Abstract: An apparatus is disclosed for fracing and gravel packing a subterranean well. The apparatus includes a packer and a liner assembly with a setting tool and crossover assembly. Abrasive wear in the wall of the crossover assembly is abated by providing for conversion of turbulent fluid flow of the fracing or gravel packing fluid into laminar flow immediate the opening within the crossover tool between the interior of the crossover tool and the exterior thereof. An isolator is also provided within the crossover such that when it is opened, a valve head is completely shielded and carried within the device whereby further cutting of the crossover tool wall by fluid flow is greatly abated.

Abstract: The present invention is directed to new enzyme breakers for breaking fracturing fluids or blocking gels, wherein the enzyme breakers only have activity above a selected temperature, i.e., no activity below the selected temperature or only active in a narrow temperature range. The present invention is preferably specifically directed to hemicellulase enzyme breakers only having activity above 100.degree. F., 150.degree. F., 200.degree. F., or 250.degree. F. and the method of making and use thereof.

Abstract: A method of fracturing a subterranean formation in a well bore is shown in which a gellable fracturing fluid is first formed by blending together an aqueous fluid, a hydratable polymer, a suitable cross-linking agent for cross-linking the hydratable polymer to form a polymer gel and an encapsulated enzyme breaker. The cross-linked polymer gel is pumped into the well bore under sufficient pressure to fracture the surrounding formation. The encapsulated enzyme breaker is allowed to degrade the cross-linked polymer with time to reduce the viscosity of the fluid so that the fluid can be pumped from the formation back to the well surface. The particular enzyme breaker uses open cellular encapsulation to protect and delay the action of the enzyme.

Abstract: A composite fracturing fluid consisting of a mixture of carbon dioxide liquid, nitrogen gas and an aqueous media. Nitrogen is present in the mixture in an amount from about 1.25 to about 15 parts by volume to about 1 part by volume carbon dioxide, and nitrogen and carbon dioxide are present in the mixture from about 1 to about 24 parts by volume to about 1 part by volume water at bottom hole conditions in a subterranean formation. Thickening agents, gelling agents, foaming agents, surfactants, cross-linking agents, proppants, and other additives may be mixed with the fluid to achieve fluid properties desired for various types of subterranean formations.

Abstract: An apparatus and method are provided for determining the relative density of a flowing fluid based upon the ratio of the fluid's flow rate before and after a material is added. Using analog or digital components, two signals are generated, representing the two flow rates, a first ratio of the two signals is derived, the ratio is compared to a constant, a second ratio of a second constant to the first ratio is derived, and the result of the comparing step is multiplied by the second ratio to generate a density signal representative of the relative density of the fluid after the material has been added.

Abstract: A method for mixing cement with water is provided. Dry cement is first slurried in oil. The slurry is easily metered and mixed with water to obtain a cement/water/oil slurry having the desired density. Cement/water/oil slurries thus produced can be used in all applications and have properties, when cured, comparable to cements not containing oil. The method allows precision metering of the cement and therefore precision control over the density of the final cement slurry.

Abstract: A stabilized ammonium polysulfide solution comprising an aqueous solution of ammonium polysulfide and a stabilizing amount of a water soluble, stabilizing compound that can be an azacyclic compound, a compound having the formula R--O--(C.sub.n H.sub.2n)NH.sub.2 or a compound having the formula (CH.sub.3).sub.2 NR.sub.1, the pH of the composition being from 7 to 14, the stabilized composition being useful in controlling the cyanide concentration in aqueous streams.

Abstract: The present invention relates to the use of oximes as thermal decomposition reduction additive for gels used in oil field drilling fluids, fluids used as proppant carriers and fluids used during well completion and workover.

Abstract: This invention record describes a method for fracturing subterranean formations utilizing a foam comprising a water-based fracturing fluid comprised of water or brine or water and brine or brine and alcohol and a polymer slurry in diesel oil. Preferably, the polymer is comprised of a guar polymer and diesel oil in equal amounts. The foamer component preferably is comprised of cocobetaine, a solvent, an alpha-olefin sulfonate and water. The energizing phase component is comprised of carbon dioxide, nitrogen or a mixture of carbon dioxide and nitrogen.

Abstract: A method for hydraulic fracturing using crosslinked guar polymers wherein the high temperature viscosity and thermal stability of said polymers is maximized by adjusting the pH such that the cationic charge density of the polymer is at its maximum. These maximums occur for guar at a pH of 10.5 and for carboxymethylhydroxypropyl guar at a pH of 10.7.

Abstract: A clay control additive for cement composition of the general formula: ##STR1## wherein the R groups are selected from a C.sub.1 to C.sub.4 substituted alkyl.

Abstract: The invention is directed toward a breaker system for breaking fluids used to fracture subterranean formations. Specifically, the invention relates to a breaker system comprised of an enzyme component and a pH component. The enzyme component is active at only certain pH levels and, at those levels, is able to break the fluid. The fluid is not initially at a pH level at which the enzyme is active. The pH component controllably adjusts the pH of the fluid to a level such that the enzyme becomes active and can break the fluid at the desired time after the formation has been fractured.

Abstract: Disclosed are cementing compositions and methods of using wherein the cementing compositions comprise: (a) aqueous solution, (b) hydraulic cement, (c) a N-vinylpyrrolidone-acrylamide random copolymer, and (d) a sulfonate containing cement dispersant. The copolymer is present in the composition in an amount of from 0.05 to 5.0 weight percent based on the weight of dry cement. Use of the present invention as a fluid loss additive will result in significant reductions in water loss rate.

Abstract: An aqueous gel comprising an aqueous fluid containing a polymeric gelling agent, a buffer, an aluminum-based crosslinking composition and a xanthan containing retardant composition. The gel is useful for fracturing and carrying propping agents within subterranean formations.

Abstract: A multiple acting lock is provided which prevents premature setting of the packer of a gravel pack tool by the setting piston of a setting tool. The lock comprises a locking cylinder which when in the locked position rotationally locks the setting tool with the gravel pack tool thereby allowing rotation of the tool during tripping to facilitate working the tool past tight spots. The lock also longitudinally locks the setting sleeve of the gravel pack tool to prevent premature setting of the packer of the gravel pack tool. The locking mechanism of the setting sleeve comprises keys located in keyholes and a sleeve inside the setting sleeve which protrude and engage with the setting sleeve. The locking cylinder when in a locked position covers the inside of the keyholes retaining the keys in engagement with the setting sleeve. When the locking cylinder is hydraulically moved to the unlocked position the keys slide inward out of the keyholes and out of engagement with the setting sleeve.

Abstract: Encapsulations comprised of a breaker enclosed within a membrane are utilized to break fluids used to fracture subterranean formations. The membrane of the encapsulation is permeable to at least one fluid in the subterranean formation or injected with the breaker such that the breaker diffuses through the membrane into the fracturing fluid. Thus, controlled amounts of breaker are released into the fracturing fluid.

Abstract: A fluid loss control additive for use in well cementing operations wherein the downhole temperature ranges from about 200.degree. to about 500.degree. F. The additive is a polymer comprised of 2-acrylamido-2-methyl propane-3-sulphonic acid, N-vinyl,-N-methylacetamide, in the presence or absence of arcylamide. This additive is also effective in saltwater cement slurries.

Abstract: A breaker system for treating subterranean formations and method of use wherein the breaker comprises (i) a diethanolamine and (ii) at least one oxidizing compound selected from the group of ammonium persulfate, alkali metal persulfates, percarbonates and perborates and the breaker system comprises borate crosslinked gels in the ambient temperature range.

Abstract: This invention involves cementing compositions for the oil industry and their use in cementing wells. More specifically, this invention involves the control of the gas migration or gas channeling phenomenon that occurs during the setting of a cement slurry. A cementing composition, capable of inhibiting gas channeling, comprised of gaseous fluid, hydraulic cement, and a gas channeling inhibiting additive comprised of a copolymer 2-acrylamido-2 methylpropane-3-sulphonic acid, N-vinylacylamide and acrylamide, is provided.

Abstract: A treatment fluid additive and method for treatment of subterranean formations to minimize formation permeability damage as a result of formation contact by the treatment fluid, wherein the fluid treatment additive is a formation control additive of the general formula: ##STR1## wherein R is independently a C.sub.1 to C.sub.4 alkyl, halogen and/or hydroxyl substituted alkyl and at least one R is a C.sub.1 to C.sub.4 halogen or hyroxyl substituted alkyl, and X.sup.- is selected from the group consisting of chloride, fluoride, bromide, iodide, nitrate, nitrite hydroxide, and sulfate.