Shale gas reservoir single-well productivity calculation method

Abstract

The invention relates to the technical field of shale gas and discloses a shale gas reservoir single-well productivity calculation method. The method includes: S1, according to a shale gas formation mechanism, fluid migration characteristics in a fracturing process and an ideal gas equation, deriving a gas-liquid displacement equation 1 / Pn=1 / Ps-1 / Pn*( Vi / Vs ), wherein Pn refers to well bottom gas pressure, Ps refers to well bottom liquid pressure, Vi refers to fracturing fluid compression volume, and Vs refers to fracturing fluid active volume; S2, according to a single-section fracturing construction curve and fracturing construction data of a horizontal shale gas well, drawing a linear regression curve of 1 / Pn and Vs, and working out a single-section productivity displacement factor Kj, a productivity coefficient Sj and a productivity index Dj; S3, according to the single-section productivity displacement factor Kj, the productivity coefficient Sj, the productivity index Dj and a well bottom pump stopping pressure Pj, calculating to obtain a single-section after-fracturing crack size SRVj and a single-section productivity Ej according to formulas as shown in the specification, and summing productivity of each single section to finally obtain the total productivity E of a single well. According to the shale gas reservoir single-well productivity calculation method, the total productivity of the single well can be calculated accurately.

Description

technical field [0001] The invention relates to the technical field of shale gas, in particular to a single well productivity calculation method of a shale gas reservoir. Background technique [0002] At present, the productivity evaluation methods of shale gas horizontal wells mainly include: empirical method, numerical simulation method and analytical method. The empirical method is greatly influenced by factors such as geographic location, basic geological conditions of gas reservoirs, mining schemes, mining tools, and on-site technicians; the analytical method is mainly derived from the establishment of a productivity theoretical model and productivity formula, both of which are Based on the correct understanding of the law of shale gas seepage, most of the domestic understanding of the law of shale gas seepage is directly imported from abroad, and there are problems of feasibility and applicability; the analysis of parameters by numerical simulation method is limited A...

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Problems solved by technology

[0004] The present invention proposes a calculation method for single well productivity of shale gas reservoirs, which solves the problem that single well productivity cannot be accurately predicted in the prior art

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