Study on Fault Sealing of the Maxi Fault in the Raoyang Depression

Faults can become pathways for migration of hydrocarbons,but they also can be barriers to reservoirs in different geologic epochs.Hence,it is important to study fault sealing performance to determine the distribution of reservoirs.Several factors can influence fault sealing performance,namely,the lithologic associations on two sides of a given fault,mudstone-smearing,the relationship between fault-movement periods and hydrocarbon migration intervals,and the stress of fracture surfaces.This study examined these factors for the fault sealing performance of the Maxi fault in the Raoyang depression.Fault sealing performance was evaluated using the synthesized evaluation method.Results show that the Maxi Fault grew actively in the Middle-late Cenozoic.Fault sealing was poor in this period,while hydrocarbon migration was at a peak during this interval.Thus,it appears the fault became a pathway for hydrocarbon migration.After that,the Maxi fault stopped growing for a long time.At the same time,fault sealing became more dominant,showed the specialties as upperbetter and lower-worse.This situation was beneficial in creating a petroleum reservoir in Shahejie strata.However,petroleum could not be trapped in the foot wall of the Maxi Fault.