Distribution of Cambrian source rocks and evaluation and optimization of favorable zones in East Tarim Basin

Abstract

Cambrian source rocks in Tarim Basin have been the focus of many scholars' research in recent years. There are still some divergences on their distribution, which become an important factor restricting Cambrian exploration and zoning optimization. Based on the knowledge of outcrop and drilling data in the basin, the sedimentary environment of Cambrian source rocks is analyzed in this paper. According to the sedimentary environment and development time, the Cambrian source rocks are divided into mild-slope style rocks and steep-slope style rocks in East Tarim. The mild-slope source rocks, deposited in the same period of the Yuertus Formation, is mainly controlled by the pre-Cambrian palaeogeomorphology. The thickness center is located in the northwest side of the Manjiar Depression, and the thickness of the source rocks is about 15-40 m. The steep-slope source rocks, developed in the sedimentary environment of the platform margin slope-basin, is located in the Lunnan-Gucheng arc belt in Manxi area, with a maximum thickness of about 150 m. Based on the distribution characteristics of two types of source rocks in East Tarim area, dolomite of Lunnan area and the Middle-Upper Cambrian platform margin belt in the north of Gucheng low uplift are selected as favorable exploration zone in East Tarim Basin.