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Solid-fluid Interaction And Reservoir Prediction Of Beach-bar Sandstone Of The Upper Part Of The Forth Member Of Paleogene Shahejie Formation, In Dongying Depression

Posted on:2012-11-09Degree:DoctorType:Dissertation
Country:ChinaCandidate:W ZhaoFull Text:PDF
GTID:1100330332988750Subject:Mineral prospecting and exploration
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Beach-bar sand has becoming a very important target of petroleum exploration in recent years. Secondary pore is a momentous style in the sandstone of beach and bar and plays an important role in the forming of effective reservoir. In this article we focus on the case study of beach-bar sand bodies of the upper part of the forth member of Shahejie Formation of Paleogene in Dongying Depression. Based on the integrated research of core observation, thin section identification, SEM observation, SEM/EDX analysis, core X-ray diffraction analysis and core physical properties analysis and so on, combined with sequence stratigraphy, depositional system distribution, tectonic evolution, thermal history of organic matter, and oil and gas accumulation history research results, a systematic study about the formation mechanism and evolution of secondary pore has been done from the research of the solid-liquid process. After this, the fluid evolution can be divided and the distribution pattern of secondary pore genesis can be found. According to the relationship of solid, fluid and diagenetic environments,"evaluation and prediction method of effective reservoir with five parameters of solid-fluid"come into being. Using this method we can evaluate and predict the development of effective reservoir in sand bodies.Secondary porosity which can be found in the study area include calcareous cement dissolved porosity and quartz dissolved pores. They are produced in different fluid environments. Different genetic types of secondary porosity distributed in the plane with a certain regularity: gravelly beach and bar in the southern slope of depression mainly develops calcareous cement secondary dissolution porosity, the bar far from shore and in the central resonance belt mainly develops quartz dissolution secondary porosity, and the bar near shore and controlled by delta develops two types of secondary porosity. The differences of secondary pore developed in different sedimentary facies are mainly due to the difference of solid and fluid characteristics; also it reflects the complexity and stages of the fluid evolution. According to the source of fluid and changes of fluid properties, combing the basin burial history, tectonic evolution history and thermal history of organic matter, fluid evolution could be divided into five stages during the whole burial history, such as diagenetic stage of the initial fluid, diagenetic stage of surrounding fluid, diagenetic stage of external fluid, diagenetic stage of hydrocarbon expulsion fluid and diagenetic stage of fluid after the hydrocarbon expulsion. The source and duration of fluid in each stage can be determined. Depending on the differences of diagenetic phenomenon, forward model of liquid properties, solid and reservoir properties evolution was established in every secondary porosity zone. There are five main parameters which were summarized can influence the content of secondary porosity in sandstone. They are calcite, dolomite, quartz, pH value of fluid and burial depth. Calcite, dolomite, quartz are solid parameters, while the pH value is a fluid parameter and burial depth is a diagenetic environment parameter. Based on the research of interaction among these five parameters, a dissolution-precipitation plate of the three minerals can be established. The X-axis stand for pH and the Y-axis is depth separately. This changed the criteria for the classification of fluid by simple acidic and alkaline in reservoir research. Formed a "evaluation and prediction method of effective reservoir with five parameters of solid-fluid" and it's applicability and reliability can be confirmed by several wells in every secondary porosity development zone. Finally, we take the key oil production in two typical development blocks as examples, and make an evaluation and prediction of effective reservoir which has achieved good results.
Keywords/Search Tags:solid-fluid interaction, secondary pore, reservoir prediction, beach-bar sand, Dongying Depression
PDF Full Text Request
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