Boring or penetrating the earth – With means movable relative to tool below ground to control...
Reexamination Certificate
1998-12-10
2001-01-16
Dickson, Paul N. (Department: 3618)
Boring or penetrating the earth
With means movable relative to tool below ground to control...
C166S321000, C166S323000
Reexamination Certificate
active
06173795
ABSTRACT:
The invention relates to circulating subs for use in wellbores, particularly but not exclusively to circulating subs used during downhole drilling operations.
It is often necessary in downhole drilling operations to bleed the flow of wellbore fluid down the drill string into the wellbore annulus. For example, this may be necessary where the desired fluid flow rate to drive a drilling tool is insufficient to carry all the drilled material up the annulus to the surface. In these circumstances, a circulating sub may be used to allow the flow rate required to remove the drilled material to be pumped into the annulus whilst maintaining the lower flow rate required at the drilling tool.
Conventional circulating subs may be moved between an open configuration, in which fluid may bleed to the wellbore annulus, and a closed configuration, in which fluid is prevented from flowing to the annulus, through the use of a PBL sub. When the circulating sub is to be activated, a deformable plastics drop ball is introduced into the drill string and carried downhole to a ball seat by the action of fluid flow and/or gravity. Once the drop ball is received by the ball seat, pump pressure generates a static pressure differential which is employed to move the circulating sub to the open configuration. If the closed configuration is then required, the drop ball may be forced past the seat with additional pump pressure and retained in a catcher adapted to allow the passage of fluid. The circulating sub then returns to its initial configuration by means of a biasing spring. However, this type of circulating sub can prevent the use of wireline or coil tubing tools (since the drop ball substantially blocks the bore through the string) and can be unreliable or inconvenient to use. Furthermore, such circulating subs may only be reset once whilst located downhole. If the circulating sub is to be reset for a second time, then the sub must be withdrawn from the wellbore and the first drop ball manually removed from the catcher.
It is an object of the present invention to provide a circulating sub which is reliable, convenient to use and capable of being reset many times whilst remaining downhole. It is also an object of the present invention to provide a circulating sub which allows the passage of tools therethrough and is thereby compatible with the use of wireline or coil tubing tools.
The present invention provides a multi-cycle circulating sub for selectively providing fluid communication between the interior of a downhole assembly and the exterior thereof, the multi-cycle circulating sub comprising: a body incorporating a wall provided with at least one aperture extending therethrough; a sleeve having a longitudinal bore extending therethrough and being slidably mounted in the body so as to be moveable between a first position relative to the body preventing fluid communication between the bore of the sleeve and the exterior of the body via the or each aperture and a second position relative to the body permitting fluid communication between the bore of the sleeve and the exterior of the body via the or each aperture; and controlling means for controlling the movement of the sleeve between the first and second positions; the controlling means comprising: a control member slidable in the body and moveable by fluid pressure in the body in a first axial direction relative to the body; a spring biasing the control member in an opposite axial direction of the body; a pin secured to one of the body and the control member; and a control groove in which a portion of the pin is received formed in the other of the body and the control member, the control groove being shaped to limit axial displacement of the control member in response to pressure variations in the body such that only after a predetermined number of movements of the control member to a first limit position is the control member able to move to a second limit position to displace the sleeve into the second position of the sleeve.
Preferably, the control member is a piston which is moveable in the body independently of the sleeve. The location of the piston in the body may be such that the piston moves towards the sleeve when axially displaced in the first axial direction relative to the body. Furthermore, the piston is preferably located relative to the sleeve so as to abut and press the sleeve when moving to the second limit position. A guide pin may be secured to one of the body and the sleeve which is received in a guide slot formed in the other of the body and the sleeve, the guide slot extending in a direction parallel to the direction of axial movement of the sleeve so as to prevent rotation of the sleeve. The sleeve is preferably biased towards the first position by means of a spring.
The control member preferably comprises a longitudinal bore extending therethrough. Also, the control groove preferably is provided in a direction having one component parallel to the direction of axial movement of the control member. It is further preferable for the control groove to encircle the longitudinal axis of the control member. The control groove may also provide at least one extension portion extending in a direction having one component parallel to the direction of axial movement of the control member so as to enable the control member to move to the second limit position. Preferably, the control groove is provided on the control member and the pin is secured to the body.
The sleeve may also incorporate a wall provided with at least one opening extending therethrough such that, in the first position the or each opening of the sleeve is offset from the or each aperture of the body so as to prevent the passage of fluid through the or each opening and the or each aperture, and in the second position the or each opening of the sleeve is in register with the or each aperture of the body so as to permit the passage of fluid through the or each opening and the or each aperture.
A bearing is preferably provided between the control member and the spring biasing the control member. A chamber may also be defined between a portion of the control member and a portion of the body, and the spring biasing the control member may be located therein.
The present invention has the advantage over the prior art of being reliable and convenient to use. The circulating sub of the present invention may also be used in conjunction with wireline or coil tubing tools.
REFERENCES:
patent: 2921601 (1960-01-01), Fisher, Jr.
patent: 3823773 (1974-07-01), Nutter
patent: 4294314 (1981-10-01), Miyagishima et al.
patent: 4407377 (1983-10-01), Russell
patent: 4645006 (1987-02-01), Tinsley
patent: 4657082 (1987-04-01), Ringgenberg
patent: 4817723 (1989-04-01), Ringgenberg
patent: 5609178 (1997-03-01), Hennig et al.
patent: 5890540 (1999-04-01), Pia et al.
Barr Lawrence Robert
McGarian Bruce
Dickson Paul N.
Gossett PLLC Dykema
Silteris Joselynn
Smith International Inc.
LandOfFree
Multi-cycle circulating sub does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multi-cycle circulating sub, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-cycle circulating sub will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2514378