North Dakota landowners, oil industry butt heads over holes in the ground Subterranean caverns known as “pore space” are as old as geology itself, but they have lately emerged as the scene of a turf war between a small landowners group and the North Dakota oil industry, which sees the underground chambers as outlets to reduce the state’s climate footprint and unlock lucrative new business opportunities. Written By: Adam Willis | × The North Dakota oil industry and a small landowners group are at odds over the use of subterranean cavities known as “pore space.” Forum News Service file photo BISMARCK — Arguments over a proposal to regulate payments for the use of holes in the ground pitted North Dakota landowners against the state’s oil and gas industry this legislative session and could foreshadow lawsuits down the line.