Abstract: A method of completing a wellbore is disclosed wherein a low density spacer fluid is introduced into a wellbore and then a completion fluid, such as a cement slurry, to displace the spacer fluid. The spacer fluid comprises a nonagglomerating carrier fluid, such as water or the like, and discrete dispersible density reducing bodies, such as hollow spheres. The density reducing bodies aid in reducing the hydrostatic head of the spacer fluid, completion fluid, and existing wellbore fluids to prevent the hydrostatic head of such fluids from exceeding the fracture gradient of a highly porous, easily fractured formation.

Abstract: A diverter tool and method of use thereof for use in setting a cement plug in a well. The tool comprises a hollow cylindrical body provided with a plurality cylindrical ports, the axes of which form a plane essentially perpendicular to the axis of the tool.

Abstract: A 9 to 12 ppg (1.08 to 1.4 kg/liter) cement slurry for use in oil well type completions which comprises hydraulic cement about 10 to about 30 weight percent hollow glass microspheres based on the weight of the cement and sufficient water to form a pumpable slurry with an API free water content of no more than about 2 volume percent. This slurry is preferably mixed with an amount of water required to produce a slurry with the hydraulic cement having at least an API minimum water content and an API free water content of no more than about 2 volume percent and an additional amount of water equal to about 1.3 to about 1.8 weight percent water based on the weight of the hydraulic cement for each weight percent of the microspheres. The microspheres have true particle densities of at least 0.2 gm/cm.sup.3, hydrostatic collapse strengths of at least 500 psi (3447 kPa) and average particle diameters of less than about 500 microns.

Abstract: A 9 to 12 ppg (1.08 to 1.4 kg/liter) cement slurry for use in oil well type completions which comprises hydraulic cement about 10 to about 30 weight percent hollow glass microspheres based on the weight of the cement and sufficient water to form a pumpable slurry with an API free water content of no more than about 2 volume percent. This slurry is preferably mixed with an amount of water required to produce a slurry with the hydraulic cement having at least an API minimum water content and an API free water content of no more than about 2 volume percent and an additional amount of water equal to about 1.3 to about 1.8 weight percent water based on the weight of the hydraulic cement for each weight percent of the microspheres. The microspheres have true particle densities of about 0.2 to about 0.5 gm/cm.sup.3, hydrostatic collapse strengths of at least 500 psi (3447 kPa) and average particle diameters of less than about 500 microns.

Abstract: A 9 to 12 ppg (1.08 to 1.4 kg/liter) cement slurry for use in oil well type completions which comprises hydraulic cement about 10 to about 30 weight percent hollow glass microspheres based on the weight of the cement and sufficient water to form a pumpable slurry with an API free water content of no more than about 2 volume percent. This slurry is preferably mixed with an amount of water required to produce a slurry with the hydraulic cement having at least an API minimum water content and an API free water content of no more than about 2 volume percent and an additional amount of water equal to about 1.3 to about 1.8 weight percent water based on the weight of the hydraulic cement for each weight percent of the microspheres. The microspheres have true particle densities of about 0.2 to about 0.5 gm/cm.sup.3, hydrostatic collapse strengths of at least 500 psi (3447 kPa) and average particle diameters of less than about 500 microns.

Abstract: A process for reducing the waiting-on-cement (WOC) time associated with the cementing of a casing string in an oil well involving the specific improvement of pumping into the well a highly retarded cement slurry containing a dispersed encapsulated accelerator, such as calcium chloride or anhydrous sodium metasilicate, wherein the encapsulating material is specifically selected such that it will melt at a temperature above the bottom-hole circulating temperature but below the bottomhole static temperature of the well to be cemented. Petroleum-derived waxes and petroleum-derived waxes in combination with vinyl resins, such as wax-compatible copolymers of ethylene and vinyl acetate, are particularly suitable as the meltable encapsulating material exhibiting excellent strength and abrasion resistance as well as serving as a moisture barrier. The improved process is particularly useful in cementing deep hot wells.

Abstract: A method for cleaning and stimulating an oil, gas or injection well, in which wax, tar and/or bituminous materials are either already deposited or would be precipitated by the injection of an acidizing solution consisting of a mixture of an octanol and a lower alcohol with an aqueous acid solution, involving the injection of an aromatic solvent either before and/or after the alcohol-acidizing solution. To enhance the interfacial miscibility of the aromatic solvent and the alcohol-acidizing solution, a small amount of amine having no more than eight carbon atoms may be added to the aromatic solvent. This method is useful in both production and injection wells.