Tight Sandstone Reservoir Assessment Of Longtanzu Formation In Xiqiao-2 Fault Block Of Huangqiao Of Xiayangzi Region

Xiqiao-2 fault block of Huangqiao Area belongs to the northeast of Nanjing Depression of Xiayangzi Basin,between the Huangqiao Slope of turning parts of the two different tectonic units of Mesozoic-Cenozoic basin in Northern Jiangsu and Cenozoic uplift in Southern Jiangsu.The main oil-bearing strata is Longtanzu Reservoir of Permian(P2l).Longtanzu Reservoir is layered lithologic-structural reservoir,the reservoir stratum distribution is mainly controlled by structure and lithology;Longtanzu Reservoir is shallow and oil layer concentrates on the top;Reservoir stratum is low porosity and low permeability and strong heterogeneity,fracture and solution pores develop in part,The carbon dioxide of Qixiazu Formation communicate to Longtanzu Formation with fracture system,and form tight sandstone reservoir with the oil and gas of natural CO2 driving.Calculation of reserves,Longtanzu Stratum is as a block in the plane,and on the top of it on the vertical,sums to one cell,calculation of IOIP is 102.24×104 t.On the basis of the comprehensive geological research and Fine reservoir evaluation,points out the favorable diagenetic facies of reservoir in the plane,and provides suggestions for the next step of oilfield development.