Study On The Characteristics Of The Chang8Reservoir In Dadonggou District Zhiluo Oilfield

Combined with petroleum geology, sedimentology and reservoir geology, this article researches the Chang8reservoir group of Dadonggou district, Zhiluo oilfield. Based on well drilling and logging data, core observation, formation testing, and section analysis and also with the test methods, such as scanning electron microscopy, mercury penetration, X-ray diffraction and so on, The author do deep and systematic researches on the sedimentary facies and reservoir of the target reservoir group. According to this study, and with the petroleum accumulation regulation, we have a forecast to the favorable exploring area.According to the distribution of lithology, electrical, sedimentary rhythm and regional key bed, the Chang8reservoir group can be divided into Chang81and Chang82two reservoir subgroups. Based on fine stratigraphic correlation, the top surface structure of each layer is the monoclinic, inclining to the west, with multiple nose-shaped uplift growth partly. The deposition of the Chang8reservoir group belongs to a set of lake delta faces and a delta front subfaces deposition. For the main rock type is fine-extremely fine-grained feldspathic sandstone, and residual intergranular pores give the first place to the the pore type, the reservoir physical properties are poor, belonging to a special low porosity-ultra-low permeability reservoirs. The diagenesis study shows that Chang8Reservoir diagenetic evolution has reached diagenetic A period, the mainly experienced diagenesis are compaction, pressure solution, cementation, metasomatism, dissolution and fracturing. Based on reservoir influencing factors analysis, reservoir properties are mainly influenced by sedimentary microfacies and diagenesis epigenesis. The mechanical compaction of early diagenetic stage and late diagenetic stage carbonate cementation are the main reasons to the deterioration of reservoir petrophysics, and throughout the entire dissolution diagenesis stage, as well as by the rupture of a tectonic stress and mechanical compaction microfractures play a critical role to the improvement of the performance of the reservoir. The reservoir layer and interlayer heterogeneity are strong. The petroleum accumulation of Chang8is mainly controlled by sedimentary facies, reservoir physical properties. The target group is typical lithologic reservoir, which is mainly distributed in the thick sandbodies with relatively good physical properties of the main channel.