High-tectonic-stress normal-pressure shale gas volume fracturing method

Abstract

The invention discloses a high-tectonic-stress normal-pressure shale gas volume fracturing method. The method comprises the following steps of 1) evaluating shale key reservoir parameters; 2) performing geological engineering double-sweet-spot evaluation and perforation position determination; 3) optimizing a crack parameter system; 4) optimizing fracturing construction parameters; 5) performing cluster perforation operation; 6) performing acid pretreatment operation; 7) performing high-viscosity glue solution high-displacement splitting vertical main crack construction; 8) performing low-viscosity slickwater variable displacement communication and extension of a branch seam system and a horizontal bedding seam system; 9) performing small-particle-size long-section plugging or continuous sand adding construction; 10) performing sand adding construction on a first high-viscosity glue solution slug; 11) performing small-particle-size medium-sand-liquid-ratio medium-displacement construction of slickwater; 12) performing sand adding construction on a second high-viscosity glue solution slug; 13) performing small-particle-size high-sand-liquid-ratio high-discharge-capacity constructionof slickwater; and 14) performing high-viscosity glue solution high-displacement sand-carrying filling vertical main crack construction. The post-fracturing transformation volume of a normal-pressureshale gas well can be increased, so that the economic development effect of the normal-pressure shale gas well is improved.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploitation, and in particular relates to a volumetric fracturing method for shale gas with high structural stress and normal pressure. Background technique [0002] At present, the recoverable resources of atmospheric shale gas are huge, but due to its complex structure, especially the synclines that are mostly in a state of stress extrusion, sometimes the minimum horizontal principal stress is close to or even higher than the vertical stress. Therefore, There may be both horizontal bedding fractures and vertical fractures during fracturing, and the minimum horizontal principal stress will continue to increase due to the induced stress during the fracturing process, which further increases the number of simultaneous extension of multiple horizontal bedding fractures. possibility. Although the horizontal bedding joints also produce a certain amount of induced stress during the extension proces...

AI Technical Summary

Problems solved by technology

This document only briefly expounds and analyzes the application of temporary plugging balls in normal pressure shale gas wells and lists the fracturing operation parameters of the applied wells, but does not conduct a detailed analysis on the main efficiency enhancement process of normal pressure shale gas well fracturing stimulation and put forward effective measures