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A Novel Approach to Predict 3D Pressure Cubes, Sapphire Field, Offshore Nile Delta, Egypt
- Source: First Break, Volume 43, Issue 1, Jan 2025, p. 43 - 49
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- 01 Jan 2025
Abstract
Pore pressure is regarded as an important branch of earth science. In exploration phase, pore pressure can provide information about trap integrity. During the drilling stage, the pre-drill pore pressure prediction helps in the casing and mud design. A good pre-drill pore pressure prediction will protect the well from drilling problems such as kicks and blowouts. In the production phase, it helps in the injection process, predicting reservoir compartments.
Sapphire field is part of the offshore Nile delta which is classified as a high-pressure basin. As a result, pre-drill pore pressure prediction is an important step in the well planning process for predicting abnormal pressures along the well path and avoiding drilling problems.
The paper presents a new workflow approach for the 3D pore pressure cube for the Nile Delta basin depends on four wells to generate a cube with the full set of pressure data (overburden, effective vertical stress, and formation (pore) pressure), it is built using Eaton and Bowers equations. In addition, Eaton and Bowers were optimised to fit the Nile Delta basin, compared to the Gulf of Mexico, which used the default optimisation value. The uncertainty in the density estimation is reduced as well by using the density sonic relation.
Three cubes overburden, vertical effective stress, and pore pressure prediction are the main outputs of the research. These three cubes almost match the actual pressure that was calculated using logging while drilling tools on the rig-site at the wells.