A high frequency variable displacement volumetric fracturing method for atmospheric shale gas reservoirs

Abstract

The invention discloses a high-frequency variable displacement volume fracturing method for normal-pressure shale gas reservoirs. Including: (1) Evaluation of key shale reservoir parameters (2) Optimization of fracture parameters (3) Determination of geological engineering sweet spot and cluster perforation location (4) Optimization of fracturing construction parameters (5) Cluster perforation operation ( 6) Acid pretreatment (7) Acidic slick water injection into main fractures (8) Neutral slick water high displacement injection construction (9) Medium displacement injection construction of 140-230 mesh or 70-140 mesh proppant (10 ) Low displacement injection of spacer fluid for construction (11) Repeat steps 8) to 10) until the total fluid volume and proppant amount of the current section are used up; (12) Replacement operation. The invention adopts the acid slick water system and the neutral slick water high-frequency variable displacement process. Improve the post-pressure production effect of atmospheric shale gas wells, and better realize the goal of economically and effectively developing atmospheric shale.

Description

technical field [0001] The invention relates to the field of petroleum exploitation, and more specifically, relates to a high-frequency variable-displacement volume fracturing method for normal-pressure shale gas reservoirs. Background technique [0002] Atmospheric shale gas resources are huge. The Silurian shale with a buried depth of less than 3,500m in the Sichuan Basin and its surrounding areas has a distribution area of ​​82,000 square kilometers, of which the normal pressure shale area is 62,000 square kilometers, and the geological resources are 198,000 square kilometers. Yifang, accounting for 75.6%. However, restricted by its special geological characteristics, the stable daily output of normal pressure shale gas horizontal wells after hydraulic fracturing is generally less than 30,000 m3, and the output is relatively low and the decline rate is fast. Therefore, the current large-scale multi-stage fracturing technology has poor adaptability to normal pressure shal...

AI Technical Summary

Problems solved by technology

However, due to its special geological characteristics, the stable daily production of normal pressure shale gas horizontal wells after hydraulic fracturing is generally less than 30,000 cubic meters, and the production is relatively low and the decline rate is fast.

[0005] The above-mentioned mismatch of geological characteristics and fracturing techniques has resulted in a reduction in the complexity of fracturing fractures in normal-pressure shale gas wells, as well as low production and rapid production decline after fracturing. Therefore, it is necessary to study and propose a new method for normal-pressure shale gas wells The new technology of horizontal well volume fracturing based on gas reservoir characteristics can solve the above limitations and truly realize the economical and effective development of normal pressure shale gas

Images