Hydraulic fracturing method for underground deep low-permeability coal reservoir

• Main Authors: YAO ZHUANGZHUANG, SU HANG, LI LIANGWEI, JIA QUANMIN, WU WENBIN, LIN FUJIN, TANG JIANPING, MA SHUYIN, PAN XUESONG, LIU YANG, SUN PENG
• Format: Patent
• Language: Chinese; English
• Published: 05.06.2020
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS; SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, ORDRAINING IN OR OF MINES OR TUNNELS

The invention relates to a hydraulic fracturing method for an underground deep low-permeability coal reservoir, and belongs to the field of coal mine underground gas disaster treatment. The method comprises the following steps that S1, a plurality of crossing drill holes are formed in a bottom drainage roadway to be used as hydraulic fracturing holes, water is circularly injected among the fracturing holes for fracturing to form zipper type fracturing, and during fracturing, according to a prepad fluid-displacing fluid sequence, the prepad fluid and the displacing fluid use different fracturing fluid and are pressed into the fracturing holes along with the fracturing fluid; S2, a directional hole is formed in each of the two sides of each fracturing hole, and a plurality of inspection holes are arranged beside each directional hole; S3, after hydraulic fracturing is finished for a period of time, water drainage is carried out on the fracturing holes for pressure relief, networking gasextraction is carried out