Abstract: A method for breaking the fracturing fluid comprises injecting into the subterranean formation a controlled release breaker capsule including an enclosure material enveloping a breaker. The enclosure material is sufficiently permeable to at least one fluid existing in the subterranean environment or injected with the controlled release capsule such that the breaker capsule is capable of dissolving or eroding upon sufficient exposure to the fluid, thereby releasing the breaker.Using the method of the present invention, breaking of fracturing fluids is significantly improved when the temperature in the subterranean environment is from about 20.degree. C. to about 65.degree. C.

Abstract: A well penetrating a subterranean fluid producing formation can effectively be gravel packed by a process which begins with an initial low gravel loading in the carrier fluid, the gravel loading gradually being increased over the course of the gravel packing operation to provide a complete gravel pack including a gravel reservoir without formation breakdown, fluid loss, bridging and/or sand-out of the gravel pack fluid.

Abstract: A method and apparatus for treating subterranean wells includes a tool supported on a one-piece support tube which operates to raise and lower the tool in the well to a position where well treatment is required. The tool provides inflatable packers and a selector valve operable in a first position to inflate or deflate the packers, in a second position to circulate fluid to spot treatment fluid at the tool, and a third position for injecting treatment fluid into the strata isolated from the remainder of the well by the packers. The tool provides a J-lock system and a time delay dashpot which cooperate to permit an operator at the well head to selectively operate the valve between the three positions solely by adjusting the weight on the support tube at the well head.

Abstract: A method of preparing either foamed or nonfoamed fracturing fluids which maintain an at least substantially constant viscosity during the introduction of varying concentrations of proppant. The at least substantially constant viscosity fluids of the present invention provide a substantially constant friction pressure, which provides improved on-site, real-time analysis and to a better evaluation of the fracture treatment.

Abstract: Process for retarding and controlling the formation of gels or precipitates derived from aluminum and corresponding compositions, plus the corresponding applications--in particular regarding oil wells.

Abstract: A packer and service tool assembly for oil or gas well preparation includes a disengageable coupling mechanism which permits the tool to be screwed into and out of the packer and which can be hydraulically disengaged so that the tool can be removed without applying torque to the tool or workstring. A releasable ratchet mechanism is also provided in the packer for trapping the setting loads when the packer is set in the casing. The ratchet mechanism is releasable by pulling up a housing portion which cammingly engages collapsible ratchet fingers thereby disengaging the ratchet finger trapping teeth from a stationary ratchet ring.

Abstract: The matrix treatment of a subterranean formation is adjusted in real time to minimize formation damage as indicated by the skin factor. The process comprises initial injecting an inert fluid into the formation and observing the variation in injection pressure over time. During the matrix treatment with a treatment fluid, the pressure is again observed over time and, by comparison with the pressure variation noted in the inert fluid injection phase, the skin factor is determined. The treatment parameters are then adjusted in real time to minimize the skin factor thereby minimizing formation damage.

Abstract: There is disclosed a method and additive to be employed in said method whereby the fouling of metal surfaces with copper deposits resulting from acid cleaning of copper alloy surfaces, be they all of the same metallurgy or merely elements with in the overall system is markedly reduced by adding to the rinse or flush formulations commonly employed following an acid treatment, a chelating agent for copper, and, subsequently adding a copper corrosion inhibitor to the conventional neutralization fluid.

Abstract: A crosslinker composition that can produce delayed crosslinking of an aqueous solution of a crosslinkable organic polymer. The composition comprises an organic titanium complex. The composition further contains an organic hydroxycarboxylic acid, preferably hydroxyacetic acid. The pH of the composition is preferably less than 5. The pH of the composition is further preferably such that when sufficient amount of composition is added to an aqueous polymer solution to result in delayed crosslinking of the polymer, the composition produces a pH in the resulting gel solution, preferably of between about 3 to about 4.5. Gel solutions produced using the composition are particularly useful in fracturing subterranean formations, and in particular in fracturing subterranean formations penetrated by an oil well in which fracturing process carbon dioxide and a proppant are added to the fracturing fluid.

Abstract: A method of packing a well, particularly an oil, gas or water well. A particle/liquid slurry is injected into the wellbore, the particle density to liquid density ratio of which is no greater than about 2 to 1. The particles are substantially free of surface adhesive. The particles are strained out of the slurry in the wellbore, so as to produce a packed mass of the particles adjacent the formation. The packed mass is such as to allow flow of fluids therethrough between the formation and the wellbore, while substantially preventing particulate material from the formation passing therethrough and into the wellbore. The well may be deviated. The fluid density is preferably about 0.8 to about 1.2 g/cm.sup.3.

Abstract: The invention consists of a new process for selectively treating a subterranean formation without affecting or being effected by the two adjacent zones (above and below).Using the invented process, the treatment fluid is injected into the formation to be treated F, at the same time as two protection fluids, whether the same or different, are injected into the two adjacent zones (above [ZS] and below [ZI]).The process can be applied even in the presence of fractures, gravel-pack and their zones.

Abstract: A mixer suitable for mixing a particulate material with a liquid. The mixer has a particulate material conduit, and a volute chamber disposed about the conduit. The volute chamber has a liquid inlet and an open lower end through which the particulate material conduit extends, to define an annular liquid outlet of the volute chamber. A transition cone communicates with the liquid outlet of the volute chamber and extends downward from it. At least a portion of the transition cone tapers inward while extending downward from a position not substantially lower than an outlet at the lower end of the conduit, to a position which is not substantially thereabove. Preferably the transition cone tapers as described, from a position above the conduit outlet to a position therebelow. A substantially straight downpipe is connected to, and extends downward from, a lower end of the transition cone.

Abstract: The invention concerns a new process for plugging and/or consolidating a permeable geological formation, notably when traversed by a borehole.The process, according to this invention, comprises the following steps: (a) insertion into the formation of an overdelayed gelling compound, composed of a gelable material and a hardener, for which the setting time is considerably longer than the suitable positioning time for the composition, in such a way that this permeates the formation over a significant distance. (b) insertion, after a mechanical or fluid plug, of a rapid-action gelling agent, which causes the instantaneous gelling of that part of the overdelayed gelling compound in the immediate neighborhood of the interface between the zone to be treated and the borehole. Thus preventing displacement of the overdelayed gelling compound toward the interior of the formation. The resultant gelling being both resistant and correctly placed.The invention application is to oil, gas, water or geothermal drillings.

Abstract: The invention consists of a centrifugal mixer with an upper rotor (3) for projection of particles, which is hard-mounted to rotor (4) allowing centrifuging of fluid (15).The invention lies in the creation of a low-pressure zone within the high-pressure zone of enclosure (23), for introduction of particles (20); this in turn requires the use of disturber (27).The result is a remarkable degree of mixing of the water and cement and has applications for oil field services.

Abstract: An apparatus designed for the introduction or removal of fluids from a wellbore, which apparatus comprises an elongated, extendable member and means for extending it; attached to said extendable member a conduit adapted for carrying fluid along said member; and located near an extremity of the extendable member, a means for securing said conduit to the head of a wellbore to permit fluid flow through said conduit and into or from said wellbore. Also, a method for employing the foregoing apparatus to introduce or remove from a wellbore a fluid by attaching a securing means to a wellbore head and introducing into or removing therefrom a fluid by transporting said fluid through the conduit with a fluid transporting means, said fluid flowing in either direction as may be appropriate.

Abstract: An improved method of mixing a fracturing fluid slurry concentrate comprising a hydrophobic solvent base (e.g., diesel No. 2) and a dispersed hydratable polymer (e.g., hydroxypropyl guar) on a real time basis thus continuously producing a fully hydrated fracturing fluid during the actual fracturing of a subterranean earthen formation. Viscosity rise times of less than 5 minutes are achieved in a continuous operation without the use of large volume storage/hydration tanks, employing primarily conventionally necessary pumps.

Abstract: A chemical method of removing thiourea from spent hydrochloric acid cleaning solutions comprising the steps of: adjusting the pH to not less than 12 by addition of base to remove metal hydroxides; oxidizing thiourea to urea by the addition of at least 4 moles of hydrogen peroxide per mole of thiourea; and further oxidizing urea to nonregulated/nonhazardous compounds by the addition of at least 3 moles of a hypochlorite per mole of urea. UV analysis confirms a greater than 98% removal of thiourea from solutions containing 0.4 to 2.7 wt. % thiourea after as little as 3 hours with an exotherm, .DELTA.t, of less than 105.degree. F.

Abstract: A novel test specimen configuration and modified ring test method for determining the fracture toughness, K.sub.Ic, using rock core is disclosed. The use of a truncated hollow cylindrical specimen under compressive load avoids the development of a large process zone (microcracked region) during testing, thus allowing accurate fracture toughness measurements on subsized specimens. Results using soft sandstones and Indiana limestone validate the procedure.

Abstract: This invention is directed to a mixing apparatus for mixing liquids and particulate solids which comprises an enclosed cylindrical housing with an inlet means and a liquid/solid outlet means coupled to said housing and a slinger disposed within said housing which comprises a flat disc with a plurality of circumferentially spaced vertical vanes and a cylindrical outer wall at the outer periphery of the cylindrical flat disc.

Abstract: A novel method and device for manipulating ferrofluids for use in cementing wells are disclosed. The cementitious fluids may comprise: (a) a hydraulic cement, (b) finely divided magnetic particles, (c) a binding agent or a surfactant, and (d) a liquid medium. The binding agent or surfactant is present in the compositions in an amount sufficient to render the compositions stable in a magnetic field. When used in cementing wells, the cementitious ferrofluids are implaced in the annulus separating a casing from the formation in a wellbore by conventional techniques and the slurry is subsequently subjected to an activating alternating magnetic field that causes movement of the flurry. The non-cementitious ferrofluids comprise: (a) finely divided magnetic particles, (b) stabilizing agent, and (c) a liquid medium. The movement of the slurry results in a "scrubbing" action against the surface of the casing and formation surfaces, and a mixing of the slurry which helps displace any residual drilling mud.