Abstract: Hydrocarbon fluid recovery from wells extending into subterranean formations is stimulated by treatment of the near-wellbore formations with cryogenic liquid.

Abstract: Methane gas recovery from wells extending into subterranean coal seams is stimulated by treatment of near-wellbore coal seam with cryogenic liquid.

Abstract: A lighted gun sight is mounted on the slide of a semi-automatic pistol which reloads by having the slide move rearwardly for ejecting the used cartridge and inserting a new cartridge. The semi-automatic pistol has a grip attached to its lower portion with a trigger for firing the pistol and a grip safety which is attached to the rearward portion of the grip so that the gun cannot be fired without the grip being squeezed. The lighted gun sight essentially comprises a power source, a switch, and an intensity control apparatus mounted in the grip of the pistol. A bridge is then mounted on the slide from the gun sight to the grip. An electrical power coupling apparatus is provided between the grip and the bridge in a manner so that power can be coupled to the gun sight when the gun is ready for firing and may be decoupled when the pistol has been fired.

Abstract: A method and apparatus for determination of earth formation permeability in situ. A logging sonde supported in a borehole derives attenuation data from at least two ultrasonic energy transmission paths which have a common alignment but differing length, the attenuation data can then be used to determine an empirical X parameter that is directly related to formation permeability.

Abstract: A dye adsorption procedure for determining clay type and amount in subterranean formation. The procedure can be carried out at a well-site, providing rapid, accurate information for treatment of the well penetrating the formation.