Wells – Processes – Assembling well part
Reexamination Certificate
2002-06-14
2004-01-20
Schoeppel, Roger (Department: 3672)
Wells
Processes
Assembling well part
C166S242100, C277S314000, C277S559000, C029S520000
Reexamination Certificate
active
06679335
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to method for preparing casing for use in a wellbore.
BACKGROUND OF THE INVENTION
Within the context of petroleum drilling and well completions, wells are typically constructed by drilling the well bore using one tubular string, largely comprised of drill pipe, then removing the drill pipe string and completing by installing a second tubular string, referred to as casing, which is subsequently permanently cemented in place. The installation of casing, in this typical construction requires that the casing be run into long boreholes, some having horizontal stretches. In these horizontal stretches, the casing must be installed by pushing it along the borehole. In so doing the casing is pushed in engagement with the borehole wall.
Recent advances in drilling technology have enabled wells to be drilled and completed with a single casing string, eliminating the need to ‘trip’ the drill pipe in and out of the hole to service the bit and make room for the casing upon completion of drilling. This change is motivated by potential cost savings arising from reduced drilling time and the expense of providing and maintaining the drill string, plus various technical advantages, such as reduced risk of well caving before installation of the casing.
Once installed either in a standard way, by running in after a wellbore is drilled or by use as the drill string and the wellbore liner, casing is often cemented in place. Cementing is often adversely affected by movement of the casing once the cement has hardened.
The use of wellbore casing, including during installation through deviated wellbores or by drilling with casing and as a wellbore liner, challenges the performance requirements of the casing.
Any advancements in the wellbore casing wherein devices are attached to the outer surface of the casing, requires the devices be attached in a rugged way to the casing, since the devices must be installed at surface and conveyed downhole with the casing. In addition, any method for attaching the devices must not compromise the integrity of the casing and the devices themselves must be inexpensive since, even if used only to facilitate installation, they must be left downhole with the casing.
SUMMARY OF THE INVENTION
A method has been invented for preparing casing for use in a wellbore. The casing produced by the method is particularly suited to overcome one or more problems encountered in running casing into a borehole, using the casing as a drill string and cementing the casing in place in the borehole. In the method, a device supporting use of the casing in a wellbore is crimped onto the outer surface of the casing. The device supporting use of the casing in a wellbore can be a device for supporting installation of the casing, either by standard run in operations or by use as a drill string, or can be a device for supporting the cementing of casing into the borehole.
The device supporting casing installation can be to facilitate run in through the borehole, to maintain casing positioning relative to the borehole and/or to accommodate wear against the wall of the borehole into which the casing is run.
The device supporting casing cementing, can be to enhance engagement between the casing and the annular cement between the casing and the borehole wall.
The devices supporting the use of casing in a wellbore are attached to the casing to create a connection having structurally significant axial and torque load transfer capacity. When using methods according to the present invention, the load transfer capacity of the connection between the device and the casing can be arranged to substantially prevent significant relative movement of the device on the casing under loads that may be encountered when installing one or more of the casing joints as a liner into a wellbore which has been drilled using a conventional drilling operation or when using one or more of the casing joints as components of a tubular string used for drilling and lining a well bore.
Thus, in accordance with one aspect of the present invention, there is provided a method for preparing a casing joint for use in a wellbore, selecting a joint of casing having an outer diameter and an outer surface and capable of receiving a device thereon by crimping and selecting a device supporting the use of the casing in a wellbore, the device having an outer facing surface, an inner bore sufficiently large to allow insertion therethrough of the joint of casing, and at least one tubular section on the body, the portion of the inner bore extending through the tubular section having an internal diameter capable of loosely fitting about the outer diameter of the joint of casing; positioning the device on the joint of casing such that the joint of casing extends through the inner bore; and crimping the device onto the joint of casing by applying an inward, substantially radially-directed force to a plurality of points about an outer circumference of the tubular section causing it to plastically deform inwardly and come into contact with the outer surface of the joint of casing, applying such additional inward, substantially radially directed force as required to force both the tubular section of the device and the outer surface of the casing to displace inwardly an amount at least great enough so that when the force is released, an interference fit is created between the device and the casing.
The step of applying substantially radially-directed force to a plurality of points about an outer circumference of the tubular section is termed herein as “crimping”.
Preferably, by selection of casing, device supporting use of the casing in a wellbore and/or force applied, the inward displacement of the casing outer surface is not so great that the drift diameter of the casing is excessively reduced. In one embodiment, the casing is not displaced inwardly beyond the drift diameter. However, in another embodiment, the inward displacement of the casing outer surface causes the inner diameter of the casing to be reduced beyond the drift diameter of the casing.
In one embodiment the method can be used to produce casing for wellbore completion, in another embodiment the method can be used to produce casing for use in a drill string and in another embodiment the method can be used to produce a casing joint particularly suited for cementing into a wellbore. The device supporting use of the casing can be selected from those useful for facilitating run in of the casing, those for controlling the positioning of the casing within the borehole, those for accommodating wear against the wall of the borehole into which the casing is run, those for use in anchoring the casing in the wellbore to inhibit relative movement between the casing string and the wellbore wall or those providing combinations of the foregoing.
Frictional forces enabled by the interference fit at the inwardly displaced section provide the mechanism by which structurally significant axial and torsional load may be transferred between the device and the casing substantially without slippage therebetween.
The casing on for use in the present invention must be capable of accepting the hoop stresses of crimping without becoming unstable, for example, without buckling or crumpling. This generally requires that the casing be thick-walled, for example, having an external diameter to thickness ratio (“D/t”) less than 100 and preferably less than 50.
To be most generally useful for this method, the devices useful in the present invention should be amenable to rapid field installation on joints of casing having at least one non-upset end.
The tubular section of the device under application of load at a plurality of points about its circumference has an elastic resiliency less than the elastic resiliency of the casing onto which it is crimped. The tubular section can be cylindrical or largely cylindrical with some radial or axial variations to the internal diameter or outer surface. The tubular section should be substantially circumferentially continuous such that a
Kaiser Trent Michael Victor
Slack Maurice William
Bennett Jones LLP
Schoeppel Roger
Tesco Corporation
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