Current research status and development trends of fault sealing

Abstract

The controlling effect of faults on hydrocarbon pool formation is mainly reflected in their impact on the processes of hydrocarbon migration, accumulation and distribution. Its essence is the problem of fault sealing. Fault sealing is typically influenced by a variety of factors, and the mechanism and the main controlling factors of fault sealing differ significantly across different layers, regions and geological periods. At present, there is no complete research system for the evaluation of fault sealing, and the accuracy of its evaluation needs to be improved. By comprehensively and systematically investigating recent research hotspots in the area of fault sealing, we summarize the mechanism of fault sealing, analyze the main controlling factors, systematically categorize the evaluation methods, and discuss the practical issues faced in fault sealing research. We also propose the development trends of future research. Fault sealing mechanisms can be divided into vertical and lateral sealing mechanisms. The former includes fault surface sealing and displacement pressure difference sealing within fault zones, while the latter includes sand and mud juxtaposition sealing, lateral sealing formed by shale smearing, and high displacement pressure sealing within fault zones. The main factors affecting fault sealing include fault development characteristics, lithology of the two fault walls, stress field environment, and diagenetic processes such as compaction, cementation, and dissolution. Different factors influence fault sealing in various ways, and fault sealing varies significantly with location and time. The research methods for fault sealing evaluation can be classified into four categories: (1) traditional geological methods: including qualitative and semi-quantitative analyses; (2) mathematical geological methods: including logistic information method, nonlinear mapping analysis, fuzzy comprehensive evaluation, grey correlation analysis, etc.; (3) numerical simulation of the tectonic stress field and calculation of parameters related to fault sealing; and (4) geochemical methods. Future research directions include fault opening and sealing mechanism and sealing evaluation of carbonate rock strata, the impact mechanism of stress and fluid coupling on fault sealing, comprehensive quantitative evaluations of fault sealing with multiple factors, the temporal and spatial evolution of fault sealing, and the assessment of fault connectivity.

Keywords

• fault sealing
• fault sealing mechanism
• displacement pressure
• mudstone smearing
• controlling effect of faults on hydrocarbons