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GEOREF RECORD

Mechanism and continuity of gypsum smears in the east Qiulitage Anticline, Kuqa foreland basin, China

Wu Tong, Fu Xiaofei, Wang Haixue, Lu Mingxu, Meng Lingdong and Gong Lei
Mechanism and continuity of gypsum smears in the east Qiulitage Anticline, Kuqa foreland basin, China
AAPG Bulletin (August 2022) 106 (8): 1605-1623

Abstract

Smears are formed when faults cross-cut layered sequences. They have been observed within mudstone, shale, siltstone, carbonate, coal, and others. Gypsum smears were observed on a section of the East Qiulitage anticline in the Kuqa foreland basin when describing segmented reverse faults. Samples including gypsum and mudstone were collected to study why gypsum developed smears instead of mudstone. Based on mechanical tests, we investigated the formation mechanism of gypsum smears. The uniaxial compressive strength tested using a Schmidt hammer and the peak strength and cohesion tested using a triaxial test system at different confining pressures suggest that mudstone is stronger than gypsum; as the confining pressure increases, the strength contrast increases, and gypsum is more ductile than mudstone. Finally, we propose that the competence contrast between layers is the most fundamental factor controlling the formation of smears in the process of fault deformation. Once a smear is formed, the fault throw and source bed thickness control its continuity. The gypsum smear factor derived from the shale smear factor is used to evaluate the continuity of sheared gypsum smears, which are continuous where the gypsum smear factor is 3.5-4 or less. Faults seal when smears are continuous; determining the mechanism and continuity of smears is important in cross-fault fluid flow problems, especially in oil and gas transport situations.


ISSN: 0149-1423
EISSN: 1558-9153
Coden: AABUD2
Serial Title: AAPG Bulletin
Serial Volume: 106
Serial Issue: 8
Title: Mechanism and continuity of gypsum smears in the east Qiulitage Anticline, Kuqa foreland basin, China
Affiliation: Northeast Petroleum University, Key Laboratory of China National Petroleum Corporation Fault Controlling Reservoir, Heilongjiang, China
Pages: 1605-1623
Published: 202208
Text Language: English
Publisher: American Association of Petroleum Geologists, Tulsa, OK, United States
References: 54
Accession Number: 2022-047945
Categories: Structural geologyEconomic geology, geology of energy sources
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., strat. col., 4 tables, sketch maps
N41°00'00" - N42°25'00", E80°30'00" - E85°00'00"
Secondary Affiliation: Daqing Oilfield Company, CHN, ChinaKey Laboratory of Oil and Gas Reservoir and Underground Gas Storage Integrity Evaluation of Heilongjiang Province, CHN, China
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by American Association of Petroleum Geologists, Tulsa, OK, United States
Update Code: 2022
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