Seismic-based De-risking of Unconventional Plays by Integrating Rock Physics, Inversion, Geopressure, and Geomechanics

“Based on pressure information obtained during drilling, the various shale units within the Wolfcamp Formation in the Delaware Basin are known to be variably pressured with depth, and the pressure can change laterally within the same rock formation. Zones with anomalous high pressure are generally linked to wells with better production rates. Unknown overpressured areas are also considered a drilling hazard and being able to predict these cells is of high interest.

A pre-stack, facies-based seismic inversion process, capable of producing physical estimates of impedances and density, was used to invert the seismic land dataset for facies and elastic properties. The predicted elastic properties then honour the rock physics relationships observed in the well log data with greater fidelity. This is important when considering the subsequent geological characterization and geomechanical analysis using the property volumes. The well-based workflow was then applied to inversion results to generate a regional understanding of the distribution of pore pressure and geomechanical properties which allows for identification of sweet spots leading to more efficient and safer drilling. The predicted pressures and stresses match the magnitude of measured data and the vertical and lateral distribution of observed wellbore damage from DFIT and Image Log data.”