Velocity based pore pressure prediction—A case study at one of the Iranian southwest oil fields

Pore pressure could be estimated prior to drilling using estimated rock velocities. Applying this approach, the final acquired pore pressure, is highly affected by the accuracy of the obtained velocity data. In order to generate an accurate velocity cube with proper resolution, velocities from well logs and post-stack 3-D seismic inversion are used along with stacking velocities from velocity analysis of 3-D seismic data. Using Bowers' effective pressure method, including known velocity and density values at well locations, the coefficients of Bowers' equation can be calculated. Also, through applying Gardener's equation, one could relate velocity to density in each well location and finally, it is possible to determine overburden stress for the entire survey.In this study, we have estimated pore pressure with acceptable accuracy at one of the Iranian southwest oil fields. Estimated rock velocities from processing of 3-D seismic data, rock densities and calibrated Bowers' equation are key tools, through our pore pressure assessment workflow.

► We estimate pore pressure by using velocity base approach.
► We obtain a high resolution velocity and density model.
► Velocity model is obtained by using stacking velocity, seismic inversion and sonic logs.
► Increase in resolution of velocity model results in increase in resolution of pressure model.