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GeoScienceWorld
Date
2022
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Abstract
Diagenesis varies greatly from basin to basin and has been considered as the key control of the reservoir quality of tight sandstones. In this study, we analyzed the petrographic characteristics, diagenesis, and pore types and characteristics of the Permian Lower Shihezi Formation in the Ordos Basin. Results show that most of sandstones are litharenites with minor sublitharenites and feldspathic litharenites. The tight sandstones have ultralow permeabilities (averaging 0.67 mD) and porosities (averaging 8.35%), with pore-throat sizes ranging from 0.035 to 13.29 ?m with 94.12% less than 5 ?m. Overall, the tight sandstone reservoirs have undergone complex diagenetic alteration. Compaction and clay mineral cements are the two crucial diagenetic factors that controlled the tightness of the reservoirs. The compaction destroyed most of primary porosity, and the effective pores are mainly dissolved micropores, intragranular dissolved micropores, and micropores in clay minerals and mineral grains. The chlorite coating might have helped preserve a certain amount of porosity, but pore-lining chlorites significantly obstructed pore throats and reduced permeability. Results of the study provide insights and direct implications for the future success of exploration and production of the tight gas sandstone in the Ordos Basin and other similar tight sandstone reservoirs © 2022. Qinghai Xu et al. Exclusive Licensee GeoScienceWorld. Distributed under a Creative Commons Attribution License (CC BY 4.0)
Contents
Subject
Clay minerals
Compaction
Metamorphic rocks
Microporosity
Petroleum prospecting
Quality control
Sandstone
Sedimentology
Tight gas
Key control
Micropores
Northern Ordos Basin
Permian
Petrographic characteristics
Reservoir quality
Tight gas sandstones
Tight sandstone reservoirs
Tight sandstones
Chlorine compounds
chlorite
clay mineral
coating
diagenesis
hydrocarbon reservoir
mineral
mineral exploration
Permian
sandstone
China
Ordos Basin
Shihezi
Xinjiang Uygur
Compaction
Metamorphic rocks
Microporosity
Petroleum prospecting
Quality control
Sandstone
Sedimentology
Tight gas
Key control
Micropores
Northern Ordos Basin
Permian
Petrographic characteristics
Reservoir quality
Tight gas sandstones
Tight sandstone reservoirs
Tight sandstones
Chlorine compounds
chlorite
clay mineral
coating
diagenesis
hydrocarbon reservoir
mineral
mineral exploration
Permian
sandstone
China
Ordos Basin
Shihezi
Xinjiang Uygur
Subject(s)
Research Projects
Organizational Units
Journal Issue
Genre
Description
Format
Department
Geological Sciences