Refracturing field tests for enhanced coalbed methane production with gas wettability alteration

Gas wettability alteration (GWA) technology has been used for better methane drainage underground. Our previous field tests of underground fracturing demonstrated a large increase in coalbed methane (CBM) production compared with those in the boreholes fractured without GWA treatments. However, the general drainage rate of each fracturing borehole with GWA treatment is not high enough because no proppant was used in the underground fracturing. To this end, field tests of surface refracturing in two CBM wells (Wells A-2 and 4) were conducted with an innovative fracturing measure with GWA treatments and elongated coal-like proppants in XJ coal mine, Yangquan, China. The water and CBM production with the novel and the conventional fracturing technologies were compared and analyzed. The field test results showed that the CBM production with the novel refracturing technologies (29 697 and 26 844 m(3) for Wells XJ-2 and 4) is greater than those with conventional refracturing (22 746 m(3) for Well XJ-6) and initial-fracturing (25 297.4 and 2847.2 m(3) for Wells XJ-2 and 4). The significant increase in CBM production demonstrates that the novel fracturing technology could be applied for enhanced CBM production.