| Because of the big change of sedimentary microfacies, intensely reformation of diagenersis and the strongly heterogeneity of Chang4+5 reservoir, which increased the difficulty of the study, that the reservoir haven't made a breakthrough.Based on previous research and modern analysis techniques, which show that delta plain subfacies is the main sedimentary facies of the study area, aquatic distributary channel with coarse sediment and sizable thickness is the main microfacies; medium to fine feldspar sandstone is the main sandstone types in study area, with psephicity of subangularity and with characteristics of medium composition maturation and low maturation; Average porosity is 10.2% and average permeability is 0.8×l0-3μm2; Intergranular pore is the main pore types of the reservoir, minor is corrosion intergranular pore, and fracture pore also developed, according to pore types and throat types, pore structure can be divided into three groups.Chang4+5 reservoir experienced a series of complex diagenetic processes, including compaction, cementation, dissolution and so on, diagenetic stage is in phase A. compaction and cementation which destroyed the primary pore, reduce the reservoir property, induced the porosity, secondary porosity which produced by dissolution is positive to improve reservoir properties; Some diagenetic parameters, such as lithology, grain size, and the content of authigenic mineral and so on which affect the quality of the reservoir, it is show that the transformation of the original porosity and development of secondary porosity are mainly determined by diagensis, according to deposition characteristics, characteristics of diagenesis, Micro-pore structure characteristics, characteristics of reservoir property and per well production, defined the reservoir evaluation criteria of the study area, because of the bad reservoir property of Chang4+5 reservoir, the study area mainly developed classⅡand classⅢclass reservoirs.
|
PDF Full Text Request