Well-bore reservoir evaluation technologies to optimize field revitalization

Abstract

The economic success of field revitalization projects depends upon draining reservoir compartments that frequently contain smaller reserves volumes than those targeted by the initial field development, in a cost-effective manner. Well-bore measurements can contribute to risk management of redevelopment by identifying and monitoring the drainage of remaining hydrocarbons. Applications of cased-hole and open-hole measurements to optimizing field redevelopment are illustrated using case studies from the Brent Field, UK; Block IV, Venezuela and the T&J Ashworth Lease, USA. Cased-hole logging using nuclear tools has evolved from time-lapse monitoring to detect changes in saturation to also include through-casing formation evaluation. Where deep invasion prevents the use of these nuclear methods, through-casing resistivity tools can successfully detect hydrocarbons. Open-hole formation pressures can significantly impact redevelopment strategies, as can evaluation of filtrate invasion using open-hole array resistivity tools. Emerging permanent sensor technologies enable continuous monitoring of both water saturation and formation pressure, thereby offering the potential to improve the performance of future field revitalization projects.

Design of an Acoustic Through-Casing Logging Tool

“…Given the vast number of cased exploration wells, through-casing logging is indispensable in mature fields and for wells that are cased without logging [ 10 , 11 , 12 , 13 ]. Through-casing resistivity and nuclear technologies have been applied commercially [ 14 , 15 , 16 ], but acoustic through-casing technology is still an unresolved issue [ 17 ]. This issue is caused by the strong interference of casing waves in the useful formation waves, especially when the formation and casing are poorly bonded [ 13 ].…”