Electrical connectors – With coupling movement-actuating means or retaining means in... – Coupling part with relatively pivotable concentric...
Reexamination Certificate
2000-03-24
2004-07-13
Estremsky, Gary (Department: 3677)
Electrical connectors
With coupling movement-actuating means or retaining means in...
Coupling part with relatively pivotable concentric...
C285S039000
Reexamination Certificate
active
06761574
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
FIELD OF THE INVENTION
The present invention relates generally to devices used to connect lengths of coiled tubing and more particularly to devices used to connect lengths of composite coiled tubing. Another feature of the present invention relates to providing a mechanical connection of sufficient strength so that forces of tension, compression, and torque can be transferred from one length of tubing to the other through the connector. Further the connection between lengths of tubing is hydraulically sealed so as to separate fluids conducted inside the tubing and the connector from any fluids on the outside of the tubing and connector. The connector also permits the fluids inside a length of tubing to flow through the connector on to the sequential length of tubing. The connector of the present invention also provides a mechanism that permits the lengths of tubing to be connected without imparting any rotation on either length of tubing. Additionally, the invention relates to connectors that will also allow an electrical connection from the joining of electrical wires, or other types of signaling cables, embedded within each multi-conductor pair of tubing to be joined. The electrical connection provides seals and insulation that insulates both wire-to-wire and wire-to-fluid.
BACKGROUND OF THE INVENTION
Many existing wells include hydrocarbon pay zones which were bypassed during drilling and completion because such bypassed zones were not economical to complete and produce. Offshore drilling rigs cost approximately $40 million to build and may cost as much as $250,000 a day to lease. Such costs preclude the use of such expensive rigs to drill and complete these bypassed hydrocarbon pay zones. Presently, there is no cost effective methods of producing many bypassed zones. Thus, often only the larger oil and gas producing zones are completed and produced because those wells are sufficiently productive to justify the cost of drilling and completion using offshore rigs.
Many major oil and gas fields are now paying out and there is a need for a cost effective method of producing these previously bypassed hydrocarbon pay zones. The locations and size of these bypassed hydrocarbon zones are generally known, particularly in the more mature producing fields.
To economically drill and complete the bypassed pay zones in existing wells, it is necessary to eliminate the use of conventional rigs and conventional drilling equipment. One method of producing wells without rigs is the use of metal coiled tubing with a bottom hole assembly. See for example U.S. Pat. Nos. 5,115,151; 5,394,951 and 5,713,422, all incorporated herein by reference. The bottom hole assembly typically includes a downhole motor providing the power to rotate a bit for drilling the borehole. The bottom hole assembly operates only in the sliding mode since the metal coiled tubing is not rotated at the surface like that of steel drill pipe which is rotated by a rotary table on the rig. The bottom hole assembly may include a tractor which propels the bottom hole assembly down the borehole. One such tractor is a thruster that pushes off the lower terminal end of the coiled tubing and does not rely upon contacting or gripping the inside wall of the borehole. The depth that can be drilled by such a bottom hole assembly is limited.
Coiled tubing, as currently deployed in the oilfield industry, generally includes small diameter cylindrical tubing having a relatively thin wall made of metal or composite material. Coiled tubing is typically much more flexible and of lighter weight than conventional drill pipe. These characteristics of coiled tubing have led to its use in various well operations. For example, coiled tubing is routinely utilized to inject gas or other fluids into the well bore, inflate or activate bridges and packers, transport well logging tools downhole, perform remedial cementing and clean-out operations in the well bore, and to deliver or retrieve drilling tools downhole. The flexible, lightweight nature of coiled tubing makes it particularly useful in deviated well bores.
Typically, coiled tubing is introduced into the oil or gas well bore through wellhead control equipment. A conventional handling system for coiled tubing can include a reel assembly, a gooseneck, and a tubing injector head. The reel assembly includes a rotating reel for storing coiled tubing, a cradle for supporting the reel, a drive motor, and a rotary coupling. During operation, the tubing injector head draws coiled tubing stored on the reel and injects the coiled tubing into a wellhead. The drive motor rotates the reel to pay out the coiled tubing and the gooseneck directs the coil tubing into the injector head. A rotary coupling provides an interface between the reel assembly and a fluid line from a pump. Fluids are often pumped through the coiled tubing during operations. Such arrangements and equipment for coiled tubing are well known in the art.
The use of metal coiled tubing has various deficiencies. Metal coiled tubing tends to buckle the deeper the bottom hole assembly penetrates the borehole. Buckling is particularly acute in deviated wells where gravity does not assist in pulling the tubing downhole. As the tubing buckles, the torque and drag created by the contact with the borehole becomes more difficult to overcome and often makes it impractical or impossible to use coiled tubing to reach distant bypassed hydrocarbon zones. Further, steel coiled tubing often fatigues from cyclic bending early in the drilling process and must be replaced. It has also been found that coiled tubing may be as expensive to use as a conventional drilling system using jointed steel pipe and a rig.
While prior art coiled tubing handling systems are satisfactory for coiled tubing made of metal such as steel, these systems do not accommodate the relatively long spans or drill string lengths achievable with coiled tubing made of composites. Such extended spans of composite coiled tubing strings are possible because composite coiled tubing is significantly lighter than steel coiled tubing. In fact, composite coiled tubing can be manufactured to have neutral buoyancy in drilling mud. With composite coiled tubing effectively floating in the drilling mud, downhole tools, such as tractors, need only overcome frictional forces in order to tow the composite coiled tubing through a well bore. This characteristic of composites markedly increases the operational reach of composite coiled tubing. Thus, composite coiled tubing may well allow well completions to depths of 20,000 feet or more, depths previously not easily achieved by other methods.
Moreover, composite coiled tubing is highly resistant to fatigue failure caused by “bending events,”a mode of failure that is often a concern with steel coiled tubing. At least three bending events may occur before newly manufactured coiled tubing enters a well bore: unbending when the coiled tubing is first unspooled from the reel, bending when travelling over a gooseneck, and unbending upon entry into an injector. Such accumulation of bending events can seriously undermine the integrity of steel coiled tubing and pose a threat to personnel and rig operations. Accordingly, steel coiled tubing is usually retired from service after only a few trips into a well bore. However, composite coiled tubing is largely unaffected by such bending events and can remain in service for a much longer period of time.
Hence, systems utilizing composite coiled tubing can be safely and cost-effectively used to drill and explore deeper and longer wells than previously possible with conventional drilling systems. Moreover, completed but unproductive wells may be reworked to improve hydrocarbon recovery. Thus, composite coiled tubing systems can allow drilling operations into formations that have been inaccessible in the past and thereby further maximize recovery of fossil fuels.
However, these dramatic improvements in drilling operations cannot be realized without handl
Estep James W.
Song Haoshi
Terry James B.
Wilson Thomas Platt
Conley & Rose, P.C.
Estremsky Gary
Halliburton Energy Service,s Inc.
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