Abstract: A system and method to model and analyze the mixing energies of high-yielding non-Newtonian fluids to prevent chemical lost circulation. Laboratory tests are performed under varying conditions from which data on the mixing energies needed to optimize the use of high-yielding non-Newtonian fluids to prevent lost circulation is obtained. This data is then applied to a non-linear mathematical modeling system that is capable of scaling the data to give a dimensionless value. This value can be combined with historic information to predict optimal flow rates and mixtures to prevent chemical lost circulation. This data may be verified by means of simulation, lab testing, or application to a full-size well.

Abstract: Methods of improving the pressure containment integrity of subterranean well bores are provided. The methods include pumping a fracture sealing composition into the well bore that rapidly converts into a high friction pressure sealing composition which is impermeable, deformable, extremely viscous and does not bond to the faces of fractures. Thereafter, the fracture sealing composition is squeezed into one or more natural fractures or into one or more new fractures formed in the well bore to thereby increase the pressure containment integrity of the well bore. The methods also include the prediction of the expected increase in pressure containment integrity.

Abstract: The invention discloses an additive for weighted aqueous slurries to reduce lost circulation during well drilling operations, a method of preparing the additive, and a method of reducing lost circulation utilizing the additive. The additive comprises a hardenable alkaline composition comprising mixtures of diatomaceous earth, finely ground paper, a hydrophobic liquid, micronized cellulose and lime. The hydrophobic liquid decreases the time required to prepare the weighted aqueous slurries, i.e., pills, containing the additive.

Abstract: A lost circulation composition, that comprises a first portion of particles having a weight mean particle size of less than about 20 microns, a second portion of particles having a weight mean particle size in the range of from about 25 microns to about 400 microns, and a third portion of particles having a weight mean particle size in the range of from about 450 microns to about 1,500 microns, wherein the lost circulation composition has a multimodal particle size distribution, is provided, wherein resilient particles, particles comprising a thermoset polymer laminate, or a combination thereof are present in the lost circulation composition in an amount of at least about 20% by weight of the lost circulation composition, is provided. Drilling fluids, methods of controlling lost circulation, and methods of increasing an effective fracture gradient while drilling also are provided.

Abstract: An arrangement and a method to control and regulate the bottom hole pressure in a well during subsea drilling at deep waters: The method involves adjustment of a liquid/gas interface level in a drilling riser up or down. The arrangement comprises a high pressure drilling riser and a surface BOP at the upper end of the drilling riser. The surface BOP havs a gas bleeding outlet. The riser also comprises a BOP, with a by-pass line. The drilling riser has an outlet at a depth below the water surface, and the outlet is connected to a pumping system with a flow return conduit running back to a drilling vessel/platform.

Abstract: A method for pressure- and flow-prevetive fixing of well pipes, preferably liners and casings (14, 54, 60, 66) in a well when drilling the well, wherein the method also may be used in a completed well in order to place a pressure- and flow-preventive barrier in an annulus (16) surrounded by at least one leaking well pipe. The method comprises the use of granular particles of unconsolidated matter which, by means of their particle sorting, are arranged with a suitably small permeability, and wherein the particles of unconsolidated matter thereafter are mixed with water and potential other additives to become a fluidised mixture of unconsolidated matter (22) subsequently being placed, preferably by pumping, as a pressure- and flow-preventive barrier of unconsolidated matter (38, 56, 62, 68) in the pertinent annulus (16).

Abstract: A region of a borehole with one or more openings to be sealed off, such as one or more fractures, voids, and or pores, may or may not be sealed off around a tubular string with a borehole seal such as a packer or plug. A carrying fluid may be utilized to transport a filtration material into the opening to create a bridge, which at least partially seals the opening, but still provides a flow path that permits fluid flow therethrough. A solid material and/or settable material may then utilize the fluid flow subsequently or be simultaneously spotted with or behind the filtration material to thereby form compositions which effectively seals off the flow path into the one or more openings.

Abstract: The present invention concerns a water-based drilling mud for utilization in the drilling of oil wells comprising an aqueous phase wherein the aqueous phase contains an oil soluble polymer in the form of a gel as a fluid loss reducer. The subject invention further reveals a method of lubricating a drilling bit during the drilling of a well which comprises circulating a water-based drilling mud in the vicinity of the drilling bit wherein the water-based drilling mud is comprised of an aqueous phase, and wherein the aqueous phase contains an oil soluble polymer in the form of a gel as a fluid loss reducer.

Abstract: A method of injecting a stream of treatment fluid into an earth formation in the course of drilling a borehole into the earth formation, using an assembly having a drill string provided with at least one sealing means arranged to selectively isolate a selected part of the borehole from the remainder of the borehole, the drill string further being provided with a fluid passage for the stream of treatment fluid into the selected part of the borehole, the method involving: operating the drill string, and stopping the drilling operation when a zone for which treatment is desired is arranged adjacent to the part of the selected part of the borehole; isolating the selected part of the borehole using the sealing means so as to seal the drill string relative to the borehole wall; and, pumping the stream of treatment fluid via the fluid passage into the selected part of the borehole and from there into the treatment zone.

Abstract: The present invention relates to settable compositions that comprise magnesium oxide and at least one divalent salt and associated methods of use. In some embodiments, the present invention discloses methods of a forming a hardened mass comprising providing a settable composition comprising magnesium oxide, and a brine comprising water and a divalent salt; placing the settable composition into a desired location; and allowing the settable composition to set to form the hardened mass. In other embodiments, the present invention discloses methods of forming a hardened mass in a subterranean formation comprising placing a brine comprising water and a divalent salt into the subterranean formation; contacting the brine with magnesium oxide; and allowing the brine and the magnesium oxide to react to form the hardened mass. In other embodiments, the present invention discloses methods forming a casing in a well bore, and converting a drilling fluid to a settable composition.

Abstract: Methods for performing wellbore operations using a treating fluid that includes zeolite, an activator, and an organic acid or salt thereof. The treating fluid used in the methods includes a zeolite having a mean particle size that is less than or equal to 100 microns.

Abstract: Methods of improving the pressure containment integrity of subterranean well bores are provided. The methods include pumping a fracture sealing composition into the well bore that rapidly converts into a high friction pressure sealing composition which is impermeable, deformable, extremely viscous and does not bond to the faces of fractures. Thereafter, the fracture sealing composition is squeezed into one or more natural fractures or into one or more new fractures formed in the well bore to thereby increase the pressure containment integrity of the well bore. The methods also include the prediction of the expected increase in pressure containment integrity.

Abstract: The present invention relates to spacer fluids used in subterranean operations and, more particularly, to spacer fluids that comprise water-soluble relative permeability modifiers and methods of using the spacer fluids in subterranean operations. In one embodiment, the present invention provides a method of displacing a first fluid from a well bore that comprises introducing the first fluid into the well bore; and displacing the first fluid with a spacer fluid, the spacer fluid comprising water, and a water-soluble relative permeability modifier comprising a hydrophobically modified polymer or a hydrophilically modified polymer. In another embodiment, the present invention provides a spacer fluid that comprises water, and a water-soluble relative permeability modifier comprising a hydrophobically modified polymer or a hydrophilically modified polymer.

Abstract: The present invention relates to methods and compositions for degrading filter cakes in subterranean formations, and more specifically, to improved methods and compositions for degrading filter cakes that comprise acid-soluble portions and polymeric portions.

Abstract: The present invention relates to subterranean treatment fluids. In particular, the present invention relates to subterranean treatment fluid compositions that comprise polyoxazoline compositions and methods for using such compositions in subterranean applications. In one embodiment, the present invention provides a method of controlling shale swelling in a subterranean formation comprising introducing a treatment fluid into the subterranean formation, wherein the treatment fluid comprises a base fluid and a polyoxazoline composition. In another embodiment, the present invention provides a method of treating a portion of a subterranean formation comprising the steps of: introducing a treatment fluid that comprises a base fluid and a polyoxazoline composition; and treating a portion of the subterranean formation. Other embodiments are provided.

Abstract: A drilling system and method for drilling a borehole into an earth formation is provided. The drilling system has a drill string having a lower section provided with a sleeve which is radially expandable from a retracted mode in which the sleeve extends around the lower drill string section and is releasably connected thereto, to an expanded mode in which the sleeve is released from the lower drill string section and is expanded against the borehole wall. The drilling system further has a control means for selectively releasing the sleeve from the lower drill string section and expanding the sleeve against the borehole wall.

Abstract: Improved methods for drilling well bores penetrating producing zones while controlling formation particulates are provided. Some embodiments provide methods of drilling a well bore into a subterranean formation comprising the steps of providing a drilling composition comprising a drilling fluid and a consolidating material; and, using the drilling composition while drilling the well bore and allowing the consolidating material in the drilling composition to penetrate into the walls of the well bore.

Abstract: Methods and compositions for wellbore treating fluids, especially settable spotting fluids, that include zeolite and at least one carrier fluid.

Abstract: Methods and compositions for wellbore treating fluids, especially drilling fluids, that comprise zeolite and a carrier fluid.

Abstract: Methods and compositions for wellbore treating fluids, especially remedial compositions such as pills, that include zeolite and at least one carrier fluid.

Abstract: The invention discloses methods of formulating an alkali metal silicate-containing drilling fluid and drilling a well therewith. Thus an alkali metal silicate is added to an aqueous base drilling fluid, when the drilling fluid is being circulated while drilling, at a rate sufficient to react with the drilled cuttings and freshly exposed surface of the borehole while leaving very little excess soluble silicate in the drilling fluid circulated to the surface. The rate of addition of the silicate is based on the circulation rate of the drilling fluid in the wellbore and the volume of the hole being drilled.

Abstract: Single phase microemulsions improve the removal of filter cakes formed during drilling with invert emulsions. The single phase microemulsion removes oil and solids from the deposited filter cake. Optionally, an acid capable of solubilizing the filter cake bridging particles may also be used with the microemulsion. In one non-limiting embodiment the acid may be a polyamino carboxylic acid. Skin damage removal from internal and external filter cake deposition can be reduced.

Abstract: The present invention provides a method and treatment fluid for blocking the permeability of an elevated-temperature zone in a reservoir of a subterranean formation penetrated by a wellbore, the method comprising the steps of: a) selecting the zone to be treated, wherein the upper limit of the temperature range of the zone is equal to or greater than 190° F. (88° C.); b) forming a well treatment fluid comprising: water; a water-soluble polymer comprising polymerized vinyl amine units; and an organic compound capable of crosslinking with the vinyl amine units of the water-soluble polymer; c) selecting the water-soluble polymer and the organic compound of the well treatment fluid such that the gel time of the well treatment fluid is at least 2 hours when measured at the upper limit of the temperature range of the zone; and d) injecting the well treatment fluid through the wellbore and into the zone.

Abstract: A method for drilling a borehole includes; providing a drill string of drill pipe including a center bore, a distal end, a bit assembly at the distal end; hanging a liner from the drill string, thereby forming an annular space between the drill string and the liner and with the bit assembly extending from a lower end of the liner; positioning the drill string with the liner attached thereto in a borehole such that a second annular space is formed between the liner and the borehole wall; operating the bit assembly to proceed with drilling the borehole; and circulating drilling fluid down through the center bore of the drill string out through the bit assembly and down through the second annular space between the liner and the borehole wall, the drilling fluid returning up through the annular space between the drill string and the liner.

Abstract: The present invention provides variable density fluid compositions and methods for using such compositions in a subterranean formation. One exemplary embodiment of the variable density fluid compositions of the present invention comprises a variable density fluid comprising: a base fluid, and a portion of variable pressure weighting material particles.

Abstract: The present invention concerns a water-based drilling mud for utilization in the drilling of oil wells comprising an aqueous phase wherein the aqueous phase contains an oil soluble polymer in the form of a gel as fluid loss reducer. The subject invention further reveals a process for preparing an oil soluble polymer fluid loss control agent comprising the steps of dissolving at least one polymer in a hydrocarbon oil to form a clear solution or a gel, adding an emulsifier to the solution or the gel, and keeping the mixture under conditions of agitation until a clear creamy mixture is obtained.

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: An additive for controlling filtration loss from a well working fluid in contact with a permeable formation, which comprises sugar cane ash, or sugar cane ash and a cellulose-like material, or sugar cane ash, a cellulose-like material and an oleaginous liquid, wherein the sugar cane ash and cellulose-like material have a particle size no more than 300 microns.

Abstract: The present invention relates to substantially hydrated cement particulates. More particularly, the present invention relates to compositions comprising substantially hydrated cement particulates and associated methods of use in drilling and subterranean applications. These substantially hydrated cement particulates may be included in drilling and subterranean treatment fluids, inter alia, as carrier particles for admixtures, lost circulation materials, density-varying additives, proppants, and the like.

Abstract: An improved composition and method is provided for preventing or alleviating lost circulation during the drilling of wellbores in subterranean formations, and particularly during the drilling of oil and gas wells. The method is suited for horizontal and directional wells as well as more vertical wells. The composition of the invention comprises a synergistic blend of resilient, angular, carbon-based material and a water-swellable, crystalline synthetic polymer. The method employs the composition of the invention in preventing lost circulation.

Abstract: A method of increasing shale formation stability with a water based drilling fluid, the method including: delivering to the shale formation a drilling fluid formulated to include an aqueous fluid; a first reactant which is a soluble monomer, oligomer, or polymer with exposed ketone, aldehyde, or aldol groups or with groups which can be shifted to ketone or aldehyde functionality; and, a second reactant which is a primary amine, diamine, or polyamine which by condensation reaction forms a semi-soluble or precipitated filming product with the first reactant.

Abstract: Zeolite compositions having enhanced compressive strength and methods therefor are provided. In particular, methods and compositions for wellbore treating fluids, especially settable spotting fluids having enhanced compressive strength are provided.

Abstract: Methods and compositions relating to fluid loss control operations are provided. Examples of compositions may comprise ceramic particulate bridging agents and improved fluid loss control additives, and methods of using those compositions to provide fluid loss control. An embodiment of a method of providing fluid loss control from a first location to a second location may comprise the steps of: providing a treatment fluid comprising ceramic particulate bridging agents, a modified starch composition, and a base fluid; introducing the treatment fluid to the first location; and allowing the treatment fluid to form a filter cake to prevent fluid loss from the first location to the second location.

Abstract: A method of drilling a bore hole into a stratum, wherein via the drill hole drilling fluid is introduced and fed to the drill head. In order to avoid dilution or leak-off of the drilling fluid the same is in accordance with the invention a magnetorheological drilling fluid, and when an undesirable pressure difference occurs between the drilling fluid at the height of the drill head and a fluid present in the stratum surrounding the drill head, a magnetic field is applied. The inventions also provide a permanent solution.

Abstract: A method and materials for stabilizing a wellbore against excess fluid pressure is described. It comprises forming or placing a flexible and essentially impermeable lining on or in the wellbore wall. The flexibility of the lining ensures that it remains in compression as the pressure in the wellbore is increased above the fluid pressure in the surrounding rock and it therefore does not need high tensile strength. The lining may be a preformed elastomer sleeve or formed in situ by the use of a reactive drilling fluid. Appropriate reactive formulations are described for the situation where the rock contains significant quantities of clay.

Abstract: A method is disclosed that affords improved stability to wellbores during drilling in argillaceous formations with water-based drilling fluids. The method comprises adding to the drilling fluid a compound of the invention having the capacity in water to generate a highly efficient membrane on argillaceous materials. The compound is soluble in the drilling fluid at least at the pH at which the compound is added to the drilling fluid or exists in the drilling fluid, but is insoluble in the water in the pores of the argillaceous formations, or at least at the pH of the water in such pores.

Abstract: A method for drilling a borehole employing a drilling fluid including an additive comprising a glucose derivative with pH lowering acid, buffers and surface active agents. The drilling fluid additive preferably exhibits the following properties: activity of approximately 30%–45% in water solution; pH of about 4.5 to 5.5; a light amber to clear liquid appearance and a density of approximately 1.200 grams per cubic centimeter.

Abstract: Methods of cementing in a subterranean formation include passing a swelling agent to a permeable zone in a subterranean formation. The swelling agent is combined with a carrier fluid before being passed to the permeable zone. Upon contacting an aqueous fluid, the swelling agent swells in the permeable zone. The aqueous fluid may already be present in the subterranean formation, or alternatively, it may be introduced to the subterranean formation after passing the swelling agent into the subterranean formation. The swelling agent substantially inhibits a cement slurry subsequently pumped into the subterranean formation from passing through the permeable zone. The cement slurry therefore continues flowing down through the casing and up through the annulus where it sets and forms a strong cement column.

Abstract: A method and apparatus for delivering a well treatment fluid to a productive zone of a subterranean formation at the same time that a well bore is being drilled is provided. The method includes the steps of delivering a drill-in fluid to a drill bit drilling a well bore in, or adjacent to, the productive zone; removing drill cuttings from the well bore; and simultaneous with these steps injecting the treatment fluid into the productive zone. The apparatus includes at least three nested tubes, which form one internal flow path and two annuluses. The drill-in fluid and drill cuttings are delivered to, and removed from, the drill bit, respectively, through the internal flow path and one of the two annuluses. The treatment fluid is delivered to the subterranean formation through the remaining annulus and an expandable bladder mounted to the intermediate and outer tubes.

Abstract: A method is provided for reducing lost circulation when aqueous, oil, or synthetic based drilling fluid is used. The method includes injecting two fluids into the well bore and lost circulation zone. The first fluid is an aqueous liquid containing at least one polymer capable of absorbing water in an alkaline environment. The aqueous liquid has a pH that inhibits at least one polymer from absorbing water. The second fluid contains a hardening composition in a base fluid having a pH sufficient to increase the pH in situ to allow at least one polymer to absorb water and expand with the absorbed water and substantially increase in size to close off the lost circulation zone and allow the hardening composition to create a plug in the well bore and set up.

Abstract: A method for drilling a wellbore in a formation using a drilling fluid, wherein the drilling fluid has a first temperature, and wherein the wellbore has a first wellbore depth. In one embodiment, the method comprises determining at least one fracture gradient, wherein the fracture gradient is determined at about the first wellbore depth; increasing the temperature of the drilling fluid from the first temperature to a desired temperature at about the first wellbore depth; drilling into the formation at increasing wellbore depths below the first wellbore depth, wherein at least one equivalent circulating density of the drilling fluid is determined at about the first wellbore depth; and setting a casing string at a depth at which the equivalent circulating density is about equal to or within a desired range of the fracture gradient. In other embodiments, an automated system is used to maintain the temperature of the drilling fluid at about first wellbore depth.

Abstract: A method of injection of a higher density fluid into the top of the annulus of a well while lower density fluid is withdrawn from the top of the annulus of the well, wherein the higher density fluid has a composition such that it will drop through the lower density fluid without dispersing therein, thus flowing into the deeper reaches of the annulus and not short circuiting through the top of the annulus to the point from which the lower density fluid is intended to be withdrawn.

Abstract: A method and a system for minimizing circulating fluid return losses during drilling of a well bore are disclosed. Circulating fluid, or mud, is heated above conventional temperatures for circulating fluids. The heated circulating fluid then contacts a region of a formation, in which a well bore is to be drilled, maintaining the formation at a relative higher temperature than if no special sources of heat were used to add heat to the circulating fluid. The region, at the relatively higher temperature, has a tendency to expand and to be placed in a relatively higher compressive state as compared to a formation at a lower temperature. Consequently, the use of the heated circulating fluid minimizes fracture initiation and growth and circulation fluid losses into the formation.

Abstract: For well plug treatment to plug an abandoned well, a well plug additive including a dry mixture of water soluble crosslinkable polymer, a crosslinking agent, and filter aid, and optionally, a reinforcing material preferably of fibers and/or comminuted plant materials. The method of forming a well plug fluid includes contacting the additive with water or an aqueous solution, with a method of plugging the well further including the step of injecting the fluid into the wellbore.

Abstract: In accordance with a method of this invention, formation integrity problems are discovered, diagnosed and corrected in successively drilled subterranean well bore intervals. If one or more of well bore fluid outflows, formation fluid inflows or inadequate well bore pressure containment integrity are discovered in a drilled well bore interval, well logs are run and other relevant well bore data is collected in the drilled well bore interval and analyzed to provide a specific treatment using a specific pumpable sealing composition for sealing and increasing the pressure containment integrity of the well bore. Thereafter, the sealing composition is pumped into the drilled well bore interval whereby the well bore interval is sealed or the pressure containment integrity is increased, or both.

Abstract: A method is provided for reducing loss of drilling fluid and for stabilizing a wellbore during drilling through depleted sands in a subterranean formation comprising depleted sands. The method comprises introducing into said wellbore and into said depleted sands an aqueous fluid comprising silicate or siliconate and resilient graphitic carbon in an amount effective at substantially plugging pores in said depleted sands.

Abstract: A method and composition is provided for sealing a subterranean zone penetrated by a well bore to restore lost circulation. In one embodiment, the composition comprises a pellet comprising a mixture of lost circulation materials (LCMs).

Abstract: A water-base drilling fluid for use in drilling wells through a formation containing a shale which swells in the presence of water. The drilling fluid preferably includes: an aqueous based continuous phase, a weight material, and a shale hydration inhibition agent having the formula: H2N—R—{OR?}x—Y.[H+B?]d in which R and R? are alkylene groups having 1 to 6 carbon atom and x is a value from about 1 to about 25. The Y group should be an amine or alkoxy group, preferably a primary amine or a methoxy group. The acid H+B? is a protic acid selected from the group consisting of inorganic acids and organic acids, illustrative examples of which include: hydrochloric, hydrobromic, sulfuric, phosphoric, nitric, boric, perchloric, formic, acetic, halogenated acetic, propionic, butyric, maleic, fumeric, glycolic, lactic, citric and combinations of these. The shale hydration inhibition agent should be present in sufficient concentration to reduce the swelling of the shale.

Abstract: Methods of forming chemical casings include drilling a well bore with a drilling fluid having a pH in the range of from about 6 to 10 and comprising water, a water soluble or water dispersible polymer which is capable of being cross-linked by a thermoset resin and causing the resin to be hard and tough when cured, a particulate curable solid thermoset resin, a water soluble or dispersible thermoset resin, and a delayed dispersible acid-catalyst for curing the solid thermoset resin and the water soluble thermoset resin, whereby the drilling fluid forms a filter cake on the walls of the wellbore that cures into a hard and tough cross-linked chemical casing thereon.

Abstract: Methods of consolidating formations include drilling a well bore with a drilling fluid that comprises water, a polymeric cationic catalyst which is adsorbed on minerals and rocks in weak unconsolidated zones or formations and then further contacting the unconsolidated formation with a treating fluid comprising a water soluble or dispersible polymer which is cross-linked by a thermoset resin and causes the resin to be hard and tough when cured, and a water soluble or dispersible thermoset resin which cross-links the polymer, is catalyzed and cured by the catalyst and consolidates the weak zone or formation so that sloughing is prevented.