Pressure responsive auxiliary disc valve and the like for well cleaning, testing and other operations

Claim 1

A well tool for location in a tubing string disposed in a well bore for performing surging operations, wherein annulus fluid is present in the annulus between the tubing string and the well bore, and tubing fluid is present within the tubing string, and there is further included means for selectively pressurizing the annulus fluid and pressurizing the tubing fluid, and wherein packer means is provided for separating the annulus fluid from the tubing fluid, comprising: a. an annulus-pressure responsive rupture disc valve, including: a first tubular valve body; means for connecting the first tubular valve body to said tubing string in communication therewith; a first rupture disc carried within the first tubular valve body and normally blocking flow through the valve body and said tubing string; and means carried by the first tubular valve body responsive to pressurization of the annulus fluid for rupturing the first rupture disc to allow flow therethrough; b. a tubing-pressure responsive rupture disc valve, including: a second tubular valve body; means for connecting the second tubular valve body to said tubing string in communication therewith; a second rupture disc carried within the second tubular valve body and normally blocking flow through the second valve body and said tubing string; and means carried by the second tubular valve body responsive to pressurization of the tubing fluid for rupturing the second rupture disc to allow flow therethrough; and c. a cylindrical tubular air chamber located between said annulus-pressure responsive valve and said tubing-pressure responsive valve and joining said valves together, with said valves and air chamber adapted for being interposed in a tubing string.

Claim 4

A method of cleaning a well formation by surging debris out of the perforations comprising the steps of: a. lowering into the fluid in said formation a tool string containing a tubing-pressure responsive rupture disc valve, and air chamber attached thereto, an annulus-pressure responsive disc valve attached to the air chamber and a packer; b. setting the packer in the annulus at the lower end of said tool string; c. applying fluid pressure to the annulus between said tool string and the well bore thereby opening said annulus-pressure responsive valve into said air chamber; d. unsetting said packer; and e. applying fluid pressure to the interior of the tubing of said work string thereby opening said tubing-pressure responsive rutpure disc valve.

Claim 5

A method of cleaning a well formation by surging debris out of the perforations comprising the steps of: a. lowering into the fluid in said formation a tool string containing a tubing-pressure responsive rupture disc valve, and air chamber attached thereto, an annulus-pressure responsive disc valve attached to the air chamber and a packer; b. setting the packer in the annulus at the lower end of said tool string; c. applying fluid pressure to the annulus between said tool string and the well bore thereby opening said annulus-pressure responsive valve into said air chamber; d. unsetting said packer; and e. applying fluid pressure to the interior of the tubing of said work string thereby opening said tubing-pressure responsive rutpure disc valve.