摘要
Based on the data of drilling and logging,paleo-pressure of Chang 7 undercompacted shale in Xifeng area was restored by using statistic analysis,buried history simulation and formation pressure calculation.The results show that the formation porosity is always influenced by buried depth and geological time. There is a exponential relationship between undercompacted porosity increment and buried depth of Chang 7 shale.Porosity of Chang 7 undercompacted shale during accumulation period could be easily figured out by employing this function in combination with formation buried history.Significant overpressure develops in Chang 7 undercompacted shale during accumulation period.