A lot of hydrocarbon traps are associated with tectonic shielding by faults. Tectonic shifts can lead to both shielding of hydrocarbon deposits and cross flows into adjacent blocks or along tectonic faults. The study considers a technology for assessing the faults fluid permeability based on the determination of hydrodynamic windows in the both hanging-wall and footwall tectonic blocks. 1D Allan sections, shale gouge ratio and different techniques of modern structural geology are discussed. Requirements for the quality of geological models based on the structural approach are considered. A workflow for the application of the technology for assessing the fluid permeability of faults and possible restrictions are proposed. The considered methodological approaches should be used for risk assessment of hydrocarbons saturation of shielded traps in the practice of geological exploration of oil and gas. The authors' researches were based on practical experience of geological exploration in the Western Caucasus and Eastern Siberia. The examples illustrated in the article came from the western part of the Vilyui syneclise, especially, for graben and half- graben zone systems. The target geological features are the Vendian-Cambrian terrigenous-carbonate traps. The risk matrix and the probable height of the hydrocarbon traps associated with shielding by normal faults are the result of the work.
References
1. Allan U.S., Model for hydrocarbon migration and entrapment within faulted structures, AAPGBull., 1989, V. 73, pp. 803-811, DOI: https://doi.org/10.1306/44B4A271-170A-11D7-8645000102C1865D
2. Knipe R.J., Juxtaposition and seal diagrams to help analyze fault seals in hydrocarbon reservoirs, AAPG Bull., 1997, V. 81, pp. 187-195, DOI: https://doi.org/10.1306/522B42DF-1727-11D7-8645000102C1865D
3. Yielding G., Freeman B., Needham D.T., Quantitative fault seal prediction, AAPG Bull., 1997, V. 81, pp. 897-917, DOI: https://doi.org/10.1306/522B498D-1727-11D7-8645000102C1865D
4. Yielding G., Shale Gouge Ratio-calibration by geohistory, Norwegian Petroleum Society Special Publications, 2002, V. 11, pp. 1-15, DOI: http://doi.org/10.1016/S0928-8937(02)80003-0
