Diagenetic Evolution Modeling And Reservoir Secondary Pore Predicting In Qijia Oil Field

Applying comprehensively reservoir microcosmic analyzingtechnology and combining with reservoir macroscopic research and oil geologic feature,we conduct a systemic research on diagenetic environment, diagenetic stage,diagenetic processe and the features,developing regularities,genetic mechanism of secondary pore in Qijia oil field in Songliao basin.Based on the process oriented simulation principles of diagenesis in this paper, the effects of temperature, pressure, fluid and time four factors on diagenesis were considered comprehensively. By simulating the vitrinite reflectance of diagenetic parameters, paleogeotemperature, the smectite content in I/S mixed layers, the percentage content of authigenic quartz and the changing rules of sterane isomerization rate in time and space, the diagenetic history of Qijia oil field was simulated and the spreading characteristics of diagenetic stages were predicted.The measured porosity data and the observations of the thin sections and blue epoxy resin-impregnated thin sections show that there exist two anomalously high porosity zones vertically in the Cenozoic reservoirs in Qijia oil field.The two secondary pore zones corresponding to Gaotaizi and Fuyang Reservoir. The study found that the developing regularities of the abnormal high porosity and the organic acids is very similar, which caused the high-quality reservoirs.We Conduct a comprehensive analysis on clay minerals, organic matter thermal evolution, temperature, pressure, formation water salinity, organic acid, carbonic acid, sandstone diagenesis types, sedimentary facies and depth, layer, and other factors which can affect the developing regularities of secondary porosity, and sum up the developing regularities of secondary pore. The main controlling factors of secondary pore in Qijia oil field are the dissolution of organic acid and carbonic acid (organic and inorganic) .We have forecasted the secondary pore zone of Qijia oil field by superposing the contour map of controlling factors.The forecasting result is very similar to the known oil region,which provide an effective indicator to forecast effective target.