One of the early centers of American shale drilling is roaring back to life, boosted by a building boom of petrochemical plants, fertilizer factories and gas-export terminals along the Gulf Coast.

The Haynesville Shale, a giant natural-gas field in northwest Louisiana, was one of fracking’s hottest spots a decade ago. But it fizzled out about five years ago as gas prices plunged and drillers focused on finding oil next door in Texas. Now, the Haynesville is being reborn as companies with longstanding positions in the area,...