Microscopic Reservoir Characteristics Study Of Jianchang Basin

Due to many phases of tectonic movements, karst caves, vugs, faults and fractures developed very well in this area. As long as the volcanic rocks and sandy conglomerates developed, making the reservoir very complex. Mesozoic-Proterozoic sequences have been studied before, however, it is mainly macroscopic. As the sedimentary work moves to the microscopic field, the microscopic reservoir characteristics study becomes very important.Observation of microscopic thin sections, fluorescence thin sections, casting thin sections, MICP, XRD and SEM of drilling core and cutting samples, as long as field sections and logging analysis are listed in this thesis. A detailed study is carried on, including rock types, storage types and petrophysical properties.The rock types are comprised of sedimentary rocks and volcanic rocks, and can be further categorized into 20 types. Carbonate rock is the main reservoir rock, followed by quartz sandstone.Physical Diagenesis, chemical diagenesis and biological diagenesis dominate the diagenesis. The reservoir storage spaces are comprised of 2 types, which are pores and fractures. The pores are intergranular pores, intercrystalline pores, vugs, and caves. The fractures are pressure solution fractures and stress induced fractures. There are 3 types of storage combinations, which are combination of intergranular pores, fractures, pressure solution fractures, combination of various fractures, and combination of pressure solution fractures, fissures, and intercrystalline pores.The experiments on the cores shows that the porosity varies from 0.7% to 9.7%, with a mean of 2.9%. The permeability varies from 0.002mD to 18.4mD, with a mean of 1.84mD. It is believed that the reservoir is characterized of ultra-low porosity and ultra-low permeability.