Abstract
<title>Abstract</title> <p>In the central Sichuan area, shallow continental clastic strata and deep marine carbonate formations are vertically developed. The mechanisms that generate abnormal pressure differ between these two types of strata, and the overall heterogeneity is strong. Conventional empirical pore-pressure prediction methods are markedly inadequate in deep carbonate rocks, exhibit poor universality, and fail to achieve accurate prediction over the entire well section. Therefore, using logging, geological and well-test data from the study area, this paper compares the Eaton, effective‑stress and Fillippone methods for pore-pressure prediction. The results indicate that both the Eaton and effective‑stress methods are based on the normal compaction trend line and yield relatively large prediction errors in deep carbonate formations, whereas the Fillippone method performs best. On this basis, the paper further modifies the Fillippone method by adjusting the velocity‑ratio relationship so that the velocity response in abnormally high‑pressure intervals changes from “attenuated feedback” to “compensatory uplift”. The research results demonstrate that the proposed method achieves higher prediction accuracy, and the predicted pressure coefficients agree well with fracture and electrical image data, making it more suitable for pore‑pressure prediction in deep carbonate formations and capable of effectively supporting rapid and efficient drilling operations.</p>