oa Reservoir connectivity: Definitions, strategies, and applications

Reservoir connectivity and compartmentalization are critical areas of research and business application. A general review of reservoir connectivity reveals significant differences among companies and academics regarding its definition, measurement, modeling and action. However, most agree that connectivity depends on a field’s structural framework, stratigraphy and fluid characteristics. We approach reservoir connectivity by first defining two types: static and dynamic. Static connectivity refers to the original state of a field, prior to production start-up. Evaluation of static connectivity is the basis for proper assessment of original hydrocarbons- in-place and prediction of fluid contacts in untested compartments. Dynamic connectivity describes movement of fluids in response to production. Initiation of production perturbs original fluid distributions, as pressure and saturation changes propagate in a complex fashion across field compartments. Barriers and baffles play varying roles over field life, becoming more-or-less <br>important over time, suggesting that compartment boundary is itself a dynamic designation. Analysis of dynamic connectivity is essential to estimating ultimate recovery. Our technology called reservoir connectivity analysis (RCA) investigates static field compartments and associated connections. We define a static compartment as a trap with no internal boundaries (e.g. faults, channel margins) so that over geologic time, it can develop only one gas-oil and/or one oil-water contact. Connections between compartments include fault juxtaposition windows and erosional scours between channels. Examples of RCA application and its impact on our fields are discussed. In these mature producing fields, RCA has explained production anomalies, generated new drill well opportunities, and boosted field reserves above original estimates.