STUDY OF REPEATED FRACTURING TECHNOLOGY IN LOW-PERMEABLE SAND OIL RESERVOIR IN ANSAI OILFIELD

The propped fracture generated during primary fracturing induces a stress field that changes original stress field and further reorients new fracture during repeated fracturing,the extension direction is still controlled by stress status.By means of altering confining pressure,hydraulic fracturing simulation experiment proves the possibility of new fracture generation during repeated fracturing.Temporarily blocked repeated fracturing is applied in Ansai oilfield,a temporary blocking agent is injected during old fractures’ reopening to form a high-pressure environment and newly generated fracture connects the natural fractures which establishes new high-conduction fracture system with later added proppant and the oil-draining area enlarges.Pilot fracture supervision and effect analysis proves the generation of new fractures during repeated fracturing.