Abstract: A hydraulic fracturing process in which substantial quantities of both nitrogen and carbon dioxide are incorporated into the fracturing fluid. Nitrogen and carbon dioxide are separately incorporated into an aqueous based fracturing fluid in amounts to provide a volume ratio of nitrogen to carbon dioxide at wellhead conditions within the range of about 0.2-1.0. The volume ratio of the total of carbon dioxide and nitrogen to the aqueous phase of the aqueous fracturing fluid at wellhead conditions within the range of about 1-4. The aqueous fracturing fluid containing the nitrogen and carbon dioxide is injected in the well under a pressure sufficient to implement hydraulic fracturing of the subterranean formation undergoing treatment. A thickening agent may be incorporated into water to provide a viscous aqueous based fracturing fluid to which the carbon dioxide and nitrogen are added. The carbon dioxide is incorporated in liquid phase and the nitrogen in gaseous phase.

Abstract: This invention relates to the breaking of high viscosity aqueous fluids in which xanthan gum was used as a thickening agent. The invention provides a breaker system comprising two oxidizers, an organic acid, and two catalysts. The invention is particularly useful in oil field operations such as placement of a gravel pack or distribution of a proppant in a fractured formation.

Abstract: Hydraulic fracturing process in which a normally gaseous energizing phase is incorporated into an aqueous fracturing fluid in a manner to effect good dissemination and stabilization of the energizing phase in the fracturing liquid. A normally gaseous energizing phase is incorporated into an aqueous fracturing fluid having a viscosity at wellhead conditions within the range of 10-300 centipoises. The fracturing fluid containing the energizing phase is introduced into the well and displaced from the wellhead down the well to the vicinity of the subterranean formation. During the displacement of the fracturing fluid from the wellhead to the vicinity of the formation, the viscosity of the fracturing fluid is increased by a factor about 2 or more. The higher viscosity fracturing fluid is displaced from the well into the formation in the course of the fracturing process. The energizing phase is provided by incorporating a substantial amount of liquid carbon dioxide into the aqueous fracturing fluid.

Abstract: A mechanical setting tool for setting a flow control tool in an oil or gas well using the drill string includes a mandrel with means for attachment to the end of the drill string. Slips are releasably carried on the mandrel by a first release structure. A cone is releasably carried on the mandrel by a second release structure and has tapered surfaces confronting the slips. A stinger is carried on the lower end of the mandrel and has a third release means for releasably engagement to the flow control tool being set. A setting sleeve is releasably engaged to the mandrel by way of a fourth release structure between the sleeve and the cone.

Abstract: A downhole tool for controlling the flow of fluids through the well casing includes a tubular mandrel with a flow control valve therein. A radially expandable seal member encircles the mandrel and a sub-bottom defines an abutment member, attached to and movable with the mandrel, for engaging one side of the seal member. A bottom cone is positioned around the mandrel and on the opposite of the seal member from the sub-bottom. The cone has a sleeve extending therefrom positioned between the seal and the mandrel on which the seal member is carried. An upper cone is positioned around the mandrel with slips segments being positioned between the upper and bottom cones. An upper radially expandable seal member encircles the mandrel and its carried on a sleeve extending from the upper cone. A lock hub is positioned around the mandrel and on the side of the upper cone opposite the upper seal and slip segments.

Abstract: In an oil or gas well, a cement retainer setting tool for setting and pumping cement therethrough includes an inner piston defining a bore and an activation sleeve carried on the piston and defining an annular space between the piston and sleeve. A sleeve ring is formed inwardly from the activation sleeve and is positioned within the annular space beween the piston and the sleeve. Ports are provided to the piston above the sleeve ring for communicating a retainer setting pressure to the sleeve ring to move the sleeve downwardly relative to the piston upon application of such pressure. A plug means for plugging the lower end of the piston is provided therein. The plug means is disengagable upon application of a predetermined pressure greater than the retainer setting pressure. A second port structure is provided for connecting the lower end of the piston to a cement retainer, or other tool.

Abstract: An apparatus (10) for concentrating the level of a proppant in a slurry under pressure includes a cyclone chamber (22) having a reduced diameter end with an exhaust outlet (40) therein. A slurry and proppant mixture is introduced under pressure into the chamber at an inlet (120) substantially along a path tangential to the side wall of the chamber. Flow of fluid into the cyclone chamber causes the slurry and proppant mixture to follow a spiraled path toward the exhaust outlet such that the heavier constituents in the mixture move near the inside wall of the chamber. A reflux tube (140) is positioned within the chamber and permits the removal of fluid from the low proppant concentration area of the fluid chamber and directs the fluid across a choke (90, 90') and to a deenergizer (94, 94'). The deenergizer includes a housing having an inner longitudinal tube (184) with an inlet (180) for receiving fluid from the cyclone chamber and a closed end opposite the inlet.

Abstract: Well servicing agents and processes for use with fluids circulated into wells penetrating subterranean formations in the earth's crust. Circulation losses of well servicing fluids including drilling muds, workover and completion fluids, and the like, are alleviated by incorporating a particulate material into the servicing liquid. The particulate material is formed of a thermoplastic polymer in a flexible, elongated laminar form in which its length is substantially greater than its width and its width substantially greater than its thickness. A second particulate material in a rigid granular form may be employed an admixture with the laminar particulate material. A particular lost circulation agent is a blend of a particulate thermoplastic polymer in a flexible, elongated form and a particulate thermoset polymer in a rigid granular form with the ratio of the laminar material to the granular material being at least 1:6.

Abstract: A main screw feeder having a main screw housing set at an incline from the base of a bin. The main screw housing has two outlets, the advanced outlet and the recycle outlet. The advance outlet communicates with a metering screw housing in which twin screws of identical pitch are rotated in synchronous, intermeshed revolution. The delivery outlet for the metering screw housing communicates with the processing stages. The recycle outlet is positioned at an elevation higher than the advance outlet and discharges to the bin. A flow measuring device measures the return flow of granulated or powdered material expelled from the recycle outlet. The flow measuring device projects a prestressed cable into the recycle path of the return flow. A device for measuring any deflection of the cable and fluctuations in the tension thereon produce a signal which is a function of the return flow and which is used to control the speed of the main screw feeder.

Abstract: A transition metal complex useful as a crosslinking agent for high temperature, high pH, water-based fracturing fluids incorporating polysaccharide polymers is provided. The crosslinker comprises a zirconium/triethanolamine complex having a Zr/TEA molar ratio of between about 1/6.0 and 1/10.0, with 1/6.5 to 1/9.5 being preferred. Methods for preparing the zirconium/triethanolamine crosslinker are also provided. The methods comprise mixing effective amounts of either n-butyl zirconate or n-propyl zirconate with triethanolamine until a uniform blend is obtained. Further, an improved hydraulic fracturing fluid incorporating a polysaccharide polymer, buffer, crosslinker, pH adjusting agent and antioxidant is provided wherein the improvement is utilizing a zirconium/triethanolamine crosslinker. Improved methods for crosslinking fracturing fluids and for hydraulically fracturing well formations are also provided.

Abstract: A tool (20) for washing the perforated zone of a well casing in an oil or gas well includes a tubular mandrel (24) having a flow passage (26) with means for connecting one end of the mandrel to a drill string (160) and the second end to a flow blocking valve (162). The mandrel (24) has a plurality of apertures (42) through its sidewall. A first and second radially expandable packer (64, 132) completely encircles and is carried on the mandrel at spaced positions. An outer sleeve (100) surrounds the mandrel between the packers and defines an annular chamber (116) between the sleeve and mandrel. The sleeve has apertures (104) therethrough having a combined area less than the combined area of the apertures (42) through the mandrel. First and second annular pistons (74, 100) are carried within the annular chamber (116) having one face communicating with the annular chamber and an opposite face engaging, respectively, the first and second packers.

Abstract: A control system (10) is provided for maintaining a constant fluid level in a mixing container of a delivery and metering device. Structure (12) is provided for monitoring the fluid level in the mixing container and for generating a level signal (14) representing the fluid level present in the mixing container. Structure (18) is further provided for establishing a desired amount of fluid entering the mixing container and for generating a first control signal (20). Structure (22) is provided for establishing a desired amount of fluid discharged from the mixing container and for generating a second control signal (24). Measuring devices (30, 34) are utilized for measuring the amount of fluid discharged from the mixing container and for generating a discharge signal (36) representing the amount of fluid discharged from the mixing container.

Abstract: Disclosed is an apparatus for blending sand and solid additives selectively and at selected rates into water for injection into a well. The apparatus may be truck mounted, and includes a frame, an input line with manifold and pump, a mixing tank, a variable venturi nozzle for delivering water to the tank, and an output line with pump, manifold, and recycle line. An auger delivers sand to the mixing tank. Dry chemicals are fed to the tank adjacent the variable venturi nozzle where the water is turbulent, at low pressure, and in high shear. Liquid chemicals may also be pumped into the tank.

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: An improved fluid loss additive for use in well cements, preferably comprising from about 30 to about 70 weight percent polyvinylpyrrolidone, from about 5 to about 19 weight percent carboxymethylhydroxyethyl cellulose, and the sodium salt of naphthalene sulfonate. Improved cement slurries comprising the subject fluid loss additive and an improved method for cementing well bores through use of the novel slurries are also provided. The improved cement slurries of the invention preferably comprise from about 26 to about 60 percent water and from about 0.75 to about 2 percent of the improved fluid loss additive, by weight of the cement.

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 solution of an oxygenated polyamine, which is the reaction product of dimethylamine and epichlorohydrin, has been discovered to possess excellent stabilization properties when used as a treatment for stabilizing a clay containing formation, for example in the treatment of oil and gas producing boreholes which penetrate clay containing formations. Preferred copolymers of this type which are useful in clay formation treatments include those having epichlorohydrin to dimethylamine mole ratios in the range of from about 0.79 to about 0.93.

Abstract: A radioactive charge is ejected into the borehole and a subsurface unit including a radiation detector is moved upwardly through this charge a number of times. The total radiation count as the unit moves up through the charge is obtained by integrating the output of the radiation detector during the period when the counter output exceeds the background radiation. The integrated count is displayed on a digital display unit. Compensation is provided for background radiation within the borehole. Also correction is made for the dead time of the radiation detector so that an accurate indication of the total amount of radioactivity remaining in the borehole during successive runs is obtained.

Abstract: An improved well logging system of the type utilizing a single conductor cable to provide power from the surface equipment to a down hole subsurface unit and for simultaneously supplying current mode telemetry signals from one or more radiation detectors in the subsurface unit to the surface equipment. The surface equipment includes a power supply for the subsurface unit comprising a constant current source having a high output impedance connected to a series pass voltage regulator having a low output impedance. A switching mode voltage regulator is employed within the subsurface unit to compensate for variations in the voltage supplied to the subsurface unit which result from variations in cable resistance and other factors.

Abstract: A method of increasing the permeability of a subsurface formation by the utilization of a Bingham plastic fracture fluid. The Bingham plastic fracture fluid is pumped into a preformed fracture or a fracture formed with the Bingham plastic fluid and hydraulic pressure is imparted to the formation which is greater than that which was required to initially fracture the formation (i.e., the formation is overpressurized) by either (1) relieving the pumping pressure on the Bingham plastic fluid in the fracture and allowing the fracture to heal and thereafter reapplying the pumping pressure on the Bingham plastic fluid in an increased amount, e.g., an amount sufficient to move the Bingham plastic fluid in the fracture; or (2) continuing pumping of the Bingham plastic fluid into the fracture such that the friction drop caused by the continued pumping results in such increase in pressure.