The provenance feature of Jurassic Qigu Formation and its effect on reservoir development in the southern margin of Junggar basin

Abstract：There exists great potential of oil and gas resources in deep Jurassic strata of southern Junggar basin; nevertheless, the research on Jurassic formation remains in the stage of exploration, and the provenance and main controlling factors of the reservoir development are not yet clear. Based on the study of heavy mineral combination in combination with rare earth element distribution characteristics, the authors infer that there are different provenances in different tectonic units., and at the early and late development stage of the strata in the same area, the main direction of provenance was also varying. It is concluded that there are two provenances in northern Sikeshu depression, i.e., the Chepaizi provenance in the northeast and the provenance in the northwest. In southern Sikeshu area, the provenance is the southern part. The provenance of Qigu Formation varied in the period of sedimentation, the southern and eastern provenances were dominant at the early stage, whereas the northern provenance gradually became dominant at the late stage. The eastern area was close to the provenance, and the parent rock was primarily metamorphic rocks. Studies show that rock debris was under the influence of parent rock types, and this further affected the development characteristics of the reservoir.