Method and means for controlling kicks during operations in a borehole penetrating subsurface formations

Claim 2

Means for controlling kicks during operations in a bore hole penetrating subsurface formations, said means being adapted to be included between two portions of tubular bore hole equipment and comprising: an elongated body member with a conduit longitudinally therethrough, and a first valve system arranged in this conduit for controlling the passage of fluid therethrough; an inflatable packer around the body member and comprising an elastic annular element connected at each end thereof to an annular sleeve arranged slidingly in axial direction on part of the outer wall of the elongate body member and sealing against the said outer wall; and a second valve system to control fluid communication between the exterior of the body member and the conduit extending longitudinally through the body member and between the interior of the inflatable packer and the said conduit through the body member, said second valve system including one of the annular sleeves, means being provided for retaining said sleeve during inflation of the packer when supplying fluid to the interior thereof in a position in which it closes off the communication between the exterior of the body member and the conduit through the body member but allows communication between this conduit and the interior of the inflatable packer.

Claim 3

Means according to claim 1, wherein the annular sleeve forming part of the second valve system has a cross-section greater than the crosssection of the other annular sleeve, and is mounted on part of the body member having a smaller cross-section than the part on which the other annular sleeve is mounted.

Claim 4

Means according to claim 1, wherein the annular sleeves of the packer are freely rotatable around the body member.

Claim 5

Means according to claim 1, wherein the annular sleeve forming part of the second valve system is movable between two end positions and cooperates with at least one bore in the wall of the body member, which interior of the packer in the second and third position, and the other sleeve closing off the entrance to the bore leading from the exterior of the body member to the cylinder/piston system of the first valve element of the first valve system in the third position.

Claim 6

Means according to claim 4, wherein the second valve system includes fluid control means arranged in the conduit through the body member and actuatable by the first valve system, these fluid control means being displaceable between two end positions and closing off the bore in one of the end positions.

Claim 7

Means according to claIm 5, wherein a vent conduit is provided to vent the interior of the packer to the exterior of the body member in one of the end positions of the sleeve and of the fluid control means of the second valve system.

Claim 8

Means according to claim 5, wherein the first valve system comprises a first valve element and a second valve element, each element being movable between two end positions, means adapted to urge the valve elements apart to positions in which there is a free passage through the conduit extending longitudinally through the elongated body member, and dampening means adapted to control the relative speed between the elements when they are urged apart, the two valve elements when contacting each other closing off the passage through the said conduit, the first valve element being a non-return valve and the second valve element being coupled to the fluid control means of the second valve system.

Claim 9

Means according to claim 7, wherein the dampening means operate only when the valve elements of the first valve system are moved in the direction of the flow of drilling liquid when passing through the tubular borehole equipment.

Claim 10

Means according to claim 7, wherein the dampening means is of the hydraulic type and arranged between the two valve elements of the first valve system.

Claim 11

Means according to claim 7, wherein the dampening means is of the hydraulic type and arranged between the first valve element of the first valve system and the body member.

Claim 12

Means according to claim 7, wherein a cylinder/piston system is arranged between the second valve element of the first valve system and the body member, said cylinder communicating with the exterior of the body member via a bore in the wall of the body member, which bore can be closed off by that annular sleeve of the inflatable packer, which sleeve does not form part of the second valve system.

Claim 13

Means according to claim 7, wherein a cylinder/piston system is arranged between the first valve element of the first valve system and the body member, said cylinder communicating with the interior of the inflatable packer.

Claim 14

Means according to claim 7, wherein a cylinder/piston system is arranged between the first valve element of the first valve system and the body member, said cylinder communicating with the exterior of the body member via a bore in the wall of the body member.

Claim 15

Means according to claim 13, wherein the packer cooperates with the body member via a pin and slot system allowing the packer when inflated to be positioned in three distinct positions with respect to the body member, the annular sleeve forming part of the second valve system closing off the communication between the exterior of the body member and the conduit extending through the body member in the first position and second position, said sleeve closing off the communication between the said conduit and the bore in one end position of the sleeve forms a communication between the conduit through the body member and the exterior of the body member, and in the other end position of the sleeve forms a communication between the conduit through the body member and the interior of the inflatable packer.

Claim 16

Means according to claim 7, wherein a cylinder/piston system is arranged between the first valve element of the first valve system and the body member, said cylinder communicating with the conduit extending axially through the body member via a bore, the entrance to which bore being controlled by the fluid control means of the second valve element that are arranged in the conduit.

Claim 17

Means according to claim 15, wherein a second cylinder/piston system is arranged between the first valve element of the first valve system and the body member, said cylinder communicating with the interior of the packer and with the exterior of the body member via separate communication bores in the wall of the body member, the communication between the cylinder and the exterior of the body member being controlled by an annular Sleeve of the packer, and the communication between the cylinder and the interior of the packer being controlled by a piston on the first valve element of the first valve system.

Claim 18

Means according to claim 1, wherein the annular sleeve forming part of the second valve system is movable between two end positions and cooperates with a first bore in the wall of the body member and forming a communication between the conduit through the body member and exterior of the body member, and with a second bore in the wall of the body member and forming a communication between the conduit through the body member and the interior of the inflatable packer, said annular sleeve closing off the first bore in one of the end positions and closing off the second bore in the other end position.

Claim 19

Means according to claim 17, wherein the second valve system includes fluid control means arranged in the conduit through the body member and actuatable by the first valve system, these fluid control means being displaceable between two end positions and closing off the second bore in one of the end positions.

Claim 20

Means according to claim 1, wherein the body member comprises a telescopic joint with torque transmission means, said first valve system comprises a first valve element connected via a connecting element to one of the elements of the telescopic joint and movable between two end positions, said first valve element closing off the passsage through the conduit extending through the body member in the extended position of the joint and leaving this passage free in the contracted position of the joint.

Claim 21

Means according to claim 19, wherein the first valve system comprises a second valve element being of the non-return type and displaceable between two end positions along the connector element, said second valve element closing off the passage through the said conduit in one of the end positions.

Claim 22

Method for controlling kicks during operations in a borehole penetrating subsurface formations, in which equipment including a drill string and a means as claimed in claim 1 is suspended, said method comprising the steps of: a. stopping the operations; b. closing off the annular space around the drill string at a level near the entrance of the borehole and actuating the first valve system to closing position; c. pumping down fluid through the drill string to inflate the packer to close off the annular space around the drill string; d. stopping the pumping fluid; e. displacing the drill string with respect to the inflated packer set against the wall of the borehole, to operate the second valve system to open the communication between the exterior of the body member and the conduit extending through the body member; f. opening the annular space at the level near the borehole entrance; g. resuming pumping of fluid through the drill string and changing the composition of this fluid; h. displacing fluid in the annular space by the fluid of different composition; i. stopping the fluid circulation and subsequently displacing the drill string with respect to the inflated packer set against the wall of the borehole to operate the second valve system to close the communication between the conduit and the exterior of the body member to deflate the packer, and j. resuming operations.

Claim 23

Method according to claim 21, wherein the step of lifting the drill string is included between the steps (a) and (b).

Claim 24

Method according to claim 21, in which the equipment includes the means as claimed in claim 8 in which the first valve system is actuated into closing position in step (b) after closing off the annular space around the drill string at a level near the entrance of the borehole, by temporarily opening the upper end of the drill string and allowing an upward flow of fluid through the drill string.

Claim 25

Method according to claim 21, wherein the actuation of the first valve system in step (b) is performed by lifting the equiPment free from the borehole.

Claim 26

Method according to claim 21, wherein the actuation of the first valve system in step (b) is performed by the step of closing the first valve element thereof by lifting the equipment free from the bottom of the borehole and by the step of closing the second valve element thereof by opening the upper end of the drill string and allowing an upward flow of fluid through the drill string, and to the step of closing off the annular space around the drill string at a level near the borehole entrance.

Claim 27

Method according to claim 21, in, and including between steps (e) and (f) the step of measuring the pressure in the annular space below the packer set against the bore-hole wall, said measuring step comprising slowly lowering the pressure within the upper end of the drill string to open the first valve system, measuring the pressure variation in the string until the lowest value has been reached, followed by opening the upper end of the drill string to close the first valve system.

Claim 28

Method according to claim 21, including the step of measuring the pressure in the annular space below the packer set against the wall of the borehole, this step being carried out between the steps e) and f).

Claim 29

Method according to claim 27, in which the measuring step includes gradually varying the pressure at the entrance of the drill string and measuring the pressure at said entrance.

Claim 30

Method according to claim 28, wherein the annular space at the level near the borehole entrance is opened and the pressure at the entrance of the drill string is measured when there is change in conditions of the fluid in said annular space.