Abstract: A flameless nitrogen vaporizing unit includes a first internal combustion engine driving a nitrogen pump through a transmission. A second internal combustion engine drives three hydraulic oil pumps against a variable back pressure so that a variable load may be imposed upon the second engine. Liquid nitrogen is pumped from the nitrogen pump driven by the first engine into a first heat exchanger where heat is transferred from exhaust gases from the first and second internal combustion engines to the liquid nitrogen to cause the nitrogen to be transformed into a gaseous state. The gaseous nitrogen then flows into a second heat exchanger where it is superheated by an engine coolant fluid to heat the gaseous nitrogen to essentially an ambient temperature. The superheated nitrogen is then injected into the well. The engine coolant fluid flows in a coolant circulation system. Heat is transferred to the coolant fluid directly from the internal combustion engine.

Abstract: A tank handling and protection apparatus is particularly suitable for handling tanks carrying liquid additives for oil field servicing operations on offshore vessels. The apparatus includes a frame base and first and second mounting racks attached to the frame base each of those mounting racks having a full-size tank base location defined thereon. Releasable connecting devices are provided for releasably connecting at least one tank to each mounting rack. A protective cage is I0 attached to the frame base and surrounds the tank locations. The protective cage includes removable side walls which allow the tanks to be placed on the frame base with a forklift or the like. The protective cage also has top openings which allow the tanks to be placed on the mounting racks with a sling and crane lifting them through the top openings. The apparatus itself may also be handled with either the forklift or crane and sling.

Abstract: A sample draining apparatus includes a hydraulic circuit having a sampler vessel and a drain vessel disposed therein. A first pump is located outside the hydraulic circuit and pumps fluid from a fluid source outside the hydraulic circuit into the hydraulic circuit to pressurize the circuit. A second pump is disposed in the hydraulic circuit for circulating fluid in the hydraulic circuit so that a fluid sample flows from the sampler vessel into the drain vessel while the sample is maintained within the closed hydraulic circuit.

Abstract: A rotationally operated back pressure valve includes a flapper valve with a sliding stinger tube located thereabove in a housing. An operating mandrel has a lower end portion received in a bore of the housing and the operating mandrel extends upward out of the upper end of the housing. The operating mandrel may be connected to a work string for rotation by the work string. A threaded engagement is provided between the operating mandrel and the stinger tube so that the stinger tube can be selectively moved between a first and second position thereof relative to the housing in response to selected right-hand or left-hand rotation of the operating mandrel relative to the housing. In the first position of the stinger tube it is located above the flapper valve so that the flapper valve closes the housing bore. In the second position of the stinger tube it extends downward through the housing bore past the flapper valve to hold the flapper valve fully open.

Abstract: Casing slip joints are provided on opposite sides of a fracture initiation location to accommodate casing and formation movement during fracturing of a well. In another aspect of the invention, the fracture initiation location is provided by forming openings through the well casing and then forming fan-shaped slots in the formation surrounding the casing. Those slots are formed by a hydraulic jet which is directed through the opening and then pivoted generally about the point of the opening. These fan-shaped slots circumscribe an angle about the axis of the casing substantially greater than the angle circumscribed by the opening itself through which the slot was formed. These techniques are particularly applicable to fracturing of horizontal wells.

Abstract: A differential pressure actuating system for downhole tools provides endless operation by the use of the differential pressure between two isolated zones of a well as a power source for the tool. That differential pressure is applied across a power transfer element to operate the downhole tool.

Abstract: A reciprocating full flow tester valve is provided with a shock absorber and tolerance adjustment device for absorbing an impact between a power mandrel of the tool and an operating assembly of the tool. An improved hydraulic impedance system is also provided for providing a time delay in telescopingly collapsing movement of the tool when weight is set down on the tool to open the tester valve.

Abstract: A downhole formation test pump includes a progressive cavity pump having a helical rotor received in a helical cavity of a stator. The pump may be disengaged by withdrawing the rotor from the stator to provide a bypass position so that the downhole formation being tested can be allowed to flow freely if it is capable.

Abstract: An annulus pressure responsive downhole tool includes a housing with a power piston slidably disposed therein. First and second pressure conducting passages communicate a well annulus exterior of the housing with first and second sides of the power piston. A flow restrictor is disposed in the second pressure conducting passage so that a relatively rapid increase in well annulus pressure creates a pressure differential across the power piston to move the power piston. A volume of silicone oil is contained in a first portion of the second pressure conducting passage between the second side of the power piston and the flow restriction, for accommodating displacement of the power piston as it moves. An operating element is disposed in the housing and movable from an initial position to a final position. The operating element is associated with the power piston so that the power piston moves the operating element from its initial position to an intermediate position.

Abstract: A bypass valve for bypassing well fluids, and method of use thereof. The valve comprises a tubular housing defining a bypass port therethrough with an inner sleeve mandrel defining a bypass port initially aligned with the bypass port in the housing. The valve also comprises a power mandrel slidably disposed within the housing such that, as weight is set down on the power mandrel, pressure is increased in a first oil chamber which has a rupture disc in communiction therewith. When the pressure reaches a predetermined level, the rupture disc ruptures so that the oil chamber is emptied into the well annulus. This allows the power mandrel to move and strike an operating mandrel which is also slidably disposed in the housing. The jarring force shears a shear pin which allows the operating mandrel to move a floating piston disposed in a second oil chamber. A metering cartridge restricts flow of fluid out of the second metering chamber, thereby providing a time delay for movement of the operating mandrel.

Abstract: A wedge lock ring apparatus includes an outer housing having a housing bore with a housing groove defined therein. The housing groove has at least one and preferably has upper and lower housing groove tapered sides. An inner sleeve has a cylindrical outer surface with a sleeve groove defined therein, and the sleeve groove has at least one and preferably has upper and lower sleeve groove tapered sides. A wedge lock ring is received in the housing groove and the sleeve groove and has ring tapered edges complementary to the housing groove tapered sides and sleeve groove tapered sides, such that the sleeve and housing are locked against relative rotation by wedged engagement with the lock ring.

Abstract: A downhole electrical power supply apparatus has a high fluid pressure source zone and a low fluid pressure discharge zone each defined at least partially within the apparatus. A fluid powered engine provides rotational mechanical output and is powered by fluid flowing from the source zone through the engine to the discharge zone. An electrical powered generator converts the rotational mechanical output of the engine into electrical output.

Abstract: A floor construction includes a metal floor decking having a plurality of parallel multi-cell cellular metal floor raceways each of which includes at least one cell for high voltage power wiring. This one cell has a first wiring opening defined in a top thereof. A limited access feeder raceway transversely spans and rests upon the cellular metal floor raceways. The feeder raceway includes an enclosed first wiring raceway separating bottomless second and third wiring raceways. The enclosed first wiring raceway has a plurality of spaced second wiring openings defined through a bottom thereof, one of said second wiring openings being located directly above and in registry with each of the first wiring openings. The feeder raceway includes a closed top having a plurality of spaced access openings defined therethrough, one of which access openings is located directly above each of the second wiring openings.

Abstract: A downhole tool includes a hydraulic power supply containing a volume of compressed gas. The hydraulic power supply can be recharged while the tool is located downhole in the well by recompressing the gas in the power supply chamber.

Abstract: A downhole tool apparatus includes an operating mechanism and a hydraulic timer. The hydraulic timer is operably associated with the operating mechanism for providing a time delay prior to operation of the operating mechanism. The hydraulic timer includes a fluid flow restriction and a spring biased piston which pushes a predetermined volume of hydraulic fluid through the fluid flow restriction.

Abstract: A differential pressure actuating system for downhole tools provides endless operation by the use of the differential pressure between two isolated zones of a well as a power source for the tool. That differential pressure is applied across a power transfer element to operate the downhole tool.

Abstract: A well fluid sampling apparatus provides a time delay after actuation of the tool and before a sample is taken. The tool is operated by well pressure acting on a piston. The piston is initially hydraulically blocked so that it cannot move. The time delay is provided after the piston begins moving. Additional time delay devices can optionally be included.

Abstract: A retrievable bridge plug apparatus, and associated methods, are provided for sealing the bore of a drill pipe string to control a well that is flowing out of control.

Abstract: A system for cementing a casing string in a slant well includes a slant drilling rig including a slanted mast having a pair of spaced rails with an elevator spanning between the rails and reciprocable along a length thereof for reciprocating a casing string with the casing string lying generally between and parallel to the rails. The mast has an open generally upward facing side. A cement plug container apparatus has a cementing manifold and a release plunger assembly attached thereto and positioned about the container relative to each other such that an angle of substantially less than 180.degree., and most preferably approximately 980.degree., is defined therebetween. Thus, the container is substantially free of any radial protrusions outside of that angle and can lie generally flat within the confines of the space between the rails of the tilted mast.

Abstract: An annulus pressure responsive tool is temporarily deactivated so as to no longer be responsive to changes in well annulus pressure. The tool includes a tool housing with a power piston slidably disposed in the housing. A first pressure conducting passage in the housing communicates the well annulus to one side of the power piston. A reference pressure means is disposed in the housing for providing pressure to the second side of the power piston. Thus, a pressure differential is created across the power piston. Also, a selectively operable temporary deactivating means is provided so that the power piston is no longer responsive to changes in the well annulus pressure.