Abstract: A communication nipple for communicating control fluid flow from the outside of a well tool to the inside of a well tool through a fluid passage in the well tool without the use of elastomer seals. A metal breakable screw extends vertically into and initially blocks the passageway with a metal-to-metal seal and extends to the inside of the well tool. The screw includes a cavity exposed to the passageway. A vertically-moving breaking sleeve is connected to the screw and is adapted to break the screw in tension and expose the cavity to the interior of the well tool when the sleeve is moved away from the screw. The present apparatus is particularly useful for supplying hydraulic control fluid into the valve bore of a first well safety valve for controlling a second safety valve positioned in the first valve bore.

Abstract: A method is disclosed for producing viscous petroleum from subsurface deposits. The method employs a vertical well and a horizontal well through the petroleum deposit. A combination of injection procedures through the horizontal and vertical well heat the viscous petroleum in the annulus around the horizontal well. Successive completion intervals are installed in the horizontal well to produce the heated petroleum. The petroleum is driven by a drive fluid passing through previously produced intervals.

Abstract: A first well is directionally drilled to intersect a second well. The second well is magnetized along its well casing to produce a magnetic anomaly which is sensed by a magnetometer located in the first. The drilling of the first well is redirected in accordance with the magnitude of the sensed anomaly so as to cause intersection of the first well with the second well.

Abstract: A well which is producing slowly by artificial lift can be economically heated by first inflowing a nitrogen-generating solution, to form a pool of reacting liquid near the uppermost opening into the reservoir, then inflowing more solution while artificially-lifting liquid from near the lowermost opening into the reservoir at a rate substantially equalling the inflow rate.

Abstract: The invention is particularly adapted for use with a longwall mining machine of the type having a rack extending along a track for the mining machine, a gear wheel on the machine engageable with the rack for moving the machine along a track, at least two shearer drums carried by the machine, at least one driving motor on the machine, and gear train means connecting the driving motor to the shearer drums to rotate the same. Two inductive clutches having a common armature are connected through reduction gearing to the aforesaid driving gear wheel; while separate rotors connect the respective clutches to the gear train such that one rotor will rotate in a direction opposite to the other. A magnetically-actuated, spring-biased friction brake is disposed between the two inductive clutches for braking the clutches when the machine is at rest.

Abstract: Disclosed is a method for recovering oil from a dipping subterranean, viscous oil-containing reservoir having an underlying body of water. An in situ combustion operation is initiated using an oxidizing gas injected through an injection well in fluid communication with the lower portion of the reservoir near the oil/water interface. Fluids including oil and effluent gas are recovered from the reservoir through a production well in fluid communication with a shallower portion of the reservoir. After a predetermined amount of time, injection of the oxidizing gas is terminated and the reservoir is allowed to undergo a soaking period for a predetermined amount of time. Thereafter, a water drive is initiated by injecting water into the injection well and fluids including oil are recovered from the reservoir through the production well.

Abstract: An assembly for cleaning deposited minerals from the interior passages of first and second axially aligned tubular laterals that extend outwardly in opposite directions from a geothermal well head and removably support first and second gate valves from the free ends thereof. The cleaning of the passages in the tubular laterals as well as passages in the first and second gate valves may be conducted with the assembly without killing the well. The assembly also permits a third vertically disposed gate valve on the well head to be removed for repair and maintenance purposes without killing the well, and this is also possible with the first and second gate valves.

Abstract: A cutting device for a mining or tunnelling machine takes the form of a roller with cutter bits which rotates at the end of a movable arm as is known. Grooves in the roller receive plate-like components which support water spray nozzles radially within the extremities of the cutter bits. The support components are stationary but are adjustable about the axis of rotation of the roller to bring the nozzles into the appropriate location during operation.