Reservoir Technical Limits: A Framework for Maximizing Recovery From Oil Fields

The Reservoir Technical Limits (RTL (TM)) approach described herein has proved highly effective at identifying those activities and technologies required to push oilfield recovery factors toward their maximum potential. It combines classical reservoir engineering approaches, together with knowledge of existing and novel recovery-enhancing technologies, to create a common framework for identifying specific actions to increase recovery factor. RTL is implemented in a structured workshop supported by a software toolkit. The RTL workshop involves the cross-disciplinary field team (in-depth field knowledge), external technical experts (challenge, cross-fertilization), and trained facilitation. The software toolkit encourages innovation in a structured and reproducible manner and documents the outcomes in a consistent format. The RTL conceptual framework represents a recovery factor as the product of four efficiency factors: (1) pore-scale displacement (microscopic efficiency of the recovery process); (2) drainage (connectedness to a producer); (3) sweep (movement of oil to producers within the drained volume); and (4) cut-offs (losses related to end of field life/access). RTL encourages identification of new opportunities, specific activities or projects that, if implemented, increase one or more efficiency factor, and thus increase recovery relative to the current field Depletion Plan. New ideas are stimulated by comparing current efficiency values with the effects of successful prescreened activities from analogue fields. The identified opportunities are validated by benchmarking: (a) internally, comparing recovery factors derived from summing the opportunity volumes with recovery factors derived from the expected efficiency factor increments; and (b) externally, comparing with analogue fields. The result is a prioritized list of validated opportunities and an understanding of how each activity affects the reservoir to increase recovery. The opportunities (and any required new technologies) are valued in terms of the resultant incremental barrels. The RTL approach is a significant innovation, because it provides a systematic,framework to: (a) identify new recovery-increasing activities across a portfolio of fields; (b) engender ownership of these activities by the individual field teams; and (c) identify the technology requirements to progress the opportunities. Now, having been implemented in more than 200 fields, this systematic approach has enabled opportunity descriptions/values and technology requirements to be compared consistently across all fields, thereby improving project prioritization and focusing corporate technology development and deployment onto the highest impact areas.