Detailed Characterization of Pore Results of Continental Shale Reservoir in Fengcheng Formation, Mahu Sag

Abstract

The exploration potential of shale oil in the Fengcheng Formation of the Mahu Sag, located in the Junggar Basin, is significant. However, there is a notable dearth of research on shale oil within this formation. This study addresses this gap by focusing on the pore structure and associated development factors of the Fengcheng Formation in Mahu Sag. A total of 113 samples from well X of the Fengcheng Formation were meticulously selected for analysis. The mineral components and pore structure of these samples were characterized using advanced techniques, including X-ray diffraction (XRD), low-temperature nitrogen adsorption (LTNA), high-pressure mercury injection (HPMI), and scanning electron microscopy (SEM). The findings reveal that, despite a relatively low content of clay minerals in the Fengcheng Formation, their presence is intricately linked to pore development. The high content of feldspar in the formation contributes significantly to the formation of clay minerals through dissolution processes. This dual influence plays a crucial role in shaping the overall pore development within the Fengcheng Formation. In addition, a comparative analysis was conducted with shale samples from other wells within the Fengcheng Formation in Mahu Sag, as well as from different basins, such as the Songliao Basin and Ordos Basin. Different from Qingshankou Formation in Songliao Basin and Yanchang Formation in Ordos Basin, the samples from Fengcheng Formation in Mahu Sag are composed of a large number of felic minerals and carbonate minerals with less clay minerals. This study underscores the paramount importance of mineral components and their respective content in influencing the pore development of shale oil reservoirs. The unique characteristics of the Fengcheng Formation in Mahu Sag, as revealed through comprehensive analyses, contribute valuable insights to the understanding of shale oil exploration potential in the Junggar Basin.