Abstract: A method for shutting off or decreasing the production of water from an oil well. An oil well producing excess water is taken off production and a gas is injected into the well, followed by a slug of clean oil containing an emulsifier. The well is then produced as fast as possible. The previously injected gas and water in water-producing zones begin to finger back through the oil slug and forms a viscous emulsion which blocks the further flow of water into the producing well.

Abstract: An erosion-resistant sand screen assembly is described for use in petroleum wells of the type in which sand tends to become entrained in the stream of petroleum entering the wellbore. The assembly is especially useful in cased holes in formations which consist of very find sand, such as have been encountered in the Gulf Coast region of the United States and off the east coast of Trinidad. The assembly uses a sleeve with an erosion-resistant wall at least one-fourth inch thick, positioned around the outside layer of wire screen. Preferably, the assembly has an outer surface of a resilient elastomeric material.