Model-Informed Reservoir Appraisal Strategy to Reduce Reservoir Performance Uncertainty for Unconventional Development in Delaware Basin, New Mexico, United States

Abstract This study discusses an integrated reservoir assessment, including reservoir surveillance and analysis, fracture modeling, and reservoir simulation, carried out for an unconventional development prospect located in the Delaware Basin of New Mexico, United States. The objective was to assess reservoir performance, estimate the potential for vertical and lateral communication between reservoir intervals, and determine optimal well density. The assessment enabled the development of a fit-for-purpose appraisal strategy, grounded in modern reservoir data collection, which will effectively reduce uncertainty in the development plan. This study used data from offset wells as a reference to conduct the analysis. The logs and reservoir data were used to develop reservoir and geomechanical property inputs for hydraulic fracturing and simulation modeling. Reservoir stress maps were created, and multiple stress scenarios, including isotropic and anisotropic, were generated and used as input to fracture simulation. Mechanistic fracture models were constructed for different reservoir intervals based on analog stimulation recipes and stress curve sensitivities. The resulting fracture geometries were input to reservoir simulation to determine the economically optimum well density. The geomechanics analysis shows lateral variation in stress properties through the prospect area with limited stress barriers observed in some reservoirs. The hydraulic fracture models suggest limited vertical interaction between intervals. Simulation results suggest an optimum well spacing that is tighter for the shallower 2nd Bone Spring interval vs. the deeper Wolfcamp. Simulation results are supported by offset analogues which show well performance degradation at tighter spacing. Simulation shows reservoir performance is most affected by matrix permeability and fracture half-length. The models suggest significant remaining uncertainty. To reduce uncertainties, a robust, tailored data collection plan is proposed, including vertical and slanted horizontal monitoring wells instrumented with fiber and gauges, quad combo logs, core sampling, time lapse geochemistry sampling on ten wells, and six PVT samples. The study highlights the significance of effective data integration from different subsurface domains to enhance field uncertainty understanding and avoid unnecessary costs during appraisal data collection.