The Cambrian sedimentary sequences and paleogeographic evolution in the Bachu-Maigaiti area, southwestern Tarim Basin.

The Bachu-Maigaiti area in the Tarim Basin is an important oil-gas-bearing area. Based on the latest drilling and seismic data, this paper divides the Cambrian into 13 third-order sequences in the Bachu-Maigaiti area of ​​the Tarim Basin. Detailed descriptions of the sedimentary sequences and lithofacies and paleogeography of each period were provided. It was proposed that the Bachu-Maigaiti area experienced an evolution process from a carbonate gentle slope to a rimmed carbonate platform. Through the study of up-drilling, logging data, and seismic characteristics of the Bachu uplift, the sedimentary environment of the Maigaiti slope, which lacks physical data such as drilling, was reasonably speculated, and finally the lithofacies paleogeographic map was compiled in units of groups. The results show that the Bachu-Maigaiti area in the Tarim Basin experienced two large-scale transgressions during the Cambrian sedimentary evolution (SQ1-SQ13), forming a good source-reservoir-cap assemblage in the Cambrian subsalt. In this context, the Maigaiti slope is the most favorable area for the formation of large oil and gas reservoirs in the Cambrian exploration area in the southwest of the Tarim Basin, and has good exploration prospects.