Abstract: Improved methods of generating gas in and foaming aqueous well fluids introduced into a subterranean zone are provided. A method of the invention includes the steps of combining with an alkaline aqueous well fluid one or more gas generating chemicals and a mixture of foaming and foaming stabilizing surfactants so that the gas generating chemical or chemicals react with the alkaline aqueous well fluid and gas and foam are formed in the well fluid while it is being pumped, and then pumping the well fluid into the subterranean zone.

Abstract: Oil-based settable spotting fluid compositions for cementing in wells and subterranean formations are provided. The oil-based settable spotting fluid compositions basically comprise an oil external emulsion comprising oil, water and an emulsifying surfactant, a hydraulically settable component and a de-emulsifying surfactant for de-emulsifying the oil-external emulsion when the emulsion is cured.

Abstract: Methods of cementing subterranean zones penetrated by well bores and well cement compositions are provided. A well cement composition of the invention is basically comprised of a hydraulic cement, water in an amount sufficient to form a pumpable slurry and a fluid loss control polymer additive comprised of 69 weight % of the calcium salt of 2-acrylamido-2-methyl propane sulfonic acid, 14 weight % of the calcium salt of maleic acid, 14 weight % of N-vinyl caprolactam and 3 weight % of 4-hydroxybutyl vinyl ether.

Abstract: Drill cuttings slurries and the like are transported by high pressure pumping the slurry through an extended pipeline, if necessary after treatment of the slurry to render it suitable for high pressure pumping. Apparatus for pumping the slurry includes a tank for receiving the slurry to be pumped, means for agitating the slurry in the tank to mix it, and a high pressure pump for receiving slurry from the tank for pumping away from the tank.

Abstract: Methods of cementing in subterranean zones, improved cement compositions and improved additives are provided. The compositions are basically comprised of a hydraulic cement, sufficient water to form a slurry and an additive for providing improved rheology, fluid loss control and set retardation comprised of carboxymethylhydroxyethylcellulose having in the range of from about 0.62 to about 2.21 moles of hydroxyethyl substitution and in the range of from about 0.44 to about 0.52 degrees of carboxymethyl substitution and a 2% by weight aqueous solution of the carboxymethylhydroxyethylcellulose has a Höppler viscosity in the range of from about 55 mPa.s to about 359 mPa.s.

Abstract: The present invention provides improved well drilling fluids containing hardenable furan sealant compositions and methods of drilling well bores and sealing pipe strings therein utilizing the drilling fluids. The drilling fluids are basically comprised of a base fluid, a viscosity increasing material and a hardenable furan sealant composition which becomes part of the filter cake formed on the walls of the well bore and hardens therein.

Abstract: Methods of consolidating formations or forming chemical casing or both while drilling are provided. One method of the invention comprises drilling a well bore with a drilling fluid comprised of water, a polymeric cationic catalyst which is adsorbed on weak zones or formations formed of unconsolidated clays, shale, sand stone and the like, a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble thermoset resin, and a delayed dispersible acid catalyst for curing the solid and water soluble resins. The drilling fluid forms a filter cake on the walls of the well bore that cures and consolidates the unconsolidated weak zones and formations penetrated by the well bore so that sloughing is prevented and forms a hard and tough cross-linked chemical casing on the walls of the well bore.

Abstract: A method is provided for selecting a cementing composition for sealing a subterranean zone penetrated by a well bore. The method involves comprising determining a group of effective cementing compositions from a group of cementing compositions given estimated conditions experienced during the life of the well, and estimating the risk parameters for each of the group of effective cementing compositions.

Abstract: An electrically conductive oil mud meeting the fluid requirements for resistive logging tools and a method for preparing such mud is disclosed. The fluid has been optimized to deliver performance in a manner as similar to that of a traditional invert emulsion drilling fluid as is practical while still maintaining the required electrical conductivity for resistivity-based logging tools. This electrically conductive oil-based mud comprises a polar synthetic ester base and complimentary ester surfactants, one being more oil soluble, the other being more water soluble. The surfactants interact synergistically to provide dense packing of micelles at the palisade layer. This fluid is oil-wetting to solids, and in general behaves like a traditional oil mud.

Abstract: The present invention provides lightweight cement compositions, and methods for cementing in a subterranean formation using such cement compositions. The cement compositions comprise hydrated lime, vitrified shale, and sufficient water to form a slurry. Optionally, other ingredients may be included in the compositions.

Abstract: The present invention provides methods of cementing subterranean zones penetrated by well bores using biodegradable dispersants. A cement composition of the invention comprises a hydraulic cement, sufficient water to form a slurry and a water soluble biodegradable cement dispersant comprising a polyamide graft copolymer containing at least o e side chain formed from aldehydes and sulfur-containing acids or their salts.

Abstract: Methods for cementing a pipe string in a well bore containing oil-based drilling fluid using oil-based settable spotting fluid compositions are provided. The oil-based settable spotting fluid compositions basically comprise an oil external emulsion comprising oil, water and an emulsifying surfactant; a hydraulically settable component; and a de-emulsifying surfactant for de-emulsifying the oil-external emulsion when the emulsion is cured.

Abstract: Well completion foamed spacer fluids and methods of using the foamed spacer fluids are provided. A method of the invention for displacing a first fluid from a well bore with an incompatible second fluid comprises the following steps. A foamed spacer fluid is placed between the first and second fluids to separate the first and second fluids and to remove the first fluid from the walls of the well bore. Thereafter, the first fluid and the foamed spacer fluid are displaced from the well bore with the second fluid.

Abstract: A method and composition is provided for sealing a subterranean zone penetrated by a well bore, wherein the composition basically comprises a mixture of latex, dithio carbamate, zinc oxide, and sulfur.

Abstract: Methods for drilling well bores and cementing a pipe string in the well bores using oil-based settable drilling fluids are provided. The oil-based settable drilling fluid compositions basically comprise an oil external emulsion comprising oil, water and an emulsifying surfactant; a hydraulically settable component; and a de-emulsifying surfactant for de-emulsifying the oil-external emulsion when the emulsion is cured.

Abstract: A new method for evaluating the efficiency of a sweep for removing cuttings from a borehole in a subterranean formation during a drilling operation. The method evaluates sweep efficiency on a “mass in” versus “mass out” basis. The method uses downhole density readings taken with a pressure-while-drilling tool inserted in the drill string. Measurements of hydrostatic pressure are converted into equivalent circulating density measurements which in turn are used in calculating the sweep efficiency. The method affords real time estimates at the wellsite of the quantity of formation cuttings brought out of a wellbore by a sweep.

Abstract: A new composition for a spotting fluid and a method of using such spotting fluid for freeing differential stuck pipe in a subterranean well drilling operation is disclosed. The composition comprises an invert water-in-oil emulsion comprising iso-butyl oleate as its external phase and glycerin as the internal phase. In an alternative embodiment, calcium chloride and water may be substituted for glycerin.

Abstract: The present invention provides methods, lightweight well cement compositions and additives for the well cement compositions. The methods of the invention for sealing pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressure is basically comprised of the steps of providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite, placing the cement composition in the annulus between the pipe and the well bore and allowing the cement composition to set.

Abstract: The present invention provides particulate flow enhancing additives for improving the flow properties of dry particulate cementitious materials. The particulate flow enhancing additives basically comprise a particulate solid adsorbent material having a flow inducing chemical adsorbed thereon.

Abstract: A small diameter stage cementer assembly 10 and a hydraulically operated packer collar stage cementer 110, including a cementer housing 12 for interconnection with a casing string 14 positionable in a slim-hole wellbore for a cementing operation. The cementer housing 12 including a seat 11 for receiving a lower, drillable portion 335 of an opening sleeve assembly 135 after the upper drillable portion 235 of the opening sleeve assembly 135 has been drilled out. The lower, drillable portion 335 wedges into engagement with the seat 11 to prevent rotation of the drillable portion 335 during drill-out, such that the lower portion 335 may be drilled up using a small diameter bit and drill string, and accommodating a reduced weight on bit. The packer collar embodiment includes a hydraulically actuatable packer 70.