Pipe joints or couplings – With casing – lining or protector – Lined
Reexamination Certificate
1998-04-29
2001-07-24
Browne, Lynne H. (Department: 3629)
Pipe joints or couplings
With casing, lining or protector
Lined
C285S239000, C285S333000, C138S109000
Reexamination Certificate
active
06264244
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a connector for coiled tubing and more particularly to an end connector for composite coiled tubing to adapt the composite coiled tubing to be connected to various types of apparatus or equipment used in downhole operations in a wellbore.
Reeled or coiled tubing has been run into wells for many years for performing certain downhole operations, including, but not limited to, washing out sand bridges, circulating treating fluid, setting downhole tools, cleaning the internal walls of well pipes, conducting production fluids or lift gas, and a number of other similar remedial or production operations.
Conventionally, coiled tubing is made of steel. Although steel has been and is useful in such downhole operations, other materials are available which provide certain advantages over steel coiled tubing. For instance, coiled tubing may be made from a nonferrous material which will not suffer from some of the structural limitations of steel tubing and which is more resistant to chemicals. Coiled tubing may thus be made from fibrous composite material which results in a composite coiled tubing that is not as heavy as steel coiled tubing, provides greater corrosion resistance and has a longer fatigue life.
Such composite coiled tubing used in wellbore operations may be exposed to external pressures in excess of 5000 psi, and internal pressures as high as 15,000 psi. Tension and compression forces caused by the tubing being forced into or pulled out of a wellbore may exceed 60,000 lbf.
In order to perform the various wellbore operations, it is usually necessary to make connections between the composite coiled tubing and different types of apparatus or equipment used in downhole operations. The connection must be capable of handling the severe loads and pressures experienced during such operations. Numerous known connectors and connecting techniques, such as welding, are utilized with steel coiled tubing. Welding is not an option with composite coiled tubing and steel tubing connectors, like that described in U.S. Pat. No. 4,936,618 to Sampas et al., are not applicable to the composite coiled tubing being developed for use in downhole operations.
One type of end connector for use with composite coiled tubing is disclosed in application Ser. No. PCT/US96/15427. The connector shown there includes a load collar and housing arrangement disposed about the outer surface of the composite coiled tubing. Although the connector shown therein may provide an adequate structural connection capable of handling the extreme conditions that may exist in a wellbore, there are circumstances when such a connector cannot be used. For example, there may be circumstances where it is desirable to use composite coiled tubing in downhole operations where the inner diameter of the casing, production tubulars, or other downhole apparatus through which the tubing must pass, is such that a connector having a diameter greater than the tubing would cause an unacceptable amount of interference as the tubing is lowered into or raised from the wellbore. Similar difficulties may not occur with respect to steel coiled tubing, since steel tubing typically will have a thinner wall than composite coiled tubing connector.
This invention resolves any such difficulty by providing an end connector having an outer surface that is substantially flush with the outer surface of the composite coiled tubing when connected thereto, so that composite coiled tubing can be used in virtually any wellbore for which steel coiled tubing having the same inner diameter would be used, without causing any interference problems with the inner walls of the casing or production tubulars.
SUMMARY OF THE INVENTION
The present invention relates to an end connector for connecting the end of a composite coiled tubing to various tools and apparatus used in downhole wellbore operations. The invention is also directed to a method for providing a connection means to the end of composite coiled tubing.
The composite coiled tubing is spoolable and may be supplied on a large drum or reel, and is comprised of an outer composite structure containing several plies of high strength and stiffness fibers embedded in a resin material such as epoxy. The fibers are oriented to resist internal and external pressure and provide low bending stiffness. Fibers of high strength and modulus are embedded and bonded into a matrix that keeps the fibers in position, acts as a load transfer medium and protects the fibers from environmental damage. The plastic binder in which the fibers are embedded to form the matrix will have an appropriate modulus of elasticity to enclose the composite coiled tubing to withstand the aforementioned downhole conditions. Typically, a liner may be employed in the tubing to serve as a structural member, one function of which is pressure containment to resist leakage of internal fluids within the tubing. A wear surface is employed as an outer layer and may be comprised of a binder containing particles of a tough material.
The end connector for the composite coiled tubing is insertable into the end of the composite coiled tubing and is connectable thereto. The end connector has an outer surface defining an outer diameter, or periphery that is substantially flush with, or radially recessed inwardly from the outer diameter or periphery defined by the outer surface of the composite coiled tubing. In other words, the outer surface of the end connector defines an outer diameter having a magnitude that may be substantially equal to or less than the magnitude of the outer diameter defined by the composite coiled tubing, but which may not be greater than the composite coiled tubing outer diameter.
The end connector may comprise a connector body having a first end portion, an intermediate portion and a second end portion wherein the first end portion is insertable into the end of the composite coiled tubing. Preferably, the first end portion is threadably connectable with an inner surface of the composite coiled tubing.
Thus, the first end portion may include a threaded section which will engage threads defined on the inner surface of the composite coiled tubing. The end connector may also include a second end portion adapted to be connected to any apparatus, tool, or other equipment used in downhole wellbore operations. The terms apparatus, tool and/or equipment, when used in reference to what is being connected to the end connector, is all inclusive and shall be considered to include any and all couplings, connectors, adapters, tools and apparatus that might be attached to coiled tubing for use in connection with downhole operations, including couplings utilized to connect the second end portions of two end connectors, each being attached to a length of composite coiled tubing, thus connecting two lengths of composite tubing. The second end portion may therefore have threads defined on either the outer or the inner surface thereof, thereby adapting the end of the composite coiled tubing to be connected to any conventional apparatus or equipment.
The first end portion may further include a seal section. The threaded section of the first end portion is preferably positioned between the intermediate portion of the end connector and the seal section of the first end portion. Thus, when the end connector is threaded into an end of composite coiled tubing, the seal section will extend into a central opening defined by the composite coiled tubing, and will preferably extend into and sealingly engage the liner disposed in the composite coiled tubing, thus providing a sealing means to seal between the end connector and the composite coiled tubing. The seal section provides a fluid-tight seal between the end connector and the composite tubing by providing a fluid-tight seal between the seal section and the liner disposed therein.
The first end portion of the connector extends away from the intermediate portion in a first direction and the second end portion extends away from the intermediate portion in a second directi
Berning Scott A.
Headrick Dickey C.
Isennock Clint W.
Binda Greg
Browne Lynne H.
Halliburton Energy Service,s Inc.
McCully Michael D.
Shull William E.
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