Billionaire Kelcy Warren’s Energy Transfer LP will buy Crestwood Equity Partners LP in a $7.1 billion all-equity deal that will create a major expansion of its pipeline networks across the US.

The deal will extend Energy Transfer’s position in the Williston basin of Montana and North Dakota and the Permian Basin of West Texas and New Mexico, while providing entry into Wyoming’s Powder River Basin, according to a statement Wednesday. Crestwood’s system includes about 2 billion cubic feet a day of gas gathering capacity and 340,000 barrels a day of crude oil gathering capacity.

Shares of Energy Transfer were about 2% higher as of 10:19 a.m. in New York, and and Crestwood was up about 5%.

The US energy sector has seen dealmaking heat up after booming profits in recent years left producers flush with cash. Pipeline operators have been part of the activity as the transition to renewable energy makes it unlikely that major new infrastructure will be built even as demand for offtake remains robust as shale producers seek to preserve top-quality drilling locations. In May, Oneok Inc. agreed to buy Magellan Midstream Partners LP in an $18.8 billion cash-and-stock transaction that’s awaiting shareholder approval.

Read More: Oil Patch Is Poised for Buyout Wave as US Drillers Seek New Land

Warren, 67, has been on a buying spree for more than three years. Even before Wednesday’s announcement, he’d committed more than $11 billion to snap up pipelines and ancillary assets in the Permian region, the Gulf Coast and Great Plains. The value of pipeline networks has continued to increase amid the need to connect remote wells to population centers and export facilities.

The Crestwood deal includes the assumption of $3.3 billion of debt, according to the statement. Under the terms of the deal, which is expected to close in the fourth quarter, Crestwood common unitholders will receive 2.07 Energy Transfer common units for each Crestwood common unit. After closing, Crestwood common unitholders are expected to own about 6.5% of Energy Transfer’s outstanding common units.

“We view the deal as neutral for ET,” Elvira Scotto, an analyst at RBC Capital Markets, said in a report. “ET units are likely to underperform given the all-equity deal.”

BofA Securities acted as sole financial adviser to Energy Transfer and Kirkland & Ellis LLP was legal counsel. Intrepid Partners LLC and Evercore acted as financial advisers to Crestwood and Vinson & Elkins LLP was legal counsel.

(Adds analyst comment in seventh paragraph)