Method and apparatus for annulus pressure responsive circulation and tester valve manipulation

Claim 2

In a pipe string located in a fluid filled well bore so as to vertically separate said well bore into an annulus region and an axial bore region, said pipe string including a circulation valve, the method of movement of said circulating valve from a first position preventing to a second position allowing fluid communication between said regions, comprising the steps of: isolating a negligible pressure gas chamber within said pipe string from said axial bore and said annulus region; pressurizing one of said regions to a pressure of at least a predetermined magnitude above the pressure in said isolated chamber; unlocking said circulating valve when the pressure in said pressurized region reaches said predetermined magnitude; moving said unlocked circulating valve from said first position to said second position in response to the pressure in said pressurized region; and maintaining said moved valve in said second position.

Claim 3

The method as recited in claim 1, further comprising the step of: locking said moved valve in said second position so that said moved circulating valve will stay in said second position irrespective of pressure levels in said annulus.

Claim 4

The method as recited in claim 1, further comprising the additional step, subsequent to said isolating step and before said moving step, of: testing an underground formation in response to annulus pressure less than said predetermined magnitude.

Claim 5

Apparatus for circulation of well fluids in response to pressure in an isolated portion of an annulus between a pipe string and a surrounding well bore, comprising: a. a hollow cylindrical housing having a recess communicating with the isolated portion of the annulus, an axial interior bore, a passageway communicating the axial interior bore with the annulus, and means for connecting the housing in said pipe string; b. a valve body carried by said housing and at least partially overlying the recess and movable between a first position closing said passageway and a second position opening said passageway; c. a first locking means for locking said valve body in said first position to said housing and for releasing said valve body from said housing upon a predetermined force applied to said valve body; and d. piston means, attached to said valve body, including: seal means for sealingly contacting said recess so as to divide said recess into a negligible pressure compressible chamber isolated from both said axial bore and said annulus, and an annulus pressure chamber isolated from said axial bore but communicating with said isolated portion of said annulus and differential means for applying said predetermined force upon said valve body urging said valve body toward said second position in response to a predetermined higher pressure in said annulus pressure chamber than in said isolated negligible pressure chamber.

Claim 6

Apparatus for circulation of well fluids in response to pressure in an isolated portion of an annulus between a pipe string and a surrounding well bore, comprising: a. a hollow cylindrical housing having a recess communicating with the isolated portion of the annulus, an axial interior bore, a passageway communicating the axial interior bore with the annulus, and means for connecting the housing in said pipe string; b. a valve body carried by said housing and at least partially overlying the recess and movable between a first position closing said passageway and a second position opening said passageway; c. a first locking means for locking said valve body in said first position to said housing and for releasing said valve body from said housing upon a predetermined force applied to said valve body; and d. piston means, attached to said valve body, including: seal means for sealingly contacting said recess so as to divide said recess into a negligible pressure compressible chamber isolated from both said axial bore and said annulus, and an annulus pressure chamber isolated from said axial bore but communicating with said isolated portion of said annulus and differential means for applying said predetermined force upon said valve body urging said valve body toward said second position in response to a predetermined higher pressure in said annulus pressure chamber than in said isolated negligible pressure chamber.

Claim 7

The apparatus of claim 4, further comprising: a. a second locking means, engaging said housing and said valve body, for locking said valve body in said second position upon said valve body reaching said second position.

Claim 8

The apparatus of claim 5, wherein said first locking means further comprises a shear collar frangibly attached to said valve body restraining movement of said valve body with respect to said housing; and said second locking means comprises a locking ring encircling said valve body and located in the wall of said housing, and a ledge on said valve body adapted to engage said locking ring, when said valve body is in said second position, thereby restraining said valve body in said second position.

Claim 9

The apparatus as recited in claim 4, wherein said cylindrical housing has a recessed portion, and wherein: a. said valve body is a cylindrical sleeve; and b. said piston means comprises: i. a ledge on said cylindrical sleeve, said ledge being disposed within and dividing the recess of said recessed portion into a first section communicating with said annulus and a second isolated section and movable within said recess in response to said pressure; and ii. sealing means, between said recessed portion and said ledge.