Evaluation of porous carbonate reservoir of Jia 2 Member in Moxi Structure of Sichuan Basin

The crystal powder dolomite reservoir of Layer Jia2² B and micrite-crystal powder dolomite reservoir of Sub-member Jia2¹ are the principal fluid producing formation in Moxi Structure of the Central Sichuan Basin and have the favorable physical property and stable distribution in plane. The tested results show that the two reservoirs have the obviously different productivity. The detailed analysis on endoscopic features, capillary pressure features and porosity-permeability relations of reservoir rocks indicated that the microscopic pore-throat structures were greatly different in the two reservoirs. Although the Sub-member Jia2¹ has the favorable porosity, the fluid permeability is still not ideal because of its thin throat and poor connectivity. By adopting the principle component analysis method and the matrix of original variables, the inner structures of the reservoirs were investigated to locate the new leading variables. Various classification and evaluation standards for reservoirs with different pore-throat structure were established and used to objectively describe the contribution of reservoir to fluid deliverability.