A coiled tubing fracturing method for long horizontal section up-dip horizontal well

Abstract

The application relates to the field of oil and gas resource development, and particularly discloses a long horizontal section up-dip horizontal well coiled tubing fracturing method. The method comprises the following steps: S1, establishing a toe end liquid inlet channel; S2, normally lowering a coiled tubing fracturing tool to self-locking; S3, pumping the coiled tubing fracturing tool to a target depth; S4, coiled tubing tool depth calibration; S5, achieving setting by rapid blowout; S6, normal sandblasting perforation and fracturing construction; and S7, unsetting and lifting to complete full-well perforation and fracturing construction. The long horizontal section up-dip horizontal well coiled tubing fracturing method can be used for fracturing reconstruction construction of long horizontal section high-deviation up-dip wells of shale oil and gas and tight oil and gas, active water is pumped through an annular space to provide a continuous downward thrust to assist the tool to be in place, and reliable setting is achieved by using a rapid blowout pressure difference, so that the tool lowering depth and setting success rate are improved, the continuity and construction efficiency of multi-stage perforation and fracturing operation are ensured, and operation risks and costs are reduced.

Claims

1. A method for fracturing coiled tubing in a long horizontal section of an updated horizontal well, characterized in that, Includes the following steps: S1. Establish a toe-end fluid inlet channel: Establish a fluid inlet channel through a toe-end sliding sleeve or continuous tubing perforation, allowing fluid to be pumped into the formation. S2. Normally lowering the coiled tubing fracturing tool until self-locking occurs: The reversing pin (6) is located in the short groove track (9), and the bottom tool is pushed down by the reversing pin (6); after reaching the fracturing position, the reversing pin (6) is lifted and lowered to allow it to enter the long groove track (10); the lowering speed shall not exceed 15m / min, and the change in suspended weight shall be recorded. Self-locking is judged when the suspended weight drops to 0kN or there is no progress when lowering. S3. Pump the coiled tubing fracturing tool to the target depth: Active water fluid is pumped through the annulus pump, while the coiled tubing lowering speed is controlled within 10m / min, and the resulting tool position is continuously tractioned. S4. Coiled tubing tool depth calibration: Lower the tool string below the short casing and stop pumping. Then, lift the coiled tubing at a constant speed and observe the tension fluctuation generated by the locator (11) passing through the coupling. Calibrate the coiled tubing depth according to the actual well depth. After the depth calibration is completed, restart the pump according to S3 and lower the coiled tubing to the fracturing point depth. S5. Set the packer by rapid release of the blowout: After stopping the pumping, lift the coiled tubing to perform a rail change operation, and then operate the surface choke manifold to release the wellhead pressure instantly, thereby achieving packer release and settling. After settling, verify the packer seal. S6. Normal sandblasting perforation and fracturing operation: The perforation pump truck pumps the perforation fluid into the wellbore and perforates the target formation; after the perforation fluid is pumped out, sand addition is stopped, and active water is pumped in at the perforation rate to complete the perforation; after the perforation is completed, fracturing operation is carried out by pumping according to the fracturing operation plan. S7. Unsealing and lifting to complete perforation and fracturing of the entire well: Lift the coiled tubing to the next fracturing point and repeat the setting, perforation and fracturing process to complete perforation and fracturing of all fracturing points in the entire well.

2. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S3, the pumping rate of the annulus is 1~2 m³ / min.

3. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S3, the pumping process includes the following steps: S301, Annular pressure limit control: Adjust the pump injection pressure limit to be 2-5 MPa higher than the normal pump injection pressure; S302. Selection of internal displacement parameters for coiled tubing: During the running-in process, the continuous injection displacement inside the coiled tubing is 0.1 m³ / min; S303, Annular Displacement Parameter Selection: Gradually increase the displacement until the coiled tubing continues to descend, then stop increasing the displacement; the annulus pumping needs to be stopped during the coiled tubing lifting process; S304. Surface weight control of coiled tubing: After the annulus begins normal pumping, record the weight fluctuation range. If the weight changes significantly, stop the annulus pumping and perform a short start operation. S305. Selection of starting injection depth: If the self-locking point is far from the target depth, start injection at the self-locking point; if the self-locking point is close to the target depth, start injection at the position after lifting the pump.

4. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S4, the positioner (11) displays the lifting tonnage as 1.5t-1.8t over the coupling.

5. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S5, the pressure difference for venting is controlled at 8~15MPa, and the venting time is less than 0.5min.

6. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S5, the process of checking the packer seal is to set the packer by flowing back, compressing the packer rubber barrel (2). At this time, if the pressure of the plug valve remains unchanged after 15 minutes, the seal check is qualified.

7. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S5, the upper wellbore of the packer is normally pressured to check the seal. The test pressure is 5 - 10 MPa higher than the wellbore shut-in pressure. If the pressure drop does not exceed 0.5 MPa after 15 minutes, the seal check is qualified.

8. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S6, it also includes gradually reducing the displacement of the tubing, closing the casing annulus, and conducting a trial squeeze. When liquid absorption occurs in the perforated section, it indicates successful perforation. If there is no obvious pressure drop after multiple trial squeezes, re-perforation is required.

9. The method for fracturing coiled tubing in a long horizontal section of an updated horizontal well according to claim 1, characterized in that, In step S7, after the displacement fluid injection is completed, the fracturing pump truck stops pumping. The coiled tubing continuously supplements fluid at a displacement of 0.1 - 0.3 m3 / min and is evenly lifted to release the packer; when lifting to release, the initial speed is controlled within 3 m / min, and the maximum tubing lifting speed after passing the perforation point is 15 m / min.

10. A fracturing tool for a long horizontal section of updated horizontal well coiled tubing, characterized in that, A coiled tubing fracturing method for a long horizontal section up-dip horizontal well according to any one of claims 1 - 9, comprising a packer push sleeve (1) and slips (7). On the outer side of the right side of the packer push sleeve (1), there is a packer rubber barrel (2). On the outer side of the right side of the packer rubber barrel (2), there is a slip expander head (3). Below the packer rubber barrel (2), there is a packer rubber barrel (2). The lower side of the slip expander head (3) is disposed outside the sliding guide tube (4). On the right side of the sliding guide tube (4), there is a reversing push rod (5). On the side wall of the reversing push rod (5), there is a reversing pin (6). On the outer side of the left side of the slips (7), there is a friction block (8). Inside the slips (7), there are short groove tracks (9) and long groove tracks (10). On the outer side of the right side of the slips (7), there is a locator (11).

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