Mitigating Compartmentalization: Challenges in Appraisal and Field Development Planning

U.O. Onyeagoro
Shell International Exploration and Production Inc, Houston, TX

Reservoir compartmentalization has become a catch-all word for poor well performance attributable to a combination of stratigraphic, structural, differential depletion and completion technique causes. This is a major issue affecting large parts of the exploration and development business. Headline-grabbing downgrades in EURs due to compartmentalization have hit large developments in the GOM, the North Sea and the Niger Delta. Future developments are geologically much more complex than the known compartmentalized fields, and thus have a high risk of compartmentalization.

One of the key challenges in the development of compartmentalized fields is to realistically translate geological and reservoir engineering data into parameters that can be used to assess and mitigate compartmentalization. The key problem is to predict when such faults and stratigraphic barriers will occur, and breakdown, during production. This can be readily done in conventional reservoir simulations, but requires extensive stratigraphic and structural databases as input.

The importance of answering these questions and realistically defining and characterizing compartmentalized fields has been demonstrated in many Deep Water Nigeria, Deep Water Brazil, North Sea and Gulf of Mexico fields. These characterizations have yielded more accurate and more economic highly deviated and horizontal wells across faults, robust field development plans with clear economic advantages, and successful history matches.