Abstract
This study presents a holistic, multidisciplinary, and integrated geoengineering workflow that results in economic comparisons of different completion strategies on a 10 well pad spanning multiple reservoirs in the Delaware basin. The resulting economics are constrained by geophysical, geological, geomechanical, hydraulic fracture, and production forecast models validated at each step in the workflow. In the case of these wells, the completion design "Case 3" was identified as the best completion strategy from an economic standpoint, significantly increasing ROI and NPV. The planned frac order-- top-down, bottom-up, or optimized, had a varying impact on the overall economics of the pad, depending on the reservoir targeted, and a lesser impact as compared to the pump volumes and schedule--although in some geologic settings this impact could be much higher. By combining geophysical, geologic, and engineering information into geomechanical, hydraulic and fracture models, representative production forecasts and economic projections were made to optimize the strategy for this 10 well pad’s development.
The tumultuous price environment which has persisted for the past five years is here to stay, further pressuring unconventional reservoir development to seek any and all efficiency gains. As technologies continue to optimize performance on the frac site, the last gasp of factory-mode drilling and production manifests as "cube development". Cube development is a capital-intensive strategy being adopted by a number of Permian basin operators that relies on financial efficiencies gained through the simultaneous drilling and stimulation of multiple laterals in multiple benches to enhance the economics of unconventional reservoirs. Such a large undertaking is complimented by predictive iterative modeling of constrained hydraulic fracture effectiveness and production forecasting to optimize as much as possible the stimulation in light of reservoir realities. In this case study, a 10 well cube, spanning the 3rd Bone Spring to the Wolfcamp B is evaluated in a comprehensive 3G (geophysics, geology, and geomechanics) and engineering workflow to characterize the reservoirs, their geomechanical response, the resulting hydraulic fracture conductivities, and production forecast to increase the ROI of the development. The integrated workflow after Ouenes et al. 2016 leverages seismic data, log data from wireline and surface drilling parameters, reservoir test, frac data, and historical field production data to build high-resolution 3D distributions of geologic properties which will constrain geomechanical simulations, hydraulic fracture designs, and the resulting production predictions. Technologies ranging from stochastic inversions of seismic data to produce high resolution impedance models, machine learning-driven geologic property modeling, MPM-based geomechanical simulation, and fast marching reservoir simulation represent some of the key methods which enable this evaluation to be conducted. The sequential geologic workflow distributes key reservoir properties of unconventional production drivers such as porosity, OOIP, elastic properties, pore pressure, and natural fractures in a sequential manner. This reservoir characterization then constrains geomechanical simulations to capture the interactions both vertically and laterally between the various wells, which is then passed as an additional geomechanical constraint with the geomodels to the hydraulic fracture simulations and production forecasts. Consequently, the engineering component of the workflow can be quickly iterated to understand the economic viability of various development strategies to maximize ROI while honoring realistic and varying reservoir properties.
