Typically, landowners in North Dakota own the surface, subsurface formations, pore spaces, and everything lying underneath their land, including oil and gas resources or minerals that may be found in such formations. When a landowner grants an oil and gas lease, the lessee receives a mineral estate the right to find and produce the oil and gas specified under the lease as a determinable interest. In “split estate” situations, there are questions about whether the pore spaces (typically beneath the formations that hold the oil and gas or minerals in place) remain with the holder of the mineral estate or the surface owner. These questions also become more intriguing considering that a mineral lessee has, among other things, the implied right to reasonable use of the surface of the land in the process of finding and producing the oil and gas resources pursuant to its lease.
Under North Dakota law, “pore space” refers to a cavity or void, whether natural or artificially created, in a subsurface sedimentary stratum. Furthermore, the title to such pore spaces in all strata underlying the surface of lands and waters is vested in the owner of the overlying surface estate. Thus, the conveyance of a mineral estate would ordinarily not include the conveyance of pore space ownership rights. However, a mineral estate owner or lessee could claim there is an implied right to reasonably use such pore spaces that otherwise remain with the ownership of the overlaying land. That implied right of the reasonable use of the land is generally subject to (1) the notion that a mineral owner or lessee exercising the implied easement for surface use must do so with due regard for the interests of the surface landowner, and (2) the use of the surface of the land by the mineral estate owner must be exclusively to obtain the oil and gas or minerals under the land following a lease and permitted activity.
So, what are pore spaces typically used for?