A Decision Analytic Approach to Geosteering Operations

Abstract

AbstractThe technique of geosteering has been widely adopted in the petroleum industry for proper wellbore positioning. The benefits of geosteering have become more pronounced as drilling environments have become more complex. Geosteering-related technologies, such as downhole information gathering tools, real-time data transmission and data-analysis applications, have been continuously and significantly improved to support geosteering decisions. However, the full value of these advancements has yet to be realized.Due to uncertainties in predrilled geological models, information gathered while drilling is applied in making real-time reservoir navigation decisions. To achieve an optimal result requires a series of high-quality decisions regarding well trajectory adjustment.Interestingly, geosteering-related literature does not demonstrate that the industry has applied a logically consistent approach for making geosteering decisions. Common practice as described in the literature does not clearly and quantitatively state measurable objectives, key underlying uncertainties, or relevance between underlying uncertainties and real-time information. Furthermore, it is unclear how a specific geosteering decision is being reached. Lacking of a systematic and transparent framework for supporting geosteering decisions, the current approach is unlikely to result in optimal decisions for placing the well in the best possible location.