Ohio’s Utica Volatile Oil Window Revisited: EOG’s Utica Combo Play Shows Successes

     EOG Resources announced success in a revamp of Ohio Utica Shale oil production in 2022, calling it the Utica Combo Play, in the volatile oil window that runs north-south through several counties in eastern Ohio. Since then, EOG and a few other operators, Ascent Resources and Encino have announced very good wells producing oil in the play. Midstream development was also announced to move increased natural gas to market. Questions abound about how the play was “missed” when first tested about 10 years ago by some big players including Chesapeake, Anadarko, Devon, and others.  

     EOG stealthily entered the play in 2021, acquiring acreage inexpensively when no one else was looking to acquire it. They also acquired mineral rights in part of their southern area. Their acreage position is quite vast at several hundred thousand acres. While the oil windows in the Utica have been known for some time, early exploration failures suggested that the producibility was not there. The volatile oil window extends through parts of Stark, Carroll, Tuscarawas, Harrison Guernsey, Morgan, Muskingum, Noble, and Washington counties. Oil and gas analyst Tim Knobloch stated with some foresight in late 2021: “The oil window is still open in Ohio, and the story of oil in the Utica is not finished.” Richard Boakye Yiadom, in a 2017 master’s thesis analyzing Utica oil quality also considered the potential for significant oil production to still be present. The author utilized a new pyrolysis technique called the Incremental S1 or IS1. It was noted that this technique could be useful in determining oil quality as long as the interpretation was careful to account for the volatilization of short hydrocarbon chains and the cracking of longer hydrocarbon chains. The author also utilized solvent extraction and gas chromatography to understand the hydrocarbon chains in each of the four wells analyzed in different hydrocarbon windows.  

     EOG first announced successes in late 2022 after drilling and completing four wells and reiterated continued good results and increased drilling in 2023 to 20 wells. Unfortunately, the Hart Energy articles are now behind a paywall so I can’t access them, but I was able to read most of them before then. The Utica play is amenable to long laterals so that could be an economic plus going forward. BTU Analytics did some economic forecasting on EOG’s results in December 2022 and concluded that the results are comparable to those in the Eagle Ford and SCOOP/STACK plays. Newer results suggest they may even exceed those plays a little. BTU also included that there was plenty of room along the fairway for continued successes.

     In May 2023 EOG COO Lloyd Helms Jr. noted: “drilling performance of recent wells is improving on the order of 20% to 30% compared to last year’s results” and attributed the improvements to a proprietary drilling motor program and precision targeting. He said the completion program will commence in the 3^rd quarter. Two of the 2022 wells have reported production and completion data as of June 2023. Enverus reported some of this data in their Upstream Pulse: The Brookfield NBK15 3A in Noble County was completed with a 12,280-ft lateral fractured with 2,478 lb/ft of proppant and 58 bbl/ft of fluid. In the first three months, the well produced 124,778 boe (71% oil), equivalent to 1,386 boe/d or 113 boe/d per 1,000 ft. The Rose 0816 2H in Carroll County, completed with 2,540 lb/ft of proppant and60 bbl/ft of fluid across a 7,542-ft lateral, delivered an IP90 of 62,416 boe (66% oil), equivalent to 694 boe/d or 92 boe/d per 1,000 ft.”

     Between 2011 and 2014 Anadarko, Devon, BP, Chesapeake, and a few others explored the Utica’s black oil window further to the west as well as the volatile oil window. Anadarko had outfitted a gas chromatograph to detect heavy hydrocarbons during drilling. One might ask why they abandoned the oil window parts of the play. One reason is that those companies were focused on other plays that were proving to be more successful at that time. In the decade since that time, many well productivity improvements have come about and improvements specific to each play have occurred with better understanding of rock compositions, rock properties, mechanical properties, basin stresses, fracability, and organic matter preservation.

     Devin R. Fitzgerald, CPG – Geologist EMF Geoscience, Inc., M. Wes Casto, PE – President, Casto Petroleum Engineering, and Robert B. Thomas Sr. – President, EMF Geoscience, Inc., published and presented an excellent study at the AAPG Eastern Section Meeting in September 2017 that offered two reasons for variable production in Utica-Point Pleasant wells. The first concerns the structural position of the lateral in the well. Four different structural positions were given in the study based on Ohio geology: Structural High (HI), Transitional High (TH) (Slope), Platform (PL), Basinal (BA), and Deep Basin (DB). These structural positions were determined by 2^nd order residual isopach maps combined with 2D and 3D seismic lines and known erosional remnant structural features in the Knox Formation below the Utica-Point Pleasant. They used something called Organic Beds Theory to explain why production is better in the basinal areas. The highest total organic content (TOC) beds occur at bedding planes. There is more compaction in the rocks above the basinal areas than in the rocks above basement generated structural highs and the areas above Knox remnants (the Platform structural position). This is known as differential compaction. More compaction means more bedding planes and more organic beds. Since basinal areas are lower energy depositional environments there is more continuity of those organic beds. Additionally, the water was deeper in basinal areas so that oxygen content was lower and more organic matter was preserved. On structural highs, water is shallower with higher oxygen content which decomposes some of the organic matter. The Platform structural positions are generally within the basinal areas. They have a little bit less organic matter and more calcite beds. These are the two best structural positions for well productivity. Structural highs and transitional highs were the two worst structural positions for well productivity due to less organic beds preserved, lack of continuity of those beds, less organic preservation due to higher oxygen content, higher depositional energy conditions, more calcite beds, and presence of faults and slump features. The deep basin structural position has deeper water, low oxygen content, high organic matter preservation, and very low calcite content, but higher clay content. Calcite can have both positive and negative effects on shale well productivity, but high clay content has decidedly negative effects. The slides from the presentation shown below explain all this better than my introduction. The bottom line of the study is that structural position can high-grade acreage so having good structure maps or residual isopach maps can be very useful.

 

 

This one shows the higher TOC in a basinal position relative to a structural high position

    

  The second reason for lower well productivity in their study was due to difficulty in staying in zone while geosteering along the structural high and transitional high structural positions. This is especially an issue in the Utica-Point Pleasant when geosteering with gamma-ray only as there is very little contrast in the gamma through the formation and easy to misinterpret wellbore position. This may be one reason why many early wells had less than desirable productivity. The best remedy for this in hindsight would be to pay more attention to regional structure and utilize the abundant structural data and mapping, including interpreting structure through residual isopach mapping as they have done. Other supports might be utilizing azimuthal gamma ray which can help determine whether the bit is moving up or down relative to stratigraphy or steering with resistivity logs. Both add to well costs. It has been suggested that many early wells may have been far out of zone. EOG may have acknowledged this by Helms’ attributing improvements to “precision targeting.” One reason getting above zone could be undesirable is that the Upper Point Pleasant rock reflects a later influx of siliciclastic material prograding onto the craton from new southeastern sources from the buildup of the Taconic Mountains as the Island Arc System collided with the continental margin and filled the foredeep with sediment with higher clay and silica content which diluted the organic content of those zones. The authors presented a paper at the 2016 Eastern Section AAPG meeting explaining the sequence stratigraphy, clay influx, and change in geologic provenance during this time. The Point Pleasant thins to the west where the oil windows are, and the siliciclastic influx stays thick through much of that area. That means getting out of zone can be even more detrimental in the oil areas.     

     The Utica Shale is the 4^th or 5^th highest-producing shale gas formation in the U.S. and still holds massive natural gas reserves, especially in the large and largely untapped deep basin area. The oil window now appears to have plenty of room as well.

(Disclosure - I worked for EOG Resources as a geologist for 12.5 years. I also worked for EMF Geoscience (as Eastern Mountain Fuel) for about 3 years.)

 

References:

EOG reports 20-30% YOY drilling improvement in Utica Combo. Enverus. Upstream Pulse. Volume 3, No. 11. June 2, 2023. UP-20230602-i11-Sample-Report.pdf (enverus.com)

EOG Resources Unveils New Ohio Utica Combo Position. November 3, 2022. Hart Energy. EOG Resources Unveils New Ohio Utica Combo Position | Hart Energy

Here’s What Else EOG Will Say About the ‘New’ Utica. Nissa Darbonne. Hart Energy, November 10, 2022. Here’s What Else EOG Will Say About the ‘New’ Utica | Hart Energy

It’s ‘On:’ The New Ohio Utica Oil Play. Nissa Darbonne. Hart Energy. August 15, 2023. It’s ‘On:’ The New Ohio Utica Oil Play | Hart Energy

Despite Gas Price Slump, EOG Full Steam Ahead in Emerging Plays. Chris Mathews. Hart Energy. March 2, 2023. Despite Gas Price Slump, EOG Full Steam Ahead in Emerging Plays | Hart Energy

Is EOG’s Latest Discovery a Premium Play? Erica Blake. BTU Analytics. December 8, 2022. Is EOG's Latest Discovery a Premium Play? | BTU Analytics

Aubrey McClendon’s Dream of Oil in Ohio Utica Turns into Reality. Marcellus Drilling News. August 16, 2023. Aubrey McClendon’s Dream of Oil in Ohio Utica Turns into Reality | Marcellus Drilling News

Latest facts and rumors from the Marcellus, Utica, Permian, and Eagle Ford Plays. Shale Directories. May 15, 2021. Facts & Rumors Newsletter #426 May 15, 2021 - Shale Directories

Petroleum Quality Analysis Within the Utica-Point Pleasant Play of Ohio, United States. Richard Boakye Yiadom. A thesis submitted to the faculty of The University of Utah in partial fulfillment of the requirements for the degree of Master of Science in Petroleum Engineering. Department of Chemical Engineering. The University of Utah. August 2017. 276263993.pdf (core.ac.uk)

Structural Control of the Point Pleasant Formation Deposition and Production. Devin R. Fitzgerald, M. Wes Casto, and Robert B. Thomas Sr. AAPG Eastern Section 2017, September 26, 2017. Morgantown, WV. https://www.emfgeoscience.com/s/Fitzgerald-AAPG-2017.pptx

Clay Mineralogy, Provenance, and Sequence Stratigraphy of Upper Ordovician Shales in Eastern Ohio. Devin R.. Fitzgerald, Greg C. Nadon, and Bob Thomas. Search and Discovery Article #51331 (2016).Posted December 12, 2016. Clay Mineralogy, Provenance, and Sequence Stratigraphy of Upper Ordovician Shales in Eastern Ohio, #51331 (2016). (squarespace.com)