Research On Dolomite Reservoir Characteristics Of Ordovician Formation In Central Uplift Belt,tarim Basin

The Lower Paleozoic Ordovician formation in the centre uplift of Tarim basin is the main constituents in this discussion.Using kinds of data that including cores,thin sections,log,and physical property analysis to analyze the characteristics of stratigraphic,dolomite reservoir,physical property,pore type and structure and diagenesis.Investigation results show that there are several rock types such as powder-fine grained gray dolomite,medium-coarse grained residual gravel dolomite,micritic limestone and so on.The main sedimentary can be divided into such facies as evaporation platform,restricted platform,open platform,platform margin,slope,shelf and basin.And the sedimentary microfacies are intra-platform and intra-platform depression.The pore type of the Lower Ordovician reservoir including intercrystalline pore,intercrystal pore,intragranular dissolution pore,cave and microfracture developed well.The lithology and physical property show large heterogeneity in both macroscopic and microscopic aspects because of complex diagenesis.According to the test results of reservoir porosity and permeability,the reservoir can be divided into fracture reservoir,fracture-vuggy reservoirs and vuggy reservoirs.The fracture reservoir are developed in Qiaerbake Formation and Yijiangfang Formation.And fracture-vuggy reservoirs are developed in Shanying Formation and Penglaiba Formation.From the perspective of the whole basin,better type of?and ?reservoir distributes in the mid-centre uplift and west,while the poor type? reservior in north,south and east.