Introducing Hydraulic Fracture Heat Maps: Deriving Completion Changes to Increase Production in the Wolfcamp Formation
Authors: Pankaj Piyush , Morrell J. C. , Pope Timothy , Maguire Matt , Gray Danny , Smith Michael , Greenwald Jason , Ajisafe Foluke , Li James , Fan Li , Zheng Wei , Judd Tobias 
Published: October 2018

The objective of this study is to understand the impact of key completion designs such as proppant and fluid volumes, cluster spacing, number of clusters, and fluid and proppant types on production in the Wolfcamp formation. Selected completion designs from the horizontal well study were used in a multi-well pad under different well spacing and stacking scenarios to understand the fracture geometry to minimize fracture interference and optimize production. Over the course of the study, which has been conducted since 2015, hydraulic fracture heat maps for the different completion designs were innovatively created to provide comparative analysis and directional insights for optimized well completion and well spacing designs in the multi-layered Wolfcamp formation.

An integrated model was built with 3D seismic, petrophysical, geomechanical, core, and image log interpretation. The integrated model was used for complex fracture modeling and calibrated with microseismic data and production history match for multiple horizontal wellbores in the upper and middle Wolfcamp. Sensitivity analysis on various hydraulic fracture and completion designs were done to evaluate the fracture geometries, and the fracture footprint and its effect on production performance for both single and multi-well scenarios. Cluster spacing, number of clusters, fracturing fluid type, proppant types, proppant schedules, stimulation sequencing, etc. were some of the parameters evaluated in a well-scale modeling. High-tier completion designs were then translated into a multi-well pad under different well spacing and stacking scenarios for production optimization. Inter- and intra-well stress shadows honoring a realistic time sequence were also incorporated in the hydraulic fracture model. Fracture heat maps collapsing the complete wellbore hydraulic fracture geometries and their properties were created to represent the distribution of productive surface area for all the sensitivity cases. These heat maps were also compared to the observed microseismic data heat map for calibration purposes.

Numerous fracture heat maps created from the sensitivity scenarios allowed evaluating the most effective completion design to optimize well completion, spacing, stacking and stimulation sequencing strategy. Proppant and fluid volumes as well as cluster spacing showed the highest impact on production performance in a single horizontal well. Increasing fluid and proppant volumes showed an increasing trend in the stimulated area. Decreasing cluster spacing showed an increasing trend in near-wellbore contact and fracture complexity. The number of clusters was shown to have minimal impact on production performance. Incorporating a stress shadow between wells representative of a zipper operation provides better coverage around the wellbore and allows for tighter well spacing. Heat maps created from microseismic data were in good agreement with the heat maps from the modeling of the different completion scenarios. Hydraulic fracture heat maps were found to be efficient and effective means to provide directional insights for decisions on holistic multi-well asset development.

The workflow in this paper can be applied to single and multi-well pad developments in unconventional reservoirs. Understanding the impact of different completion and stimulation parameters on hydraulic fracture geometry and hydrocarbon production is crucial for proper optimization of resources. Hydraulic fracture modeling with production history match and diagnostic tests such as microseismic monitoring, tracers, production interference tests are highly beneficial in understanding key production drivers. The completion and hydraulic fracture heat maps also served as a visualization tool for providing comparative analysis of different completion scenarios. Incorporating economics in the workflow will provide the guidance needed to develop the unconventional reservoirs for maximized returns in the short and long term.