An improved research method on fault sealing capacity：taking Longmenshan thrust belt as an example

Preservation condition is a key element of oil and gas accumulation in foreland thrust belt, and fault sealing capacity plays a vital function. Due to the difference of lithologic interface of fault plates in three-dimensional space, the sealing capacity of the identical fault is different along different orientations or at different depths. The improved Allen section was applied in this paper to study the lateral sealing capacity of fault. The vertical sealing capacity of fault was evaluated based on the pressure of fault section and the net-to-gross ratio of displaced layers. Semi-quantitative comprehensive evaluation was made by means of the studies of vertical and lateral sealing capacity of fault. This method might be used to judge the fault sealing capacity initially in the places with low exploration degree, especially in those places without wells. And the places with high exploration degree, we could develop the results of evaluation from semi-quantitation to quantification based on exploration data.