Characteristics of the tuffaceous shale oil reservoir and its sweet spots: A case study of the Tiaohu depression in the Santanghu Basin

Abstract

Shale oil has become an important alternative resource for conventional hydrocarbon resources. There are many areas with great exploration potential for shale oil worldwide, but the degree of exploration is relatively low. This study focuses on the shale oil reservoirs in the Tiaohu Depression of Santanghu Basin, northeast of Xinjiang Uygur Autonomous Region, China. We used pore permeability with 50 samples of saturation, thin section identification, high-pressure mercury injection, low-temperature nitrogen adsorption, and scanning electron microscopy (SEM), and according to these measurement technologies, we found that the study area is mainly composed of a set of basic-moderate volcaniclastic sediment; the shale reservoir is dense, with higher oil saturation; the fracture development zone is a movable desert area; and tuffaceous secondary pore formation is the main object of dissolution. It contains a variety of reservoir spaces, which are conducive to shale oil enrichment. The reservoir characteristics, microscopic pore structure, and origins of geological sweet spots are systematically analyzed, which provides research direction for shale oil exploration.