DISCUSS ON COAL CORING TECHNOLOGY FOR COAL-BED GAS WELLS

Coal-bed has special physical and mechanical properties and coal-bed gas well has special requirements for coal coring. So conventional coring tool and technology can not meet the coring operation of coal-bed gas well and its core recovery is only about 30%.In order to solve the problems of difficult coring operation, bad quality of coal core and low core recovery, wire line coring tools were used. The field practice in coal-bed gas test wells showed that using wire line coring tool can get quick coring rate(15~20min) and high core recovery(more than 80%). The tool can basically meet the coring requirement of coal-bed gas well.