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Junggar basin is one of the most important oil and gas exploration blocks in China. Mahu sag, as the most important hydrocarbon generation sag, is rich in oil and gas resources and has good exploration prospects. Taking the reservoir of lower Wuerhe formation in Madong slope belt of Mahu sag as the research object, this paper studies the reservoir characteristics and main controlling factors of lower Wuerhe formation on the basis of core data and logging data. The results show that the main rock type of lower Wuerhe formation is glutenite, and there are four types of reservoir space: primary intergranular pore, residual intergranular pore, intragranular dissolved pore and intergranular dissolved pore. Reservoir porosity ranges from 5.12% to 10.30%, with an average of 7.15%, and permeability ranges from 0.01 to 100mD, with an average of 0.24mD. Reservoir development in this area is mainly controlled by tectonism, sedimentary microfacies, diagenesis and other factors, in which sedimentation is the main controlling factor. Compaction is the main factor that destroys reservoir physical properties, and the nose convex structure formed by tectonic action is the favorable area of structural reservoir. Combined with the drilling logging data and oil test and production data, the favorable area of lower Wuerhe formation in the study area is predicted, and it is pointed out that type I1, type I2 and type II are the dominant reservoirs. The study of reservoir characteristics and main controlling factors of lower Wuerhe formation in Madong slope belt has guiding significance for exploration in the study area. [ABSTRACT FROM AUTHOR]

The Jurassic in the Sanquan bulge of Luliang Oilfield, Junggar Basin, China is rich in oil and gas resources. However, the area is located in a desert area and its geological features are very complex. Therefore, the use of seismic data for reservoir prediction is an effective method. In this study, the three-dimensional seismic data system was used to carry out the fine fault characterization, structural interpretation, reservoir characterization and trap evaluation of the Jurassic strata. The research results show that the use of coherent horizontal slices can effectively realize fault recognition. The fault system of the Sanquan Uplift can be subdivided into two groups, one group is in NE-SW direction, the other group is in NW-SE direction. The study area is dominated by normal faults, which can be subdivided into two stages, the first stage is the early Yanshanian fault, and the other is the middle-late Yanshanian fault. The structural interpretation results show that different provenance sources of the Jurassic Toutunhe Formation have different seismic response characteristics. The source in the northwest direction shows a poorly continuous medium-weak reflection in the seismic axis, while the north-east source shows a superimposed feature and a moderately strong reflection with good continuity in the seismic axis. The argillaceous barrier zone between the two provenances showed blank reflection characteristics. According to regional seismic and geological fine interpretation, sedimentary reservoir research and reservoir profile analysis, we found that the Jurassic trap types are mainly: (1) Toutunhe Formation lithological traps developed on the perimeter; (2) The fault block, nose or fault anticline traps developed on the anticline belt of the Jurassic Xishanyao Formation. Finally, we identified the anticlines and fault anticlines traps in the Toutunhe Formation and the fault block traps in the Xishanyao Formation. [ABSTRACT FROM AUTHOR]