Kevin L. Burdick
Executive Vice President and Chief Commercial Officer at ONEOK
Thank you, Walt. Let's start with our natural gas liquids segment. First quarter 2023 NGL volumes increased both year-over-year and compared with the fourth quarter of 2022 with higher producer activity levels driving increased C3+ or propane plus volumes on our system. Permian Basin volumes saw the largest increase, up 17% compared with the first quarter and 14% compared with the fourth quarter of 2022.
We continue to have success contracting additional volumes in the basin and connected one new third-party natural gas processing plant during the first quarter. Permian producer activity remains strong and we continue to consider incremental expansions on our West Texas NGL system to accommodate increasing volumes. Volumes in the Rocky Mountain region increased during the first quarter compared with the same period last year and decreased slightly compared with the fourth quarter 2022.
The decrease was driven entirely by reduced ethane recovery as our propane plus volumes increased sequentially. We expect volumes to continue to grow in the spring and summer months. In the Mid-Continent region, consistent producer activity in the STACK and SCOOP continues to drive NGL volumes on our system. Raw feed throughput volumes increased compared with the fourth quarter 2022, driven primarily by higher ethane recovery. Regarding the macro ethane environment, we expect domestic petrochemical utilization rates to continue to improve as we move through 2023 with lower sustained natural gas pricing, and lower ethane inventory levels driving improved ethane economics and volumes across our system.
Through the remainder of the year, we continue to expect that the Permian Basin will stay at high levels of ethane recovery, the Mid-Continent will be in partial recovery and that we will have opportunities for incentivized recovery in the Rocky Mountain region. In April, we completed our 125,000 barrel per day MB-5 fractionator in Mont Belvieu. With MB-5 now fully operational, our system-wide fractionation capacity is nearly 900,000 barrels per day.
The added capacity will be used to accommodate volume growth and reduce third-party fractionation needs. We remain on track to complete our MB six fractionator in the first quarter 2025. In the natural gas gathering and processing segment, first quarter processed volumes averaged more than 2.1 billion cubic feet per day, an 11% increase compared with the first quarter of 2022. In the Rocky Mountain region, processed volumes averaged nearly 1.4 billion cubic feet per day during the first quarter and have recently reached more than 1.5 bcf per day. We connected nearly 150 wells in the region during the quarter compared with approximately 90 connections in the first quarter of 2022, a more than 60% increase.
Well connections in the region are currently on pace to exceed our guidance midpoint of 500 for the year. There are currently approximately 40 rigs and 23 completion crews operating in the basin with 20 rigs and approximately half of the completion crews on our dedicated acreage. We continue to expect additional rigs entering the region as we exit winter. In the Mid-Continent region, first quarter processed volumes averaged more than 750 million cubic feet per day, a 27% increase year-over-year.
We connected 11 wells in the region during the first quarter compared with six in the first quarter 2022 and are on track to be within our guidance of 45 to 55 connections. There are currently more than 50 rigs and 11 completion crews operating in the region with 10 rigs on our dedicated acreage. Despite weakness in natural gas prices, we continue to see strong activity in the higher crude and NGL-rich producing areas of the region where producers are focusing their drilling. In the natural gas pipeline segment, strong first quarter results continue to benefit from firm transportation services and the demand for natural gas storage.
We are on track to complete an expansion of our natural gas storage capabilities in Oklahoma in the second quarter allowing us to utilize and subscribe an additional four billion cubic feet of our existing storage capacity. We have subscribed 100% of this incremental capacity through 2027 and 90% through 2029. We continue to evaluate the Saguaro connector pipeline, a potential intrastate pipeline project that would provide natural gas transportation to the U.S. and Mexico border for ultimate delivery to an export facility on the West Coast of Mexico. There continue to be positive developments related to the potential LNG export project and we still expect to make a final investment decision on that ONEOK pipeline in mid-2023.
Pierce, that concludes my remarks.