In eastern Ohio’s Utica-Point Pleasant shale play, operators have access to a wealth of NGL but are facing a number of challenges in producing it and getting it to market. According to Hart Energy’s North American Shale Quarterly (NASQ), activity in the Utica has become increasingly focused on this NGL sweet spot because of the wet gas-to-oil window, where the total organic carbon is usually very high and liquids-prone.

While the Ohio Department of Natural Resources reported that, as of Jan. 11, 1,042 horizontal permits had been issued in the Utica with 679 drilled by that time, only 270 wells were actively producing or plugged back. That production has been encumbered by a lack of available pipelines in the area capable of moving the produced gas along to gas processing plants. However, that is scheduled to change as early as the end of 1Q and will culminate in 2016 after several new pipeline investments come to fruition.

Infrastructure issues scheduled for resolution

In the NASQ, Hart Energy Research & Consulting analysts reported that by the end of 1Q the Mariner West project – a pipeline project between Sunoco Logistics and MarkWest Liberty Midstream and Resources to deliver Marcellus shale ethane from the liquid-rich Marcellus processing and fractionation areas near Houston, Penn., to Marysville, Mich., and the international border near Marysville, Mich. – would begin flowing NGL at 50,000 b/d capacity.

That pipeline project and others, like Kinder Morgan and MarkWest Utica EMG’s proposed Y-grade pipeline to transport NGL produced from the Utica and Marcellus shale plays to Mont Belvieu, Texas, are garnering additional interest from operators in the Utica and Marcellus plays.

“This project will provide consumers on the Gulf Coast with access to a new source of NGL from the Utica and the Marcellus shale resource plays,” Don Lindley, president of NGL for Kinder Morgan Energy Partners, stated in a press release. “Through Kinder Morgan and Mark-West Utica EMG’s existing pipeline footprint, this project is capable of accessing all of the processing facilities in the Northeast in a cost-effective manner.”

Great promise, challenges

The US Geological Survey has estimated that the Utica holds about 1.08 Tcm (38 Tcf) of undiscovered, technically recoverable natural gas. As infrastructure issues are addressed, more operators are likely to flock to the Utica. As they do, they are likely to face challenges like constrained processing at regional plants, stabilization and fractionation of condensate, and ethane takeaway capacity.

To address these challenges, Tom Ostrye, product line director of process and treating at Exterran – a service and equipment provider for oil and gas production, processing, treating, transportation, and storage – recommends that operators who have not yet drilled in the area first partner with an experienced company to plan out the production stages of the well.

“Operators in the Utica are challenged by the variability and uncertainty about gas composition, which affects the design of NGL extraction plants,” he said. “Additional concerns include the need for local fractionation capacity (separating an NGL stream into its component products), the absence of NGL pipelines, and meeting residue gas heat value limitations while in ethane rejection.”

Constraints on regional processing plants

Like all produced gas, NGL must be treated to meet pipeline specifications before it can be introduced into the sales pipeline. While specifications may vary, Ostrye said most pipeline operators will typically limit the heat value, water content, CO, HS, and other impurities.

“If the gas is produced from the Utica formation,” he said, “gas processing is almost always required to remove NGL to reduce the heat value of the gas.”

Tower flares of varying types and sizes are also available in the Utica and are typically designed specifically for the flow conditions in each plant.

Ostrye said Exterran plants are designed to handle volumes of 1.7 MMcm/d, 4.25 MMcm/d, and 5.66 MMcm/d (60 MMcf/d, 150 MMcf/d, and 200 MMcf/d), offering custom options to accommodate higher and lower volumes of gas. However, he said the large volume of gas produced in the Utica has resulted in the 5.66 MMcm/d plant size being the capacity of choice.

“We offer build, own, and operate contracts for small-volume processing plants,” he said, adding that operators can work out a service arrangement or lease a plant, depending on their needs.

Condensate stability and fractionation

Ostrye said almost all gas extraction in the Utica requires the use of a turbo expander-based cryogenic process plant with supplemental mechanical refrigeration. Service companies typically offer several types of liquid extraction processes, including propane closed-loop refrigeration, Joule-Thomson (JT), and refrigerated JT.

“Our cryogenic systems use the reflux demethanizer gas subcooled process to recover NGL,” he said. “These facilities typically consist of a molecular sieve dehydration, optional mechanical refrigeration, turbo expander/ compressor, and demethanizer to drop the temperature of the gas and remove condensed ethane and other [NGL].”

In liquid-rich plays like the Utica, condensate stabilization is an important aspect of the NGL production process. Ostrye said that because Utica gas tends to be rich in NGL content, liquids drop out in gathering lines between wellheads and the processing plant.

“This requires slug catchers and condensate stabilizers to collect and treat the condensate,” he said, adding that the company offers condensate stabilization and flash gas recovery.

Ethane takeaway capacity

While some separation occurs along the pipeline between the wellhead and the plant, the plant is the primary extraction site. Once the gas reaches the plant, Ostrye said the stream is cleaned according to pipeline specifications and the composition of the produced gas. Ethane can sometimes be the exception.

“Ethane being pulled from the stream or left in is typically a function of the market value of ethane,” he said. “[Its value] currently is low, so extraction plants are being operated in ‘ethane rejection’ mode. However, operators are usually limited by the maximum heat value accepted by the sales pipeline and in many cases may be required to remove some of the ethane even during periods of low ethane prices.”

Err on the side of precaution

Well versed on the Utica’s proclivities, Ostrye said companies like Exterran can help operators fine-tune their plans and prevent any unhappy surprises or lost production time.

“The earlier we are brought into the process,” he said, “the greater the value from system integration and facility optimization can be realized by the operator and the less project schedule impact will occur from long lead times and fabricated equipment.”

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