Directional hydraulic injection tool string and construction method for coal-bed gas horizontal well

Abstract

Provided are a directional hydraulic injection tool string and a construction method for a coal-bed gas horizontal well. The directional hydraulic injection tool string is characterized by comprisinga guide cone, a screen pipe, a centering device one-way valve, a hydraulic anchor, a packer, an ejector, a hydraulic eccentric orientator, an upper centering device, a hydraulic releasing and an oil pipe which are sequentially connected, the hydraulic eccentric orientator is connected with the ejector through a fixed manner, the upper end of the hydraulic eccentric orientator and the lower end ofthe ejector are respectively through the upper centering device and the packer connected with an upper movable bearing and a lower movable bearing, and under the action of hydraulic, the eccentric orientator drives the ejector to achieve the function of directional ejection; the directional hydraulic injection tool string has reasonable design and complete functions, and higher reliability, stability and safety of the combined system, can achieve the function of outer pipe anti-channeling and fixed point fracturing, also achieve hydraulic sand blast perforation of large displacement, large hole, and orientation and subsection fracturing operation of large displacement and a large scale, is applied to the construction of coal-bed gas horizontal wells with complex conditions, such as cementing wells, uncementing wells and the like, and the directional hydraulic injection tool string has the advantages of high construction efficiency, low construction cost, a large scale of production increasing and improvement, high success rate of the construction and a good reconstruction effect and the like.

Description

technical field [0001] The invention relates to the technical field of surface coalbed methane development, in particular to a directional hydraulic injection tool string for a coalbed methane horizontal well and a construction method. Background technique [0002] Horizontal wells are an effective way to achieve fast and efficient extraction of coalbed methane, and staged fracturing is a technical measure to increase production of horizontal wells. The development of fractured horizontal wells has been paid more and more attention. In view of the fact that the horizontal wells drilled in the coal seam adopt the completion method of running the casing without cementing, the conventional perforating bullet perforation technology has high instantaneous construction pressure, which will cause great damage to the production casing, and will also cause compaction of the reservoir . When hydraulic sand blasting perforation is used for perforation construction, the perforation to...

AI Technical Summary

Problems solved by technology

When hydraulic sand blasting perforation is used for perforation construction, the perforation tools and techniques follow the coiled tubing dragging techniques and tools used in the oil and gas industry. When sand perforating, the perforation displacement is less than 1.0m 3 / min, the hole diameter is less than 12mm, and the suitable displacement for fracturing is 4-6m 3 / min, the amount of sand passed by the injector is small, and the function of hydraulic directional perforation cannot be realized

During coiled tubing fracturing, due to the small injection displacement of coiled tubing, the effect of hydraulic isolation and in-hole pressurization is poor, so it is impossible to solve the problems of fixed-point fracturing and prevention of cross-flow outside the tubing

The clean water and sand-carrying displacement outside the coiled tubing is also limited, and the displacement during fracturing is small (5m 3 / min), the scale of sand addition is small, and the effect of coal seam fracturing is poor, so it is difficult to meet the needs of multi-stage, large displacement and large-scale fracturing.

Moreover, the outer diameter of the tool is large, and the safety of adding sand outside the large-scale pipe is poor, which limits the large-scale promotion of CBM staged fracturing horizontal wells

[0003] To sum up, the current staged fracturing of coalbed methane horizontal wells has high construction cost, small construction displacement, and small fracturing scale, and the function of hydraulic directional perforation fracturing cannot be realized, resulting in poor effect of staged fracturing of horizontal wells and difficult Meet the needs of intensified exploitation of coalbed methane horizontal wells

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