Sandstone distribution and prediction of the favourable zones in the Triassic lower oil measures in the Jiulianpian region along the Tarim River, Xinjiang

The high-resolution sequence stratigraphic framework is constructed on the basis of well logs and 3D seismic data, with the emphasis on the types and distribution of the sandstones from the Triassic lower oil measures within the lowstand systems tract of TSQ3 in the Jiulianpian region along the Tarim River, Xinjiang. The sedimentary sandstones from the Triassic lower oil measures dominantly consist of braided delta front subaqueous distributary channel sandstones, which may be subdivided into three types:main distributary channel composite microfacies, secondary distributary channel composite microfacies and interdistributary channel microfacies. The examination of sandstone thickness and sand contents show that the sandstones display an EW-trending distribution, with larger thickness in the central part and smaller thickness northwards and southwards. The areas south of AT4-S98 zone in the southern part of the study area are believed to be the favourable zones in the Triassic lower oil measures in the study area.