Analysis Of The Fracture Physical Character In Carbonate Reservoir Of Nanpu Buried Hills Oilfield

Different from clastic reservoir, the main types of fractured reservoir is Carbonate rocks. Complicated and various pore-fracture structures lead to unique reserve space and permeable characteristics. The logging interpretation and exploration evaluation of fractured reservoir is more difficulty than that of conventional homogeneous porous reservoir because of that it has more complex structure of pore and stronger anisotropy.To evaluate physical property and permeability of carbonate reservoir in Jidong oilfield, methods of XRD, sensibility evaluation, SEM and CT analysis, which can avoid reservoir damage and protect reservoir, was established. With quantitative consideration certain factors, i.e., length of crack, width of crack, opening of crack, evaluate the fracture conductivity and ability of reserve.Based on analysis of the pore-fracture construction of 61 core samples, the results of SEM shows that, pore usually distribute among grain substance or particle substance and common diameter of micro crack is 1-4μm. XRD result shows that main stone type is limestone, mineral composition is calcite and little clay. Content ratio of limestone, sandstone, shale is 66.7%,20% and 13.3% respectively. Contact angle measurement result displays, wettability is water wet. Characteristic analyse of relative permeability curve: S_wi >30%, relative permeability of oil decline speedy,relative permeability of water rise quickly with low saturation level. When Krw= Kro=0.089, oil-water seepage disturbs critically. When K_rw= 0.238, oil drop affect water seriously. Sensibility evaluation displays,the core with intense sensibility to stress path, weak water sensitivity, without flow rate sensitivity and acid sensitivity.