CONTROLLING FACTORS OF HIGH GAS PRODUCTION IN THE UPPER PALEOZOIC OF WUSHENQI GASFIELD, THE SHANGANNING BASIN

The distribution rules of reservoir fissures and the space-time development characteristics of monosandbodies are focal points for the study of pore-fissure-typed reservoirs,and are also major controlling factors to the high gas production of gas fields in the middle part of the Upper Paleozoic in the Shanganning Basin.It was considered that the development of structural fissures in reservoirs is obviously related to the lithology and thickness of monosandbodies as well as the tectonic location where reservoirs are situated,and fissures are most developed in the coarse-grained reservoirs located at the high part of noses.According to this cognition,the distribution rules of fissure plane were predicted.Based on the establishment of high precision and isochronous stratigraphic framework,the development rules of monosandbodies and the space time changes of accumulation features were studied and the distribution of effective reservoirs was predicted starting with the Sedimentary facies and microfacies of reservoirs.