Characterization and Analysis of the Main Factors of Brittleness of Shale Oil Reservoirs in the Liushagang Formation, X Depression, Beibuwan Basin

Abstract

The analysis of the main factors of brittleness is an important basis for the selection of engineering desserts in shale oil reservoirs. In this study, with the shale oil reservoir of the Liushagang Formation in the X Depression of the Beibuwan Basin as the research object, a characterization and analysis of the main factors of brittleness of the reservoir was performed in order to further reveal the brittleness of shale reservoirs in the study area. The brittleness of reservoirs in the study area was controlled by both internal and external factors, and the main factors of brittleness in the target section included the maturity of organic matter, horizontal stress difference, and brittle minerals. As the maturity of organic matter increased, the density, elastic modulus, and hardness of casein increased and the differentially hardened internal structure occurred and significantly affected brittleness. The mineral composition of the reservoir was characterized by complex mineral types and high contents of brittle minerals, and the minerals determining brittleness were mainly quartz, feldspar, calcite, and dolomite. The horizontal stress difference of the shale oil section was relatively small and contributed to fracturing and reforming. This study clarified the brittleness characteristics of E2l shale and its main factors, and provided a basis for the selection of shale formation geo-engineering dessert layers in the study area.