TITLE:
Characteristics and Main Controlling Factors of Chang 8 Tight Reservoir in Zhijing Area
AUTHORS:
Tezheng Duan, Ke Wang, Yuanyuan Wang, Zhaolin Yang, Yanrong Zhang, Chen Chen
KEYWORDS:
Ordos Basin, Sedimentary Microfacies, Main Control Factors, Tight Reservoir
JOURNAL NAME:
Open Access Library Journal,
Vol.10 No.3,
March
28,
2023
ABSTRACT: In order to study the physical properties and main controlling factors of the reservoir in the Chang 8 member of the Zhijing area of the Ordos basin, the petrological characteristics, physical properties, pore types, pore throat structure characteristics of the reservoir were studied by analyzing core photos, sedimentary microfacies, combined with casting thin section, scanning electron microscope, mercury intrusion, clay mineral analysis and other test techniques. The results show that the sandstone types of the Chang 8 member in the study area are mainly feldspathic sandstone and lithic feldspathic sandstone, Pore fillers are mainly chlorite, iron calcite and illite; The pore types are mainly intergranular pore and feldspathic dissolved pore, in which the average porosity of Chang 8 section is 9.38% and the average permeability is 0.48 × 10-3 μm2, generally, it belongs to low porosity, ultra-low porosity and ultra-low permeability reservoir; Sedimentary microfacies are the key factors to control the physical properties of the reservoir, compaction is the main factor leading to the compaction of the reservoir, and cementation and dissolution are the fundamental reasons for the difference of the reservoir seepage relationship; According to the criteria of reservoir classification and evaluation, the Chang 8 member in Zhijing area is divided into three types. Class I and II reservoirs with large porosity and good permeability can be used as key exploration areas.