Well blowout preventer control pressure modulator

Claim 2

In a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the fluid in the first chamber being subject to excess pressure development in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to said chambers, and b. modulator means in communication with the fluid pressure supply to the first chamber and operable to relieve said excess pressure development therein in response to entry of said enlargement into the tool.

Claim 3

The combination of claim 1 wherein said tool comprises a packer annulus which is radially constrictable by the actuator, and which is expansible radially in response to string joint passage forcibly therethrough.

Claim 4

In a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the fluid in the first chamber being subject to excess pressure development in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to said chambers, and b. modulator means in communication with the fluid pressure supply to the first chamber and operable to relieve said excess pressure development therein, c. the modulator means being in operative communication with the second chamber to effect a pressure increase therein in response to excess pressure development in the first chamber.

Claim 5

In a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the fluid in the first chamber being subject to excess pressure development in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to said chambers, and b. modulator means in communication with the fluid pressure supply to the first chamber and operable to relieve said excess pressure development therein, c. the modulator means being in operative communication with the second chamber to effect a pressure increase therein in response to excess pressure development in the first chamber.

Claim 6

In a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the fluid in the first chamber being subject to excess pressure development in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to said chambers, and b. modulator means in communication with the fluid pressure supply to the first chamber and operable to relieve said excess pressure development therein, c. said modulator means including a pressure relief valve communicating with the fluid pressure supplied the first chamber.

Claim 7

In a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the fluid in the first chamber being subject to excess pressure development in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to said chambers, and b. modulator means in communication with the fluid pressure supply to the first chamber and operable to relieve said excess pressure development therein, c. said modulator means including a pressure relief valve communicating with the fluid pressure supplied the first chamber.

Claim 8

In a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the fluid in the first chamber being subject to excess pressure development in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to said chambers, b. modulator means in communication with the fluid pressure supply to the first chamber and operable to relieve said excess pressure development therein, and c. a passage communicating between said chambers, said modulator means controlling fluid pressure communication from the first to the second chambers for effecting said relief of excess pressure development in the first chamber.

Claim 9

In a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the fluid in the first chamber being subject to excess pressure development in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to said chambers, b. modulator means in communication with the fluid pressure supply to the first chamber and operable to relieve said excess pressure development therein, and c. a passage communicating between said chambers, said modulator means controlling fluid pressure communication from the first to the second chambers for effecting said relief of excess pressure development in the first chamber.

Claim 10

The combination of claim 5 including a signaling circuit comprising a switch operable in response to by-passing of fluid to the second chamber via the modulator means, and a signaling device electrically connected in circuit with the switch.

Claim 11

The combination of claim 6 including said well string suspended by a vessel to hang in the ocean and in a well below the ocean floor, said device being on the vessel and said switch being at a stack of well head equipment at the ocean floor.

Claim 12

The combination of claim 6 wherein the switch includes a spring-urged contact adapted to be displaced to increase the spring tension in response to said fluid by-passing.

Claim 13

The combination of claim 5 wherein said modulator means includes a by-pass valve controlling said fluid pressure communication from the first to the second chambers.

Claim 14

The combination of claim 9 Wherein said by-pass valve is outside the housing.

Claim 15

The combination of claim 9 wherein said modulator means also includes biasing means yieldably biasing the valve toward a position blocking said fluid pressure communication from the first to the second chambers.

Claim 16

The combination of claim 11 wherein said biasing means includes control fluid pressure from a source out of communication with said chambers.

Claim 17

The combination of claim 11 wherein said biasing means comprises control fluid pressure, and a piston responsive to said control fluid pressure to transmit biasing force to the valve.

Claim 18

The combination of claim 13 in which said biasing means also includes a spring under tension, and means to adjust said tension.

Claim 19

The combination of claim 13 including piping communicating the modulator means and said first chamber with the accumulator and of length such that an excess pressure wave from the first chamber is by-passed by said by-pass valve toward the second chamber prior to transmission of the wave via said piping to said accumulator.

Claim 20

The combination of claim 13 wherein said supply means includes a control valve having one position in which actuating fluid pressure is supplied to the first chamber but not to the second chamber, and a second position in which actuating fluid pressure is supplied to the second chamber but not to the first chamber.

Claim 21

The combination of claim 16 in which said control valve in said first position communicates the second chamber with an outlet and via piping of such length that an actuating fluid pressure wave passed by the by-pass valve is supplied to the second chamber prior to transmission to the outlet via the control valve.

Claim 22

The combination of claim 16 wherein said supply means includes a source of actuating fluid pressure and a pressure regulator connected between said source and the control valve.

Claim 23

The combination of claim 16 including an accumulator supplying said control fluid pressure.

Claim 24

The combination of claim 19 including a support body containing said accumulator and said by-pass valve.

Claim 25

The combination of claim 20 including a check valve contained by said body and operable to transmit pressure from the accumulator to said control valve but blocking reverse transmission therebetween.

Claim 26

The combination of claim 9 wherein said by-pass valve in inside the housing.

Claim 27

The combination of claim 22 wherein said by-pass valve is carried by the actuator.

Claim 28

The combination of claim 23 wherein the modulator means also includes yieladable biasing means biasing the valve toward a position blocking fluid pressure communication from the first to the second chambers.

Claim 29

The combination of claim 23 including a telescopic connection between the actuator and housing structure and defining porting through which control fluid pressure is transmissible to a biasing piston acting to bias the by-pass valve toward a position blocking said fluid pressure communication from the first to the second chambers.

Claim 30

For use in a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the pressure in the first chamber being subject to increase to excessive levels in response to engagement of a vertically passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to the chambers, and b. modulator means operable, while actuating fluid pressure is being supplied to the first chamber, to increase the fluid pressure in the second chamber and in response to displacement of the tool relatively away from the string so as to cause the actuator to move toward The interior of the first chamber.

Claim 31

For use in a system that includes housing structure for passing a well string vertically therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the pressure in the first chamber being subject to increase to excessive levels in response to engagement of a vertically passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising a. supply means to selectively supply actuating fluid pressure to the chambers, and b. modulator means operable, while actuating fluid pressure is being supplied to the first chamber, to increase the fluid pressure in the second chamber and in response to displacement of the tool relatively away from the string so as to cause the actuator to move toward The interior of the first chamber.

Claim 32

The combination of claim 26 wherein said modulator means is in fluid pressure by-passing communication with said chambers in response to said tool displacement.

Claim 33

In the operation of a system that comprises annular packer means which is radially forcibly constricted to engage a well string being passed longitudinally therethrough, and means including a packer actuator forming a first chamber receiving fluid pressure acting to urge the actuator in a direction to effect said packer constriction, and a second chamber subsequently to receive fluid pressure acting to urge the actuator in a direction relieving packer constriction to allow radial expansion of the packer away from the string, the pressure in the first chamber being subjected to increase to excessive level in response to engagement of an enlargement on the string with the constricted packer and tending to expand the packer, the steps that include a. continuing the supply of actuating fluid pressure to the first chamber, and b. suddenly increasing the fluid pressure in the second chamber in response to said engagement.

Claim 34

In the operation of a system that comprises annular packer means which is radially forcibly constricted to engage a well string being passed longitudinally therethrough, and means including a packer actuator forming a first chamber receiving fluid pressure acting to urge the actuator in a direction to effect said packer constriction, and a second chamber subsequently to receive fluid pressure acting to urge the actuator in a direction relieving packer constriction to allow radial expansion of the packer away from the string, the pressure in the first chamber being subjected to increase to excessive level in response to engagement of an enlargement on the string with the constricted packer and tending to expand the packer, the steps that include a. continuing the supply of actuating fluid pressure to the first chamber, and b. suddenly increasing the fluid pressure in the second chamber in response to said engagement.

Claim 35

The method of claim 28 wherein said sudden increase of fluid pressure in the second chamber is effected by controllably by-passing to the second chamber excess pressurized fluid from the first chamber.

Claim 36

The method of claim 29 wherein said by-passing is effected in response to detection of an increase of pressure in the first chamber to said excessive level.

Claim 37

For use in a sub-sea system that includes housing structure for passing a well string longitudinally therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the pressure in the first chamber being subject to increase to excessive levels in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising modulator means operable, while actuating fluid pressure is being supplied to the first chamber, to increase the fluid pressure in the second chamber and in response to increase of fluid pressure in the first chamber caused by force transmission from the enlargement to the actuator via the tool, said modulator means including a by-pass valve, biasing means including an accumulator for biasing the valve toward a position blocking actuating fluid pressure communication from the first to the second chambers, a first pipe to communicate the inlet side of the by-pass valve with the first chamber, a second pipe to communicate the outlet side of the by-pass valve with the second chamber, and means to controllably communicate fluid pressure to said accumulator to supply said control fluid pressure.

Claim 38

For use in a sub-sea system that includes housing structure for passing a well string longitudinally therethrough, a string engaging tool movable generally laterally in the housing toward and away from the string, and a fluid pressure responsive actuator for the tool, there being first and second chambers in the housing to receive fluid pressure acting to urge the actuator in opposite directions, the pressure in the first chamber being subject to increase to excessive levels in response to engagement of a longitudinally passing string enlargement with the tool tending to displace the latter and the actuator, the combination comprising modulator means operable, while actuating fluid pressure is being supplied to the first chamber, to increase the fluid pressure in the second chamber and in response to increase of fluid pressure in the first chamber caused by force transmission from the enlargement to the actuator via the tool, said modulator means including a by-pass valve, biasing means including an accumulator for biasing the valve toward a position blocking actuating fluid pressure communication from the first to the second chambers, a first pipe to communicate the inlet side of the by-pass valve with the first chamber, a second pipe to communicate the outlet side of the by-pass valve with the second chamber, and means to controllably communicate fluid pressure to said accumulator to supply said control fluid pressure.

Claim 39

The combination of claim 31 wherein said last named means comprises a valve operable to communicate fluid pressure from said first pipe to said accumulator when the pressure in said first chamber increases to said excessive level, and to communicate fluid pressure from said second pipe to said accumulator in response to fluid pressure communication to said second chamber tending to hold said by-pass valve closed.

Claim 40

The combination of claim 31 wherein said last named means comprises a surface control, and an elongated pipe communicating said control with said accumulator.

Claim 41

The combination of claim 31 including a pressure differential switch connected across an orifice in said second pipe, said switch being operable to electrically control an indicator at the surface.

Claim 42

The combination of claim 31 including a four-way valve connected with said first and second pipes to selectively control actuating pressure supply thereto, the four-way valve having an outlet to which another pipe is connected to pass fluid exhausted from one of the first and seCond chambers, and a pressure switch connected in said other pipe.

Claim 43

In the operation of offshore drilling equipment wherein a pipe string extends longitudinally through a closed blow-out preventer at a sub-sea location, the preventer containing a fluid pressure chamber, the string including connectors of larger diameter than the pipe diameter, the steps that include a. effecting longitudinal displacement of the pipe, b. detecting pressure change in said chamber resulting from the movement of a connector into engagement with the sub-sea closed preventer, and c. adjusting the pipe string longitudinally to move the connector away from the preventer.

Claim 44

In the operation of offshore drilling equipment wherein a pipe string extends longitudinally through a closed blow-out preventer at a sub-sea location, the preventer containing a fluid pressure chamber, the string including connectors of larger diameter than the pipe diameter, the steps that include a. effecting longitudinal displacement of the pipe, b. detecting pressure change in said chamber resulting from the movement of a connector into engagement with the sub-sea closed preventer, and c. adjusting the pipe string longitudinally to move the connector away from the preventer.

Claim 45

The method of claim 36 wherein the equipment includes a drilling barge from which the string is suspended to be subject to up and down displacement due to wave action, said adjustment step being carried out to an extent preventing subsequent engagement of the connector with the closed preventer due to said up and down displacement.