The “wet,” liquids-rich parts of the Marcellus/Utica region enable producers there to benefit from the sale of both natural gas and NGLs. The catch is that, unlike major production areas in other parts of the U.S., the Northeast has no pipelines to transport unfractionated, mixed NGLs — also known as y-grade — long distances to fractionation centers in Mont Belvieu, TX, or Conway, KS. As a result, midstream companies serving the region have developed a number of interconnected gas processing, NGL pipeline and fractionation networks within the wet Marcellus/Utica to efficiently and reliably deal with the increasing flows of NGLs coming their way. No one has done this on a larger or more impressive scale than MPLX, Marathon Petroleum Corp.’s midstream-focused master limited partnership. Today, we continue our series on recently completed and planned gas processing and fractionation projects in the Northeast with a look at MPLX, the regional leader in this space.
As we said in Part 1, natural gas production in the Marcellus/Utica has been increasing steadily this decade and now averages about 32 Bcf/d, which is 12% higher than last August and nearly double where it stood five years ago. This run-up in production volumes — and RBN’s expectation of further growth to about 40 Bcf/d by 2024 — would not be possible without the new gas-processing and fractionation capacity that midstream companies have been bringing online at a steady pace in the wet parts of the play in southwestern Pennsylvania, eastern Ohio and northern West Virginia. Over the past 10 years, gas processing capacity in the region has increased from about 600 MMcf/d to more than 10 Bcf/d, and plans are underway by MPLX and other midstreamers to add as much as another 2 Bcf/d of processing capacity over the next two or three years, with some of that scheduled to be commissioned later in 2019.
Out of necessity — namely the need to separate y-grade into so-called NGL “purity products” within the region — a lot of new fractionation capacity has been added in the Northeast too. However, midstream companies in the Marcellus/Utica have taken a different tack with “fracs” than the big fractionators in Mont Belvieu and Conway. In the “centralized de-ethanization” approach used at those fractionation hubs in Texas and Kansas (diagram to left in Figure 1), y-grade is piped to bells-and-whistles frac plants that separate the mixed NGLs they receive into all five of the primary purity products: ethane (also known as C2 because it has two carbon atoms), propane (C3), normal butane/isobutane (C4) and natural gasoline (C5). [These plants are also known as C2+ fracs because they fractionate out everything from ethane/C2 on up.] After being fractionated, these purity products can then be stored under pressure in the large, underground salt caverns that have been developed nearby for that purpose, and then piped to steam crackers (ethylene plants) or export docks.