Sedimentary Characteristics of the Lower Members of the Silurian Kepingtage Formation in Shun 9 Region, Tarim Basin

A series of marine facies clasolite structure developed in the lower members of Silurian Kepingtage formation of the Shuntuoguole lower uplift. It is an important oil-gas exploration target and a perspective position in Tarim Basin. Low-yield oil flow obtained in the way of sand fracturing in Shun 9 shows good oil and gas exploration outlook. However, because of huge divergence existed among predecessors about the sedimentary facies and sand body origin of this oil-bearing series, we could not characterize the sand distribution very well, which has already restricted our exploration and deployment process. In this paper, by using the data of drilling core, well logging, seismic and test analysis and combining with the depositional background analysis, we studied the sedimentary facies types and distribution of the lower members of the Silurian Kepingtage formation in Shun 9 region, Tarim Basin. We made three conclusions: first, the lower members of the Silurian Kepingtage formation in Shun 9 region is clasolite coastal sedimentary mainly dominated by subtidal and transitional zone, the mudstone under the oil-bearing sandstone section is shallow sea shelf mud deposits; second, the oil-bearing sandstone section in the lower members of the Kepingtage formation in Shun 9 region is mainly in the subtidal and transitional zone of tidal flat and shallow sea shelf sedimentary environment, its micro-facies types include tidal channel, tidal sand dam, mudflat, shelf sand, storm sand body and continental shelf mud; last, the reservoir sand body is the recombination sand body of tidal channel and tidal sand dam; the favorable sand body distribution belt is Shun 9 and Shun 903 well block.