A high-efficiency imbibition and drag-reducing water system suitable for normal pressure shale gas reservoirs, its preparation method and application

Abstract

The invention discloses an efficient imbibition and drag-reducing water system applicable to an atmospheric pressure shale gas reservoir. The efficient imbibition and drag-reducing water system applicable to the atmospheric pressure shale gas reservoir comprises the following components: 0.04-0.1 percent of a high-molecular polymer drag reducer, 0.05-0.2 percent of a moisture regulator, 0.1-0.3 percent of an efficient shale inhibitor, 0.01-0.03 percent of an environment-friendly fungicide, 0.05-0.1 percent of an imbibition conditioner and the balance of water. The efficient imbibition and drag-reducing water system applicable to the atmospheric pressure shale gas reservoir has the advantages that the efficient imbibition and drag-reducing water system is prepared by using a low molecular weight high-molecular polymer as a drag reducer and introducing the moisture regulator, the imbibition conditioner, the efficient shale inhibitor and the environment-friendly fungicide. Therefore, therock core spontaneous imbibition amount can be effectively increased, the imbibition of a fracturing fluid to a deep ground mass can be promoted; smoothness of a spontaneous imbibition passage can bekept; the desorption of adsorbed gas can be promoted; effects of water soluble replacement of the adsorbed gas, energy increasing and drainage are achieved; atmospheric pressure shale fracking construction requirements are satisfied; the drainage of atmospheric pressure shale gas drag-reducing water fracturing fluid flow-back fluid is reduced; and the development of economic benefits of an atmospheric pressure shale gas field is realized.

Description

technical field [0001] The invention belongs to the technical field of exploration and development of oil and gas fields, and in particular relates to a high-efficiency imbibition and drag-reducing water system suitable for normal pressure shale gas reservoirs, a preparation method and application thereof. Background technique [0002] At present, the staged fracturing of horizontal wells in high-pressure marine shale gas reservoirs such as Changning-Weiyuan and Fuling blocks mainly adopts the conventional drag-reducing water fracturing fluid system. For example: Patent CN103589416A discloses a low-friction recyclable slippery water fracturing fluid suitable for tight oil and gas reservoirs and its preparation method. After adding demulsification aids, clay stabilizers, and degradation agents, it is formulated to form a reverse microemulsion The slick water system solves the problems of low drag reduction rate of guar gum slick water and difficult reuse of flowback fluid; ho...

AI Technical Summary

Problems solved by technology

[0004] 1) Shale cores in normal pressure reservoirs generally exhibit the characteristics of mixed wetting and stronger lipophilicity. Conventional drag-reducing water systems cannot penetrate into the deep part of the rock matrix, which reduces the efficiency of liquid stimulation of the reservoir;

[0005] 2) The organic matter has a great influence on the adsorption of hydrocarbons, and the conventional drag reducing water system cannot promote the desorption of adsorbed gas;

[0006] 3) The conventional drag-reducing water fracturing fluid system has a high flowback rate after fracturing in normal-pressure shale gas reservoirs, increasing environmental protection pressure and increasing construction period