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The Pore Structure Characteristics Of Tight Sandstone Reservoir Of Sha-3 Member In Gaoliu Tectonic Belt

Posted on:2015-02-03Degree:MasterType:Thesis
Country:ChinaCandidate:R L ChiFull Text:PDF
GTID:2180330503455828Subject:Mineral prospecting and exploration
Abstract/Summary:PDF Full Text Request
The hydrocarbon resources of tight sandstone have great potential in the Es3 of Gaoliu tectonic belt in Napu depression. However, the research on tight sandstone was still in its infancy, especially in reservoir characteristics and reservoir formation mechanism, because it was the large burial depth and the complex geologic condition that brought barriers to the process of exploration. Based on a variety of data analysis and test methods, the thesis carried out the study on the petrological characteristics of tight sandstone reservoir and focused on the microscopic structure of reservoir space. Combined with other geological processes, the factors that affected the pore structure of reservoir and the reason that made the reservoir densification were discussed further.Tight sandstone in Gaoliu Tectonic Belt was characterized as low compositional maturity, low cement content, and medium textural maturity. According to the homogenization temperature of fluid inclusions and vitrinite reflectance, the diagenetic stage of tight sandstone in Gaoliu Tectonic Belt could be divided as the A2 stage of middle diagenesis. The microscopic observation showed that the secondary pore was the main reservoir space and the contracted neck throat and slice-shape throat were the dominated throat types. Based on the microscopic analysis on casting thin sections, SEM and the data of intrusive mercury curve, I study the microscopic pore structure. Compared with the conventional sandstone, tight sandstone pore structure was characterized by high displacement pressure, small pore throat radius and poor sorting. According to seepage coefficient of structure and porosity, I had defined comprehensive evaluation index of pore structure to evaluate pore structure quantitatively. Based on the above data, pore structure of this area could be divided into three classes.From the influence of sedimentation, diagenesis, tectonism, and the overpressure on pore structure, it could be concluded that the sedimentation and diagenesis were the main factors influencing the pore structure. The sediment grain size of tight sandstone was thin and the rigid particle concentration was low, so the reservoir could be compacted easily. Under the action of compaction, the primary pore structure was damaged by turning the reservoir space and throat small and thin. Therefore, the genetic mechanism of tight sandstone reservoir was mainly controlled by the filling of plastic particles, the strong compaction and the cementation.
Keywords/Search Tags:Napu depression, Sha-3 member, Tight sandstone, Pore structure
PDF Full Text Request
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