Abstract: A method of evaluating a slurry mixing and placing process, such as a cementing process, for an oil or gas well comprises identifying and measuring specific subprocesses and parameters thereof, statistically summarizing the parameters and creating a database thereof, and analyzing the statistically summarized parameters to identify or compare against process capabilities to reduce variation, thereby improving specific job performance and the overall process.

Abstract: This invention relates to a dry, fine particle size hydraulic cement composition, which is directly dispersable in both water and a hydrocarbon liquid and to the use of said composition in oil well cementing operations and methods of terminating water flow in subterranean hydrocarbon producing formations.

Abstract: Improved methods of displacing a first liquid through a pipe with a second liquid while preventing the first and second liquids from mixing are provided. In accordance with the methods, a plug is formed in-situ in the pipe between the first and second liquids by injecting a self-thickening liquid therein and permitting the liquid to thicken. The formed plug and the first liquid are then displaced through the pipe with the second liquid. The methods are particularly suitable for carrying out subterranean well bore cementing operations wherein cement slurries are displaced through pipes disposed in well bores.

Abstract: Improved hydraulic cement compositions and methods for cementing wells drilled through low temperature earth formations wherein the cement is subjected to freeze-thaw cycling are provided. The compositions are comprised of a hydraulic cement, gypsum cement, fly ash, an alkali metal halide, water, and an alcohol freezing point depressant.

Abstract: Fine particle size cement compositions and methods of using such compositions for cementing in a subterranean zone penetrated by a well bore are provided. The compositions are basically comprised of a fine particle size hydraulic cement, a fine particle size pozzolanic material and sufficient water to form a pumpable slurry.

Abstract: Cement set retarding additives, set retarded hydraulic cement compositions and methods of using the cement compositions for cementing zones in wells are provided. The set retarding additives are copolymers containing monomer units formed from a first monomer of acrylic acid or methacrylic acid and a second monomer of acrylamide or a derivative of acrylamide.

Abstract: Improved liquid fluid loss reducing additives, well cement compositions containing the additives and methods of using the compositions are provided by this invention. The liquid fluid loss reducing additives are basically comprised of water, polyethylene imine, an alkali metal salt of alkylbenzene sulfonic acid and an alkali metal salt of naphthalene sulfonic acid condensed with formaldehyde.

Abstract: A method of cementing a wellbore which penetrates a subsurface gas-containing formation is provided whereby gas migration is reduced. The method features the use of an additive consisting of a tannin backbone having grafted thereto at least two different vinylamide derivatives. The additive causes the cement slurry employed in the method to exhibit a Zero Gel Time of greater than about one hour, a Transition Time of less than about one hour and controls fluid loss from the slurry.

Abstract: The present invention relates to methods of ensuring the maximum removal of drilling fluid from a well bore including gelled drilling fluid and filter cake deposited on the walls of the well bore prior to placing cement in the well bore between a pipe disposed therein and the walls thereof. The methods basically comprise circulating the drilling fluid through the well bore while monitoring the drilling fluid pressure, flow rate, viscosity, temperature and density. The circulating volume of drilling fluid in the well bore is then calculated and compared with the total volume available in the well bore to determine the volume of drilling fluid remaining on the walls of the well bore.

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: Set retarded ultra fine cement compositions which remain pumpable for a predictable period of time at temperatures up to about 240.degree. F. are provided. The compositions are basically comprised of an ultra fine hydraulic cement, sufficient water to form a pumpable slurry and a set retarder comprised of a methylenephosphonic acid derivative.

Abstract: A method of forming a gel in a subsurface formation is provided whereby a monomer is polymerized in the formation in the presence of a crosslinker by an initiator selected from azo compounds which are temperature activated over a range of temperatures. The method is particularly useful to substantially terminate or at least decrease the flow of water from a subterranean formation into a wellbore penetrating the formation.

Abstract: Set-activated cementitious compositions and methods of using such compositions in cementing subterranean zones penetrated by well bores are provided. The compositions are basically comprised of water, particulate condensed silica fume suspended in the water; a dispersing agent for facilitating the dispersal of the silica fume particles in the water and maintaining the particles in suspension therein, a set-activator and a set delaying additive for increasing the time in which the composition sets after the set-activator is combined therewith.

Abstract: The present invention provides methods of cementing a well with a cementing composition utilizing a portion of the drilling fluid used to drill the well as a component in the cementing composition. The methods basically comprise forming a set-activated cementing composition comprised of water, silica fume, a dispersing agent, a set-activator, a set delaying additive and a portion of the drilling fluid, introducing the resulting set-activated cementing composition into the well and permitting the cementing composition to set into a hard mass therein.

Abstract: The present invention provides a method of preventing gas migration during primary well cementing. The method basically comprises the steps of displacing a cement slurry into the annulus between a string of pipe to be cemented in a well bore and the walls of the well bore, determining the initial surface pressure in the pipe after the cement slurry is placed in the annulus, displacing additional cement slurry into the annulus as is necessary to make up for losses in the surface pressure due to cement slurry gel strength development and volume reduction whereby the surface pressure is maintained substantially equal to the initial surface pressure until the cement slurry develops a predetermined gel strength sufficient by itself to prevent gas migration, and then allowing the cement slurry to set into a hard impermeable mass in the annulus.

Abstract: Methods and apparatus for cementing a pipe in a well bore penetrating one or more subterranean gas-containing formations without incurring substantial gas inflow are provided. The methods basically comprise the steps of placing a hydraulic cement slurry in the annulus between the pipe and the well bore, and moving the pipe during the transition period of the slurry. The moving of the pipe maintains the hydrostatic pressure exerted by the slurry on the gas-containing formations and prevents gas flow into the slurry and the well bore. The movement of the pipe is stopped when the slurry develops sufficient gel strength to substantially block gas flow through the well bore.

Abstract: Methods of measuring the erodability of drilling fluid deposits and the shear stress required to remove drilling fluid deposits formed on the walls of a well bore are provided. The methods basically include introducing a drilling fluid into a test apparatus which simulates a permeable section of a well bore. Drilling fluid deposits are caused to be formed on the walls of the permeable section, and the drilling fluid is circulated through the permeable section at progressively increasing flow rates to determine the pressure drop below which no appreciable erosion of the drilling fluid deposits takes place which corresponds to the minimum shear stress required to erode the deposits. The erodability of the drilling fluid which is inversely proportioned to the minimum shear stress can also be determined. Apparatus for carrying out the methods is also provided.

Abstract: Low density well cement compositions which set into hard substantially impermeable masses, but which are removable by dissolution in acid, and methods of utilizing such compositions for forming removable cement plugs or seals in subterranean zones are provided. The compositions are comprised of pumpable foamed slurries of magnesium oxychloride cement.

Abstract: Methods of drilling a well bore utilizing a circulating drilling fluid and subsequently disposing of the drilling fluid by converting it to a cementitious composition are provided. The methods basically comprise the steps of forming the drilling fluid with an aqueous suspension of condensed silica fume as a component thereof, drilling a well bore using the drilling fluid, activating the drilling fluid whereby it will subsequently set into a hard cementitious mass and placing the set activated drilling fluid in one or more desired locations whereby it sets therein.

Abstract: A method of forming in a desired location in a well bore a dual-state composite of a hardened hydraulic cement and a solid rubber which features the use of a composition consisting essentially of a mixture of a slurry of a hydraulic cement and a vulcanizable rubber latex.