Study On The Reservoir Characteristics Of Es₃ In Baimiao Area Of Dongpu Depression

Baimiao area is one of the important oil and gas regions of Dongpu depression with huge potential in deep exploration. But the deep zone's exploration was restricted because of the superficial degree of understanding. This dissertation focused on the study of reservoir of Es3 in Baimiao area. Based on the conjunction of core observation, thin section identification, SEM observation, fluid-inclusion analysis, core X-ray analysis, testing of vitrinite reflectance and other methods, and the research achievements as the tectonic evolution history and the history of hydrocarbon accumulation, the characteristics of deep reservoir were systematically studied.The deep reservoir of Baimiao area experienced complex diagenetic evolution. The main diagenetic processes that affected the sandstones include compaction, cementation, dissolution and asphalt filling. The diagenetic evolution stage of Baimiao area is in middle diagenetic B phase to late diagenetic stage. Diagenetic facies can be concluded as four types: matrix filling-compaction diagenetic facies, dissolution diagenetic facies, carbonate cementation diagenetic facies and quartz overgrowth diagenetic facies, then established the distribution mode of diagenetic facies. The diagenetic environment experienced early weakly alkaline environment, middle acid-base alternation environment and the later weakly alkaline environment.Storage spaces were divided into three kinds: primary pore, secondary pore-cleavage and mixed pore. According to the capillary pressure curve, the pore structure was divided into four types. Three anomalously high porosity zones were divided in vertical, and their respective formation mechanism were analysed. Beside sedimental micro-facies and diagenesis, the influence of hydrocarbon emplacement and overpressure on deep reservoir are also obvious.Based on the above research, combined with regional sedimentary facies and physical property values of sandstone, reservoirs are evaluated, and the results are as below: the main type of reservoirs in the middle part of Es3 belong toâ… ~â…¡; the main type of reservoirs in the lower part of Es3 belong toâ…¢~â…£.