AGRs Advisor Geology, Ole-Gunnar Tveiten, recently coauthored an article published in the Petroleum Geoscience magazine
The image below displays the Halten Terrace 3D pore pressure cube constructed using the seismic interval velocities model to calibrate and understand the correlation between velocity and pressure profiles in offset wells.
The latest article co-published by Ole-Gunnar Tveiten, our Advisor Geology, describes how the unique pore pressure prediction technique was implemented in the Norwegian Sea in Halten Terrace. This is an area with complex patterns of pore pressure anomalies which previously have been difficult to predict.
Pre-drill pore pressure prediction is essential for safe and efficient drilling and is a key element in the risk reducing toolbox when designing a well.
On the Norwegian Continental Shelf pore pressure prediction commonly relies on traditional 1D offset analysis whereas velocity data from seismic surveys are often not considered.
The article discusses seismic interval velocities and shows that the velocity field can provide an important basis for pressure prediction and enable construction of regional 3D pressure cubes. This increases the confidence in the pore pressure models and aids the pre-drill geo-hazard screening process.
Ole-Gunnar with other co-authors demonstrate how a 3D velocity field can be converted to a 3D pore pressure cube using reported pressures in offset wells as calibration points. The algorithm is searching for a velocity to pore pressure transform that best matches the reported pressures. The 3D velocity field is a proxy of rock velocity and is derived from seismic surveys and verified to check shot velocities and sonic data in the offset wells.
For full version of the article, please contact Ole-Gunnar
or download the paper here