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 Eagle Ford Shale Formation 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, re-fracturing, and subsequent huff and puff gas injection as an enhanced oil recovery (EOR) method. This knowledge will allow optimized production from less new wells with less material and energy use.

Texas A&M University, College Station, TX
Lawrence Berkeley National Laboratory, Berkeley, CA
Stanford University, Stanford, CA
INPEX Eagle Ford, LLC, San Antonio, TX

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. Meanwhile, as stimulation methods continue to improve rapidly allowing significant improvements in stimulated volume, a very large fraction of the recoverable oil remains in the ground after initial production. Therefore, operators have recently started to explore options for enhanced recovery from existing wells, via two methods, (1) the “re-fracturing” of wells that have been hydraulically fractured during the past decades based on “old” less-than-optimal stimulation technology, and (2) the injection of natural gas or other gases to significantly enhance oil recovery after initial production. In each of these areas crucial for effective and sustained production from unconventional reservoirs—better understanding of fracture characteristics created from state-of-the-art stimulation, optimized re-fracturing of legacy wells, improving sweep efficiency of shale EOR—there is a clear need for more and better field diagnostic experiments.

The ultimate objective of this 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 enhanced recovery via re-fracturing and EOR. If successful, this project will provide key insights into the fracture stimulation and EOR processes, and develop new methodologies and operational experience for optimized production of oil from fractured shale, an end result that would allow for more production from less new wells with less material and energy use. While aspects of the proposed project are site-specific to the 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 oil and gas recovery and tight gas sand reservoirs.

Utilizing newly developed monitoring solutions, the EFSL site will deliver unprecedented and comprehensive high-quality field data to improve the scientific knowledge of multi-stage hydraulic fracturing of unconventional shales by implementing three field research stages: (1) a Refracturing Stage where a previously fractured legacy well will be characterized in detail and then re-stimulated for improved production, (2) a new Stimulation Stage where the most advanced new hydraulic fracturing and geosteering technology will be applied in two new production wells, and (3) a Gas-EOR Phase where the refractured well will be later tested for the efficiency of huff and puff gas injection as an EOR method. Advanced field monitoring will be complemented by laboratory testing on cores and drill cuttings and coupled modeling for design, prediction, calibration, and code validation.

• INPEX Eagle Ford, LLC is a new  project partner to the project.
• The Shaw-Klattenhoff Unit has been selected as the project’s field test site after comprehensive evaluation of candidate locations. The field site is leased by INPEX Eagle Ford, LLC.  The Klattenhoff Unit has one horizontal producing well on a single pad location and is located in La Salle County, TX, on existing leased property by INPEX Eagle Ford, LLC. Observation well locations have been identified.
• 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.
• Acquisition and reviewing of all available historical field data for the test site has been completed and is currently being analyzed to be integrated into numerical reservoir simulation models.
• 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.
• The tracer program for re-fracturing monitoring has been designed.
• Field monitoring equipment construction and services planning is underway.
   

$8,000,000

$2,000,000

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 979-862-1272)

The Eagle Ford Shale Laboratory: A Field Study of the Stimulated Reservoir Volume, Detailed Fracture Characteristics, and EOR Potential (Oct 2020)
Presented by Dan Hill, Texas A&M University, Oil and Gas Project Review Meeting, October 13, 2020

The Eagle Ford Shale Laboratory (EFSL) Project