Oneok Partners LP Thursday launched plans to invest up to $500 million between now and 2015 to build additional natural gas liquids (NGL) infrastructure in some of its Midcontinent operations, with the bulk of the funds earmarked for the Williston Basin.

Included is another plant at the Garden Creek facility and related infrastructure to be built in eastern McKenzie County, ND, which is in the Williston. The third plant, Garden Creek III, would have 100 MMcf/d of processing capacity. The second Garden Creek plant was announced last July (see Shale Daily, July 27, 2012).

A 95-mile NGL pipeline also is on the drawing board to run between existing fractionation infrastructure at Hutchinson, KS, and Medford, OK. The partnership also wants to modify NGL infrastructure at Hutchinson to accommodate lighter, unfractionated NGLs produced in the Williston Basin.

“The new Garden Creek III plant increases our natural gas processing capacity to meet producers’ needs in the Williston Basin, and the expansion of our downstream NGL infrastructure will offer additional fractionation and transportation capacity for NGLs coming from the region,” said Executive Vice President Pierce H. Norton, who handles commercial projects.

The Garden Creek infrastructure, including expansions and upgrades to existing systems, is expected to cost $325-360 million; it could be in service in early 2015. The facility is to be built near the first Garden Creek plant; the second plant is scheduled to be in service in the second half of 2014.

About $140 million is put aside for a 95-mile NGL pipe to connect fractionation facilities in Hutchinson to similar facilities in Oklahoma and would include modifications to existing infrastructure at Hutchinson to accommodate more unfractionated NGLs from the Williston Basin. The pipeline and related modifications are expected to be in service in early 2015.

The Oneok Inc. partnership noted that to date it has announced a total of $4.7-5.3 billion in infrastructure investments through 2015. Of that total, $2.4-2.7 billion alone is for growth related to the Williston.

“The partnership has a $2 billion-plus backlog of unannounced growth projects that it continues to evaluate,” management said. “Additional projects included in this backlog will be announced when sufficient supply commitments are completed.”