Abstract: A treatment fluid composition for treating a subterranean formation penetrated by a wellbore is formed from an aqueous fluid, a hydratable polymer and a water-soluble, non-symmetrical, inorganic peroxide breaking agent, which is capable of undergoing heterolytical cleavage. A method of treating a subterranean formation penetrated by a wellbore may also be performed by forming a treatment fluid from an aqueous hydrated polymer solution. This is combined with a water-soluble, non-symmetrical, heterolytically cleavable inorganic peroxide breaking agent. The treating fluid is introduced into the formation. An optional crosslinking agent capable of crosslinking the polymer may also be included.

Abstract: Methods of incorporating a chemical breaker onto a proppant that will permit release of the breaker after the proppant has been placed in a hydraulic fracture are provided. The methods utilize a chemical breaker coated on the surface of a non-porous proppant grain or placed in the pore space of a porous proppant grain and secondarily coated with an outer layer which can be tailored to delay the release of the breaker.

Abstract: Viscoelastic surfactant (VES) based fluid systems for zone isolation and flow control are effective in water and/or gas shutoff applications. The fluid systems may include brine, a viscosity enhancer, as well as the VES, and optionally a stabilizer for high temperature applications. The stabilizer may be an alkali earth metal oxide, alkali earth metal hydroxide, alkali metal oxide, alkali metal hydroxide, Al2O3, and mixtures thereof. The viscosity enhancer may include pyroelectric particles, piezoelectric particles, and mixtures thereof. The fluid system is easy to pump into the formation, and after pumping, the fluid system will generate very high viscosities to prevent the VES fluid from flowing back to stop undesirable water and/or gas production.

Abstract: It has been discovered that carbonate powders and bicarbonate powders are useful to increase the pH and corrosion resistance of high-density brines, such as zinc bromide brines, without significantly reducing their densities. The carbonates and/or bicarbonates should be water-soluble and may be sodium, potassium, magnesium and/or ammonium carbonates and/or bicarbonates and the like. The carbonates and/or bicarbonates are easily added in powder or other finely divided solid form and are completely dissolved in the brine prior to pumping the brine into a subterranean formation.

Abstract: Sintered, spherical composite pellets or particles comprising alumina fines, at least one of clay and bauxite and optionally a sintering aid, are described, along with a process for their manufacture. The use of such pellets in hydraulic fracturing of subterranean formations and in grinding is also described.

Abstract: An aqueous, viscoelastic fluid gelled with a viscoelastic surfactant (VES) may suspend solids such as proppants, gravel, drilling debris, waste solids and the like with an effective amount of a nano-sized additive including, but not necessarily limited to alkali earth metal oxides, alkali earth metal hydroxides, alkali metal oxides, alkali metal hydroxides, transition metal oxides, transition metal hydroxides, post-transition metal oxides, and post-transition metal hydroxides. The additives may also reduce the amount of VES required to maintain a given viscosity. These viscoelastic surfactant gelled aqueous fluids may be used as treatment fluids for subterranean hydrocarbon formations, such as in hydraulic fracturing, gravel packing and the like. The magnesium oxide, zinc oxide or other nanometer scale-sized additives are at a scale that may provide unique particle charges that use chemisorption, crosslinking and/or other chemistries to associate the micelles and suspend the solids.

Abstract: Alkaline earth metal compounds may be fluid loss control (FLC) agents for viscoelastic surfactant (VES) fluids used for fluid loss control pills, lost circulation material pills and kill pills in hydrocarbon recovery operations. The FLC agents may include, but not be limited to oxides and hydroxides of alkaline earth metal, and in one case magnesium oxide where the particle size of the magnesium oxide is between 1 nanometer to 0.4 millimeter. The FLC agent may alternatively be transition metal oxides and/or transition metal hydroxides. The FLC agent appears to associate with the VES micelles and together form a novel pseudo-filter cake quasi-crosslinked viscous fluid layer that limits further VES fluid flow into the porous media. The FLC agent solid particles may be added along with VES fluids. The pills may also contain internal breakers to reduce the viscosity thereof so that the components of the pill may be recovered.

Abstract: A well treating fluid useful in slickwater fracturing processes contains polyacrylamide friction reducer and a viscosity breaker capable of reducing the viscosity of the well treating fluid to about the viscosity of water at ambient temperatures of typical underground formations. The viscosity breaker is selected from the group consisting of hydrogen peroxide, calcium peroxide, magnesium peroxide, and zinc peroxide and is present in an amount above about 0.002% by weight.

Abstract: Treatment fluids that may comprise an aqueous fluid, a gelling agent, and a zirconium triisopropylamine crosslinking agent are provided. Also provided are crosslinking agents that may comprise a zirconium triisopropylamine crosslinking agent, and a zirconium IV-containing crosslinking agent.

Abstract: A method of treating a subterranean formation is provided, the method may comprise providing a fluid comprising an aqueous fluid, a gelling agent, and a zirconium triisopropylamine crosslinking agent; and introducing the fluid into a well bore that penetrates the subterranean formation. Also provided are methods of fracturing a subterranean formation.

Abstract: The present invention relates to methods of chemically generating gas in aqueous fluids utilized in the drilling and completion of wells such as drilling fluids, spacer fluids, and aqueous acid solutions. In one embodiment, the invention provides a method of preventing the formation of fractures in a subterranean formation during a drilling operation. In other embodiments, the present invention provides methods of separating a first fluid and a second fluid in a subterranean formation; methods of forming lightweight well treatment fluids; methods of enhancing the permeability of a subterranean zone; lightweight drilling fluids; lightweight spacer fluids; foamed aqueous acidic well treatment fluids; and methods of making foamed aqueous and aqueous acidic well treatment fluids.

Abstract: A viscous aqueous high density well treatment fluid composition stable at high temperature containing a surfactant and inorganic salts is described. Methods of preparing the fluid and increasing the stability and viscosity of the fluid are given. The fluid is useful for wellbore cleanout, hydraulic fracturing, gravel packing, completion, acid diversion, lost circulation reduction, well killing, cementing, selective water shutoff, and fracture fluid diversion.

Abstract: A process to substantially reduce fluid loss in which an appropriate amount of a non-flowing gel of sufficient strength is emplaced to substantially eliminate or reduce loss of the drilling fluid. The gel composition of the process includes: (1) a non-cellulose containing copolymer having vinyl phosphonate co-monomer units which may be incorporated into the polymer by copolymerization with the other co-monomer(s) comprising the polymer or by grafting upon an already existing polymer or co-polymer, (2) a crosslinking agent active upon the phosphonate groups, (3) a crosslinking initiator comprising a Bronsted Lowry base or Lewis base and (4) an aqueous solvent.

Abstract: Methods and compositions for reducing the permeabilities of subterranean formations or zones are provided. The methods of the invention are basically comprised of introducing an aqueous composition into the formation or zone comprised of water, a water soluble organic polymer, an organic gelling agent for cross-linking the organic polymer and a gel retarder comprised of a chemical compound that hydrolyzes or thermolyzes to produce one or more acids in the composition and then allowing the aqueous composition to form a cross-linked gel in the formation or zone.

Abstract: Methods are provided for removing filter cake containing a bridging agent soluble in a carboxylic acid salt from a formation fluids producing zone penetrated by a well bore. The methods basically comprise the steps of introducing in an aqueous carrier liquid a carboxylic acid ester and a base for slowly catalyzing the hydrolysis of the ester and forming a carboxylic acid salt therewith into the producing zone, and allowing the base to catalyze the hydrolysis of the carboxylic acid ester to form the carboxylic acid salt so that the carboxylic acid salt dissolves the bridging agent and the filter cake is removed.

Abstract: Viscous well treating fluids and methods of treating subterranean zones penetrated by well bores are provided. The viscous fluids are basically comprised of water, a gelling agent and a delayed viscosity breaker comprising pentanedione peroxide.

Abstract: It has been discovered that carbonate powders and bicarbonate powders are useful to increase the pH and corrosion resistance of high-density brines, such as zinc bromide brines, without significantly reducing their densities. The carbonates and/or bicarbonates should be water-soluble and may be sodium, potassium, magnesium and/or ammonium carbonates and/or bicarbonates and the like. The carbonates and/or bicarbonates are easily added in powder or other finely divided solid form.

Abstract: A wellbore fluid including a peroxide degradable polymer and an encapsulated peroxide source. The peroxide degradable polymer may be a polysaccharide. The peroxide source may include an inorganic peroxide, including zinc and alkaline earth metal peroxides, such as magnesium peroxide. The encapsulating material may be a polymer, including enteric polymers. The release of peroxide, from peroxide sources generally, can be controlled by means of pH such that peroxide source can be activated, and peroxide released, by a change in pH. In a wellbore, this pH change can be effected by using produced fluids to lower the pH of a more basic wellbore fluid.

Abstract: Well drilling and servicing fluids for use in producing formations and methods of removing filter cake therefrom are provided. The methods basically comprise using a drilling or servicing fluid comprised of water, a density increasing water soluble salt, a fluid loss control agent, a hydratable polymer solid suspending agent and a particulate solid bridging agent which is soluble in an aqueous ammonium salt solution. Thereafter, the filter cake deposited by the drilling or servicing fluid is contacted with a clean-up solution comprised of water and an ammonium salt for a period of time such that the bridging agent is dissolved thereby.

Abstract: Compositions and methods for determining the source of treatment fluids being produced from a production formation having multiple zones by introducing a treatment composition having a tracking material into a zone in the subterranean formation, and detecting the tracking material in treatment composition that flows back from the subterranean formation.

Abstract: A method for removing filter cake from a subterranean borehole comprising drilling the borehole with a drilling fluid that includes additives to form a filter cake having an oxidation-degradable component, preferably a polysaccharide. The filter cake is contacted with a clear brine containing a mixture of a persulfate salt in a variable density brine to degrade the polymers within the filter cake. The persulfate mixture breaks down the filter cake in well bores having temperatures ranging from about 65° F. to 165° F. Concentration of the persulfate sets the pace of the reaction.

Abstract: Compositions and methods for tracking the transport of particulate solids during the production of hydrocarbons from a subterranean formation.

Abstract: Anti-corrosion additives and processes useful for oil drilling and similar applications. Heteropoly complex anions of transitional metal elements can be added to an oil well drilling solution which includes a metallic salt, optionally in combination with transition metal compounds or compounds of the metallic elements of Groups IIIa to VIa of the Periodic Table of Elements, to minimize corrosion of systems within which the solution is used.

Abstract: Disclosed is a method of increasing the low shear rate viscosity and the shear thinning index of aqueous fluids containing a divalent cation salt, a crosslinked amylopectin starch which functions as both a viscosifier/suspending agent and as a fluid loss control additive, and a bridging agent, the fluids resulting from the method, and the use of the fluids in drilling a well, wherein the bridging agent is a sized particulate magnesium carbonate or a mixture of sized magnesium carbonate and sized calcium carbonate. The median (D50) particle size of the magnesium carbonate is from about 2 &mgr;m to about 10 &mgr;m. The weight ratio of calcium carbonate to magnesium carbonate is from about 70/30 to about 0/100.

Abstract: A well service fluid and method using same for brine-sensitive formations is disclosed. The fluid is an invert oil emulsion comprising heavy, solids-free brine, an oil or synthetic, and sufficient emulsifier to create the emulsion. The fluid has particular applicability in gravel packing a horizontal well.

Abstract: The invention provides clay-free, preferably biopolymer free, well drilling and servicing fluids comprising an aqueous divalent cation-containig water soluble salt, a bridging agent, and a pre-gelatinized crosslinked amylopectin starch suspending agent and fluid loss control additive. The concentration of the starch derivative is sufficient to provide the fluid with the following charactristics: (a) a low shear rate viscosity less than about 10,000 centipoise; (b) a high shear rate viscosity at 511 sec−1 in the range from about 15 to about 70 centipoise measured at 120° F.; (c) a fluid loss less than about 10 milliliters as measured at 185° F. and 250 psi differential pressure across a 5 micron disk for 30 minutes; and (d) anti-settling characteristics as exhibited upon static aging the fluid for 16 hours at 185° F.

Abstract: Methods and compositions for preventing precipitation of iron compounds during acid treatments of wells by catalyzing the rate of iron reduction during such treatments. Reduction of ferric ions is accelerated utilizing co-catalytic amounts of antimony ions in combination with other materials to minimize precipitation and other complications which result from iron compounds during acid treatments. Such other materials may include co-catalytic amounts of copper ions and optional iodide ions; as well as at least one of phosphinic acid, salt of phosphinic acid, or a mixture thereof.

Abstract: The invention relates to iron control in an acid medium for forestalling the formation of precipitates known as “sludges” (asphaltic products) in contact with certain crude oils. Use is made of compounds comprising a mercaptan function, and, in combination, a selection of catalysts. Application to acid treatments for oil, gas, water, geothermal and analogous wells, as well as to industrial cleaning.

Abstract: The invention provides clay-free, preferably biopolymer free, well drilling and servicing fluids comprising an aqueous divalent cation-containing water soluble salt, a bridging agent, and a pre-gelatinized crosslinked amylopectin starch suspending agent and fluid loss control additive. The concentration of the starch derivative is sufficient to provide the fluid with the following charactersitics: (a) a low shear rate viscosity less than about 10,000 centipoise; (b) a high shear rate viscosity at 511 sec−1 in the range from about 15 to about 70 centipoise measured at 120° F.; (c) a fluid loss less than about 10 milliliters as measured at 185° F. and 250 psi differential pressure across a 5 micron disk for 30 minutes; and (d) anti-settling characteristics as exhibited upon static aging the fluid for 16 hours at 185° F.

Abstract: A composition and method for acidizing a formation in the presence of ferric ion, free sulfur and/or sulfides is disclosed. The composition employs a ferric ion reducing agent and a sulfide reactant separately or in combination. The ferric ion reducing agent is a thioalkyl acid. The sulfide reactant compounds include &agr;-diketones and saturated and &agr;-unsaturated cyclic ketones. In another aspect, the reducing activity of the thioalkyl acid is accelerated by the presence of a catalytic quantity of a compound or mixture of compounds which yield in acid solution cuprous ion, cupric ion or combinations thereof with iodide ion.

Abstract: Methods and compositions for reducing the permeabilities of subterranean zones are provided. The methods of the invention are basically comprised of introducing an aqueous composition comprised of a chelated organic gelling agent and a copolymer of an ethylenically unsaturated polar monomer and an ethylenically unsaturated ester or a terpolymer or tetrapolymer of an ethylenically unsaturated polar monomer, an ethylenically unsaturated ester and a monomer selected from AMPS® and/or N-vinylpyrrolidone into the zone and then allowing the aqueous composition to form a cross-linked gel in the zone.

Abstract: A method for removing filtercake from a subterranean borehole comprising drilling the borehole with a drilling fluid that includes additives to form a filtercake having an oxidation-degradable component, preferably a polysaccharide. The filtercake is contacted with a clear brine containing bromine or bromate generating agents to degrade the polymers within the filtercake. The brine contains bromide salts and an oxidant capable of delayed oxidation of the bromide to bromine at downhole conditions.

Abstract: Improved high temperature epoxy resin compositions, additives and methods are provided. A hardenable epoxy resin composition of the present invention is comprised of an epoxy resin, an aromatic diluent, a hardening agent and a hardening retarder for delaying the hardening of the epoxy composition at high temperatures comprised of a liquid which is soluble in the epoxy resin composition having a halide salt dissolved therein.

Abstract: A solubilized iron reducing additive for acid solutions and method for preparing such a solubilized iron reducing additive. The additive includes an iron reducing agent reactable with ferric ions to produce therefrom ferrous ions and a spent iron reducing compound. The spent iron reducing compound is incapable of reacting with ferric ions to produce ferrous ions. So that the reducing process may continue, a regenerating agent is mixed with the iron reducing agent, the regenerating agent being reactable with the spent iron reducing compound for regenerating the spent iron reducing compound back to the iron reducing agent state. Because it has been found that the iron reducing agent and regenerating agent readily fall out of suspension as precipitates after short periods of time after mixing, a solubility facilitator is admixed thereto for facilitating establishment of the solubilized additive for acid solutions.

Abstract: The invention provides alkaline water base well drilling and servicing fluids which deposit an easily degradable and removable filter cake on the sides of a borehole during well drilling and servicing operations. The fluids contain one or more polysaccharide polymers, sized bridging particles, and a peroxide selected from the group consisting of alkaline earth metal peroxides, zinc peroxide, and mixtures thereof. The fluids deposit a filter cake containing the peroxide.

Abstract: Disclosed are low solids, high density fluids useful as drilling, workover, and completion fluids and the like in oil and gas well operations. The fluids comprise a brine having dissolved therein a zinc salt such as zinc bromide, and optionally one or more additional water soluble salts, a viscosifier which is a high surface area silica, a biopolymer viscosifier, a fluid loss control additive which is preferably a starch derivative, zinc carbonate, and, optionally, an alkaline buffer, a polar additive, and a bridging agent.It has been found that zinc carbonate will increase the low shear rate viscosity of fluids containing a zinc salt dissolved therein. Additionally, the combination of zinc carbonate and zinc oxide as the alkaline buffer provides fluids having increased thermal stability as indicated by the low shear rate viscosity of the fluids.

Abstract: Aqueous compositions for use as drilling fluids or as workover fluids/completion fluids comprise calcium chloride and calcium nitrate. The compositions have a density of at least 1.35 g cm.sup.-3 and the weight ratio of calcium chloride to calcium nitrate is 5:95 to 95:5. The compositions may be formulated so as to have low crystallisation temperatures. Additional densifying agents such as calcium bromide and/or zinc bromide may also be included.

Abstract: A composition of matter for matrix conformance formed from an aqueous solution of an alginate polysaccharide and a method of forming an alginate polysaccharide gel. A Group IIA cation, Fe.sup.2+, Fe.sup.3+, Al.sup.3+, Mn.sup.2 +, Zn.sup.2+, a dialdehyde, or a diamine may be used to crosslink the resulting alginate gel. The gel may also comprise a modifier, such as a polyvinyl alcohol, a polycarboxylic acid, or a polyacrylamide. The rate and extent of crosslinking are controlled by varying the alginate molecular weight, the alginate concentration, or the type and concentration of crosslinker, or by adding a sequestering agent such as EDTA or citrate.

Abstract: A process for increasing the viscosity of a zinc compound-containing brine which can be used for workover and completion fluids in oil field operations is provided. The process comprises contacting the zinc compound-containing brine with a polymer which comprises repeating units derived from an unsaturated amide having the formula of CH.sub.2 .dbd.CH--R--C(O)--NH.sub.2 and a vinylic sulfur compound selected from the group consisting of CH.sub.2 .dbd.CH--R'--SO.sub.3 M, CH.sub.2 .dbd.CH--R"--C(O)--N(H)--R"'--SO.sub.2 M, and mixtures thereof; wherein M is selected from the group consisting of hydrogen, an alkali metal, and combinations thereof; and R is selected from the group consisting of hydrogen, a hydrocarbyl radical having from 1 to about 20 carbon atoms, and combinations thereof.

Abstract: A method and combination of materials for freeing stuck pipe involves first the spotting of a clear brine, preferably calcium chloride, calcium bromide or zinc bromide, or mixtures thereof, for a given period of time, preferably at least about 8 hours, in the stuck region of the pipe, followed by the spotting of a spotting agent selected from wetting agents, surfactants, lubricants, or mixtures thereof, in the stuck region of the pipe.