HFTS 2 is one of the highly measured hydraulic fracturing pads in the world. In 2021, the HFTS 2 consortia and ResFrac collaborated on a modeling study to incorporate all the advanced diagnostics in HFTS 2 into a single, comprehensive model. This model was then employed in an automated optimization workflow to assess opportunities to improve NPV by adjusting well spacing, proppant loading, fluid loading, cluster spacing, and landing zone. Pudugramam et al. presented the ResFrac model calibration and optimization in URTeC 3723620 in 2022, showing a 60% possible improvement in NPV by optimization of well placement and completion design.
The US Department of Energy and 16 consortia members (primarily oil and gas operators) funded the HFTS 2 project to better understand the complex cause-and-effect relationships in hydraulic fracturing using a field-scale laboratory. The project is located in the Permian Basin, and involved drilling four horizontal wells offsetting two existing horizontal wells, as well as a vertical pilot well (for data acquisition). Horizontal and vertical well DAS/DTS/DSS fiber, downhole microseismic arrays, pressure gauges, core-through data, image logs, DFITs, proppant-in-cuttings analysis, interference tests, and production data were collected during the fracturing and production of more than 100 stages on the horizontal wells to characterize the behavior of the system.
Pudugramam et al. present the calibration of the ResFrac model to the HFTS 2 data set, including observations of fracture geometry from the cross-well strain and microseismic data; post shut-in propagation of fractures; zonal depletion as measured by distributed pressure gauges in the vertical pilot well; fracture asymmetry in the direction of depletion as measure by microseismic, and well productivity.
The calibrated model then served as the basis for a multi-parameter optimization of well spacing, cluster spacing, perforation friction (limited entry), proppant loading, fluid loading, injection rate, and landing depth. Using the ResFrac optimization capabilities (video or blog), Pudugramam et al. efficiently search the opportunity space by running 228 full simulation and 1000 proxy model runs, ultimately identifying an opportunity to increase NPV by 60%.
For additional examples of ResFrac used for optimization of fracture design, refer to Kaufman et al. (2019).
Pudugramam, Sriram, Irvin, Rohan J., McClure, Mark, Fowler, Garrett, Bessa, Fadila, Zhao, Yu, Han, Jichao, Li, Han, Kohli, Arjun, and Mark D. Zoback. Optimizing Well Spacing and Completion Design Using Simulation Models Calibrated to the Hydraulic Fracture Test Site 2 (HFTS-2) Dataset. Paper presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, Houston, Texas, USA, June 2022. doi: https://doi.org/10.15530/urtec-2022-3723620