Morteza Azadpour - Department of Petroleum Exploration Engineering, Faculty of Mining Engineering, Sahand University of Technology, Tabriz, Iran
Navid Shad Manaman - Department of Petroleum Exploration Engineering, Faculty of Mining Engineering, Sahand University of Technology, Tabriz, Iran

Pore pressure is defined as the pressure of the fluid inside the pore space of the formation, which isalso known as the formation pressure. When the pore pressure is higher than hydrostatic pressure, it isreferred to as overpressure. Knowledge of this pressure is essential for cost-effective drilling, safewell planning, and efficient reservoir modeling. The main objective of this study is to estimate theformation pore pressure as a reliable mud weight pressure using well log data at one of oil fields in thesouth of Iran. To obtain this goal, the formation pore pressure is estimated from well logging data byapplying Eaton’s prediction method with some modifications. In this way, sonic transient time trendline is separated by lithology changes and recalibrated by Weakley’s approach. The created sonictransient time is used to create an overlay pore pressure based on Eaton’s method and is led to porepressure determination. The results are compared with the pore pressure estimated from commonlyused methods such as Eaton’s and Bowers’s methods. The determined pore pressure from Weakley’sapproach shows some improvements in comparison with Eaton’s method. However, the results ofBowers’s method, in comparison with the other two methods, show relatively better agreement withthe mud weight pressure values.

Pore Pressure, Well-logging, Weakley’s Approach, Eaton’s Method, Carbonate Reservoirs