours, which exceeds the use time of a drill bit, so it will not affect the pure drilling time due to the reason that the drill-drill cannot be used
Drilling jar working principle
The working principle of the upper stroke: the drill string is lifted up, the jar is in the tightened position, and the drill string is forced to store energy by the following set of elastic sleeves, which delays. When the slip of the running mandrel goes down and reaches the predetermined tonnage, the locking state is released, and the slip of the slip of the slip shaft is generated, resulting in an upswing. Repeat the above process to make the tool hit again.
Working principle of down-hitting: The drill string is pressed down, the jar is in the locked position, and the drill string is forced to store energy by the set of elastic sleeves above. When the slip of the running mandrel moves upwards and reaches the predetermined tonnage, the locking state is released, and the slip of the slipper shaft slips out, causing a down strike.
Calculation of the pull force G during the upward stroke operation
The general method is: the suspension of the drill string in the upper part of the jar and the adjusted tonnage. But in fact, there are many factors that affect this load. Considering the frictional resistance of the well wall, the mud effect, and the weight table error, the following formula can be used to calculate: directional well
G = G1-G2 + G3 + G4 + G5 + G6-G7
G1-original suspended weight (drilling tool in the well)
G2—Suspended weight of drill string below jar
G3—The ground is set at the tonnage
G4—Mud resistance (about 5% of pull-up force)
G5—Friction resistance (approximately 10 to 20% of pull-up force)
G6—finger scale error
G7—pumping force (G7 = pump pressure × seal area, see Figure 1 for seal area)
Negligible part of the resistance:
G = G1-G2 + G3 + G4 + G6
6.2.4 When a stuck accident needs to be hit, follow the steps below:
1) Same as the method of returning position when hitting upwards, return the jar to the "preparing firing position" position.
2) The drill is pressed with pressure G 'to produce a shock.
Calculation of the pressure G 'when the operation is down:
The general method is: G '= ground-set tonnage + mud resistance + friction resistance + weight indicator error
The utility model relates to a special tool assembled from two pieces, which is a special tool for protecting a drill string in drilling, workover and oil test projects.
It is suitable for downhole accident handling, as well as for halfway testing of drilling and coring. Connect it to the required part of the drill string used to protect the drill string and not affect the normal operation of the drilling tool. Once the tool is stuck in the downhole, the drill string above the card point can be pulled out by the safety joint, and it can be docked when drilling again. .
1. Connection position: The safety joint is connected to a position where it is not easy to get stuck and can minimize the remaining tools and tubing strings in the downhole after withdrawal. When the downhole condition allows, the striker should be connected to the upper part of the safety joint to release the safety joint.
2. Method for retreating safety joints downhole
3. Apply a reverse torque to the safety joint (approximately 1 to 2 turns / 1000 meters, the left-hand safety joint is forward torque). Use a down striker or the weight of the original drill to stop the safety joint.
4. The lifting force of the lifting drill is 5-10KN less than the weight of the drill above the safety joint. At this time, the safety joint is under a slight pressure.
5. Reverse suspended weight drops rapidly, should be raised in time to maintain a pressure of 5 ~ 10KN
Soft lead is inserted into the lower end surface of the alloy structural steel body for fishing operations. This structure can be probed into the well hole to detect the shape of the top of the falling fish.
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