Aging assets and higher depletion levels means increased challenges in terms of operations, well integrity and field development – completion and/or casing damage/collapse, restricted well access, low well pressure and restrictions in (or complete elimination of) conventional and/or safe drilling and completions windows. Nonetheless, the need to increase recovery factor and produce remaining reserves remains; thus, an ever-increasing number of fields are considering late-life development strategies where understanding the feasibility of future operational margins is critical. Through numerous related studies on this topic in recent years, we have developed an approach which focuses on the key elements affecting reservoir stress path, and subsequently, how our operational windows change with depletion/time. Focus is first given to adequate laboratory testing, specifically on uniaxial strain testing and identification of potential non-linear effects over the depletion range in question. A field-scale geomechanical modeling approach accounting for both stress dependency of elastic parameters and poroelastic effects is then implemented to consider also the potential effects of geometry and material heterogeneity. Last, supported by recent operational experiences, updated best practice suggestions with regards to fracture gradient considerations in depleted sections are implemented as direct model output, specifically for the future wellpaths and/or areas to be developed. Such critical thinking about the parameters most influential in controlling stress changes with pore pressure reduction has been used in numerous recent instances within Equinor in attempts to optimize field development decisions and build confidence in field development decisions. To demonstrate the value of this approach, examples are given where stress-dependent material parameters are implemented to match in situ stress testing results and the entire late-life workflow is applied to aid assets in critical development decision-making.

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