Quantifying Structural Uncertainty in Anisotropic Model Building and Depth Imaging: Hild Case Study

The paper describes a collaborative project between Total and WesternGeco on quantifying structural uncertainty in application to the development of the Hild field. The key motivation for the project was to improve the seismic uncertainty inputs into the workflows for assessing uncertainty for the gas reserves and risks associated with the development well placement. The main focus of this work was related to the anisotropy ambiguity analysis for more accurate quantifying the structural uncertainty of the BCU top. The workflow used a novel technology of uncertainty analysis in anisotropic model building based on eigen decomposition of the tomography operator and a null-space projection. The main lesson learned was that prior information about anisotropy should be defined thoroughly from the geologic and rock physics perspective and also to be calibrated with the available well data. Overall, the project turned out to be successful and the results enabled more confident decision making in the Hild field development.