Coiled tubing butt joint well descending method

Abstract

The invention discloses a coiled tubing butt joint well descending method, and relates to the field of downhole operation. The problem that only the coiled tubing meeting the depth can be replaced in ultra-deep well and long horizontal well operation is solved. Comprising the following steps: S1, preparation before construction; s2, the coiled tubing on the first skid-mounted roller penetrates through an injection head and then is put into a well, a blowout preventer slip and a semi-closed flashboard are closed, a blowout preventer is disconnected, and the tubing is sheared; s3, the first set of coiled tubing is connected with a lower slip connector; the lower slip connector is connected with a lower rotary joint; s4, after the coiled tubing on the second skid-mounted roller penetrates through an injection head, a slip connector is installed; the upper slip connector is connected with an upper rotary joint; s5, connecting the lower rotary joint with the lower rotary joint to form a lockable rotary joint; the first set of coiled tubing and the second set of coiled tubing are connected and locked through the lockable rotary joint, are in butt joint with a wellhead, and are put into a preset depth for construction operation. According to the coiled tubing butt joint well descending method, the construction time efficiency is improved, and the cost is saved.

Description

Technical Field

[0001] This invention relates to the field of oilfield downhole operations technology, and in particular to a method for running coiled tubing into a well. Background Technology

[0002] In the past, coiled tubing fracturing, drilling bridge plugs, and sand flushing operations all used whole coiled tubing coils. However, when dealing with ultra-deep wells and long horizontal wells, the length of the coiled tubing truck-mounted drum is sometimes insufficient, requiring replacement with coiled tubing of the appropriate depth. This method of replacing tubing reduces construction time and increases production costs. Summary of the Invention

[0003] This invention addresses the problem in the prior art where operations in ultra-deep wells and long horizontal wells require replacing coiled tubing with tubing of the appropriate depth, reducing construction efficiency and increasing production costs. It provides a method for connecting and running coiled tubing in the well. This method uses a lockable rotary joint to connect two coiled tubing reels, effectively overcoming the drawback of insufficient length of the onboard coiled tubing drum, improving construction efficiency, and saving time, labor, and costs.

[0004] The present invention solves its problem through the following technical solution: a method for running coiled tubing into a well, comprising the following steps: S1: Preparations before docking and running-in: Place two sets of skid-mounted rollers with coiled oil pipes on the ground, namely the first skid-mounted roller and the second skid-mounted roller. S2: Activate the first set of skid-mounted rollers. The coiled tubing on the first set of skid-mounted rollers is called the first set of coiled tubing. First, thread the injection head through the coiled tubing on the first set of skid-mounted rollers, lower the first set of coiled tubing into the well, close the blowout preventer slips and the semi-sealing gate, disconnect the blowout preventer, and cut the first set of coiled tubing. S3: The first set of coiled tubing after shearing is connected to the lower slip connector; the lower slip connector is connected to the lower rotary joint. S4: Activate the second set of skid-mounted rollers. The continuous oil pipe on the second set of skid-mounted rollers is called the second set of continuous oil pipes. Thread the continuous oil pipe on the second set of skid-mounted rollers through the injection head. Install the slip connector on the continuous oil pipe below the injection head, i.e., the second set of continuous oil pipes. Connect the upper slip connector to the rotary joint. S5: Connect the upper rotary joint and the lower rotary joint to form a lockable rotary joint; connect and lock the first set of coiled tubing and the second set of coiled tubing through the lockable rotary joint, dock at the wellhead, and run into the predetermined depth for construction operations.

[0005] Furthermore, the preparatory work for the docking and downhole construction in step S1 includes setting up a coiled tubing power unit on the ground.

[0006] Furthermore, in step S2, before the first set of coiled tubing is lowered into the well, the double-sealed single-clamp fracturing tool is connected.

[0007] Furthermore, the dual-seal single-card fracturing tool is equipped with a pressure-controlled switch valve.

[0008] Furthermore, after the tubing is lowered to the predetermined depth for construction work in step S5, the coiled tubing is pulled out.

[0009] Furthermore, the method for retrieving the coiled tubing is as follows: when the lockable rotary joint is moved to the blowout preventer, the blowout preventer is disassembled, the locking connector is disconnected, and the second set of coiled tubing is coiled back.

[0010] Furthermore, after the second set of coiled tubing is reconnected, the tubing inside the well is reversed and the first set of coiled tubing is reconnected at the injection head.

[0011] Furthermore, the construction operation performed in step S5 is coiled tubing fracturing.

[0012] Furthermore, the construction operation performed in step S5 is the drilling and grinding of bridge plugs.

[0013] Furthermore, the construction operation performed in step S5 is a sand flushing operation.

[0014] Compared with the above-mentioned background technology, the present invention has the following beneficial effects: Coiled tubing docking technology is suitable for docking two coiled tubing coils. For ultra-deep wells and long horizontal wells, it eliminates the need to replace the coiled tubing with tubing suitable for the required depth. This improves construction efficiency, saves time and labor, and reduces production costs. It is also suitable for fracturing, drilling bridge plugs, and sand flushing operations. It effectively overcomes the drawback of insufficient length of the coiled tubing roll-mounted drum. Attached Figure Description

[0015] Figure 1 This is a flowchart of the continuous tubing connection and downhole method of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, a method for running coiled tubing into a well includes the following steps: S1: Preparations before docking and running-in: Place a continuous tubing power unit and two sets of skid-mounted rollers with coiled tubing on the ground, namely the first set of skid-mounted rollers and the second set of skid-mounted rollers. S2: Activate the first skid-mounted drum. The coiled tubing on the first skid-mounted drum is called the first coiled tubing. First, thread the injection head through the coiled tubing on the first skid-mounted drum and connect the double-seal single-clamp fracturing tool, which is equipped with a pressure-controlled switch valve. Run the first coiled tubing into the well, close the blowout preventer slips and the half-seal gate, disconnect the blowout preventer, and cut the first coiled tubing. Here, the pressure-controlled switch valve is used to achieve blowout prevention inside the tubing. By using the half-seal gate of the blowout preventer to partially seal, annular blowout prevention can be achieved. The blowout preventer is used to close the annular space between the tubing and the casing. The injection head provides sufficient pushing and pulling force for running and pulling coiled tubing. The main function of the injection head is to provide sufficient thrust to continuously deliver the coiled tubing downhole for construction operations, and to provide sufficient pulling force to smoothly retrieve the coiled tubing after the operations are completed.

[0018] S3: The first set of coiled tubing after shearing is connected to the lower slip connector; the lower slip connector is connected to the lower rotary joint. The clamp connector is used to secure the oil pipe and prevent it from falling off. S4: Activate the second set of skid-mounted rollers. The continuous oil pipe on the second set of skid-mounted rollers is called the second set of continuous oil pipes. Thread the continuous oil pipe on the second set of skid-mounted rollers through the injection head. Install the slip connector on the continuous oil pipe below the injection head, i.e., the second set of continuous oil pipes. Connect the upper slip connector to the rotary joint. S5: Connect the upper rotary joint and the lower rotary joint to form a lockable rotary joint; connect and lock the first set of coiled tubing and the second set of coiled tubing through the lockable rotary joint, dock at the wellhead, and run into the predetermined depth for repeated drag fracturing, drilling and grinding bridge plugs and sand flushing operations.

[0019] After the tubing has been lowered to the predetermined depth for construction operations, the coiled tubing is retrieved. The method for retrieving the coiled tubing is as follows: when the lockable rotary joint is moved to the blowout preventer, the blowout preventer is disassembled, the locking connector is disconnected, and the first coil is re-coiled; the tubing in the well is then reversed through the injection head and re-coiled into the second coil.

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the following description of the invention will be based on a field test of coiled tubing. Example

[0021] Initially, a tubing connection test was conducted at the coiled tubing base. Two coils of 2.3-inch tubing, each 1500 meters long, were connected. Slip connectors and upper and lower rotary joints were installed at the ends of the tubing. After pulling out the tubing from both ends, the rotary joints were connected, and then the tubing from the first drum was recoiled. This test verified the stability and reliability of the tubing connection.

[0022] The invention will be further described in detail below using the Xingfuyu 5-30-Xie 725 well in Daqing Oilfield No. 4 Plant as an example.

[0023] Utilizing the coiled tubing docking method of this invention, the Coiled Tubing Team 4 of the Second Operations Brigade of Daqing Oilfield Well Operations Branch successfully completed the docking and running of two coiled tubing coils in the Xingfuyu 5-30-Xiang 725 well in the Fourth Plant. The well depth is 1781.94m, and the first fracturing depth is 1664m-1667.4m. The experimental team used a 1500m long vehicle-mounted drum coiled tubing. After cutting 338m of the first drum coiled tubing into the well, the tubing was docked with the second drum coiled tubing, which is 1500m long, using docking technology. Slip connectors and upper and lower rotary joints were installed at the ends of the tubing. The first and second sets of coiled tubing were locked together using a lockable rotary joint, docked at the wellhead, and successfully run into the fracturing depth for fracturing operations. This breakthrough expands the application of coiled tubing in fracturing and production enhancement technology.

[0024] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the implementation methods of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the present invention.

Claims

1. A method for running coiled tubing into a well, characterized in that: The following steps are involved: S1: Preparations before docking and running-in: Place two sets of skid-mounted rollers with coiled oil pipes on the ground, namely the first skid-mounted roller and the second skid-mounted roller. S2: Activate the first set of skid-mounted rollers. The coiled tubing on the first set of skid-mounted rollers is called the first set of coiled tubing. First, thread the injection head through the coiled tubing on the first set of skid-mounted rollers, lower the first set of coiled tubing into the well, close the blowout preventer slips and the semi-sealing gate, disconnect the blowout preventer, and then cut the first set of coiled tubing. S3: The first set of coiled tubing after shearing is connected to the lower slip connector, which is connected to the lower rotary joint; S4: Activate the second set of skid-mounted rollers. The continuous oil pipe on the second set of skid-mounted rollers is called the second set of continuous oil pipes. Thread the continuous oil pipe on the second set of skid-mounted rollers through the injection head. Install the slip connector on the second set of continuous oil pipes below the injection head. Connect the upper slip connector to the rotary joint. S5: Connect the upper rotary joint and the lower rotary joint to form a lockable rotary joint; connect and lock the first set of coiled tubing and the second set of coiled tubing through the lockable rotary joint, dock at the wellhead, and run into the predetermined depth for construction operations.

2. The method for running coiled tubing into a well according to claim 1, characterized in that: The preparatory work for step S1, docking and running-in well construction, includes setting up a coiled tubing power unit on the ground.

3. The method for running coiled tubing into a well according to claim 1, characterized in that: Before running the first set of coiled tubing into the well in step S2, connect the double-sealed single-clamp fracturing tool.

4. The method for running coiled tubing into a well according to claim 3, characterized in that: The dual-seal single-card fracturing tool is equipped with a pressure-controlled switch valve.

5. The method for running coiled tubing into a well according to claim 1, characterized in that: After the construction work is completed in step S5 (lowering the tubing to the predetermined depth), the continuous tubing is pulled out.

6. The method for running coiled tubing into a well according to claim 5, characterized in that: The method for retrieving the coiled tubing is as follows: when the lockable rotary joint is moved to the blowout preventer, the blowout preventer is disassembled, the locking connector is disconnected, and the second set of coiled tubing is coiled back.

7. A method for running coiled tubing into a well according to claim 6, characterized in that: After the second set of coiled tubing is reconnected, the tubing inside the well is reversed and the injection head is reconnected to the first set of coiled tubing.

8. The method for running coiled tubing into a well according to claim 1, characterized in that: The construction operation performed in step S5 is coiled tubing fracturing.

9. A method for running coiled tubing into a well according to claim 1, characterized in that: The construction operation performed in step S5 is the drilling and grinding of bridge plugs.

10. A method for running coiled tubing into a well according to claim 1, characterized in that: The construction operation performed in step S5 is a sand flushing operation.

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