Demonstration Of The Cambro-Ordovician Carbonate Ramp And Potential Play In Southwestern Tarim Area

Recent years, there have been several studies about the structure and reservoir characteristics of the Southwestern Tarim area. The researches almost all focused on the genetic mechanism and the dynamics mechanism of the foreland thrust belt, structural evolution, structural types or the hydrocarbon systems and so on. While the study on the sedimentary stratigraphy is quite limited, and the Southwestern Tarim area is located in the transition zone of basin and mountains, which makes the exploration of this area quite difficult. After decades of researches and exploration, this area achieved a certain stage progress, but there is no breakthrough accordingly to the relatively rich oil and gas resources in the area.In this paper, using "sequence analysis technology" and "sedimentary systems analysis" as the two leading methods, analyzed the sedimentary and sequence characteristics of the Cambrian - Ordovician Southwestern Tarim area, the platform structure. This paper, fully used the outcrop, core, drilling, logging, seismic data and testing data, established the regional sequence stratigraphic framework, revealed the sequence background of reservoir development; through the anatomy of the development and migration of the Cambrian - Ordovician carbonate platform in different periods, revealed the effect of platform structural changes in sedimentary facies and reservoir development. In this research, we revealed the favorable zone for oil and gas exploration from the sequences and sedimentary facies.The results showed that: the Cambrian - Ordovician platform margin sedimentary facies existed in the study area, and there were multiple phases of the platform margin reef complex deposition. And enabling the study area has several sets of favorable source rocks, reservoirs and seal rocks, some areas also have excellent structures may work as oil and gas migration conditions, there are prospects for the formation of large oil and gas reservoirs. Especially the junction point of the the Bachu uplift and the Magaiti Slope, the ramp region within the southern margin of the Magaiti Slope and the intraplatform carbonates, which have favorable combination of source rocks, reservoirs and seal rocks, are the southwestern most prospected regions for oil and gas exploration and development.