Abstract: Aqueous silicate solutions when admixed, intermingled or otherwise contacted with hydraulic cement slurries cause a very rapid gelation and accelerated setting of the hydraulic cement composition.It has now been discovered that this rapid gelation/accelerated setting phenomenon can be controlled and substantially delayed by incorporating a water soluble inorganic phosphate salt into an aqueous spacer fluid positioned between said silicate solution and said cement slurry as such materials are being sequentially injected into a subterranean formation.

Abstract: A process for plugging a porous formation in a well bore which comprises pumping a shear-thickening composition into drill pipe in the well under conditions of low shear to the point desired to be plugged at which point the composition is forced through the orifices of a drill bit at the end of the drill pipe and subjected to high shear of at least about 1,000 sec..sup.-1 which forms a paste in the well bore which plugs the porous formation. The shear-thickening composition comprises a water-in-oil emulsion having granular bentonite dispersed in the continuous oily phase, wherein the oily phase has a polyamine derivative surfactant dissolved therein, and the aqueous phase comprises an aqueous solution of a polyacrylamide and a polycarboxylic acid. This process may be used for plugging wells having depths in excess of 8,000 feet.

Abstract: A method for use in a cased well bore for placing cement in a vertical channel existing in the annulus between the casing and a well bore to seal off vertical channels in a prior cement job. In the method, where a vertical channel exists, the interval of the casing along the vertical channel is perforated circumferentially with the perforations at 15.degree. angles with respect to one another about a vertical axis. The perforations number can be as many as twenty-four over a six foot interval. The interval of the casing is located near a water bearing formation and between permeable zones. A known volume of cement is then pumped through the perforations and into the vertical channel to seal off the annulus between the casing and the well bore and excess cement is reverse circulated out of the well bore.

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 spacer comprising the water-in-oil emulsion portion of a shear-thickening well control fluid is used to separate drilling mud from the shear-thickening fluid in the drill pipe in the well bore to avoid premature thickening of the shear thickening fluid in the drill pipe. The shear-thickening well control fluid comprises a water-in-oil emulsion in which is dispersed granular particles of hydratable, water expandable clay.

Abstract: Drilling muds and waste fluids pumped to reserve pits and other on-site locations during drilling operations are recycled to the drilled well after the drilling operation is terminated and after the rig is removed from the site of the driling operations. The well is then plugged and abandoned without a rig on location.

Abstract: A cementing plug container for enclosing and injecting cementing plugs into the casing of an oil or gas well to reduce contamination on the interface between the well fluid and the cement, which container includes a shaped housing containing one or more plugs, a plug release mechanism for each plug, which release mechanism is characterized by an air cylinder and a cooperating plug support and release assembly which function to drop the plug or plugs from an upper interior segment of the housing into a lower interior segment or bore responsive to operation of the cylinder.

Abstract: A method and apparatus for placing a cement thermal packer is disclosed. The cementing collar of the present invention is assembled into a stream or hot fluid injection string and positioned along the well in the location where the packer is to be placed. Cement material for the packer is pumped down the injection string preceded by a separation plug and followed by a sealing plug. The separation plug seats in the cementing collar to cause the cement to be diverted to the annulus between the well casing and the injection string. The sealing plug seats in the collar while the placed cement sets to form the packer. The internals of the collar are sheared from the collar leaving a smooth injection string to the injection zone of the well.

Abstract: This is a method of cementing casing under tension. Internal pressure is applied to a casing string set in the borehole after cement has been placed between the casing and the borehole wall. This results in a lengthening of the string. Anchor means are next set in the well wall and pressure released prior to setting of the cement to leave the string with an additional tensile loading.

Abstract: This process comprises injecting into the formations a liquid organic mixture containing at least one polymerizable chemical compound and a catalyst. The organic mixture reacts with a limited amount of injected oxidizing gas to produce a solid compound which consolidates the formations without substantially reducing their permeability. The process is characterized by the combined use of a polyethylenic hydrocarbon and of a catalyst which comprises at least one element of the group consisting of zirconium, cerium, lanthanum and lanthanides and at least one element selected from the group formed by vanadium, manganese, cobalt and zinc.

Abstract: An apparatus and method are provided for holding and selectively mechanically releasing at least one plug device utilized in cementing a subterranean well, preferably a subsea well. The apparatus is securable and carryable on a manipulatable conduit, such as a drill string, communicating with the well. The apparatus comprises a cylindrical housing control head means positioned within the housing, shiftable in response to manipulation of the conduit from closed position, whereby the plug device is prevented from passing through the control head means, to open position, whereby the plug device is permitted to pass through the control head means. Means are provided for transferring at least one of longitudinal and rotational manipulation of the conduit to the control head means to selectively shift the control head means between closed and open positions. Subsequent to shifting of the control head means to open position, the plug device may be pumped through the control head means.

Abstract: Method and apparatus for cementing a casing in a borehole in two distinct stages by connecting the tool of the invention in series relationship respective to the casing and running the entire tool string downhole into the borehole. The tool which connects the upper and lower casing strings together includes a coupling member actuated by relative movement between the upper and lower strings. The tool always captures the upper and lower casing strings to one another and when the tool is unlatched and the upper casing string lifted, a lateral flow passageway is opened which enables cement to be pumped downhole to the tool and laterally directly into the borehole annulus.

Abstract: This invention relates to an improved method of cementing a casing string in a wellbore where the casing string will subsequently be heated by the injection of steam or by flowing of other hot fluids through the casing. The annulus between the wellbore and casing is at least partially filled with cement. A J-slot is positioned on the lower portion of the casing string. The lower end of a tubing string is provided with a stressing tool and lug, the lug being engageable with the J-slot and the tubing string is lowered into the casing and the lug is engaged with the J-slot. The tubing string is stressed until the cement in the annulus sets, thereby allowing the casing to be set under stress.

Abstract: A cementing head is disclosed, which is particularly designed for injecting an omega-type cementing plug into a well casing. Prior to cementing, the plug is retained in a housing. Located above the plug is a movable plunger, actuated by an operating fluid, such as hydraulic fluid. Below the plug is a control valve. When the valve is closed, it prevents any accidental downward movement of the plug into the well casing. Following injection of the cement slurry into the casing, the valve is opened, and the plunger is moved down to push the plug through the valve and beyond the cement inlet. A fluid such as water is passed through the cement inlet, under pressure, to push the plug down the casing behind the cement slurry.

Abstract: This invention relates to improved methods for cementing a casing in a wellbore to prevent poor cement jobs by twisting the casing string under tension or compression while circulating the cement in the annulus between the casing and wellbore in a conventional manner. A J-slot is positioned on the lower portion of the casing. The lower end of the tubing string is provided with a turning and stressing tool and a lug, the lug being engagable with the J-slot. The lug and J-slot are engaged and the lower portion of the casing is caused to twist and stress while cement is being circulated in the wellbore/casing annulus.

Abstract: Gelled aqueous fluids, solid blends for forming such fluids and methods of using the fluids for treating wells are provided. The gelled fluids are stable over a broad temperature range and are comprised of water, a first hydratable polymer for increasing the viscosity of the fluid to a desired level at temperatures within a first lower range and a second hydratable polymer for maintaining the viscosity of the fluid at temperature within a second higher range.

Abstract: Gelled aqueous fluids, solid blends for forming such fluids and methods of using the fluids for treating wells are provided. The gelled fluids are stable over a broad temperature range and are comprised of water, a first hydratable polymer for increasing the viscosity of the fluid to a desired level at temperatures within a first lower range and a second hydratable polymer for maintaining the viscosity of the fluid at temperatures within a second higher range.

Abstract: A workover fluid, a kill fluid, or completion fluid having potassium hydroxide dissolved therein is injected into a well bore penetrating and communicating with a subterranean sandstone formation containing water-sensitive fine particles, including clays, and invades the sandstone formation. Potassium hydroxide contacts and stabilizes the fine particles for a substantial period of time thereby substantially preventing formation permeability damage caused by encroachment of aqueous solutions having a distinct and undesired ionic constituency.

Abstract: A spacer composition for use in borehole cementing operations is disclosed which has excellent high temperature stability and compatability with cement slurries and drilling fluids. The spacer composition comprises a single phase water base system containing stabilized attapulgite clay.

Abstract: A cementing head apparatus is disclosed, for injecting a cementing plug into a well casing. The basic apparatus is made up of a head unit, manifold unit, and a tubular mandrel slidable within the manifold unit. Prior to injecting cement into the well casing, the cementing plug is mounted in the head unit and held in place by a shearable O-ring. During the cementing operation, part of the slurry stream flows through the head unit below the cementing plug, and part of the slurry collects in a "head" space above the plug. This arrangement provides an equal pressure force on both sides of the plug, to prevent premature injection of the plug into the well casing. When the desired amount of cement has been pumped, the mandrel is moved to a position which cuts off the cement flow and diverts another fluid only into the space above the plug. The resulting pressure above the plug shears the O-ring and allows the plug to follow the slurry down the well casing.

Abstract: Portions of a subterranean reservoir are temporarily plugged by injecting an aqueous liquid solution which contains nitrogen gas-generating reactants, a foaming surfactant and a pH controlling system arranged so that the solution remains relatively unreactive within the well but forms a relatively immobile foam within the pores or other openings within the reservoir formation.

Abstract: New application of microemulsions as buffers between the slurry and the cement in the cementation of oil wells. The microemulsions contain an amphoteric surfactant selected from the group of alkyl dimethyl betaines.

Abstract: A high stability, nondamaging spacer fluid is provided containing readily available weighting agents such as calcium carbonate and iron carbonate dispersed in water using a polymer viscosifier, a salt inhibitor, a primary sulfonated dispersant and a secondary fatty acid amide dispersion. Conventional high density weighting agents can also be used. The spacer fluid is stable over a temperature range of about 32.degree.-300.degree. F. for extended periods with densities ranging from 11 to 17.6 pounds per gallon.

Abstract: Fluid loss control for aqueous chemical washes of the type used in well cementing is provided by incorporating in the wash, an effective amount of an oil-soluble resin mixture comprising a particulate friable resin and a particulate pliable resin.

Abstract: An improved pump down wipe plug has at least one tooth protruding from its bottom surface capable of engaging, denting and penetrating the surface on which the plug comes in contact within the well. An improved process of cementing and drilling through a plug comprises inserting a pump down wipe plug having at least one tooth protruding from its bottom surface at the interface of wet cement and another fluid within the well, pumping the wet cement and the plug into position so that the tooth engages, dents and penetrates the surface below it, then when the cement has set, lowering a drill bit onto the plug and drilling the plug, the tooth or teeth retarding the tendency of the plug to rotate over the surface with which it is in contact thereby enhancing the drilling action of the drilling bit.

Abstract: A spacer composition for use in borehole cementing operations is disclosed which has excellent high temperature stability and compatability with cement slurries and drilling fluids. The spacer composition comprises a single phase water base system containing stabilized attapulgite clay.

Abstract: A cementing/plug drilling apparatus consists of a flat plate slightly less in maximum diameter than the pipe in which it will pass having at least one protrusion or tooth on both faces, the tooth being strong enough and sharp enough to engage, dent and penetrate a cement surface and a pump down wipe plug and, the plate having an opening on each face in fluid communication with each other through a fluid passage. An improved process of cementing and drilling through a pump down wipe plug comprises placing a plate having teeth on both faces between a pump down wipe plug and the surface that the bottom of the plug contacts during the cementing process, so that when the drill bit contacts the plug the teeth on the top of the plate engage and hold the plug and the teeth on the bottom of the plate engage and hold the surface on which they are in contact, thereby retarding the tendency of the plug to slide over the surface below it and enhancing the drilling action of the drill bit.

Abstract: An improved well shoe or collar has at least one tooth protruding from the top of the cement shoulder of the shoe or collar capable of engaging, denting and penetrating a pump down wipe plug and retarding the tendency of the plug to rotate when engaged by a drilling bit, thereby enhancing the drilling action of a drill bit on a pump down wipe plug. An improved process of cementing within a well and drilling through a plug comprises inserting a pump down wipe plug at the interface of a fluid and wet cement, pumping the plug down the well until it comes into contact with a shoulder of a shoe or collar having at least one protrusion extending from the surface of the shoulder capable of engaging, denting and penetrating the plug, subsequently after the cement has set, lowering a drill bit onto the top of the plug, the protrusion retarding the tendency of the plug to rotate with the rotating action of the drill bit and enhancing the drilling action of the bit.

Abstract: A new and improved apparatus and method for cementing casings in wells that is particularly advantageous for use in subsea wells. The cementing plug apparatus contains the cementing plugs which are released by a predetermined manipulation of the support string for the apparatus. Inadvertent or premature release of the cementing plug is prevented by a telescoping tubular stinger member which protects the cementing plugs from circulation flow.

Abstract: A high stability, nondamaging spacer fluid is provided containing readily available weighting agents such as calcium carbonate and iron carbonate dispersed in water using a polymer viscosifier, a salt inhibitor, a primary sulfonated dispersant and a secondary fatty acid amide dispersion. Conventional high density weighting agents can also be used. The spacer fluid is stable over a temperature range of about 32.degree.-300.degree. F for extended periods with densities ranging from 11 to 17.6 pounds per gallon.

Abstract: Fluid loss control for aqueous chemical washes of the type used in well cementing is provided by incorporating in the wash, an effective amount of the oil-soluble resin mixture described in U.S. Pat. No. 3,891,566.

Abstract: This specification discloses a method of cementing pipe in a well and discloses the use of a designed oil-wetting liquid and cement slurry for cementing pipe against evaporite sections penetrated by the well. The cement slurry is formulated from hydraulic cement, silica flour, ionization control agent, sodium chloride, weighting agent, dispersing and retarding agent, and water, and has a density within the range of about 15.8 to 21.0 pounds per gallon.

Abstract: The invention of this application is a dispersant system with various embodiments and subcombinations with exceptional dispersions including colloidal suspensions, aqueous hydrocarbon emulsions and emulsions with solid particulate additives dispersed therein. The basic dispersant system which makes the high stability, high weight dispersions or emulsions possible comprises an emulsifier composition containing a fatty acid amide, oleic acid, dimerized oleic acid and a particular type of surfactant dispersant. For certain applications the following optional components can be used: particulate filler or carrier; a hydrocarbon phase which can be either liquid or a colloidal solid; water soluble salts weighting agents; insoluble salts and conventional additives.

Abstract: In cementing a well with a thixotropic cement, such as with the portland cement/CaSO.sub.4.1/2H.sub.2 O/water slurry described in U.S. Pat. No. 3,563,313, an effective means for controlling fluid loss from the slurry is to precede the slurry with a fluid comprising water, a water soluble alkali metal compound capable of releasing a multivalent metal cation to react with the soluble silicate to form a pumpable gel, and a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to the fluid. Optionally, the fluid may contain one or more of: a chelating agent for polyvalent metal cations; a weighing material; a material to minimize lost circulation, and a salt to stabilize fresh water sensitive sandstones and shales, e.g., those having a high clay content.

Abstract: Methods of use of cementitious material within sub-surface formations are considerably enhanced by the use of sonic or energy carrying waves therewith; and by the further use of fluids containing a gas, foam, emulsion or solvent in combination therewith a cleansing and better penetration into the formation is achieved; thus effecting further benefits of the use of sonic or energy carrying waves with cementitious materials.

Abstract: A composition comprising water, a water soluble alkali metal silicate, and a water soluble metal compound capable of releasing a multivalent metal cation to react with the soluble silicate to form a pumpable gel is employed as a spacer for displacing a drilling mud from a borehole, particularly immediately preceding injection of a fluid, such as a cement slurry, containing compounds capable of detrimentally reacting with the mud. Optionally, the composition may contain one or more of: a water dispersible cellulose compound and an inert particulate which cooperate to provide fluid loss control; a chelating agent for polyvalent metal cations; a weighting material; a material to minimize lost circulation, and a salt to stabilize fresh water sensitive sandstones and shales.