The Deliberate Search for Subtle Traps

James Pickens¹, Stephane Gesbert¹, Tomas van Hoek¹, David Potter¹, Peter van Toorn¹, Andre van der Muelen¹, Maartje Koning¹, Ron Masters², Ezequiel Gonzalez², and Claus Otto^1
1Shell International E&P, Rijswijk, Netherlands
²Shell International E&P, Houston, UT

As conventional opportunities become more rare, either for technical or political reasons, it is critical that we accelerate our efforts to detect and appropriately risk subtle traps. To date, attempts to exploit this upside have achieved mild success or fields have been discovered due to serendipity. Even when identified, such prospects are commonly not drilled due to perceived high risk. We have chosen to focus on defining the critical trap elements of such prospects and geophysical methods to highlight and de-risk them. The search for such features can be challenging as they often appear as single cycle features with little or no Direct Hydrocarbon Indicator support. In addition, prospect seal is often cited as a critical risk that cannot be resolved and, therefore, dooms the prospect.

To step outside of conventional exploration workflows, we are focusing on tools and techniques that allow one to co-visualize and co-analyze multiple data types. This ability to cross-correlate disparate data sets, from seismic attributes to well logs, is considered critical for the evaluation and de-risking of critical trap elements. Fundamental to our workflows is also the incorporation of sequence stratigraphic architecture and geological prior information to define our trap search windows and establish our de-risk criteria. Within this context, the key elements to our workflows include: 1.Disassembly of seismic volumes into sequences and associated system tracts. 2.Stratigraphically constrained visualization and attribute analysis. 3.Data Fusion: the ability to interactively co-visualize and co-analyze any or all available data (seismic, wells, potential fields, etc.). 4.Underlying all of the processes, are a series of geological constraints acquired through the development of an analogue Knowledge Base. 5.Integration of risk analysis with interpretation.

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