Study on sedimentation distribution based on cooperative analysis of geologic–geophysical in less well area: A case study of Suweiyi sandstone in the DB area, Kuqa Depression in Tarim Basin

Abstract

The Kuqa Depression in Tarim Basin develops fan deltaic, braided river deltaic, and lacustrine sedimentation, especially extensive braided river deltaic sedimentation, in the Cretaceous-Paleogene Systems. However, fine sedimentary pattern of the Kuqa Depression and North Tarim Uplift belt since the Middle Cenozoic still needs to be studied. As a combination zone of the Kuqa Depression and North Tarim Uplift, the sedimentary characteristics of the DB area in the southern margin of the east of the Kuqa depression have been paid more attention. To better understand the sedimentary framework in the Kuqa Depression and North Tarim Uplift in the Mesozoic and Cenozoic, through joint geologic-geophysical study, sedimentation of sandstone at the bottom of the Paleogene Suweiyi Formation in the DB area and its peripheral area is investigated. Sedimentary facies and sandstone distribution in the area are identified through core observation, component analysis, logging interpretation and seismic inversion. Based on seismic facies analysis, sedimentary facies distribution in the area is delineated. Results show that sandstone at the bottom of the Paleogene Suweiyi Formation in the DB area and its peripheral area is developed in shore-shallow lacustrine beach-bar facies. The beach-bar arenaceous sediments are mainly distributed in the southern DB area and the shallow lacustrine mudstone is developed in northern DB area, showing obvious north-south differentiation characteristics.