Pore-Pressure Prediction from Corrected D-Exponent Analysis: A Case Study of Hamra East-8, Muglad Basin

Accurate pore-pressure prediction is essential for safe mud-weight selection, casing-seat planning, and avoidance of kicks, losses, stuck pipe, and non-productive time. This paper presents a reproducible corrected D-exponent and Eaton-method workflow for Hamra East-8, Hamra oil field, Block 2A, Heglig area, Muglad Basin. The paper responds to reproducibility requirements by specifying the shale-screening rule, corrected D-exponent equation, reference mud weight, drilling-report averaging interval, overburden-density source, normal compaction trend fitting approach, Eaton exponent, depth reference, and a manual verification point inside the 1600 - 1700 mKB watch zone. Shale screening used a gamma-ray-derived shale volume criterion of Vsh ≥ 0.35, with shale-prone intervals checked against lithological descriptions. Corrected D-exponent values were computed from 10 m mKB drilling-parameter averages and corrected with a 9.2 ppg reference mud weight. Overburden was calculated from a sonic-derived density curve using a Gardner-type velocity-density transform when measured density was unavailable. Eaton calculations used an exponent of 1.2, adopted from drilling-engineering practice and checked locally by manual verification. Five verification depths, including 1650 mKB in the watch interval, show close agreement between software and manual calculations, with an average absolute difference 26.8 psi and RMSE 32.8 psi. The 1600 - 1700 mKB interval shows only a slight pressure increase and remains close to normal hydrostatic conditions.