Shale gas horizontal well segmented fracturing variable density cluster perforation method and perforation gun

Abstract

The invention provides a shale gas horizontal well segmented fracturing variable density cluster perforation method and a perforation gun and belongs to the field of oil-gas field production increasing development. The shale gas horizontal well segmented fracturing variable density cluster perforation method comprises the steps that (1) the ground stress profile and longitudinal ground stress profile in the horizontal shaft direction as well as the geological sweet spot and engineering sweet spot are gained; (2) cluster perforation parameters are preliminarily determined; (3) the cluster perforation parameters are optimized; (4) perforation in the circumferential direction of a horizontal shaft is conducted on the perforation fracturing position determined by the step (3), and thus perforation holes are distributed on the circumference of one plane; (5) different perforation clusters adopt variable density perforating, specifically, if the difference of the ground stress profile along the horizontal shaft is large, variable density perforation is adopted for the different perforation clusters; and (6) if shale ground stress of the position where one certain perforation cluster is located is high, the number of perforated holes in the position is increased in the circumferential direction, or the hole diameter is increased; and on the contrary, the number of the perforated holes is decreased, or the hole diameter is decreased, so that the cluster perforated holes achieve uniform liquid inflowing and obtain the same crack length.

Description

technical field [0001] The invention belongs to the field of production increase and development of oil and gas fields, in particular to a shale gas horizontal well staged fracturing variable density cluster perforation method and a perforating gun, which is suitable for unconventional shale gas horizontal well staged fracturing variable density cluster perforation Operation. Background technique [0002] In staged fracturing of shale gas horizontal wells, the optimal design of cluster perforation parameters is crucial. The current cluster perforation optimization mainly focuses on cluster spacing, cluster length, total perforation number per section, perforation aperture, azimuth, and penetration depth, etc., and the cluster perforation method basically follows the helical axis of the horizontal wellbore commonly used in vertical wells. perforation method. The cluster perforation method and parameter optimization technology have been successfully applied in shale gas frac...

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Problems solved by technology

[0006] (3) The perforation method is basically spiral perforation, which is difficult to fully ensure that the fracturing fluid is concentrated into the formation, and the probability of multiple fractures is very high, especially when the heterogeneity of shale is weak, how many perforations may be There are as many cracks as there are perforations. In this case, only one perforation for each crack enters the liquid, which makes it difficult to ensure sufficient follow-up reconstruction and smooth sand addition.

Uniform distribution does not take into account the distribution characteristics of geological sweet spots and engineering sweet spots, while non-uniform distribution cannot make use of the induced stress interference of fractures between adjacent clusters, which is not conducive to increasing the complexity of fractures

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