Abstract: A method for injecting fluid, such as an accelerator, into a wellbore comprises storing the fluid in a reservoir, locating the reservoir downhole in the wellbore, and then transferring the fluid from the reservoir into the wellbore. More particularly, one embodiment of the method comprises storing the fluid in a reservoir in a plug, pumping the plug down casing in a wellbore, and transferring the fluid at the bottom of the wellbore via a venturi effect. Another embodiment of the method comprises storing the fluid in a reservoir integrated into the wall of a portion of casing, setting the casing in the wellbore, and then transferring the fluid via a venturi effect from the reservoir into the annulus defined between the casing and the wellbore.

Abstract: A dispersant for drilling fluids, spacer fluids, cement slurries, completion fluids and mixtures of drilling fluids and cement slurries used for drilling and cementing subterranean wells.

Abstract: A dispersant for spacer fluids, cement slurries, completion fluids and mixtures of drilling fluids and cement slurries used for drilling and cementing subterranean wells.

Abstract: Spacer fluids providing an effective buffer between drilling fluids and cement slurries during well completion. The spacer fluids comprise a sulfonated styrene copolymer dispersant and one or more additional components such as surfactants, viscosifiers and weighting materials to form a rheologically compatible fluid between the drilling fluid and the cement slurry.

Abstract: A cement method and composition for cementing a well penetrating subterranean formations and aqueous based drilling fluid containing at least one cement retarder characterized by a major proportion of the drilling fluid from the well as it was drilled; water; a lesser proportion of dry cementitious material; a minor amount of a dispersant that does not effect satisfactory set cement within an acceptable time interval; and an accelerator selected from the class consisting of acetic acid; the first 4 carbon esters thereof; acetamide; monoethanolamine; and diethanolamine. The first 4 carbon esters are the methyl; ethyl; propyl, both normal and isopropyl; and butyl ester, normal, isobutyl and tertiary butyl.

Abstract: A cement method and composition for cementing a well penetrating subterranean formations and aqueous based drilling fluid containing at least one cement retarder characterized by a major proportion of the drilling fluid from the well as it was drilled; water; a lesser proportion of dry cementitious material; a minor amount of a dispersant that does not effect satisfactory set cement within an acceptable time interval; and an accelerator selected from the class consisting of acetic acid; the first 4 carbon esters thereof; acetamide; monoethanolamine; and diethanolamine. The first 4 carbon esters are the methyl; ethyl; propyl; both normal and isopropyl; and butyl ester, normal, isobutyl and tertiary butyl.

Abstract: Spacer fluids providing an effective buffer between drilling fluids and cement slurries during well completion. The spacer fluids comprise a sulfonated styrene copolymer dispersant and one or more additional components such as surfactants, viscosifiers and weighting materials to form a rheologically compatible fluid between the drilling fluid and the cement slurry.

Abstract: A method of cementing in a wellbore penetrating subterranean formations characterized by employing a graded density spacer fluid intermediate a displacing fluid and a displaced fluid. This is particularly advantageous where a cement slurry is employed as displacing fluid to displace drilling fluid employed to drill a well penetrating subterranean formations. This alleviates problem with intermixing of the two fluids. This invention is doubly advantageous where a well contains both a substantially vertical portion and a substantially horizontal portion, since in the latter portion, the use of this invention enables controlling under-running or over-running of a displacing fluid with respect to a displaced fluid.

Abstract: What is disclosed is a method of accelerating the set of a retarded cement. The cement may range from a drilling fluid containing dispersants or retarders that will slow down the set of the drilling fluid when cementitious fluid is added thereto, through overwashing, or treating a retarded primary or remedial cement that may have been injected into fractures or areas within a well to overwashing a plug or any volume of retarded cement that needs to be set in a well.The specific uses are discussed.

Abstract: A method of accelerating the set of retarded cement characterized by contacting the retarded cement slurry with a solution containing an effective amount of a compatible accelerator. The compatible accelerator is selected from the group consisting of triethanolamine, diethanolamine and monoethanolamine. This may be employed in overwashing operations, treating retarded cement that is injected into open areas in the well or treating the set of a plug of retarded cement in a well to effect acceleration and/or viscosification of the cement. Also disclosed are specific uses.

Abstract: What is disclosed is a method of accelerating the set of a retarded cement. The cement may range from a drilling fluid containing dispersants or retarders that will slow down the set of the drilling fluid when cementitious fluid is added thereto, through overwashing, or treating a retarded primary or remedial cement that may have been injected into fractures or areas within a well to overwashing a plug or any volume of retarded cement that needs to be set in a well.The specific uses are discussed.

Abstract: Wellbores are cemented with a cement composition formed from drilling fluid occupying the wellbore by circulating a quantity of drilling fluid mixed with a cement material and a dispersant such as a sulfonated styrene copolymer with or without an organic acid into the wellbore to displace the drilling fluid and to continuously convert the drilling fluid into the cement composition. The cement composition may be recirculated through the space in the wellbore to completely evacuate any drilling fluid not converted to cement so as to minimize any faults in the cement composition occupying the wellbore. A preflush composition containing the dispersant and being rheologoically compatible with both the drilling fluid and the drilling fluid converted to cement slurry may be used as a displacement fluid.

Abstract: A squeeze silicate operation carried out through a coiled tubing for sealing upper perforations in a well casing to prevent flow of excess gas. A sodium silicate mixture is used which has a diverter material therein which rapidly builds a filter cake on the formation as the silicate is squeezed through the perforations. This filter cake forms a barrier which, in turn, prevents further flow of silicate into the formation. This effectively limits the depth of penetration of the silicate into the formation while still providing a good seal against flow through the squeezed perforations.

Abstract: A composition for use in cementing a string of pipe or other apparatus in the permafrost region of a borehole of a well which composition is a dry cementitious mix which can be mixed with water on site for pumping into the wellbore and consists essentially of from about 40 to about 60 weight percent aluminate cement, from about 20 to about 30 weight percent alkaline earth metal sulfate, from about 10 to about 30 weight percent of at least one halide salt of an alkali metal and/or alkaline earth metal, from about 3 to about 8 weight percent attapulgite, from about 0.1 to about 1 weight percent of a mixture of at least one water soluble hydroxy carboxylic acid and a sulfoalkylated lignin, and from about 0.1 to about 1 weight percent of an alkali metal citrate.

Abstract: A process for cementing a string of pipe in the permafrost region of a borehole of a well wherein aqueous drilling fluid actually used in drilling the wellbore in the permafrost region of a wellbore is employed. The drilling fluid contains or is adjusted to contain from about 2 to about 16 volume percent solids. Mixing with the drilling fluid (1) an additive selected from the group consisting of ligno-sulfonate, lignite, tannin, and mixtures thereof, (2) sufficient base to raise the pH of the drilling fluid into the range of from about 9 to about 12, and (3) cementitious material which will harden in from about 30 to about 40 hours at 40.degree. F. The resulting mixture is pumped into the permafrost region of a wellbore to be cemented and allowed to harden in the wellbore. There is also provided a process for treating an aqueous drilling fluid after it has been used in drilling the wellbore in permafrost, and a cementitious composition for cementing in a permafrost region of a wellbore.

Abstract: A process for cementing a string of pipe in the permafrost region of a borehole of a well wherein aqueous drilling fluid actually used in drilling the wellbore in the permafrost region of a wellbore is employed. The drilling fluid contains or is adjusted to contain from about 2 to about 16 volume percent solids. Mixing with the drilling fluid (1) an additive selected from the group consisting of lignosulfonate, lignite, tannin, and mixtures thereof, (2) sufficient base to raise the pH of the drilling fluid into the range of from about 9 to about 12, and (3) cementitious material which will harden in from about 30 to about 40 hours at 40.degree. F. The resulting mixture is pumped into the permafrost region of a wellbore to be cemented and allowed to harden in the wellbore. There is also provided a process for treating an aqueous drilling fluid after it has been used in drilling the wellbore in permafrost, and a cementitious composition for cementing in a permafrost region of a wellbore.