In order to study the role of fault in hydrocarbon accumulation and preservation

a comparative study was carried out on vertical sealing capacity of faults between overpressure and normal pressure mudstone caprocks.On this basis

displacement pressure of fault rock was calculated by using the empirical relationship between displacement pressure and shale content and buried depth.A set of methods for evaluating the vertical sealing capacity of fault in overpressure mudstone caprock was established and applied to Surennuoer fault zone of Wuerxun Sag in Hailar Basin.The displacement pressure of faults was quantitatively calculated

and the vertical sealing ability of overpressure mudstone caprock was eva-luated.The results indicate that K

1

d

1

overpressure mudstone caprock has a weak sealing capacity in Surennuoer fault zone and is unfavorable for hydrocarbon accumulation and preservation.This result is in good agreement with the phenomenon that oil/gas are widely distributed in this fault zone but the reserves abundance is low.This shows that this method is feasible for quantitative calculation of the vertical sealing capacity of fault in overpressure mudstone caprock.