Fuxin Mining Group Co., Ltd.
China Coal Technology and Engineering Group Shenyang Research Institute
State Key Laboratory of Coal Mine Safety Technology

为研究煤层水力压裂过程中其单位注液量的变化特征，采用工程试验的方法，以四川省宜宾市筠连县金钟煤矿1703采煤工作面为试验地点，通过对煤层钻孔水力压裂过程中各管路单位液体流量的监测和分析，发现在正常水力压裂过程中，进液管及回液管的单位液体流量拟合曲线均呈“抛物线”状，而单位注液量则可以划分为下降阶段和波动阶段；结合水力压裂过程中其注液压力的变化情况，发现注液压力在煤体出现开裂及裂缝扩展时会出现明显的“卸压-恢复”现象，而单位注液量则相应的出现“升高-恢复”的现象，并且两者具有同步性；此外，根据水力压裂过程中其单位注液量的变化特征将整个水力压裂过程划分为3个阶段：充液阶段、蓄能与煤体开裂循环阶段及停止开裂阶段。

In order to study the change characteristics of unit liquid injection volume during hydraulic fracturing of coal seams, using the engineering test method, taking the 1703 working face of Jinzhong Coal Mine in Junlian County, Yibin City, Sichuan Province as the test site. Through monitoring and analyzing the unit liquid flow of each pipeline in the process of borehole hydraulic fracturing, it is found that the fitting curves of unit liquid flow of liquid inlet pipe and liquid return pipe are “parabola” in the process of normal hydraulic fracturing, while the actual unit liquid injection volume can be divided into falling stage and fluctuating stage. Combined with the change of liquid injection pressure in the process of hydraulic fracturing, it is found that the liquid injection pressure will appear obvious “pressure relief-recovery” phenomenon when the coal body appears cracking and crack propagation, and the unit liquid injection volume will appear “ rise-recover ” phenomenon, and the two phenomenon are synchronous. In addition, the whole hydraulic fracturing process is divided into three stages according to the change characteristics of the unit liquid injection volume in the hydraulic fracturing process: filling stage, energy storage and coal cracking cycle stage and stop cracking stage.

贾宗凯，张云龙，宋广明，等. 水力压裂过程中单位注液量变化特征研究[J]. 煤矿安全，2023，54（10）：36−42.

JIA Zongkai, ZHANG Yunlong, SONG Guangming, et al. Study on change characteristics of unit liquid injection volume during hydraulic fracturing[J]. Safety in Coal Mines, 2023, 54（10）: 36−42.