The sandstone reservoir characteristics and controlling factors of Shanxi Formation and Lower Shihezi Formation in Southeastern Ordos Basin. (18th October 2020)

• Record Type: Journal Article
• Authors: Xu, Wenguo; Deng, Hongwen; Wang, Yating
• Is Part Of: Geological journal. Volume 56:Number 3(2021)
• Page Start: 1673
• Page End: 1698
• Publication Date: 2020-10-18
• Subjects: controlling factors -- Lower Shihezi Formation -- Ordos Basin -- reservoir characteristics -- Shanxi Formation; Geology -- Periodicals; 551
• DOI: 10.1002/gj.4019
• Languages: English
• ISSNs: 0072-1050

Abstract

Abstract : The southeastern Ordos Basin hosts considerable resource potentials and contains significant hydrocarbon discoveries in the Shanxi Formation and Lower Shihezi Formation, making it a significant petroliferous exploration area. In this study, wireline logs, mud logs, cores, thin sections, scanning electron microscope, heavy minerals, porosity and permeability data, and grain size are employed to carry out research on reservoir differentiation characteristics and associated controlling factors in the Shanxi Formation and Lower Shihezi Formation. The results indicate that reservoir sandstone mainly includes lithic sandstone, quartz sandstone, and lithic quartz sandstone. The pore types are dominated by secondary intergranular pore, intragranular dissolution pore, followed by intercrystal pore and microcracks. The porosity and permeability attain 7.9% and 0.59 10 −3 μm 2 respectively which shows low porosity and low permeability. The differences of sandstone reservoirs in the Lower Shihezi Formation and Shanxi Formation are controlled by tectonic movements, sedimentary environments, and diagenesis. Tectonic movements not only provide potential provenance but also reconstruct physical property. Sedimentary environments determine sandstone composition and texture and controls reservoir heterogeneity. The diagenesis affects the preservation, evolution, and development of reservoirs and determines the quality of physical property. Abstract : The considerable hydrocarbon discoveries in Lower Shihezi Formation and Shanxi Formation have been found in Southeastern Ordos Basin which are of great potential and scientific interests to oil industry and scholars. Previous studies have conducted in the field of tectonics, sequence stratigraphy, and sedimentology. Few public reports have been focused on reservoir characteristics and controlling factors. In this article, it aims to employ wireline logs, mud logs, cores, thin sections, scanning electron microscope, heavy minerals, por‐per data, and grain size to carry out a detailed description and analysis of reservoir characteristics (petrological characteristics, pore types and textures, physical properties) and associated controlling factors. The results indicate that the reservoir sandstone includes lithic sandstone, quartz sandstone, and lithic quartz sandstone. The pore types are dominated by secondary intergranular pore, intragranular dissolution pore, followed by intercrystal pore and microcrack. The porosity and permeability arrive at 7.9% and 0.59 10 −3 μm 2 respectively which is characterized by low porosity and low permeability. The differences of sandstone reservoirs in Lower Shihezi Formation and Shanxi Formation are controlled by tectonic attributes, sedimentary environments, and diagenesis. Tectonic attributes not only provide potential provenance but also reconstruct physical property. Sedimentary environments determine sandstone composition and texture and controls reservoir heterogeneity. The diagenesis affects the preservation, evolution, and development of reservoirs and determines the quality of physical property.