Abstract: The present invention provides methods of preventing the flow of water or gas or both through a subterranean zone having a high temperature and a depth such that a long pumping time is required to place a sealing composition therein. The methods basically comprise the steps of preparing a polymeric sealing composition comprised of water, a cross-linking agent and a selected water-soluble polymer which reacts with the cross-linking agent and forms a sealing gel which is stable for a desired period of time at the temperature of the zone and has a pumping time before gelation in the presence of the cross-linking agent whereby the composition can be pumped to the depth of the zone and placed therein. Thereafter, the sealing composition is pumped into the zone and allowed to form a sealing gel therein.

Abstract: Hydrocarbon base drilling fluids which are selectively convertible to cementitious compositions that set into hard substantially impermeable masses and methods of using such drilling fluids are provided. The drilling fluids are basically comprised of a hydrocarbon liquid having particulate hydraulic cement suspended therein. The drilling fluids are converted to cementitious compositions by admixing water and a surfactant therewith.

Abstract: A method of stimulating a subterranean formation using a foamed cement composition. When hardened, the cement composition has a permeability of at least about 0.3 darcies. The inventive formation stimulation method comprises the steps of: (a) injecting the foamed cement composition into the formation at a pressure sufficient to fracture the formation and (b) allowing the cement composition to harden in the formation.

Abstract: A method of cementing a well casing or liner in a well bore wherein an annulus exists around the exterior of the casing or liner. The method comprises the step of placing a foamed cement slurry composition in the annulus. A method of treating a well bore comprising the steps of: (a) filling an uncased portion of the well bore with a foamed cement slurry composition; (b) allowing the cement composition to harden; and (c) drilling a hole through the hardened cement composition along at least a portion of the uncased portion of the well bore.

Abstract: This invention relates to a method of terminating the undesirable flow of water from a highly permeable portion of a portion of or a fracture in a subterranean formation into a wellbore, which method involves the use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement, which is utilized in a slurry of a hydrocarbon liquid and a surfactant, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.

Abstract: A method of reducing the water produced from a subterranean formation penetrated by a wellbore without appreciably reducing the oil produced therefrom is provided. In accordance with the method, the formation is contacted with a hydrocarbon treating solution having dissolved therein a surface active agent comprosed of one or more fatty acid imidazolyl compounds.

Abstract: This invention relates to a method of terminating the undesirable flow of fluid through a gravel pack in a wellbore, or from a highly permeable portion of or fracture in a subterranean formation into a wellbore, which method involves the use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement, which is utilized in either a slurry of water or hydrocarbon liquid, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.