The goal of this project is to improve efficiency of oil and gas recovery from hydraulically fractured horizontal wells. This field-based research will be conducted in the Austin Chalk and Eagle Ford Shale Formations with the purpose of addressing fundamental questions such as the extent of the true stimulated reservoir volume and the complexity of the resulting fracture system. Utilizing newly developed and comprehensive monitoring solutions, the team will deliver unprecedented and comprehensive high-quality field data to improve scientific knowledge of the hydraulic fracturing process when multiple wells are fractured from a single pad location. This knowledge will allow optimized production from less new wells with less material and energy use.

Texas A&M University, College Station, TX 77840
Lawrence Berkeley National Laboratory, Berkeley, CA 94720
Stanford University, Stanford, CA 94305
SM Energy, Denver, CO 77079

Multi-stage hydraulic fracturing of unconventional reservoirs, implemented in tens of thousands of wells, has been the enabling technology for the tremendous growth in oil and gas production in the U.S. in the past decade. Throughout this development, much of the technology has resulted from expensive trial and error approaches applied in the field. This approach continues today, even as the technology is evolving rapidly. In spite of the thousands of wells drilled and hydraulically fractured, and the billions of dollars spent, the industry is still in the dark about fundamental features of the created fracture systems, such as the stimulated reservoir volume and the complexity of the fracture system that was created. Without this basic knowledge of the true stimulated reservoir volume, operators cannot optimize key development parameters including well spacing and vertical placement of laterals. 

This project, led by Texas A&M University, has developed a science-based field laboratory in the Austin Chalk/Eagle Ford Shale Formation to determine the stimulated reservoir volume created by the fracturing of multiple wells. Utilizing newly developed monitoring solutions, the team has acquired unprecedented and comprehensive high-quality field data on the extent and morphologies of productive fractures created from these wells. Advanced field monitoring has been complemented by laboratory testing on cores and drill cuttings, and coupled modeling for design, prediction, calibration, and code validation. The Austin Chalk/Eagle Ford Field Laboratory is hosted by SM Energy, which has provided access to the wells of opportunity. 

The ultimate objective of the Austin Chalk/Eagle Ford Field Laboratory Project is to improve the effectiveness of shale oil production by providing new scientific knowledge and new monitoring technology for both initial stimulation/production as well as longer term production after fracture stimulation. The project will provide key insights into the fracture stimulation processes, and develop new methodologies and operational experience for optimized production of oil from fractured unconventional reservoirs, an end result that would allow for more production from fewer new wells with less material and energy use. While aspects of the proposed project are site-specific to the Austin Chalk/Eagle Ford formation, there will be many realistic and practical learnings that apply to other unconventional plays, or even apply to other subsurface applications such as unconventional gas recovery and geologic carbon sequestration and storage.
 

Planned Research Activities
SM Energy is the field operator that hosts the field site for the Austin Chalk/Eagle Ford Field Laboratory led by Texas A&M University (TAMU) to conduct a science-based field laboratory project in the Austin Chalk/Eagle Ford Formation. Utilizing newly developed and integrated monitoring solutions, the project team has collected comprehensive high-quality field data to improve scientific knowledge of unconventional reservoir stimulation with the most advanced hydraulic fracturing being applied. Multi-stage hydraulic fracturing of six producing wells conducted in December, 2021 through January, 2022 was monitored using Distributed Temperature Sensing/Distributed Acoustic Sensing (DTS/DAS) fiber optic cables in two of the wells, downhole pressure gauges, and surface seismic sources and receivers for active seismic interrogation and microseismic mapping. Other supporting measurements that were made include openhole fracture imaging logs, oil and water soluble tracers added to some of the fracture fluid, downhole video imaging of perforations before and after fracturing, and production logs run in some of the wells after production begins. In the two wells equipped with fiber, fracturing conditions were varied stage by stage to determine the effects of parameters like fracture fluid volume, proppant amount, fracture fluid characteristics, and perforating conditions on the created fracture system. Field monitoring was complemented by laboratory testing on cores and drill cuttings, and coupled modeling for design, prediction, calibration, optimization, and code validation.

 SM Energy, the site host, conducted these activities as part of the field laboratory:

1. Drilling and multi-stage fracture stimulation of six new wells
2. Running a fracture imaging log on one of the wells
3. Installation of fiber optic cables and surface equipment on two of the wells
4. Installation of downhole pressure gauges in some of the new wells, and in some previously drilled wells near the new wells
5. Installation of surface orbital vibrators (SOVs) for active seismic sources
6. Installation of a surface array of geophones for microseismic monitoring
7. Injection of oil and soluble chemical tracers in some stages of the fracture treatments
8. Running downhole video cameras before and after fracturing to image perforations in one of the wells
9. Running production logs in one of the wells after they are placed on production

The ultimate objective of the Austin Chalk/Eagle Ford Field Laboratory Project is to help improve the effectiveness of oil production in unconventional reservoir by providing new scientific knowledge and new monitoring technology.  The main scientific/technical objectives of the proposed project are:  

• Build and test surface active seismic monitoring with fiber optics in observation wells with DAS and SOVs to conduct: (1) real-time monitoring of fracture propagation and stimulated volume for new stimulation of multiple wells, and (2) time-lapse seismic monitoring of reservoir changes during production. 
• Test distributed temperature sensing (DTS), distributed acoustic sensing (DAS) and distributed strain sensing (DSS) with fiber optic technology and develop protocols for field application.
• Assess spatially and temporally resolved production characteristics and explore relationship with stimulated fracture characteristics by DFIT, openhole logging, production logging, and tracer technology. 
• Understand rock mechanical properties and reservoir fluid properties and their effects on stimulation efficiency through coring, core analysis and drilling cutting analysis. 
• Develop forward and inverse modeling to calibrate simulation models using all monitored data.
   

Utilizing newly developed monitoring solutions, the Eagle Ford Shale Laboratory (EFSL) site has delivered unprecedented and comprehensive high-quality field data to improve the scientific knowledge of multi-stage hydraulic fracturing of unconventional reservoirs.  Advanced field monitoring was complemented by laboratory testing on cores and drill cuttings and coupled modeling for design, prediction, calibration, and code validation. Improved methods for monitoring hydraulic fracturing, and analyzing the monitored data are expected to be developed in the project.

• The field work of the project was conducted on 6 wells located on 2 pads in Webb County, Texas.
• During fracturing operations on the wells during December 2021 – January 2022, the following data was acquired:
  • DFIT tests were run in the toe section of one of the fiber wells.
  • DTS and DAS responses in the two wells equipped with fiber optic cables.
  • DAS responses to SOV signals sent from 5 installed SOV sites located over the well area.
  • Microseismic responses measured with a large surface array of geophones.
  • Sealed wellbore pressure response in one monitoring well.
  • Downhole pressure gauge responses.
  • All normal fracture treating parameters (rates, pressures, proppant loading.
• Additional monitoring performed after the fracture treatments includes production monitoring after the 6 wells were place on production.
• A production log was run on one of the fiber wells a few months after it was placed on production.
• Theoretical models to interpret distributed temperature and acoustic sensors (DTS and DAS) were applied to interpret the distribution of fracture fluid into each stage for the two fiber wells.
• Fracture growth rates were determined by analyzing the low-frequency DAS response of one of the fiber wells while the other well was being fractured. Fracture conductivity using the proppant pumped in these treatments was measured in the laboratory.
• Rock mechanical properties were measured on drill cuttings samples using nano-indentation and scratch tests.

• SM Energy is a new project partner to the project.
• The field work of the project will be conducted on one of 2 six-well pads in Webb County, Texas.
• A Surface Orbital Vibrator (SOV) test was conducted by Lawrence Berkeley National Laboratory at an existing well pad, for use as a surface seismic source for time lapse monitoring.  The SOV’s are intended to provide insight into the stimulated reservoir volume, by enabling active seismic imaging of the fractured region.
• Theoretical models to interpret distributed temperature and acoustic sensors (DTS and DAS) have been developed and are ready to test with field data once collected.Comprehensive investigations of monitoring techniques that will be implemented in the field tests, fiber optic sensing, tracer, well logging, coring/core analysis, etc., have been conducted, and potential technology providers have been identified.
• Field monitoring equipment construction and services planning is underway.

$9,778,835

$10,671,667

NETL – Joseph Renk, Program Manager (joseph.renk@netl.doe.gov or 412-386-6406)
Texas A&M University – Dan Hill, Principal Investigator (danhill@tamu.edu or 979-845-2244)