Baode block Huaibei coalfield Jimsar Depression Jixi Basin Junggar Basin Ordos Basin accumulation big-data analysis biogenic methane cementing coalbed methane comprehensive productivity impact index different CBM geology effective pressure relief range enrichment and high yield model expansion deformation exploration and development strategy flowback fracturing fluids gas extraction gas occurrence genesis of coalbed methane geological factor heat control heavy oil high waterflooding PVs horizontal well hydration heat hydrocarbon generation evolution low-permeability tight sandstone gas reservoir