Geostatistics

Extensive geostatistical modeling of data from the Bachaquero fields (east coast of Lake Maracaibo, Venezuela) has been conducted within the framework of a large-scale integrated study. These stochastic models have been used for several reservoir-management applications, where a fast and effective response is necessary to satisfy operational requirements. Such requirements include identification of infill drill locations, planning of horizontal well trajectories, and thermal-simulation studies for the optimization of cyclic steam injection projects. Because reservoir management applications commonly concern individual wells (small scale), a specific procedure has been established to extract and statistically analyze the geologic information from geostatistical models (large scale). The procedure has worked very effectively, with most of the operational requirements of corporate field exploitation units being addressed in the required timeframe. In fact, after almost 2 yr of fast-response applications in the Bachaquero fields, most of the operations currently performed by the exploitation unit are supported by geostatistical models. Recommendations based on such fast-response studies have been implemented, and in all cases, very good agreement between predictions and actual results has been observed.