STUDY ON PERMIAN SEDIMENTARY ENVIRONMENT AND RESERVOIR CHARACTERISTICS IN MAHU SAG, JUNGGAR BASIN, CHINA

摘要

The Mahu Sag in the northwestern margin of the Junggar Basin is a world-famous lacustrine hy-drocarbon-rich sag. The latest exploration results show the characteristics of large oil(gas)regions. The basic theories of sedimentology and petroleum geology, core observation,logging and various thin-film data, the provenance, sedimentary environment, high quality ofthe Permian Wuerhe Formation in the Yanbei area reservoir characteristics and genesis have been comprehensively studied the main factors. These factors affected the reservoir properties which can be used to guide the next step of exploration and development. The research shows that the Lower Wuerhe Formation is a fan-delta sedimentary envi-ronment, dominated by delta front subfacies, and the types of sedimentary microfacies are mainly Heman Lake, braided channel, crest fan, underwater diver-sion channels, estuary dams, distant sand dams, in-ter-channels, etc. There are two major provenances, Madong provenance and lower summer salt prove-nance, with summer salt provenance as the main source. The Permian Lower Wuerhe Formation res-ervoir is mainly affected by sedimentary environ-ment and diagenesis. The lower Wuerhe Formation reservoir rock type is mainly conglomerate, and the sedimentary facies is the key factor to control the res-ervoir physical properties. The facies belt is the un-derwater distributary channel in the front edge of the fan delta, which is a favorable area for further explo-ration.