The goal of the project research is to improve the ultimate recovery from the oil window of the Utica/Point Pleasant (UPP) shale by using natural gas liquid (NGL) treatments (Y-Grade NGLs, or a similar combination of NGLs), which is to be accomplished through the development of innovative methods designed to improve the effectiveness of well completions and optimize oil and gas recovery over the life of the well.  

Battelle Memorial Institute — Columbus, OH 43201 

Collaborators 
Hopco, Ltd. — Columbus, OH 43231 
Linde, LLC — Bridgewater, NJ 08807 
Ohio Geological Survey — Columbus, OH 43229 
 

Current fracturing, stimulation, and treatment techniques leave behind more than 90% of oil in liquid-rich unconventional oil and gas (UOG) reservoirs. Slick water fracturing has emerged as the preferred technique for fracturing and proppant placement in ultra-low permeability UOG reservoirs. However, a significant number of these completions fail to perform as well as expected. This could be due to poor reservoir quality, inefficient completions, or non-optimal flow back controls. Advances in stimulation or treatment techniques could improve oil recovery significantly. The current common practice in producing shale oil reservoirs is to use horizontal wells with multi-stage transverse hydraulic fractures. Historically, primary production from shale oil reservoirs, even with hydraulic fracturing techniques, has been 5–10% or less original-oil-in-place (OOIP). This project proposes that unrefined Y-Grade NGLs have the potential to be an effective treatment fluid in UOG reservoirs, such as the UPP oil window. 

The use of NGLs as a well treatment fluid is a promising approach that could increase production and efficiency from shale plays. Tests have been conducted with refined NGLs and liquid propane gas, but there are currently no field validation studies looking into the use of Y-Grade NGLs as treatment fluids and methods to enhance their use will not be investigated by industry alone. Despite the perceived benefits of using Y-Grade NGLs (they do not require infrastructure or investment in refining and are already being produced from many UOG reservoirs), significant challenges must be overcome before it can be used in widespread commercial operations. This project seeks to help overcome those challenges and test the potential of Y-grade NGL as a production improvement treatment in the UPP.

The fundamental impact of this research is to improve oil and gas production from UOG resources using readily available Y-Grade NGLs as a treatment for low-production unconventional oil plays with specific emphasis on enhancing resource recovery in the UPP oil window. The technology has the potential to unlock several hundred million barrels of oil in the UPP alone. The low surface tension of NGLs will allow for easier migration into the formation to maximize the stimulated reservoir volume. Compatibility of the NGLs with the formation will result in less formation damage and quicker, more efficient post-treatment clean-up. This research technology can potentially be applied to other UOG resources, improving recovery of oil and gas while reducing the impact of the use of fresh water and disposal of wastewater. All these factors have the potential to improve overall U.S. energy production and energy security.

The Y-Grade NGL treatment was successfully completed in the field test well in August 2021. Monitoring of produced oil and gas showed increased production of both gas and oil from the test well compared to the two UPP completions in the area. The research has also completed geotechnical characterization of the UPP, field plug back work on the two test wells, and design of the NGL field treatment test. Data collected from wells at the field site was used to characterize the UPP. The NGL treatment test and micro seismic monitoring was completed in August 2021. Oil production was monitored in the test well and used to upscale the treatment to higher volume applications in common vertical/horizontal well scenarios. The results suggest that the NGL treatment is most likely to produce profitable results in horizontal wells that self-source their Y-grade injectate. Key takeaways from the project are:

• The first every Y-grade EOR treatment of the UPP was completed in late August, 2021 with zero safety incidents
• The Y-grade treatment turned a non-flowing UPP oil well into one that produced a p50 estimate of 239 bbls of “new” oil
• Devising an effective frac that uses Y-grade/proppant would eliminate the need for a nitrogen frac, lowering costs
• The UPP Y-grade/new oil ratio estimate of ~4/1 is among the best ratios seen, compared to NGL injection results or simulations in other unconventional oil plays
• The cost of Y-grade and the Y-grade/new oil ratio are the biggest controls on the economic results
• The optimal economic scenario for this treatment is a horizontal UPP well with self-sourced Y-grade. Most other scenarios lose money.
• A larger pilot study with better data on initial oil composition and more consistent pressure/production data would allow a more rigorous upscaling, via a compositional reservoir simulation model

Geotechnical characterization of Upper Point Pleasant at the targeted field site, NGL treatment field test design, 941-barrel y-grade injection test in a Utica-Point Pleasant reservoir, and monitoring microseismic activity were completed. Post-treatment production results from late September, 2021 to mid-June, 2022 were tracked and analyzed.

Analysis of the production stream estimated that the treatment caused incremental production of 239 bbls of oil, giving an approximate ratio of 1 “new” oil barrel for every 4 barrels of injected Y-grade. This is a favorable ratio compared to that seen or simulated in other unconventional oil plays in the U.S., which are typically around 8/1. Upscaling reservoir simulations of the NGL treatment were hindered by the lack of original oil composition data (the well did not flow naturally), and consistent production/pressure data. Upscaling to common higher volume vertical and horizontal well treatment scenarios was therefore done by assuming the Y-grade/new oil ratio remained consistent with our test results, during each quarterly injection cycle.

Economic estimates of the scenarios indicates that a horizontal well with Y-grade self-sourced will have the most profitable results, with most other scenarios having a low chance of profitability. The biggest drivers of the economic results are the Y-grade cost, and the Y-grade/new oil ratio.

Project activity is now complete and is summarized in more detail in the final report, which is accessible from the additional information section below.

$2,581,233

$711,734

NETL – Richard C. Baker (Richard.Baker@netl.doe.gov or 304-285-4714)
Battelle – Joel Sminchak (Sminchak@battelle.org)

Final Technical Report (Nov 2022)

Data Analysis and Integration Summary Report (July 2022)