Rotary guiding sidetrack drilling method for inclined shaft section

Abstract

The invention relates to the technical field of petroleum well drilling and completion, in particular to an inclined shaft section rotary guiding sidetrack drilling method which comprises the following steps that firstly, a section of cement plug is drilled in an open hole of an inclined shaft section, and the strength of the cement plug meets the design and pressure bearing requirements; 2, plug sweeping operation is conducted, well entering condition evaluation of the rotary steering tool is completed, and continuous construction after the rotary steering tool enters a well is ensured; and thirdly, after plug sweeping operation is completed, a rotary guiding tool is assembled, downward drilling is carried out to the position 4-6 m above the cement plug, and the rotary guiding tool starts up-down borehole scratching and pulling operation to carry out step making operation. In the drilling process, the deflecting capacity of the rotary steering tool is changed in real time, sidetrack drilling operation construction is carried out, the drilling jamming risk caused by sticking and jamming of an underground drilling tool can be effectively reduced, after sidetrack drilling succeeds, pulling-out for drilling tool combination replacement is not needed, the tool face and the deflecting capacity are adjusted by sending an instruction, the lateral force of the rotary steering tool is changed, and the drilling efficiency is improved. And subsequent well sections continue to be constructed, tripping times are reduced, and drilling time efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling and completion, and is a rotary steering side drilling method for an inclined well section. Background Art

[0002] At present, side drilling wells use high-degree single-bend screws or screw drilling tools with bent joints at the bottom to carry out side drilling operations. During the side drilling process, it is necessary to control the sliding drilling for a long time, the drill bit has little activity, the drill bit assembly is in contact with the wellbore wall for a long time, and there is a risk of stuck drill; the zero length of the MWD measurement while drilling instrument in the screw drill bit assembly is 12 to 14 meters, and the measuring point is far away from the drill bit. The borehole trajectory at the drill bit cannot be measured in time through MWD. ​​The separation of the side drilling wellbore and the original wellbore can only be judged by the formation cuttings ratio. During the side drilling process, the formation cuttings are often mixed in the cement, and the accuracy of judging the formation cuttings ratio is not high; due to the lag in calculating the separation of the side drilling wellbore and the original wellbore, it is necessary to wait for the returned formation cuttings to reach 100% and then control the time and direction for 3 to 5 meters before pulling out the drill to replace the drill bit assembly. In this process, the time waiting for the cuttings to return and controlling the drilling is long, which affects the drilling time efficiency; after the side drilling is successful, the screw angle or elbow in the side drilling drill bit assembly is not suitable for the lower trajectory construction, and the drill needs to be pulled out to replace the screw drill bit, which adds one trip to the drill. Therefore, a new rotary steering side drilling method for inclined well sections is needed to reduce the complex risks of downhole accidents, improve the accuracy of side drilling judgment, and improve drilling efficiency, so as to solve the current problems of difficult and low efficiency side drilling of screw drilling tools. Summary of the invention

[0003] The present invention provides a method for rotary steering side drilling of an inclined well section, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of difficult side drilling and low efficiency of the existing screw drilling tools.

[0004] The technical solution of the present invention is achieved by the following measures: A method for rotary steering sidetracking in an inclined well section, comprising the following steps: Step 1: drive a cement plug in the open hole of the inclined well section, and the strength of the cement plug meets the design and pressure requirements; Step 2: Perform plugging operations and complete the well entry condition assessment of the rotary steerable tool to ensure continuous operation after the rotary steerable tool enters the well; Step 3: After the plugging operation is completed, assemble the rotary steerable tool, drill down to 4 to 6 meters above the cement plug, and start to pull the wellbore up and down to create steps; Step 4: During the time-controlled drilling process, the well inclination and azimuth changes near the drill bit are monitored in real time, anti-collision calculation and analysis are performed, and the spatial distance between the side-drilled wellbore and the original wellbore is calculated; Step 5: Determine the formation lithology changes based on the near-bit gamma data and obtain the formation cuttings ratio; Step 6: After confirming that the sidetracking is successful, send a rotary steering command based on the wellbore curvature requirements of the trajectory to be drilled to control the lower wellbore trajectory of the sidetracking.

[0005] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned step four is to calculate the spatial distance between the side-drilled wellbore and the original wellbore based on the well inclination and azimuth data measured near the drill bit during the time-controlled drilling process, evaluate the thickness of the sandwich wall between the side-drilled wellbore and the original wellbore, and change the rotary steering tool command after the thickness of the sandwich wall meets the requirements, and perform normal inclination drilling.

[0006] The fifth step is to determine the formation lithology changes based on the near-bit gamma data and obtain the formation cuttings ratio. If the formation cuttings ratio is greater than 50%, the speed of time-controlled drilling is gradually reduced, and combined with the assessed sandwich wall thickness, it is decided whether to use normal drilling parameters.

[0007] The above-mentioned initial time-controlled drilling speed is 2 to 4 h / m, the time-controlled drilling is 10KN, and then the time-controlled speed and drilling pressure are gradually increased.

[0008] The first step is to drill a cement plug in the open hole of the inclined well section 50 to 100 m above the accident complexity point. The strength of the cement plug meets the following requirements: the drill bit is pressurized to 100 KN without rotation, and there is no back drilling pressure and cement plug sinking.

[0009] The well entry condition assessment described in the above step 2 includes: whether the drilling rig's drilling capability, the surface equipment's pressure bearing capacity, the top drive equipment's torsion resistance, the solids control equipment's purification capability and the overall performance of the drilling fluid all meet the rotary steerable tool drilling requirements.

[0010] In the above step three, the rotary steering tool repeatedly scratches the wellbore up and down at a speed of 1 to 5 min / m at 4 to 6 meters above the cement plug to form a step. The rotary steering tool includes a drill bit, a rotary steering tool, an MWD, a non-magnetic drill collar, a weighted drill pipe and a slope drill pipe connected together in sequence from bottom to top.

[0011] The present invention changes the deflection capability of the rotary steering tool in real time during the drilling process to carry out side drilling operations, which can effectively reduce the risk of drill sticking caused by sticking of the downhole drill bit. After the side drilling is successful, there is no need to pull out the drill bit to replace the drill bit assembly. By sending instructions to adjust the tool face and deflection capability, the lateral force of the rotary steering tool is changed, and the subsequent well section can be continued to be constructed, thereby reducing the number of times the drill bit is pulled out and the drilling time efficiency is improved. DETAILED DESCRIPTION

[0012] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0013] The present invention will be further described below in conjunction with embodiments: Embodiment 1: The method for rotary steering sidetracking in a deviated well section comprises the following steps: Step 1: drive a cement plug in the open hole of the inclined well section, and the strength of the cement plug meets the design and pressure requirements; Step 2: Perform plugging operations and complete the well entry condition assessment of the rotary steerable tool to ensure continuous operation after the rotary steerable tool enters the well; Step 3: After the plugging operation is completed, assemble the rotary steerable tool, drill down to 4 to 6 meters above the cement plug, and start to pull the wellbore up and down to create steps; Step 4: During the time-controlled drilling process, the well inclination and azimuth changes near the drill bit are monitored in real time, anti-collision calculation and analysis are performed, and the spatial distance between the side-drilled wellbore and the original wellbore is calculated; Step 5: Determine the formation lithology changes based on the near-bit gamma data and obtain the formation cuttings ratio; Step 6: After confirming that the sidetracking is successful, send a rotary steering command based on the wellbore curvature requirements of the trajectory to be drilled to control the lower wellbore trajectory of the sidetracking.

[0014] The present invention changes the deflection capability of the rotary steering tool in real time during the drilling process to carry out side drilling operations, which can effectively reduce the risk of drill sticking caused by sticking of the downhole drill bit. After the side drilling is successful, there is no need to pull out the drill bit to replace the drill bit assembly. By sending instructions to adjust the tool face and deflection capability, the lateral force of the rotary steering tool is changed, and the subsequent well section can be continued to be constructed, thereby reducing the number of times the drill bit is pulled out and the drilling time efficiency is improved.

[0015] The above-mentioned rotary steering sidetracking method for inclined well sections can be further optimized and / or improved according to actual needs: Embodiment 2: As an optimization of the above embodiment, step 1 is to drill a cement plug in the open hole of the inclined well section 50 to 100m above the accident complexity point, and the strength of the cement plug meets the following requirements: the drill bit is pressurized to 100KN without rotation, and there is no back drilling pressure and cement plug sinking.

[0016] The well entry condition assessment described in step 2 includes: drilling rig drilling capability, surface equipment pressure bearing capacity, top drive equipment torsional resistance, solid control equipment purification capability and whether all performance of drilling fluid meets the rotary steerable tool drilling requirements.

[0017] In step three, a rotary steerable tool repeatedly scratches the wellbore up and down at a speed of 1 to 5 min / m at 4 to 6 meters above the cement plug to form a step. The rotary steerable tool includes a drill bit, a rotary steerable tool, an MWD, a non-magnetic drill collar, a weighted drill pipe and a slope drill pipe connected together from bottom to top.

[0018] Step four is to calculate the spatial distance between the side-drilled wellbore and the original wellbore based on the well inclination and azimuth data measured near the drill bit during the time-controlled drilling process, evaluate the thickness of the sandwich wall between the side-drilled wellbore and the original wellbore, and change the rotary steering tool command after the thickness of the sandwich wall meets the requirements, and perform normal inclination drilling; the initial time-controlled drilling speed is 2 to 4h / m, the time-controlled drilling is 10KN, and then gradually increase the time-controlled speed and drilling pressure.

[0019] Step five is to determine the formation lithology changes based on the near-bit gamma data and obtain the formation cuttings ratio. If the formation cuttings ratio is greater than 50%, the speed of time-controlled drilling is gradually reduced, and combined with the assessed sandwich wall thickness, it is decided whether to use normal drilling parameters.

[0020] The rotary steerable tool of the present invention can measure well inclination, azimuth, and gamma data, and can change the inclination capability of the rotary steerable tool in real time during drilling to carry out sidetracking operations, which can effectively reduce the risk of drill bit sticking caused by sticking of downhole drill bits. After successful sidetracking, there is no need to pull out the drill bit and replace the drill bit assembly. By sending instructions to adjust the tool face and inclination capability, the lateral force of the rotary steerable tool can be changed to continue construction of subsequent well sections, thereby reducing the number of trips and drills and improving drilling efficiency.

[0021] Take a well in well area 2 as an example. The well was injected with cement from the bottom of the inclined pilot hole into the casing. After waiting for 48 hours, the cement was swept to 3220m and the drilling situation was recorded: the drilling pressure of the rotary steering tool was 40KN, the rotation speed was 60r / min, and the time-controlled drilling speed was 5 to 6min / m; the cement was swept to a depth of 3250m for static pressure bearing: the rotary steering tool was not rotating, and the drilling pressure was increased to 100KN, without back drilling pressure and sinking, which met the quality requirements of the ash plug; During the plugging operation, the drilling rig's drilling capacity, surface equipment's pressure bearing capacity, top drive equipment's torsion resistance, solid control equipment's purification capacity and drilling fluid's overall performance all meet the rotary steerable tool drilling requirements before pulling out of the well, ensuring continuous operation after the rotary steerable tool is put into the well. After the plug sweeping operation is completed, a rotary steering tool is assembled, which includes a drill bit, a rotary steering tool, an MWD, a non-magnetic drill collar, a weighted drill pipe and a slope drill pipe connected together from bottom to top. Specifically, the rotary steering tool includes a Φ165.1mm drill bit + a rotary steering tool + an MWD + a Φ120mm non-magnetic drill collar + 3 Φ101.6mm weighted drill pipes + a Φ101.6mm slope drill pipe connected together; after the rotary steering drilling tool is assembled, drilling begins, and circulating well washing begins when drilling to the bottom. After sending a rotary steering command, the wellbore is repeatedly scratched up and down at a speed of 1min / m at 4 to 6 meters above the cement plug (3250m) to form a step; The drilling was carried out at a speed of 50r / min and 3h / m. When drilling to 3266m, it was found that the measured well inclination near the drill bit began to decrease, and the proportion of returned formation cuttings was 39% to 41%. It was decided to reduce the time control and carry out the time control drilling at a speed of 2h / m. When drilling to 3267m, it was found that the measured well inclination near the drill bit was still decreasing continuously, and the proportion of returned formation cuttings was 49% to 51%. It was decided to continue to reduce the time control and carry out the time control drilling at a speed of 1h / m. When drilling to 3268m, it was found that the measured well inclination near the drill bit was still decreasing continuously, and the well inclination change rate also increased, and the proportion of returned formation cuttings was 59% to 61%. It was decided to continue to reduce the time control and carry out the time control drilling at a speed of 30min / m. When drilling to 3269m, the top drive speed was increased to 90r / min, and the drilling pressure was gradually increased to 40KN. As the well inclination decreased more and more obviously and had separated from the original pilot hole trajectory, it was determined that the side drilling was successful, and instructions were issued to reduce the dogleg degree. At the same time, the thickness of the sandwich wall was continued to increase by slightly increasing the well inclination and decreasing the azimuth. When drilling to 3273m, the tool became sticky and the vibration was normal. The drilling pressure was increased to 80KN to start the inclination section, and the subsequent well sections were drilled normally until the drilling was completed.

[0022] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for rotary steering sidetracking in an inclined well section, characterized in that The steps include: Step 1: drive a cement plug in the open hole of the inclined well section, and the strength of the cement plug meets the design and pressure requirements; Step 2: Perform plugging operations and complete the well entry condition assessment of the rotary steerable tool to ensure continuous operation after the rotary steerable tool enters the well; Step 3: After the plugging operation is completed, assemble the rotary steerable tool, drill down to 4 to 6 meters above the cement plug, and start to pull the wellbore up and down to create steps; Step 4: During the time-controlled drilling process, the well inclination and azimuth changes near the drill bit are monitored in real time, anti-collision calculation and analysis are performed, and the spatial distance between the side-drilled wellbore and the original wellbore is calculated; Step 5: Determine the formation lithology changes based on the near-bit gamma data and obtain the formation cuttings ratio; Step 6: After confirming that the sidetracking is successful, send a rotary steering command based on the wellbore curvature requirements of the trajectory to be drilled to control the lower wellbore trajectory of the sidetracking.

2. The method for rotary steering sidetracking in a deviated well section according to claim 1, characterized in that: Step four is to calculate the spatial distance between the side-drilled wellbore and the original wellbore based on the well inclination and azimuth data measured near the drill bit during the time-controlled drilling process, evaluate the thickness of the sandwich wall between the side-drilled wellbore and the original wellbore, and change the rotary steerable tool command after the thickness of the sandwich wall meets the requirements, and perform normal inclination drilling.

3. The method for rotary steering sidetracking in a deviated well section according to claim 2, characterized in that: Step five is to determine the formation lithology changes based on the near-bit gamma data and obtain the formation cuttings ratio. If the formation cuttings ratio is greater than 50%, the speed of time-controlled drilling is gradually reduced, and combined with the assessed sandwich wall thickness, it is decided whether to use normal drilling parameters.

4. The method for rotary steering sidetracking in an inclined well section according to claim 1 or 2, characterized in that The initial time-controlled drilling speed is 2 to 4 h / m, the time-controlled drilling pressure is 10KN, and then the time-controlled speed and drilling pressure are gradually increased.

5. The method for rotary steering sidetracking in an inclined well section according to claim 1, 2 or 3, characterized in that: Step one is to drill a cement plug in the open hole of the inclined well section 50 to 100 m above the accident complexity point. The strength of the cement plug meets the following requirements: the drill bit is pressurized to 100 KN without rotation, and there is no back drilling pressure and cement plug sinking.

6. The method for rotary steering sidetracking in an inclined well section according to claim 4, characterized in that: Step one is to drill a cement plug in the open hole of the inclined well section 50 to 100 m above the accident complexity point. The strength of the cement plug meets the following requirements: the drill bit is pressurized to 100 KN without rotation, and there is no back drilling pressure and cement plug sinking.

7. The method for rotary steering sidetracking in an inclined well section according to claim 1, 2, 3 or 6, characterized in that: The well entry condition assessment described in step 2 includes: drilling rig drilling capability, surface equipment pressure bearing capacity, top drive equipment torsional resistance, solid control equipment purification capability and whether all performance of drilling fluid meets the rotary steerable tool drilling requirements.

8. The method for rotary steering sidetracking in an inclined well section according to claim 4, characterized in that: The well entry condition assessment described in step 2 includes: drilling rig drilling capability, surface equipment pressure bearing capacity, top drive equipment torsional resistance, solid control equipment purification capability and whether all performance of drilling fluid meets the rotary steerable tool drilling requirements.

9. The method for rotary steering sidetracking in a deviated well section according to claim 5, characterized in that: The well entry condition assessment described in step 2 includes: drilling rig drilling capability, surface equipment pressure bearing capacity, top drive equipment torsional resistance, solid control equipment purification capability and whether all performance of drilling fluid meets the rotary steerable tool drilling requirements.

10. The method for rotary steering sidetracking in a deviated well section according to claim 1, 2, 3, 6, 8 or 9, characterized in that: In step three, a rotary steerable tool repeatedly scratches the wellbore up and down at a speed of 1 to 5 min / m at 4 to 6 meters above the cement plug to form a step. The rotary steerable tool includes a drill bit, a rotary steerable tool, an MWD, a non-magnetic drill collar, a weighted drill pipe and a slope drill pipe connected together from bottom to top.