Determining whether a seismic re-processing and inversion project has delivered its technical objectives is fairly straightforward. A comparison and analysis of the structural and stratigraphic imaging, reflector continuity, bandwidth, noise content and synthetic well ties can all be used to determine technical success. It is sometimes more difficult, however, to quantify the value derived from the new seismic products. The value proposition is particularly relevant when seeking approval for future re-processing projects especially in the current difficult economic climate. We present an example from offshore Trinidad where the value of a seismic reprocessing and inversion project have been quantified by reviewing the impact decisions made as a direct result of the new data has had on the cost and Net Present Value of the project.

The Cassra and Iris fields are Pliocene and Pleistocene aged gas sands deposited in a shallow marine environment and basin floor setting respectively and are located 15-20km off the north coast of Tobago. Both fields are covered by 3D seismic data and are currently in the pre-development project phase. A post migration gather conditioning and inversion project has recently been completed over both fields with the primary objective of improving the pre-stack data and subsequent inversion products for reservoir characterization, dynamic simulation and development well planning. A full re-interpretation on the new data is ongoing but initial observations have already dramatically influenced field development decisions.

Detailed mapping of the reservoir on improved resolution data allows for a confident assessment of reservoir architecture, mapping of individual sedimentary clinoforms and determining the areal extent of individual sand bodies. This has changed our views on the risk of reservoir compartmentalization and when integrated with other data types have influenced the development concept and well count required to develop these fields. A seismically derived net pay estimate on both fields has also influenced project volumes and an assessment of the Net Present Value (NPV) impact of the volume change has also been used to quantify the value of the new data.

The financial impact of the new data as a result of changes to the field development plan may be either positive or negative in terms of overall development cost, but provides an indication of the true value of the data. This is based on the premise that if the new data merely confirms the existing interpretation and has not impacted any business decisions, then no additional value has truly been achieved.

Specifically, we aim to answer the question most managers will pose…‥"You have spent a lot of time, money and effort on this project and delivered some imaging improvements, but what value has it brought and why should I spend any more money on another project?" We hope to answer that question!

You can access this article if you purchase or spend a download.