The Study Of Fluid Inclusions From Reservoirs Of Weixi'nan Depression, Beibuwan Basin

In the Weixi'nan depression, Southwest Beibuwan Basin, there are lots of oil and gas, which exhibits actively. It is important for this area's oil-gas exploration and development to distinguish the stage of hydrocarbon reservoirs and the direction of migration. 4 representative wells of Weixi'nan depression are chosen to have fluid inclusion research in this paper, and the followings are main results and conclusions:(1) The types of fluid inclusions from Weixi'nan depression's reservoirs include aqueous inclusions, gas-liquid aqueous inclusions, gas inclusions, gas-bearing inclusions and hydrocarbon inclusions. Aqueous inclusions exist commonly and there is little petroleum inclusions. Petroleum inclusions have three types: type I inclusions from the margin of quartz or quartz overgrowths, type II inclusions from early crack of quartz debris grains or the overgrowths inside, type III inclusions from late crack of quartz debris grains.(2) According to PVTsim software, Ptr and Ttr of inclusions are modeled and calculated. The results are: type I 97.9℃ 19.13 MPa; type II, 112.6℃ 35.05 MPa; type III, 157.4℃ 47.52 MPa.(3) Based on the resource rocks distributing and the three populations of reservoirs' inclusions, three fluid events occurred in the Weixi'nan depression: the end of Liushagang, the end of Weizhou and Jiaowei-Quaternary.