Abstract: In oil well remedial operations, a powerful generally acidic solution is pumped down a pipestring and out into the well annulus at the level of casing perforations wherein the solution will pass through the perforations and clean them out to facilitate oil flow into the annulus for subsequent recovery. When increasing the depth of the pipe string as by adding further pipe sections at the surface of the well, it is desirable to retain the solution within the pipe string and towards this end, there is provided an internal fluid control valve normally closed to retain fluid but responsive to an increase in the fluid pressure above a given value to open and permit the treating fluid to pass into the annulus and treat the casing perforations. Basically the internal valve comprises a valve seat and ball, the ball being positioned on the upstream side of the valve so that should any seals fail in the valve structure, the valve will failsafe to a closed position.

Abstract: The dewaxing valve comprises a ball and valve seat where the ball is on the upstream side of the flow of hot dewaxing fluid through a production pipe string to the well annulus. The design of the dewaxing valve is such that it can be readily attached to a production tube in the production tubing string by simply boring a hole in the side of the production tube and welding a supporting T-collar for the valve to the periphery of the side opening.

Abstract: A simplified means for draining oil well tubing to equalize the hydrostatic pressure of oil pumped up through the tubing with the oil in the annulus defined between the exterior of the tubing and the well casing is provided. Essentially, the pump barrel is extended beyond the lowermost point of reciprocation of the plunger in the barrel. A perforation is provided in the extended portion for communication between the well annulus and the interior of the extended portion. The polish rod connecting sucker rods to the plunger in the barrel in turn is treated to decrease its cross sectional area over a given length. This treated section of the polish rod is above the upper end of the pump barrel when the plunger is at its lowermost reciprocable position while pumping so that pumping operations can be carried out normally.

Abstract: The hydraulic unloading and circulating device is adapted to be inserted in a threaded joint of a well tool connected to sucker rods and including a pumping tube surrounding said tool and supported on the end of a pipe string through which said sucker rods extend, for passing fluid between the exterior of the tool and interior of the pumping tube and pipe string to the interior of the tool and well annulus to thereby relieve the difference of hydrostatic pressure between fluid in the well annulus and interior of the pumping tube and pipe string. The device itself includes a housing with a telescoping mandrel having a straight through passage and lateral port, which, when the mandrel is telescoped in the housing to a first telescoped position, the port is eclipsed and when the mandrel is telescoped upwardly from the housing to a second telescoped position, the port is exposed to thereby effect communication between fluid in the pipe string and the well annulus.