Is it worth the effort? — why state-of-the art reprocessing of old seismic data was an indispensable tool for a reservoir simulation study in the Murzuq Basin (Libya)

Field development and reservoir simulation studies are usually performed relatively late in the life of an oil or gas field. At this time, specific questions such as mitigating early water breakthrough, infill well locations, fracture behaviour and so on need to be addressed. Typically, this is done through reservoir simulation studies. Commonly, the available 3D seismic data was acquired early in the field life for exploration or appraisal purposes. In many reservoir simulation studies the question arises as to whether it is worth the effort to reprocess vintage seismic data, or use only available fault and horizon interpretation of the original or previous processing for building the static model and simulation grid. Unfortunately, the latter approach is often followed, since seismic reprocessing is time-consuming and often perceived as awkward. We cannot deny the fact that seismic processing has made significant progress in recent years. However, the application to relatively old data is often regarded as suspect. The applicability of methods developed for high density, wide azimuth/large offset surveys, to poorly sampled data, is questioned.