부산대학교 도서관

A prediction model for formation pore pressure and fracture pressure gradient in X offshore area from seismic data has been established in this study. We have used this model successfully to estimate the formation pore pressure and fracture pressure gradient for the casing and mud design before the drilling of X-14. It has been found most of the predicted formation pore pressure and fracture pressure gradient are close to those field data from Dc exponent and well logging. Due to the limited resolution of the seismic data, it is not easy to predict the formation pore pressure of the thin abnormal high pressure zone well. Modified Hubbert ＆ Willis's model can be used to predict the fracture pressure gradient of non-fracture sands tone and shale formation. The poroelastic constant is 0.7. Eaton's model can be used to predict the fracture pressure gradient of fracture sandstone. The veloctiy of P-wave ＆ S-wave from sonic log can be used to calculate the Poisson's ratio of deep formation. The Poisson's ratio from calculation is very close to the data from lab rock mechanics testing and does not need any correction. This model can be used to estimate the formation pore pressure and fracture pressure gradient for the casing and mud design for onland, offshore and international exploration well before drilling to reduce the risk of lost circulation and blowout during drilling operations.