Pressure-balanced well service valve
AssigneeDresser Industries, Inc.
InventorRobert Houston Canterbury
Life of this patent
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Abstract
A well service valve used primarily for the injection of closely controlled batches of well treating fluids into low pressure formations utilizes a biased one-way flow valve in a tubing string to hold the treating fluid in the column until the tubing is pressurized to open the valve and expose flow ports in the wall of the tubing to the formation. A partial pressure-balancing of the flow valve allows the use of a lower biasing force in the flow valve, thereby greatly increasing the reliability and useful life of the valve.
Claims3
An underground wellbore treating valve assembly for the injection of predetermined quantities of fluids into low pressure downhole formations, said valve assembly comprising:
- an elongated tubular housing having a central bore passage therethrough and adapted for sealing engagement in a conduit string;
- an annular valve seat formed in the wall of said housing in said bore passage;
- an inner annular shoulder formed in said housing below said valve seat;
- seal means in said annular shoulder;
- a sliding valve member closely fitting in said annular shoulder and having a valve-seat-closing upper portion arranged for sealing engagement with said valve seat;
- upward biasing means located below said valve member and in abutment therewith;
- bottom abutment means below said biasing means, in abutment therewith, and arranged to retain said biasing means in said housing;
- a first pressure response area on top of said valve member and exposed to said valve seat;
- a second pressure response area on said valve member below said annular shoulder and of less cross-sectional area than said first pressure response area;
- port means through the wall of said housing between said valve seat and said annular shoulder;
- and,
- a pressure bypass passage communicating from above said valve seat to below said annular shoulder.
Dependencies are inferred from the claim text.