The objective of this project is to conduct a field-based hydraulic fracturing research program in the Delaware Basin portion of the Permian Basin in West Texas. This project will advance hydraulic fracturing technology, optimize well spacing, and mitigate environmental impacts of shale development operations. The research will advance our understanding of the hydraulic fracturing process in shale reservoirs, thus enabling the design and execution of effective fracture stages that significantly contribute to production. Improved design and execution of fracture stages will also reduce the number of future infill wells drilled and reduce water volume and energy input. This project will build upon the learnings from the HFTS1 project and advance the understanding of hydraulic fracturing.
Gas Technology Institute, Des Plaines, IL 60018
The Permian Basin is one of the most prolific oil and natural gas geologic basins in the U.S. It is central to America’s energy resurgence, enabled by development of the shale resources within U.S. geologic basins. The Permian-Delaware Basin produces more than 50,000 barrels of oil per day and is an area of active development. The Permian Basin is approximately 250 miles wide and 300 miles long across West Texas and southeastern New Mexico. It encompasses several sub-basins, including the Delaware Basin and the Midland Basin, where the HFTS1 test site was located. Given the complexity of shale formations, significant geotechnical differences occur within the respective basins over very short distances. The Delaware Basin is a deeper basin than the Midland with vertical well depths up to 10,000 feet. The Delaware Basin is also a geo-pressured basin, adding to the difference between the two basins. From a geologic and geotechnical perspective, industry considers them separate and distinct basins.
Despite the long history of hydraulic fracturing, the optimal number of fracturing stages during multi-stage fracture stimulation in horizontal wells is not known. In addition to the increased expense of multistage fracturing in horizontal wells, increasing the number of fracturing stages does not always correlate with an increase in production. The problem is the application of a uniform fracture stimulation design to all stages with no consideration for geological variations along the wellbore. The result is an inefficient use and a costly waste of energy and water.
Optimization of the fracturing process requires an understanding of the cause-and-effect relationship between fracturing parameters and local geological properties at a given location along the wellbore. Realizing that the generalized rock mechanics theories and hypotheses are not truly applicable to fractured and laminated shales, quantifiable impacts of a shale’s geomechanical and depositional features are a prerequisite for design and implementation of optimized hydraulic fractures. The overarching goal of this project is to understand and define the relationships of shale geology and fracture dynamics using detailed field data that includes coring of the fracture domain. Analyses of the data will aid in updating fracture design models and improve the effectiveness of individual hydraulic fracture stages.
The HFTS2 field test site provides the opportunity to address the “billion-dollar problem,” or the optimal development of a “stacked pay” resource which requires simultaneous drilling and completion of tens-of-thousands of wells across multiple geologic horizons. Drilling too many wells results in a waste of resources such as water, steel casings, and other infrastructure while adding to emissions issues and land footprint. Drilling too few wells, from the perspective of well spacing, leaves valuable resources in the ground. Research results from this project are expected to have positive impact on economic, environmental, and resource recovery factors.
Simultaneous drilling and completion of wells in multiple geologic formations can reduce the overall cost of oil and gas production on a per-well basis, thus providing more drilling locations in the future, even at lower oil/gas prices. Continued long-term production adds jobs and increases economic output of the producing region and the U.S. economy.
The greatest beneficial impact to be derived from the proposed research will be achieved through determination of optimum well spacing and hydraulic fracture design. If the resulting optimization leads to a resource recovery increase of 1%, an additional 1.6 billion barrels of oil could be recovered from the Permian Basin. This optimization further leads to elimination of many wells currently drilled at non-optimum well spacing.
With hydraulic fracturing completed in May 2019, the team is reviewing diagnostic data and integrating it with various datasets to assess hydraulic fracturing geometry and performance. The horizontal test wells are now being put on production to evaluate production performance of various hydraulic fraction designs, including fracture stages with:
The planning of a slant core well has begun. The well will be used to sample created hydraulic fractures. While the final well trajectory and design is still being evaluated, the current plans are to cut 800 feet of continuous core at an inclination of 77 degrees. Plans also include the logging of the core well and instrumenting it with discrete pressure gauges. The slant core well is scheduled to spud in September 2019.