Ein modifiziertes Eaton-Modell zur Vorhersage des FPG im Niger-Delta-Gebiet

The knowledge of the fracture pressure gradient (FPG) from the prediction of pore pressure and overburden pressure is one of the prerequisites for safe drilling. This provides drilling engineers with sufficient information about the appropriate mud weight, the criteria for casing design, optimal penetration rates, and adequate logistics for drilling operations. In this research, several models for predicting the formation fracture pressure gradient (FPG) were evaluated, which proved to be inaccurate for the Niger Delta environment. A modified Eaton model was developed that takes into account the variation of the Poisson's ratio v with depth. Based on the obtained log data, it was found that formations in the Niger Delta area tend to fracture at a Poisson's ratio of about 0.35 to 0.40, on average, at a depth of approximately 1,000 to 1,000 meters. Furthermore, the sensitivity analysis revealed that the input parameter density is an important parameter of the model. This played a significant role in the development of the modified model. Considering the above, the modified model proved to be very accurate for predicting the FPG, especially for the Niger Delta area.