While-drilling salvage method

Abstract

The invention provides a method for salvaging while drilling, the salvaging method uses a salvaging while drilling tool combination including a salvaging while drilling device for salvaging, and the salvaging method comprises the following steps: tripping the salvaging tool combination into a preset distance position in a well; a pump is started to circulate the drilling fluid, and the displacement needs to ensure that magnetic and non-magnetic substances can be scoured by the drilling fluid and move upwards; the drilling tool combination continues to be lowered, and lowering is stopped after resistance is met; the drilling tool assembly is lifted to the position 0.5-1 m above the resistance meeting point, and in the lifting process, magnetic and non-magnetic substances are fished under the action of upward returning, eddy current and magnetic force carried by drilling fluid; when the pumping is stopped, the displacement is gradually reduced until the pumping is stopped, upward magnetic and non-magnetic substances carried by the drilling fluid descend to a magnet area of the fishing device while drilling and are adsorbed by magnetic force, and the substances which are not adsorbed by the magnetic force fall into the cup body. By means of the salvage method, the service life of the drilling tool is prolonged, underground accidents are reduced and prevented, the tripping times are effectively reduced, and the salvage efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling technology, and more specifically, to a method for fishing while drilling. Background Technology

[0002] In oil and gas drilling operations, to maintain a clean well bottom, extend the lifespan of drill bits or milling tools, and reduce and prevent downhole accidents, a drilling retrieval cup is often installed on the drill bit. This cup is used to retrieve heavier iron filings and metal debris that cannot be carried out of the wellbore during normal drilling fluid circulation, such as casing accessories, drill bit bearings, and drill bit teeth (magnetic and non-magnetic objects). However, due to the large outer diameter of the drilling retrieval cup and the small clearance between it and the wellbore annulus, and the small diameter of the mandrel at the cup opening and the large clearance between it and the wellhead annulus, the drilling fluid velocity drops sharply at the cup opening, creating a vortex that pulls the rock cuttings generated during drilling into the cup. Furthermore, the limited volume of the drilling retrieval cup means that there is insufficient space to hold the magnetic and non-magnetic objects generated after drilling, preventing the well bottom from remaining clean and increasing drill string wear and the risk of stuck pipe.

[0003] Chinese patent application number "202121365284.6" entitled "A Ring-Shaped Strong Magnetic Multifunctional Salvage Device" discloses a ring-shaped strong magnetic multifunctional salvage device. This device has an upper connector at the upper end of the mandrel and a lower connector at the lower end. An upper stabilizing sleeve is connected to the outer wall of the upper end of the mandrel, and a ring-shaped magnetic sleeve is located at the lower end of the upper stabilizing sleeve. The ring-shaped magnetic sleeve is fitted onto the mandrel, and its lower end is limited by a stop block, which is fixed to the mandrel. A salvage cup is connected to the lower outer wall of the mandrel, and a lower stabilizing sleeve is located at the lower end of the salvage cup, connected to the lower outer wall of the mandrel. This patent enables the salvage of both ferromagnetic and non-magnetic debris during salvage operations, ensuring the cleanliness of the casing inner wall and facilitating the normal operation of the drilling tools. However, this application has a different structure. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to solve one or more of the problems existing in the prior art. For example, one objective of this invention is to provide a drilling and retrieval method that is highly feasible, can effectively retrieve magnetic and non-magnetic objects while drilling, keeps the bottom of the well clean, and reduces and prevents downhole accidents.

[0005] To achieve the above objectives, the present invention provides a method for fishing while drilling. This method utilizes a fishing while drilling assembly including a fishing while drilling device. The fishing while drilling device includes: an upper connector, a body, a mandrel, and a lower connector that can be connected sequentially. The upper connector has threads on its upper part for connecting to the drilling tool; the body has a magnetic area for attracting magnetic materials; the lower part of the mandrel has a cup sleeve, which connects to the lower connector to form a cup body for containing non-magnetic materials. The fishing method may include the following steps: [The text abruptly ends here, so the translation stops.] The drill string is lowered to the predetermined distance within the well. The drilling fluid is circulated by pumping, with a flow rate sufficient to ensure that both magnetic and non-magnetic materials are flushed and returned to the surface. The drill string assembly is then lowered to explore the bottom of the well, stopping when resistance is encountered. The drill string assembly is then raised to 0.5–1 m above the point of resistance. During the raising process, the magnetic and non-magnetic materials are retrieved using the upward flow of the drilling fluid, eddies, and magnetic forces. The flow rate is gradually reduced until the pump is stopped. The magnetic and non-magnetic materials carried upward by the drilling fluid descend to the magnetic area of ​​the drilling retrieval device and are attracted by the magnetic force. Materials not attracted by the magnetic force fall into the cup.

[0006] According to one or more exemplary embodiments of the present invention, the displacement may be 1.2 to 1.5 times the displacement of normal drilling, milling or sleeve milling operations.

[0007] According to one or more exemplary embodiments of the present invention, the drilling and fishing assembly can be a drilling and milling assembly, and the step of continuing to lower the assembly can include: rotating the drill string and lowering the assembly to explore the bottom of the well, and stopping the lowering after encountering resistance of 10-20 kN.

[0008] According to one or more exemplary embodiments of the present invention, a wait of 1 to 3 minutes may be made after the cessation of lowering.

[0009] According to one or more exemplary embodiments of the present invention, the drilling and fishing tool assembly may be a drilling and milling tool assembly, and the further lowering of the drilling tool assembly may include: lowering the drilling tool assembly to the top of the fish, and stopping the lowering after encountering resistance of 5 to 10 kN.

[0010] According to one or more exemplary embodiments of the present invention, during the process of lowering the drill string assembly to explore the top of the fish, if the lowering depth exceeds the theoretical top well depth of the fish by 2m without encountering any obstruction, the lowering of the drill string can be stopped.

[0011] According to one or more exemplary embodiments of the present invention, if the drilling tool assembly is not obstructed when the lowering depth exceeds the theoretical top depth of the fish landing point by 2m, it can be slowly raised to 0.5 to 1m above the theoretical top depth of the fish landing point.

[0012] According to one or more exemplary embodiments of the present invention, after the lifting drill string assembly is moved to a position 0.5 to 1 m above the obstruction point, the retrieval method may further include rotating the drill string.

[0013] According to one or more exemplary embodiments of the present invention, the lifting drill assembly may include slow lifting, the speed of which may be 0.05 to 0.10 m / s.

[0014] According to one or more exemplary embodiments of the present invention, the stepwise reduction of discharge to stop the pump may include: reducing the pump discharge by 10% as one step, waiting 10 to 20 seconds after each reduction in discharge before continuing the reduction operation until the pump stops; after stopping the pump, waiting 1 to 3 minutes before proceeding to the next step.

[0015] According to one or more exemplary embodiments of the present invention, the retrieval method may further include: repeating all the processes of starting the pump and circulating the drilling fluid until the pump is gradually reduced to stop, performing drilling milling or casing milling operations, continuing to repeat all the processes of starting the pump and circulating the drilling fluid until the pump is gradually reduced to stop after the drilling milling or casing milling operations are completed, and finally circulating and retrieving the drill string assembly.

[0016] According to one or more exemplary embodiments of the present invention, the magnet region may include an upper magnet region and a lower magnet region, the upper magnet region being disposed on the upper part of the body, and the lower magnet region being disposed on the lower part of the body and located on the back slope of the upper magnet region.

[0017] According to one or more exemplary embodiments of the present invention, the accommodating space between the upper and lower chamfered surfaces of the magnet region may be an adsorption region to accommodate magnetic materials.

[0018] According to one or more exemplary embodiments of the present invention, the adsorption region may include an upper adsorption region and a lower adsorption region, the upper adsorption region and the lower adsorption region corresponding to the upper magnet region and the lower magnet region, respectively.

[0019] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0020] (1) The drilling and retrieval method provided by the present invention effectively improves the service life of the drilling tools, reduces and prevents downhole accidents, effectively reduces the number of trips to and from the well, and improves the efficiency and effectiveness of retrieval of magnetic and non-magnetic materials at the bottom of the well.

[0021] (2) The drilling and fishing method provided by the present invention can achieve the purpose of combined fishing of magnetic and non-magnetic materials. Under the combined fishing conditions of pump start-up and pump stop, it can effectively adsorb and fish out magnetic and non-magnetic materials generated in the well before drilling, milling or milling, during drilling, milling or milling, and after drilling, milling or milling.

[0022] (3) The drilling and retrieval device used in this invention has high body strength, convenient connection, and wide coverage. It can be used in left-hand and right-hand rotary drilling and milling and sleeve milling tool combinations. It is convenient to process, install and disassemble, and facilitates the maintenance and replacement of strong magnet blocks and cup sleeves in the magnet area.

[0023] (4) The adsorption zone and holding zone of the drilling fishing device used in this invention have large capacity, which can effectively improve the fishing efficiency and keep the bottom of the well clean. Attached Figure Description

[0024] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A schematic diagram of the method for salvage using a drilling and milling tool assembly in Example 1 of the present invention is shown.

[0026] Figure 2 A schematic flowchart of the method for salvage using a drilling and milling tool assembly in Example 2 of the present invention is shown.

[0027] Figure 3 A schematic diagram of the drilling and retrieval device in Example 3 of the present invention is shown;

[0028] Figure 4 A schematic diagram of the drilling and fishing device in Example 4 of the present invention is shown;

[0029] Figure 5A A schematic diagram of a drilling and milling tool assembly for retrieval during drilling, as shown in Example 5 of the present invention, is presented.

[0030] Figure 5B This diagram illustrates another structural schematic of the drilling-while-drilling-milling-fishing assembly in Example 5 of the present invention.

[0031] Figure 6 A schematic diagram of the drilling tool assembly for milling and fishing while drilling is shown in Example 6 of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1-Upper connector, 2-Body, 3-Mandrel, 4-Lower connector, 51-Upper magnet area, 52-Lower magnet area, 61-Upper adsorption area, 62-Lower adsorption area, 7-Cup sleeve, 8-Drain hole, 91-First female thread, 92-Second female thread, 93-First male thread, 10-Flow channel, 100-Drill bit, 200-Drilling fishing device, 300-Drill tool check valve, 400-Drill collar, 500-Drill rod, 600-Milling tool, 700-Grinding tool. Detailed Implementation

[0034] In the following description, a highly feasible drilling and fishing method, a drilling and fishing device that can effectively retrieve magnetic and non-magnetic objects while drilling, keep the bottom of the well clean, reduce and prevent downhole accidents, and a drilling and fishing tool assembly that can improve the service life of drilling and milling tools and sleeve milling tools will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0035] In the description of this application, it should be understood that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] Exemplary Example 1

[0038] This exemplary embodiment provides a method for fishing while drilling. The method can use a fishing while drilling assembly, including a fishing while drilling device, for fishing. The fishing while drilling device may include: an upper connector, a body, a mandrel, and a lower connector that can be connected sequentially. The upper connector has threads on its upper part for connecting to the drilling tool; the body has a magnetic area for attracting magnetic materials; the lower part of the mandrel has a cup sleeve, which connects to the lower connector to form a cup body for containing non-magnetic materials. The fishing method may include the following steps: running the fishing assembly into the well. Position the drill string at the predetermined distance; start the pump to circulate the drilling fluid, ensuring the flow rate is sufficient to flush and return magnetic and non-magnetic materials; continue lowering the drill string assembly to explore the bottom of the well, stopping when resistance is encountered; raise the drill string assembly to 0.5–1 m above the resistance point, using the drilling fluid's upward flow, eddy currents, and magnetic force to retrieve magnetic and non-magnetic materials during the raising process; gradually reduce the flow rate until the pump stops, allowing the drilling fluid to carry the upward-flowing magnetic and non-magnetic materials down to the magnetic area of ​​the drilling retrieval device, where they are magnetically attracted. Materials not magnetically attracted fall into the cup.

[0039] In this exemplary embodiment, the displacement of the circulating drilling fluid can be 1.2 to 1.5 times that of normal drilling, milling, or casing milling operations, for example, 1.25 times, 1.3 times, or 1.4 times.

[0040] In this exemplary embodiment, the drilling-while-drilling (DWD) fishing assembly can be a DWD milling and fishing assembly. The step of continuing to lower the assembly may include: rotating the drill string and lowering the assembly to explore the bottom of the well, stopping the lowering after encountering resistance of 10-20 kN (e.g., 11 kN, 13 kN, 15 kN, 17 kN, or 19 kN). After stopping the lowering, a wait of 1-3 minutes (e.g., 1.5 minutes, 2 minutes, or 2.5 minutes) can be allowed, relying on the flushing of the drilling fluid and the rotation of the drill bit or milling tool to agitate, crush, and mill, so that magnetic and non-magnetic objects of different sizes buried at the bottom of the well by cuttings or drilling fluid material can be effectively and fully returned to the surface under different drilling fluid densities.

[0041] In this exemplary embodiment, the drilling and fishing assembly can be a drilling and milling assembly. Continuing to lower the assembly may include: lowering the assembly to probe the top of the fish-shaped surface, stopping the lowering after encountering resistance of 5-10 kN, for example, 6 kN, 7 kN, or 9 kN. During the process of lowering the assembly to probe the top of the fish-shaped surface, if no resistance is encountered before the lowering depth exceeds the theoretical fish-shaped surface depth by 2 m, the lowering of the assembly can be stopped. Simultaneously, the assembly can be slowly raised to 0.5-1 m above the theoretical fish-shaped surface depth.

[0042] In this exemplary embodiment, after the drill string assembly is raised to a position 0.5 to 1 m above the obstruction point, the retrieval method may further include rotating the drill string. Raising the drill string assembly may include slow raising, and the slow raising speed may be 0.05 to 0.10 m / s, for example, 0.06 m / s, 0.07 m / s, or 0.09 m / s.

[0043] In this exemplary embodiment, gradually reducing the discharge rate until the pump stops may include: reducing the pump discharge rate by 10% as one stage, waiting 10 to 20 seconds after each stage of reduction before continuing to reduce the discharge rate until the pump stops, and waiting 1 to 3 minutes after stopping the pump before proceeding to the next step.

[0044] In this exemplary embodiment, the retrieval method may further include: repeating the entire process of starting the pump to circulate the drilling fluid until the displacement is gradually reduced to the point of stopping the pump, followed by drilling-milling or casing-milling operations; after the drilling-milling or casing-milling operations are completed, continuing to repeat the entire process of starting the pump to circulate the drilling fluid until the displacement is gradually reduced to the point of stopping the pump; and finally, circulating and retrieving the drill string assembly. Here, the number of times the entire process of starting the pump to circulate the drilling fluid until the displacement is gradually reduced to the point of stopping the pump can be greater than or equal to three times.

[0045] In this exemplary embodiment, the magnet region may include an upper magnet region and a lower magnet region. The upper magnet region is disposed on the upper part of the body, and the lower magnet region is disposed on the lower part of the body, located on the back slope of the upper magnet region. The accommodating space between the chamfered surfaces of the upper and lower parts of the magnet region may be an adsorption region to accommodate magnetic materials. The adsorption region may include an upper adsorption region and a lower adsorption region, which correspond to the upper and lower magnet regions, respectively. Multiple grooves are provided within the magnet region, and magnet blocks are installed within the grooves and fixed with magnetic steel pressure plates to form a magnetic surface. Fixing holes are provided within the magnet region and on the magnetic steel pressure plate, and the magnetic steel pressure plate and magnet blocks are limited and fixed by fastening bolts. The cup sleeve is threadedly connected to the upper part of the lower connector. Multiple drainage holes are provided at the lower part of the cup sleeve, and the number of drainage holes may include 2, 4, or 8. The length of the upper connector is 300-500mm, for example, 330mm, 360mm, 390mm, 420mm, 450mm, 470mm or 490mm, and the length of the lower connector is 350-550mm, for example, 355mm, 375mm, 395mm, 415mm, 435mm, 485mm, 505mm, 525mm or 545mm.

[0046] To further illustrate the above exemplary embodiment 1, a more detailed description will be provided below with reference to specific examples.

[0047] Example 1

[0048] This example provides a method for salvage using a drill-while-drilling milling and retrieval tool assembly. Figure 1A schematic diagram of the process for salvage using a drilling and milling tool assembly in Example 1 of the present invention is shown.

[0049] In this example, such as Figure 1 As shown, the method for salvaging using a drilling-while-drilling milling and fishing tool assembly may include the following steps:

[0050] S1. Assembled drilling and milling / fishing drill bit assembly. Assemble the drill bit or milling tool, drilling and fishing device, drill check valve, drill collar, and drill pipe. The drill bit or milling tool, drilling and fishing device, drill check valve, drill collar, and drill pipe are connected sequentially from bottom to top by threads and tightened to the specified torque.

[0051] S2. Lower the drill bit or milling tool assembly into the well, 5-10m from the bottom of the well. Lower the bottom end face of the drill bit or milling tool assembly into the well, 5-10m from the bottom of the well.

[0052] S3. Start the pump to circulate the drilling fluid. The displacement should be 1.2 to 1.5 times that of normal drilling and milling operations, for example, 1.25 times, 1.3 times, or 1.4 times, to ensure that magnetic and non-magnetic objects can be flushed by the drilling fluid and achieve the purpose of upward return.

[0053] S4. Rotate the drill string and lower it to the bottom of the well. Use the rotary table or top drive to rotate the drill string at 10 rpm / min and lower it to the bottom of the well. Stop lowering when encountering resistance of 10-20 kN. The drilling fluid and the rotation of the drill bit will then move, crush, and grind the magnetic and non-magnetic objects buried in the drilling fluid at the bottom of the well. These objects will be carried back by the drilling fluid and retrieved by eddy currents and magnetic forces. Wait 1-3 minutes before proceeding to the next step. Lowering the drill string at a low rotation speed effectively prevents the centrifugal force caused by high rotation speeds, which could lead to collisions between the drilling and milling tools and the wellbore, causing premature damage to the lower tools. Once the bottom is reached, the rotation speed can be increased to begin the drilling and milling operation.

[0054] S5. Slowly raise the drill string 0.5-1m. During the raising of the drill string, the drilling fluid carries the upward flow, eddy current, and magnetic force to retrieve magnetic and non-magnetic objects again. This also leaves a safe space for the next step of stopping the pump and space for magnetic and non-magnetic objects to sink, preventing the drill bit from getting stuck due to magnetic and non-magnetic objects accumulating on it while the drill bit is at the bottom of the well, and also preventing the drill string from having no space to move to release the stuck drill string.

[0055] S6. Gradually reduce the pump flow rate until the pump stops. Each reduction of 10% of the pump flow rate in step S3 is considered one stage. After each stage of reduction, wait 10-20 seconds before continuing the reduction until the pump stops. After stopping the pump, wait 1-3 minutes before proceeding to the next step. As the drilling fluid flow rate decreases until the pump stops, the magnetic and non-magnetic objects carried upwards by the drilling fluid slowly descend to the magnetic area of ​​the drilling rig's retrieval device, where they are magnetically attracted. Metal objects not attracted by the magnetism fall into the cup, achieving the combined retrieval purpose of the drilling rig and improving the retrieval efficiency and effectiveness for both magnetic and non-magnetic objects.

[0056] After repeating steps S3 to S6 three times or more, start the drilling and milling operation. After the drilling and milling operation is completed, repeat steps S3 to S6 three times or more, then cycle and pull out the drill bit.

[0057] In this example, a combined retrieval of magnetic and non-magnetic objects was achieved before, during, and after drilling and milling. Under the combined retrieval conditions of pump start-up and pump shutdown, magnetic and non-magnetic objects generated in the well during these three stages were effectively adsorbed and retrieved. This maintained a clean well bottom, improved the service life of drilling and milling tools and drill strings, reduced and prevented downhole accidents, effectively reduced the number of trips to and from the well, and avoided the need for multiple trips to retrieve magnetic and non-magnetic objects from the well bottom due to ineffective retrieval.

[0058] Example 2

[0059] This example provides a method for salvage using a drilling and milling tool assembly. Figure 2 A schematic diagram of the method for salvage using a drilling and milling tool assembly in Example 2 of the present invention is shown.

[0060] In this example, such as Figure 2 As shown, the method for salvaging using a drilling tool assembly with a milling and retrieving sleeve may include the following steps:

[0061] S1. Assembled Milling and Fishing Drill String Assembly. Assemble the milling tool, drilling fishing device, drill string check valve, drill collar, and drill pipe. The milling tool, drilling fishing device, drill string check valve, drill collar, and drill pipe are connected sequentially from bottom to top by threads and tightened to the specified torque.

[0062] S2. Lower the drill string assembly into the well 5-10m from the top of the fish. Lower the bottom end face of the milling and fishing tool assembly, i.e., the bottom end face of the milling tool, into the well 5-10m from the top of the fish.

[0063] S3. Start the pump to circulate the drilling fluid. The displacement should be 1.2 to 1.5 times that of normal milling operations, for example, 1.25 times, 1.3 times, or 1.4 times, to ensure that magnetic and non-magnetic objects can be flushed by the drilling fluid and achieve the purpose of upward return.

[0064] S4. Lowering the drill string to probe the top of the fish. Lower the drill string to probe the top of the fish. Stop lowering after encountering resistance of 5-10 kN. If the lowering depth exceeds the theoretical fish-top depth by 2m without encountering resistance, stop lowering the drill string.

[0065] S5. Slowly raise the drill string 0.5–1 m. Slowly raise the drill string to 0.5–1 m above the point of obstruction. If the lowering depth exceeds the theoretical top depth of the fish without encountering obstruction by 2 m, then slowly raise the drill string to 0.5–1 m above the theoretical top depth of the fish. Use a rotary table or top drive device to rotate the drill string at a speed of 10 rpm / min. During the raising of the drill string, the drilling fluid carries the upward flow, eddies, and magnetic forces to retrieve magnetic and non-magnetic objects. Here, using a low rotation speed to probe the bottom effectively prevents the centrifugal force of the entire drill string caused by high rotation speed, which could lead to collisions between the milling tools and the well wall and premature damage to the lower tools. Once the bottom is reached, the rotation speed can be increased to begin the drilling and milling operation.

[0066] S6. Gradually reduce the pump flow rate until the pump stops. Each reduction of 10% of the pump flow rate in step S3 is considered one stage. After each stage of reduction, wait 10-20 seconds before continuing the reduction until the pump stops. After stopping the pump, wait 1-3 minutes before proceeding to the next step. As the drilling fluid flow rate decreases until the pump stops, the magnetic and non-magnetic objects carried upwards by the drilling fluid slowly descend to the magnetic area of ​​the drilling rig's retrieval device, where they are magnetically attracted. Metal objects not attracted by the magnetism fall into the cup, achieving the combined retrieval purpose of the drilling rig and improving the retrieval efficiency and effectiveness for both magnetic and non-magnetic objects.

[0067] After repeating steps S3 to S6 three times or more, start the milling operation. After the milling operation is completed, repeat steps S3 to S6 three times or more to increase the flow rate circulation. The flow rate can be increased to 1.2 to 1.5 times that of the normal milling operation, for example, 1.25 times, 1.3 times or 1.4 times. Raise the drill string to 0.5 to 1m above the top of the fish, insert heavy slurry, and then take out the drill string.

[0068] In this example, a combined retrieval of magnetic and non-magnetic objects was achieved before, during, and after milling. Under the combined retrieval conditions of pump start-up and pump stop-up, magnetic and non-magnetic objects generated in the well during these three stages were effectively adsorbed and retrieved. This maintained a clean well bottom, improved the service life of the milling tools and drill string, reduced and prevented downhole accidents, effectively reduced the number of trips, and avoided the need for multiple trips to retrieve magnetic and non-magnetic objects from the well bottom due to ineffective retrieval. A heavy slurry was placed on top of the fallen object, suspending the magnetic and non-magnetic objects above it and preventing sedimentation that could bury the object. This provided a safety guarantee for the smooth progress of the subsequent milling and backfilling retrieval operation.

[0069] Example 3

[0070] This example provides a drilling and salvage device. Figure 3 A schematic diagram of the drilling and salvage device in Example 3 of the present invention is shown.

[0071] In this example, such as Figure 3 As shown, the drilling rig may include an upper connector 1, a body 2, a mandrel 3, and a lower connector 4 that can be connected in sequence.

[0072] The upper connector 1 has threads on its upper part for connecting to the drill string. The length of the upper connector can be 300-500mm, for example, 330mm, 360mm, 390mm, 420mm, 450mm, 470mm or 490mm. It has a first female thread 91 on its upper part, which not only provides the space required for connecting and unloading the drill string at the wellhead, but also allows for thread trimming, extends the service life of the device, and ensures the overall strength of the device. The body 2 has a magnetic area to attract magnetic materials, and the body can be cylindrical. The lower part of the mandrel 3 has a cup sleeve 7, which connects to the lower connector 4 to form a cup body for containing non-magnetic materials. The drilling and fishing device may also include a flow channel 10 to allow drilling fluid circulation.

[0073] In this example, the magnet area may include an upper magnet area 51 and a lower magnet area 52. The upper magnet area 51 is located on the upper part of the body 2, and the lower magnet area 52 is located on the lower part of the body 2, situated on the back slope of the upper magnet area 51. Multiple grooves may be provided within the magnet area, and magnet blocks are installed within these grooves and fixed with magnetic steel pressure plates to form a magnetic surface. Fixing holes may be provided within the magnet area and on the magnetic steel pressure plate, allowing for the positioning and fixing of the magnetic steel pressure plate and magnet blocks using fastening bolts.

[0074] In this example, the space between the chamfered surfaces of the upper and lower parts of the magnet region can be an adsorption region to accommodate magnetic materials. The adsorption region may include an upper adsorption region 61 and a lower adsorption region 62, which correspond to the upper magnet region 51 and the lower magnet region 52, respectively.

[0075] In this example, the cup sleeve and the upper part of the lower connector are threaded together. The length of the lower connector can be 350-550mm, for example, 355mm, 375mm, 395mm, 415mm, 435mm, 485mm, 505mm, 525mm, or 545mm. The upper end of the lower connector is provided with a male thread, and the lower part is provided with a second female thread 92. This not only meets the space required for connecting and unloading drill tools at the wellhead, but also leaves room for repairing the female thread, which can extend the service life of the device and ensure the strength of the entire device. The lower end of the cup sleeve is provided with a female thread, which connects with the male thread at the upper end of the lower connector, allowing for disassembly, repair, and replacement. The upper end of the cup sleeve is provided with a chamfer, forming a cup mouth with the mandrel. The lower part of the cup sleeve 7 can be provided with multiple drainage holes 8, the number of which can be 2, 4, or 8.

[0076] Example 4

[0077] This example provides another drilling and salvage device. Figure 4 A schematic diagram of the drilling and salvage device in Example 4 of the present invention is shown.

[0078] In this example, such as Figure 4 As shown, the drilling rig may include an upper connector 1, a body 2, a mandrel 3, and a lower connector 4 that can be connected in sequence.

[0079] The upper connector 1 has threads on its upper part for connecting to the drill string. The length of the upper connector can be 300-500mm, for example, 330mm, 360mm, 390mm, 420mm, 450mm, 470mm or 490mm. It has a first female thread 91 on its upper part, which not only provides the space required for connecting and unloading the drill string at the wellhead, but also allows for thread trimming, extends the service life of the device, and ensures the overall strength of the device. The body 2 has a magnetic area to attract magnetic materials, and the body can be cylindrical. The lower part of the mandrel 3 has a cup sleeve 7, which connects to the lower connector 4 to form a cup body for containing non-magnetic materials. The drilling and fishing device may also include a flow channel 10 to allow drilling fluid circulation.

[0080] In this example, the magnet area may include an upper magnet area 51 and a lower magnet area 52. The upper magnet area 51 is located on the upper part of the body 2, and the lower magnet area 52 is located on the lower part of the body 2, situated on the back slope of the upper magnet area 51. Multiple grooves may be provided within the magnet area, and magnet blocks are installed within these grooves and fixed with magnetic steel pressure plates to form a magnetic surface. Fixing holes may be provided within the magnet area and on the magnetic steel pressure plate, allowing for the positioning and fixing of the magnetic steel pressure plate and magnet blocks using fastening bolts.

[0081] In this example, the space between the chamfered surfaces of the upper and lower parts of the magnet region can be an adsorption region to accommodate magnetic materials. The adsorption region may include an upper adsorption region 61 and a lower adsorption region 62, which correspond to the upper magnet region 51 and the lower magnet region 52, respectively.

[0082] In this example, the cup sleeve and the upper part of the lower connector are threaded together. The length of the lower connector can be 350-550mm, for example, 355mm, 375mm, 395mm, 415mm, 435mm, 485mm, 505mm, 525mm, or 545mm. The upper end of the lower connector is provided with a male thread, and the lower part is provided with a first male thread 93. This not only meets the space required for connecting and unloading drill tools at the wellhead, but also leaves room for repairing the male thread, which can extend the service life of the device and ensure the strength of the entire device. The lower end of the cup sleeve is provided with a female thread, which connects with the male thread at the upper end of the lower connector, allowing for disassembly, repair, and replacement. The upper end of the cup sleeve is provided with a chamfer, forming a cup mouth with the mandrel. The lower part of the cup sleeve 7 can be provided with multiple drainage holes 8, the number of which can be 2, 4, or 8.

[0083] Example 5

[0084] This example provides a drill-while-drilling milling and fishing tool assembly. Figure 5A A schematic diagram of a drilling and milling tool assembly for retrieval during drilling, as shown in Example 5 of the present invention, is presented. Figure 5B This diagram illustrates another structural schematic of the drilling and milling tool assembly for fishing in Example 5 of the present invention.

[0085] In this example, such as Figure 5A As shown, the drilling and milling fishing assembly may include a drill bit 100, a drilling fishing device 200, a drill check valve 300, a drill collar 400, and a drill pipe 500, and the drill bit 100, the drilling fishing device 200, the drill check valve 300, the drill collar 400, and the drill pipe 500 are connected in sequence from bottom to top by threads.

[0086] In this example, such as Figure 5BAs shown, the drilling milling and fishing drill assembly may include a milling tool 700, a drilling fishing device 200, a drill check valve 300, a drill collar 400, and a drill pipe 500, and the milling tool 700, the drilling fishing device 200, the drill check valve 300, the drill collar 400, and the drill pipe 500 are connected in sequence from bottom to top by threads.

[0087] Example 6

[0088] This example provides a drill string assembly for milling and retrieving tools while drilling. Figure 6 A schematic diagram of the drilling tool assembly for milling and fishing while drilling is shown in Example 6 of the present invention.

[0089] In this example, such as Figure 6 As shown, the drilling and milling retrieval assembly may include a milling tool 600, a drilling retrieval device 200, a drill string check valve 300, a drill collar 400, and a drill pipe 500, and the milling tool 600, the drilling retrieval device 200, the drill string check valve 300, the drill collar 400, and the drill pipe 500 are connected by threads from bottom to top.

[0090] In summary, the advantages proposed by this invention include at least the following:

[0091] (1) The drilling and retrieval tool assembly used in this invention is highly practical. It can achieve all-round adsorption, retrieval and container of magnetic and non-magnetic objects generated during drilling and milling operations, thereby avoiding wear of the drilling tool by magnetic and non-magnetic objects.

[0092] (2) The drilling and retrieval tool assembly used in this invention can be reused after the magnetic and non-magnetic objects in the adsorption area and cup body are cleaned up after the drilling is brought out of the ground.

[0093] (3) The drilling and retrieval method provided by the present invention can reduce the number of trips to and from the well, and avoid the need for multiple trips to and from the well to retrieve magnetic and non-magnetic objects at the bottom of the well due to the inability to effectively retrieve the wellbore.

[0094] Although the invention has been described above in conjunction with exemplary embodiments, those skilled in the art will understand that various modifications and changes can be made to the exemplary embodiments of the invention without departing from the spirit and scope defined by the claims.

Claims

1. A method for fishing while drilling, characterized in that, The retrieval method uses a drilling rig assembly including a drilling rig retrieval device. The drilling rig retrieval device includes an upper connector, a body, a mandrel, and a lower connector that can be connected in sequence. The upper connector has threads on its upper part to connect to the drilling rig. The body has a magnet area to attract magnetic materials. The lower part of the mandrel has a cup sleeve, which is connected to the lower connector to form a cup body for containing non-magnetic materials. The salvage method includes the following steps: The retrieval drilling assembly is lowered to the predetermined distance within the well. When the pump is turned on to circulate the drilling fluid, the discharge rate must be sufficient to ensure that magnetic and non-magnetic substances can be flushed out by the drilling fluid and return upwards. Continue lowering the drill string assembly, and stop lowering it if resistance is encountered. Raise the drill string assembly to 0.5 to 1 m above the point of obstruction. During the raising process, magnetic and non-magnetic materials are retrieved by the upward flow of drilling fluid, eddy currents, and magnetic forces. The pump is gradually reduced until it stops. The magnetic and non-magnetic materials carried upward by the drilling fluid descend to the magnetic area of ​​the drilling rig and are attracted by the magnetic force. The materials that are not attracted by the magnetic force fall into the cup.

2. The drilling and fishing method according to claim 1, characterized in that, The displacement is 1.2 to 1.5 times that of normal drilling, milling, or kit milling operations.

3. The drilling and fishing method according to claim 1, characterized in that, The drilling and retrieval assembly is a drilling and milling retrieval assembly. The step of continuing to lower the assembly includes: rotating the drill string and lowering the assembly to explore the bottom of the well, and stopping the lowering after encountering resistance of 10-20 kN.

4. The drilling and fishing method according to claim 3, characterized in that, Wait 1 to 3 minutes after the descent is stopped.

5. The drilling and fishing method according to claim 1, characterized in that, The drilling and fishing tool assembly is a drilling and milling tool assembly. The step of continuing to lower the tool assembly includes: lowering the tool assembly to probe the top of the fish, and stopping the lowering after encountering resistance of 5-10 kN.

6. The drilling and fishing method according to claim 5, characterized in that, During the process of lowering the drill string assembly to explore the top of the fish, if the lowering depth exceeds the theoretical top depth of the fish by 2m without encountering any resistance, the lowering of the drill string shall be stopped.

7. The drilling and fishing method according to claim 6, characterized in that, If the drill string assembly is lowered to a depth 2m above the theoretical top depth of the fish without encountering any obstruction, it is then slowly raised to a depth 0.5 to 1m above the theoretical top depth of the fish.

8. The drilling and fishing method according to claim 1, characterized in that, After the drill string assembly is raised to a position 0.5 to 1 m above the obstruction point, the retrieval method further includes rotating the drill string.

9. The drilling and fishing method according to claim 1, characterized in that, The lifting drill bit assembly includes a slow lifting motion at a speed of 0.05–0.1 m / s.

10. The drilling and fishing method according to claim 1, characterized in that, The stepwise reduction of discharge volume to stop the pump includes: reducing the pump discharge volume by 10% as one step, waiting 10-20 seconds after each reduction in discharge volume before continuing the reduction operation until the pump stops; after stopping the pump, waiting 1-3 minutes before proceeding to the next step.

11. The drilling and fishing method according to claim 1, characterized in that, The salvage method further includes: repeating the process of starting the pump and circulating the drilling fluid until the pump is gradually reduced to stop, then performing drilling milling or milling operations; after the drilling milling or milling operations are completed, continuing to repeat the process of starting the pump and circulating the drilling fluid until the pump is gradually reduced to stop, and finally circulating and retrieving the drill string assembly.

12. The drilling and fishing method according to claim 1, characterized in that, The magnet region includes an upper magnet region and a lower magnet region. The upper magnet region is located on the upper part of the body, and the lower magnet region is located on the lower part of the body and is situated on the back slope of the upper magnet region.

13. The drilling and fishing method according to claim 12, characterized in that, The space between the upper and lower chamfered surfaces of the magnet region is an adsorption region to accommodate magnetic materials.

14. The drilling and fishing method according to claim 13, characterized in that, The adsorption region includes an upper adsorption region and a lower adsorption region, which correspond to the upper magnet region and the lower magnet region, respectively.

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