| abstract |
Proppant used to keep open a fissure in a reservoir created by hydraulic or other action is disclosed. The proppant demonstrates a reduced specific gravity controlled by the geometry of the structure of the proppant. Proppant must be capable of withstanding the hydrostatic environment of the hydraulic pumping system, pass through a perforation in the casing of the well, travel into the fissure, and, upon reduction of hydrostatic pressure, withstand the closure pressure of the formation. A proppant having neutral buoyancy or substantial neutral buoyancy yet capable of withstanding the hydraulic and closure pressures is described that has a tubular structure hollow in the center with a wall of material sufficiently strong to withstand the majority of closure pressures. |