Kevin L. Burdick
Executive Vice President and Chief Operating Officer at ONEOK
Thank you, Walt. Fourth quarter volumes continued to show strength, particularly in the Rocky Mountain region, where processed volumes increased 5% and NGL volumes increased 6% compared with the third quarter of 2021. Natural gas processed volumes in the Mid-Continent increased in the fourth quarter compared with the third quarter as we've seen -- as we've continued to see more activity in the region, while NGL volumes in the Mid-Continent decreased due to some reduced third-party volumes and lower ethane recovery levels.
Overall, for 2021, natural gas and NGL volumes saw significant increases from 2020 levels. We saw record natural gas and NGL volumes on our Rocky Mountain region assets with significantly higher activity in rising gas to oil ratios. In the fourth quarter alone, our team connected 130 wells, nearly doubling the amount from the third quarter for a total of more than 320 in 2021. A great accomplishment for our team in meeting the needs of our customers and continuing to provide momentum into 2022. Now taking a closer look at 2022.
At the midpoint, our volume guidance would result in an 8% increase in total NGL volumes and an 11% increase in total natural gas processing volumes compared with 2021. These higher expectations are supported by increasing producer activity, volume growth from recently completed ONEOK and third-party projects, rising gas to oil ratios in the Williston Basin and ethane recovery opportunities across our NGL system. With the recent completion of our Bear Creek plant expansion, we are already seeing increasing volumes from Dunn County, and we expect the plant will continue to ramp up over the next two to three years.
However, with activity levels in the area consistently outpacing our expectations, we could be looking at an even quicker ramp. In the natural gas liquids segment, we expect continued volume growth from our existing customers and from new third-party plant connections. In the Williston Basin, volumes are expected to increase compared with 2021, supported by higher activity levels and recently completed and expanded processing plants. The Mid-Continent also continues to pick up, particularly from private producers with very recent activity levels providing potential tailwinds not fully factored into our guidance expectations.
Our NGL system is connected to more than 90% of the natural gas processing plants in the Mid-Continent. So any increased producer activity in the region is likely to provide NGL volume to ONEOK, regardless if the activity is on our gathering and processing dedicated acreage. In the Permian Basin, we expect double-digit NGL volume growth on our West Texas NGL pipeline compared with 2021, driven by increased volumes in the Midland and Delaware basins.
The volume growth is primarily from long-term contracts entered into a few years ago as well as new contracts we have recently signed. Switching to ethane. Demand continues to increase with more than 300,000 barrels per day of incremental demand expected to come online in 2022 from new and expanding petrochemical facilities and from growth in exports. Our NGL volume guidance assumes full ethane recovery in the Permian Basin and partial Mid-Continent recovery throughout the year.
We've assumed no full rate Rocky Mountain region recovery. However, we do anticipate opportunities to incent some recovery. This opportunity will fluctuate throughout the year, but a conservative amount is assumed in our 2022 guidance. Moving on to the natural gas gathering and processing segment. We expect volume growth this year in both the Rocky Mountain and Mid-Continent regions. In the Rocky Mountain region, we expect processed volumes to grow 15% at the midpoint compared with 2021 and average nearly 1.5 billion cubic feet per day in 2022.
Just five years earlier, in 2017, volumes totaled 830 million cubic feet per day. That's an approximately 12% annual growth rate over the last five years, while crude oil production has increased in the low single digits. Accordingly, GORs have increased nearly 70% during that same time period. The Williston Basin remains resilient and highly productive. Producers continue to gain efficiencies as they drill in this proven and highly economic region, and the core of the basin is expanding. The North Dakota Pipeline Authority recently estimated that in the last two years alone, more than 7,000 drilling locations have been added to inventory that are profitable at $60 per barrel.
This is consistent with what our customers are telling us, as most of them still have decades of inventory remaining. There are currently 33 rigs and 10 completion crews operating in the basin with 15 rigs and five completion crews on our dedicated acreage. This is more than enough activity to grow gas production on our acreage, and we expect that as DUCs are completed through the spring, rigs across the basin will increase. As we've said previously, approximately 14 to 15 rigs, which can drill around 300 wells per year, is enough to maintain 1.4 billion cubic feet per day of production on our system.
Any additional rigs combined with the rising gas to oil ratios of wells already connected to our system would provide additional volume growth. Additionally, more than 475 DUCs remain basin-wide with more than 250 on our dedicated acreage. We expect to connect 375 to 425 wells in the region this year. In the Mid-Continent region, activity continues to increase. We expect processing volumes in the region to increase compared with 2021, and we expect to more than double our well connections in 2022 to 30 to 50 wells compared with 15 last year.
In the natural gas pipelines segment, we expect transportation capacity to be approximately 95% contracted and earnings to remain nearly fully fee-based in 2022. Following a successful open season in 2021, we're in the process of expanding our Texas natural gas storage capacity by 1.1 billion cubic feet, which will increase our total system-wide storage capacity to more than 53 billion cubic feet. We continue to work with customers seeking additional long-term transportation and storage capacity on our system, which remains highly valued as these critical services are used year around.
Pierce, that concludes my remarks.
