Abstract:

Fault plays an essential role in oil and gas accumulation, so the analysis of fault sealing capacity is quite important. There are many methods, but it’s still so hard for these methods to evaluate the fault sealing capacity accurately and widely. As a result, before we select an appropriate method and hence improve the reliability of results, we must make clear about the using condition and the key steps of different methods. This paper summarized the most frequently-used methods and their trains of thought proposed by the academician at home and abroad, and then analyzed the relevant basic datasets, key steps, merits and demerits, using conditions and the relative reliability of each method. The qualitative evaluation of fault sealing capacity has 12 respects, including direction of faults, size of faults throw, sand/strata ratio and so on. While the quantitative evaluation methods are mainly based on quantitative calculation of the normal stress on fault plane, shale smear factor and fluid pressure of mudstone. Presently, the SGR method put forward by Yielding is most mature and widest used in many methods. From the known area or some other area with similar geological character nearby, we can get the appropriate parameter or the evaluation standard of the special method, and then the unknown fault sealing capacity can be analyzed.

Key words: hydrocarbon accumulation, main controlling factors, turbidite, the middle sub-member of the third member of Shahejie Formation, Dongying Sag