Abstract:

Taking the Neogene layers of the Enping sag as an example, a new way to evaluate fault sealing of structural closure is introduced under the current exploration practice to calibrate critical values, that is, obtaining clay content in fault zone, shale smear value and normal pressure of fault surface from sealing rules of faulted reservoir. The results show that the threshold values of shale smear factor in drilled faulted reservoirs gradually increases with depth. Development of shale and its content of fault zone are prerequisites for fault sealing, and the evaluation of fault sealing is affected by structure map accuracy, structural adjustment and fault activity. The risk of fault sealing, including faults vertical and lateral sealing, could be analyzed by the evaluation method, so as to improve the success ratio of fault traps exploration. And the evaluation method could be applied to the new exploration area with the similar tectonic genesis and sedimentary background as Enping sag, which is an effective methods to evaluate fault sealing during the early exploration periods.

Key words: Pearl River Mouth Basin, Enping sag, fault sealing, evaluation method, Neogene