Depth Surface Update Using Velocity Model Integration Workflow

Abstract

Abstract This paper describes the workflow to derive a robust depth reference case map and associated depth uncertainty range suitable for use in the planning of new wells and for ‘gas in place’ calculations. DGI's Covizsoftware was used to deliver this objective. A number ofseismic and well velocity inputs and seven methodologies were tested withPre-stack depth migrated (PSDM) interval velocities chosen as the most reliable for geologic top prognoses (based on drop-out test results). All other methods were used to frame the uncertainties around this reference case. This methodology was tested in the recent ABCXX8 well with a resultant depth prediction error at the reservoir level of 0.5%. However, it should be noted that distance from nearest control point is a crucial factor in the prediction of depth and corresponding depth uncertainty. Further updates of the calibration model will be made with an upcoming regional well trade and the latest wells on the block. Covizallows rapid updating of the model with any new information.