Multi-Stage Pitching Frac Sleeves with Salvageable Seats

Abstract

The invention discloses a multi-level pitch fracturing sliding sleeve capable of fishing ball seats. The multi-level fracturing sliding sleeve capable of fishing the ball seats comprises connectors, elastic claws and an elastic claw pipe. The connectors comprise the upper connector and the lower connector. The upper connector is connected with the lower connector, and the upper end of the upper connector is provided with an upper locating groove, a lower locating groove and a side hole. The multi-level pitch fracturing sliding sleeve further comprises a sliding sleeve mechanism and a ball seat fishing mechanism. When the sliding sleeve mechanism and the ball seat fishing mechanism move downwards for opening the sliding sleeve, elastic claw gaps in the sliding sleeve mechanism correspond to the side hole, and the elastic claw pipe is communicated inside and outside. Self-locking elastic claws which are matched with a ball seat fishing mechanism inside an upper-level sliding sleeve and a ball seat fishing mechanism in a lower-level sliding sleeve to be used for fishing the ball seats are arranged at the two ends of the ball seat fishing mechanism respectively. By means of the multi-level fracturing sliding sleeve, the effect that the sliding sleeve on the lower portion can realize fracture acidizing operation through sequential opening of pitches can be guaranteed, multiple levels of sliding sleeve ball seats and balls can be fished out at a time through a continuous oil pipe after the fracture acidizing operation, and therefore a drift diameter as large as possible can be obtained inside the pipe.

Description

technical field [0001] The invention discloses a multi-stage ball throwing fracturing sliding sleeve used for fracturing and acidizing construction operations in oil and gas fields, which belongs to downhole operation tools in oil and gas fields. Background technique [0002] At present, the ball-throwing sleeves widely used in open-hole staged fracturing and acidizing technology of horizontal wells are mainly opened by throwing balls to form fracturing channels, and are constructed step by step from bottom to top. During the construction, the opening ball of the sliding sleeve sits on the ball seat, and most of the well sliding sleeves can be opened normally. After the construction is completed, the ball is discharged to the ground through drainage. For example, Chinese Patent No. "201010216524.6" discloses a drillable ball sliding sleeve suitable for horizontal wells. The publication date is November 10, 2010. It includes a joint device and a claw tube structure, and is ch...

AI Technical Summary

Problems solved by technology

[0003] However, the ball-throwing sleeves in the prior art still have the following disadvantages: if the gas production is small, especially in oil wells, the balls are not easy to return and flow out, thus affecting the construction effect

In order to ensure the effect after construction and the effective smoothness of the completion string in the well, it is necessary to drill and grind the unreturned balls in the string and the ball seats with relatively small diameters through drilling and grinding tools with coiled tubing. To obtain a larger diameter, but the sliding sleeve ball seat cannot be salvaged after operation, which is not conducive to the increase of oil and gas well production, and the later operation is also inconvenient

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