Recent Pipeline Expansion Affecting Williston Basin Natural Gas Flows

The Williston Basin, spanning across parts of Montana, North and South Dakota, and southern Canada, is known for its prolific oil resources; however, it also produces a significant amount of associated natural gas. Recently, BTU Analytics observed a dip in net gas receipts and deliveries in the basin from the start of the year through April, at which point an uptick began. This movement, visible in the graphic below, aligns with historical seasonality and is characterized by a recurring pattern that typically peaks in January and bottoms out in April. When looking at production, growth has slowed, though it continues its more-than-a-decade-long trend of steady annual increases. However, while net flows and production growth remain consistent with historical norms, BTU Analytics has identified a shift in pipeline flows within the basin that has not occurred before. 

The state of production

Examining historical Williston production, there have been two periods of strong growth, from 2010 until 2015 and then again from 2018 through 2019. Now, well after the disruptions of the COVID-19 pandemic, BTU Analytics is expecting natural gas production to exit 2025 at 3.7 Bcf/d. While net receipts and deliveries appear similar to previous years, the pace of production growth is slowing. Year-over-year growth is projected at just 1% from 2024 to 2025, representing a clear deceleration compared to prior years. Despite this subdued growth rate, BTU Analytics anticipates that net receipts and deliveries will remain consistent with recent trends.

Williston flows & expansion effects

Taking a closer look at flows on individual pipelines in the Williston Basin, Alliance pipeline has been very consistent over the past four and a half years. Flows on NBPL and WBI, however, were tracking closely to one another up to May 2025, when we see a noticeable deviation. As NBPL flows began falling this March, WBI flows increased. Notably, in April, NBPL was down 27 MMcf/d MoM, while WBI was up 40 MMcf/d. Similarly, NBPL was down 93 MMcf/d from May to June, while WBI was up 84 MMcf/d during that same timeframe, indicating that a nearly 1:1 trade-off between NBPL and WBI had occurred. Further examination into NBPL revealed several operational flow orders in addition to planned maintenance events were impacting flows during this time. This aligns with a similar trend observed in past years, as maintenance tends to occur seasonally. Last year, NBPL had six maintenance notices posted in April, more than those posted in March, May, or June of the same year. This year, five maintenance notices were posted in April, once again exceeding the number in surrounding months.

This year, however, the drop in NBPL flows occurring at the same time as the increase in WBI flows highlights that WBI has likely picked up these volumes. BTU Analytics has not observed the volumes impacted by maintenance on NBPL show up on WBI in the past. This was possible due to the WBI Line Section 27 Expansion Project, connecting a new Spring Creek Compressor Station near NBPL’s Spring Creek Interconnect and tie-in facilities. This expansion came online in mid-2024 and added 175 MMcf/d of incremental capacity. The observed shift in flows from NBPL to WBI explains why net receipts and deliveries in the Williston appear typical, even as the behavior of individual pipeline flows has diverged from historical trends.

Going forward

While production growth in the Williston is expected to slow, BTU Analytics still expects YoY growth in the near term. Furthermore, the observed deviation from historical flow patterns on NBPL and WBI is a direct result of pipeline maintenance and the recent expansion project on WBI. Despite this recent change in Williston Basin pipeline flow dynamics, BTU Analytics does not forecast a major change to net receipts and deliveries or natural gas production growth in the basin going forward.

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