Heavy-duty logging and perforating cablehead for coiled tubing and method for releasing wireline tool

Information

  • Patent Grant
  • 6196325
  • Patent Number
    6,196,325
  • Date Filed
    Friday, December 4, 1998
    25 years ago
  • Date Issued
    Tuesday, March 6, 2001
    23 years ago
Abstract
A heavy-duty logging and perforating cablehead for coiled tubing. The cablehead includes an upper and lower housing which are shearably connected by shear pins. An actuating piston is slidably disposed in the housing. When the piston is in a running position, the piston holds a lug in locking engagement with the upper and lower housings such that the shear pins cannot be sheared. When the piston is moved to a releasing position, the lugs are released so that the upper and lower housings may be separated, thereby shearing the shear pins. Actuation of the piston is accomplished by pumping fluid down the coiled tubing and through a flow path in the cablehead and by applying pressure to the piston.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to cableheads for coiled tubing logging operations, the cableheads having mechanical devices for releasing a stuck tool, and more particularly, to a cablehead which allows releasing of a tool when desired while preventing accidental and premature release of the tool.




2. Description of the Prior Art




In heavy-duty logging and/or perforating operations, the logging tool and/or perforating guns may be run into the well using coiled tubing electric line reels. This technique is used particularly often on deviated or horizontal wells. Typically, a cablehead is positioned between the end of the length of coiled tubing and the logging tool and/or perforating guns. The cablehead has a means for mechanically connecting the tubing to the tool or guns and also for providing an electrical connection between a logging cable run down the inside of the coiled tubing and the logging tool or perforating guns. Many of these cableheads also include a means for releasing the tool or guns in the event that the tool or guns becomes stuck in the well.




Prior to the present invention, most cableheads for coiled tubing logging operations have relied on mechanical disconnects to provide a means of releasing in the event of a stuck tool situation. With such a mechanical disconnect, the coiled tubing is generally released from the stuck tool or gun by applying a predetermined amount of tension on the coiled tubing, thereby breaking a set of shear pins in the cablehead. Once the shear pins are broken, the coiled tubing is removed from the well, and the stuck tool or perforating gun may be fished out on a subsequent trip into the well.




A problem with the prior art mechanical disconnect portion of these cableheads is that there is a tendency to accidentally shear during perforating operations. When the guns are shot in wells that are substantially horizontal, this is not much of a problem because the vertical, or axial, shock loading is substantially negligible. However, when a well is deviated at a shallower angle, for example 60°, a substantial vertical shock load component is created when the guns are fired. Often, this vertical shock load is enough to prematurely shear the shear pins in the cablehead. Obviously when this happens, the guns are released and left in the well unintentionally.




Another problem with the mechanical disconnect portion of these prior art cableheads is that there are limitations when the shear load for shearing the pins is selected. The natural tendency of a tool operator is to select shear pins with strengths that are very high in order to prevent accidentally releasing the tool or perforating guns when in the well. However, the tensile strength of the coiled tubing is also a factor which must be considered when making the shear pin selection. For example, in a deep well, the weight of the coiled tubing string hanging in the well may be so high that the available over-pull at the surface is limited to a few thousand pounds. If the operator pulls on the tubing string at a higher load than this, there is the risk of parting the tubing at the surface, thereby leaving the entire tubing string and tool in the well which, of course, is a very undesirable situation.




The present invention solves this problem by providing a locking means such as a set of lugs to securely lock the components of the cablehead together so that no loading is prematurely applied to the shear pins. The shear pins may only be sheared after fluid is pumped down the coiled tubing and pressure applied to actuate a piston in the cablehead to release the lugs so that a shearing force may then be applied to the shear pins. Thus, there can be no premature shearing as in prior art mechanical disconnects.




SUMMARY OF THE INVENTION




The present invention is a cablehead for use with coiled tubing electric line in well operations. The cablehead comprises a housing and an actuating piston slidably disposed in the housing. The housing comprises an upper housing adapted for connection to a length of coiled tubing, a lower housing adjacent to the upper housing, and a shearing means for shearably attaching the lower housing to the upper housing. The cablehead further comprises a locking means, disposed between the upper and lower housings, for preventing shearing of the shearing means when the locking means is in a locked position and allowing shearing of the shearing means by relative movement between the upper and lower housing when the locking means is in an unlocked position. The piston has a running position holding the locking means in the locked position and is movable to a releasing position allowing movement of the locking means to the unlocked position.




The cablehead further comprises biasing means in the housing for biasing the piston toward the running position thereof. In the preferred embodiment, the biasing means is characterized by a compression spring.




The housing and piston define a first flow path therein through which fluid may be circulated when the piston is in the running position. A nozzle is disposed across the first flow path for controlling a fluid flow rate therethrough. This nozzle is one of a plurality of interchangeable nozzles which may have various sizes of orifices or ports therein. This first flow path is closed when the piston is in the releasing position.




The housing also defines a second flow path therethrough whereby fluid may be circulated when the piston is in the releasing position.




The piston has a saddle thereon which is aligned with the locking means when the piston is in the releasing position thereof so that the releasing means may be moved inwardly into the saddle. The piston comprises an upper piston on which the saddle is located and a prop attached to the upper piston.




The apparatus may also comprise a spring rest disposed in the housing and a second shearing means for shearably attaching the spring rest to the housing. This second shearing means is sheared when the piston is moved to the releasing position thereof. In the preferred embodiment, the spring is engaged with the piston and spring rest and disposed therebetween.




The upper housing defines a recess therein, and the lower housing defines a lug window therein aligned with the recess. The locking means is characterized, in the preferred embodiment, by a lug disposed in the window and extending into the recess when in the locked position and spaced from the recess when in the unlocked position. The lug extends into the saddle on the piston when the lug is in the unlocked position.




The present invention also includes a method of releasing a wireline tool in a well. This method comprises the step of providing a cablehead for connecting the wireline tool to a length of coiled tubing. This cablehead may be said to generally comprise a housing having an upper housing connectable to the coiled tubing and a lower housing shearably attached to the upper housing and connectable to the wireline tool, a lug disposed in the housing for preventing shearing disconnection of the upper and lower housings when the lug is in a locked position and allowing shearing disconnection of the upper and lower housings when the lug is in an unlocked position, and a piston disposed in the housing and movable between a running position holding the lug in the locked position and a releasing position allowing the lug to be moved to the unlocked position.




The method further comprises the steps of running the coiled tubing, cablehead and wireline tool into the wellbore with the piston in the running position thereof, pumping fluid down the coiled tubing and applying pressure to the piston and thereby moving the piston to the releasing position, applying tension to the coiled tubing such that the lug is moved to the unlocked position substantially simultaneously with the upper housing being shearably disconnected from the lower housing, and removing the coiled tubing and the upper housing from the wellbore. The method may further comprise the step of fishing the lower housing and the wireline tool from the wellbore. A fishing tool is engaged with a fishing neck defined in the lower housing when the upper housing has been disconnected from the lower housing.




In the method, the cablehead may further comprise a spring rest shearably connected to the housing, and a spring disposed between the spring rest for biasing the piston toward the running position. The step of pumping fluid down the coiled tubing and applying pressure to the piston may comprise pumping fluid through the coiled tubing and cablehead at a volume sufficient to move the piston from the running position thereof to a sealing position in which the piston engages the spring seat, and when the piston is in the sealing position, applying pressure thereto which thereby shearably releases the spring rest from the housing and moves the piston to the releasing position.




Numerous objects and advantages of the invention will become apparent as the following detailed description of the preferred embodiment is read in conjunction with the drawings which illustrate such embodiment.











BRIEF DESCRIPTION OF THE DRAWINGS





FIGS. 1A-1D

show the heavy-duty logging and perforating cablehead for coiled tubing of the present invention with an actuating piston in a running position with lugs in a locked position for running a logging tool and/or set of perforating guns into a well on a length of coiled tubing.





FIGS. 2A-2D

show the cablehead with the actuating piston in a sealing position and the lugs still in the locked position.





FIGS. 3A-3D

illustrate the cablehead with the actuating piston in a releasing position so that the lugs may be moved to the unlocked position.





FIGS. 4A-4D

illustrate the cablehead after tension has been applied to the tubing string to separate upper and lower housings in the event of a stuck tool.











DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring now to the drawings, and more particularly to

FIGS. 1A-1D

, the heavy-duty logging and perforating cablehead for coiled tubing of the present invention is shown and generally designated by the numeral


10


. Generally, cablehead


10


comprises an outer housing


12


with an actuating piston


14


slidably disposed therein.




Housing


12


comprises an upper housing


16


and a lower housing


18


. Upper housing


16


and lower housing


18


each are formed by a number of components.




Referring now to

FIG. 1A

, at the upper end of upper housing


16


is a top adapter


20


disposed in the upper end of a quick-connect collar


22


. A sealing means, such as a pair of O-rings


24


, provides sealing engagement between top adapter


20


and collar


22


.




Referring to

FIG. 1B

, a piston sub


26


is attached to the lower end of collar


22


at threaded connection


28


. A sealing means, such as a pair of O-rings


30


, provides sealing engagement between piston sub


26


and collar


22


.




The lower end of piston sub


26


is attached to a ported sub


32


at threaded connection


34


.




The lower end of ported sub


32


is attached to a lug window sub


36


at threaded connection


38


. A sealing means, such as an O-ring


40


, provides sealing engagement between ported sub


32


and lug window sub


36


, as seen in FIG.


1


C.




Lower housing


18


is disposed below upper housing


16


. At the upper end of lower housing


18


is a lug housing


42


disposed adjacent to lug window sub


36


and shearably connected thereto as will be further described herein.




The lower end of lug housing


42


is connected to a center mandrel


44


at threaded connection


46


. See

FIGS. 1C and 1D

. A sealing means, such as an O-ring


48


, provides sealing engagement therebetween. A tool connector


50


is disposed over the lower end of center mandrel


44


, and sealing engagement is provided therebetween by a sealing means, such as a pair of O-rings


52


.




Also as seen in

FIG. 1D

, a quick-connect collar


54


is attached to tool connector


50


at threaded connection


56


. Collar


54


is of a kind known in the art and it will be seen that it connects tool connector


50


to center mandrel


44


by clamping against an outwardly extending flange


58


on the center mandrel.




Referring again to

FIG. 1A

, top adapter


20


has an internal thread


60


adapted for connection to a length of coiled tubing


62


of a kind known in the art. A logging cable


64


is run through the length of coiled tubing


62


and into the upper portion of upper housing


16


.




Disposed in collar


22


between top adapter


20


and piston sub


26


is a body


66


which generally defines a first longitudinal passageway


68


and a second longitudinal passageway


70


which is substantially parallel to the first passageway. Disposed in an enlarged portion of first longitudinal passageway


68


are a pair of check valves


72


. A sealing means, such as an O-ring


74


, provides sealing engagement between each check valve


72


and body


66


. Check valves


72


are of a kind known in the art such as ball-type or flapper-type check valves and allow fluid flow downwardly through first longitudinal passageway


68


while preventing upward fluid flow therethrough. Two such check valves


72


are used for redundancy in the event of failure of one of them. Such redundancy is required in some well operations, such as offshore operations in the North Sea.




The lower end of logging cable


64


extends into second longitudinal passageway


70


in body


66


, and the logging cable is attached to the body by a cable clamp


76


. Cable clamp


76


is of a kind known in the art and clampingly engages the outside of logging cable


64


. Cable clamp


76


is attached to body


66


at threaded connection


78


.




A bulkhead


80


is disposed in an enlarged lower portion of second longitudinal passageway


70


, and as seen in

FIGS. 1A and 1B

, a sealing means, such as a pair of O-rings


82


, provides sealing engagement between bulkhead


80


and body


66


. Bulkhead


80


is adjacent to the top of piston sub


26


.




Upper and lower halves


84


and


86


of an electrical feed-through


88


, of a kind known in the art, are attached to bulkhead


80


and extend therefrom on opposite upper and lower sides, respectively, of the bulkhead. A wire


90


extends down from logging cable


64


and terminates at electrical feed-through


88


. Another wire


91


extends downwardly from electrical feed-through


88


. Feed-through


88


provides an electrical connection between wires


90


and


91


.




Still referring to

FIG. 1B

, piston sub


26


defines a first longitudinal passageway


92


therein which is generally aligned and in communication with first longitudinal passageway


68


in body


66


. Piston sub


26


also defines a second longitudinal passageway


94


therethrough which is substantially parallel to first longitudinal passageway


92


and is substantially aligned with second longitudinal passageway


70


in body


66


. It will be seen that lower half


86


of electrical feed-through


88


extends into second longitudinal passageway


94


in piston sub


26


.




Below first longitudinal passageway


92


and second longitudinal passageway


94


, upper housing


16


defines a centrally located, longitudinally extending piston cavity


96


therein which is in communication with first longitudinal passageway


92


and second longitudinal passageway


94


in piston sub


26


. Piston cavity


96


is formed by a first bore


98


in the lower end of piston sub


26


, a second bore


100


in ported sub


32


, a third bore


102


in the ported sub and a fourth bore


104


in lug window sub


36


, as seen in

FIGS. 1B and 1C

. First bore


98


is the largest, second bore


100


is somewhat smaller than first bore


98


, and third bore


102


is smaller than second bore


100


. Fourth bore


104


is substantially the same size as third bore


102


. An upwardly facing shoulder


106


in ported sub


32


extends between first bore


98


and second bore


100


, and an angled ramp or chamfer


108


in the ported sub extends between second bore


100


and third bore


102


.




Actuating piston


14


is disposed in piston cavity


98


and is movable longitudinally therein. Still referring to

FIGS. 1B and 1C

, piston


14


comprises an upper piston


110


and a lug prop


112


attached to the upper piston at threaded connection


114


.




Referring to

FIG. 1B

, piston


14


has a first outside diameter


116


and a smaller second outside diameter


118


on upper piston


110


. An annular, downwardly facing shoulder


120


extends between first outside diameter


116


and second outside diameter


118


. A first seal


122


disposed in first outside diameter


116


provides sealing engagement between piston


14


and first bore


98


. Below first seal


122


, a second seal


124


is carried on piston


14


in second outside diameter


118


, and a third seal


126


is carried on piston


14


in second outside diameter


118


below second seal


124


. Third seal


126


provides sealing engagement between piston


14


and third bore


102


. The operation of second seal


124


will be further described herein.




Below third seal


126


, upper piston


110


of piston


14


forms an annular recess


128


which may also be referred to as a lug saddle


128


. Lug saddle


128


will thus be seen to be generally annular with chamfers


129


at the upper and lower ends thereof.




Piston


14


also has a third outside diameter


130


on lug prop


112


. Third outside diameter


130


on lug prop


112


is substantially the same size as second outside diameter


118


on upper piston


110


. Below third outside diameter


130


, piston


14


has a fourth outside diameter


132


on lug prop


112


. A downwardly facing shoulder


133


extends between third outside diameter


130


and fourth outside diameter


132


.




Upper piston


110


of piston


14


defines a bore


134


therein with a large upwardly facing chamfer


136


at the upper end thereof. Chamfer


136


insures that bore


134


is in communication with first longitudinal passageway


92


and second longitudinal passageway


94


in piston sub


26


of upper housing


16


.




A plurality of replaceable and interchangeable nozzles


138


are disposed in corresponding piston flow ports


139


and are attached by threaded connections


140


. Each nozzle


138


has a nozzle port or orifice


142


defined therein which extends transversely with respect to piston


14


and will be seen to be in communication with bore


134


in upper piston


110


. The size of nozzle ports


142


may be varied so that the flow through nozzles


138


may be changed as desired. The use of nozzles


138


and the selection of nozzle ports


142


will be more fully described herein.




Below nozzles


138


, upper piston


110


defines a transversely extending equalizing port


144


therein which provides communication between bore


134


and the outside of piston


14


below third seal


126


. Thus, it will be seen that pressure above and below piston


14


is substantially equalized.




Upper piston


110


also defines a longitudinally extending hole


146


which is spaced off center from bore


134


and extends the length of the upper piston. Hole


146


does not intersect any of piston ports


139


and is not in communication with them. Hole


146


is in communication with a bore


148


and a hole


150


both defined in lug prop


112


. Referring again to

FIGS. 1B and 1C

, wire


90


extends down from lower half


86


of electrical feed-through


88


and through second longitudinal passageway


94


in piston sub


26


, hole


146


in upper piston


110


, bore


148


and hole


150


in lug prop


112


and thus downwardly into lower housing


18


.




Referring again to

FIG. 1B

, ported sub


32


of upper housing


16


defines a plurality of housing flow ports


152


transversely therethrough. Flow ports


152


will be seen to be in communication with nozzles


138


through an annulus


154


defined between second bore


100


in ported sub


32


and second outside diameter


118


on upper piston


110


.




Above flow ports


152


, ported sub


32


also defines a plurality of transversely extending vent ports


156


therein. Vent ports


156


are substantially longitudinally aligned with a similar set of vent ports


158


defined in piston sub


26


. Communication is provided between vent ports


156


and


158


through an annulus


160


defined between piston sub


26


and ported sub


32


below threaded connection


34


and above shoulder


106


. Vent ports


156


and


158


will also be seen to be in communication with an annulus


162


defined between first bore


98


in piston sub


26


and second outside diameter


118


on upper piston


110


below shoulder


120


.




Referring again to

FIG. 1C

, upper housing


16


and lower housing


18


of outer housing


12


are connected together by a first, housing shearing means, such as a plurality of shear pins


164


. Each shear pin


164


is disposed through a hole


166


extending transversely in lug housing


42


, and the shear pins extend into a corresponding plurality of radially oriented holes


168


defined in the lower end of lug window sub


36


. A sealing means, such as an O-ring


170


, provides sealing engagement between lug window sub


36


and lug housing


32


and thus between upper housing


16


and lower housing


18


.




Below shear pins


164


and O-ring


170


, lug housing


42


defines an annular lug recess


172


having a chamfer


174


at the upper end thereof. Lug window sub


36


defines a plurality of radially extending lug windows


176


therein which generally face lug recess


172


in lug housing


42


. A lug


178


is disposed in each of lug windows


176


. Each lug


178


has a locked position in which an inner surface


180


engages third outside diameter


130


on lug prop


112


of piston


14


when the piston is in the running position thereof shown in

FIGS. 1B-1C

. Each lug


178


also has an outer surface


182


which extends into lug recess


172


in lug housing


42


when the lugs are in the locked position. Further, each lug


79


has an outwardly and upwardly facing chamfer


184


thereon which generally faces chamfer


174


in lug recess


172


. As will be further described, lugs provide a locking means for preventing relative longitudinal movement of upper and lower housings


16


and


18


, thereby preventing premature shearing of shear pins


164


.




The lower end of lug window sub


36


is attached to a spring rest collar


186


at threaded connection


188


. Both the lower end of lug window sub


36


and spring rest collar


186


extend into a bore


190


defined in lug housing


42


. Spring rest collar


186


defines a bore


192


therein which is substantially the same size as fourth bore


104


defined in lug window sub


36


. At the lower end of bore


192


is an inwardly extending shoulder


194


.




A spring rest


196


is disposed in the upper end of bore


192


in spring rest collar


186


. Spring rest


196


is attached to spring rest collar


186


by a second, spring rest shearing means, such as a plurality of shear pins


198


. Each shear pin


198


is positioned in a hole


200


defined transversely in spring rest collar


186


, and the shear pins extend into an annular groove


202


in the outside of spring rest


196


.




A biasing means, such as a compression spring


204


, is disposed between an upper end


206


of spring rest


196


and shoulder


133


on lug prop


112


of piston


14


. It will thus be seen that piston


14


is biased upwardly to the running position shown in

FIGS. 1B and 1C

.




Wire


91


extends downwardly through a hole


208


in the center of spring rest


196


and another hole


210


in the lower end of spring rest collar


186


so that the wire terminates at an electric feed-through


212


positioned in center mandrel


44


of lower housing


18


. Electric feed-through


212


is in electrical communication with a spring contact


214


which in turn is in electrical contact with a wireline tool connector


216


. Cablehead


10


is used to run a known wireline tool


218


, such as a logging tool and/or set of perforating guns. Wireline tool


218


is attached to a logging tool/gun connection in the form of threaded surface


220


on tool connector


50


of lower housing


18


. This connection is, both mechanically and electrically, of a kind known in the art in which the tool string itself is the ground.




Operation of the Invention




Referring still to

FIGS. 1A-1D

, cablehead


10


is attached at threaded surface


60


in top adapter


20


to a coiled tubing connector so that the cablehead is at the end of a string of coiled tubing


62


. Piston


14


is in the running position and lugs


178


are in their locked position. Wireline tool


218


is attached to threaded surface


220


at the bottom of tool connector


50


. As mentioned above, this wireline tool may be one of any number of known tools, such as a logging tool and/or a set of perforating guns. The entire tool string is run into a well in a manner known in the art. If wireline tool


218


includes a logging tool, the logging operation may be carried out in a known manner. If wireline tool


218


includes perforating guns, the guns may be positioned and triggered to carry out the desired perforating operation. In perforating, shock loading may be transmitted upwardly into cablehead


10


as previously discussed herein. All such shock loading will be absorbed by the locked interconnection of upper housing


16


and lower housing


18


by lugs


178


. That is, no shock loading can be transmitted to shear pins


164


when lugs


178


are in the locked position shown in FIG.


1


C. Therefore, premature shearing of shear pins


164


and separation of upper housing


16


from upper housing


18


are prevented.




If wireline tool


218


does not become stuck in the well, coiled tubing


62


, cablehead


10


and the wireline tool may be retrieved from the well in a normal manner. However, if wireline tool


218


becomes stuck in the hole, then the cablehead


10


may be operated to release the wireline tool from coiled tubing


62


so that coiled tubing and upper housing


16


may be retrieved from the well. Lower housing


18


and wireline tool


218


are then left in the well and subsequently fished on a separate trip.




Prior to actuation of cablehead


10


, the components therein are in the positions shown in

FIGS. 1A-1D

as already mentioned. Piston


14


is at its uppermost, running position within housing


12


. Lugs


178


are in the locked position in which relative longitudinal movement between upper housing


16


and lower housing


18


is prevented, and thus shearing of shear pins


164


is also prevented.




When it is desired to release wireline tool


18


, fluid is pumped down coiled tubing


62


which causes flow through a first flow path


222


. Still referring to

FIGS. 1A-1D

, first flow path


222


is formed by first longitudinal passageway


68


in body


66


, check valves


72


, first longitudinal passageway


92


in piston sub


26


, bore


134


in upper piston


110


, piston flow ports


139


, nozzle ports


142


in nozzles


138


, annulus


154


and housing flow ports


152


in ported sub


32


and out into an annulus (not shown) defined between the tool and the wellbore. Until flow reaches a predetermined level, piston


14


is held in the running position shown in

FIGS. 1B and 1C

by spring


204


.




As the flow rate of fluid pumped down coiled tubing


62


is increased, the pressure in cablehead


10


also increases. Once this pressure reaches a predetermined value, the force acting downwardly on piston


14


as a result of the differential area between first seal


122


and third seal


126


will cause the piston to stroke downwardly until the lower end thereof engages spring rest


196


as seen in

FIGS. 2A-2D

.




As piston


14


is moved to this second position, seal


124


will be moved into engagement with ramp


108


and then gradually brought into sealing engagement with third bore


102


in ported sub


32


as seen in FIG.


2


B. Nozzle ports


142


in nozzles


138


are thus sealingly separated by second seal


124


from housing flow ports


152


. Flow ports


152


, vent ports


156


and vent ports


158


are also sealingly separated from cavity


224


above piston


14


by first seal


122


. Thus, this position of piston


14


may be referred to as a sealed position.




The amount of pressure necessary to move piston


14


from the running position of

FIGS. 1B and 1C

to the sealed position of

FIGS. 2B and 2C

is determined by the spring rate of spring


204


. The flow rate necessary to achieve this pressure is a function of the size of orifices or ports


142


in nozzles


138


. The size of orifices


142


in nozzles


138


can be varied, and the nozzles are easily interchangeable because they are threadingly engaged with piston


14


. In making up cablehead


10


, the operator can determine what the sizes of orifices


142


should be for the particular well conditions that are expected. The operator can then pump fluid down coiled tubing


62


as previously described to move piston


14


from the running position to the sealed position. When piston


14


is moved to the sealed position and into contact with spring rest


196


, the operator will receive a positive indication at the surface that this has occurred, thus indicating that cablehead


10


is working properly to that point.




Once piston


14


is in the sealed position, there is no longer flow down through coiled tubing


62


or cablehead


10


because all of the ports are sealed. Thus increased pumping at the surface will simply raise the pressure in the cablehead. This pressure is thus increased to the point necessary to shear shear pins


198


, thereby allowing further downward movement of piston


14


, along with spring


204


and spring rest


196


until the spring rest contacts shoulder


194


in spring rest collar


186


. This is illustrated in

FIGS. 3A-3D

. In this position of piston


14


, lug saddle


128


is brought into alignment with lugs


178


so that they are free to be moved radially inwardly to an unlocked position as will be further described herein. Thus, this position of piston


14


may be referred to as a releasing position.




In the releasing position of piston


14


, shoulder


120


on upper piston


110


is brought into engagement with shoulder


106


on ported sub


32


. It will be seen that housing flow ports


152


and orifices


142


are still closed. However, because the top of upper piston


110


of piston


14


is moved substantially below vent ports


156


and


158


, these vent ports are now opened. That is, a second flow path


226


is defined through cablehead


10


. This second flow path


226


includes first longitudinal passageway


68


in body


66


, check valves


72


, second longitudinal passageway


92


in piston sub


26


, cavity


224


, vent ports


158


in piston sub


26


, annulus


160


and vent ports


156


in ported sub


32


. Thus, circulation is regained through cablehead


10


so that fluid may again be pumped down coiled tubing


62


and out vent ports


158


and


156


into the well annulus. When circulation is then regained, the operator receives an indication of this at the surface so that it is known that the cablehead has been properly actuated, and that coiled tubing


62


and upper housing


16


and the components therein are ready to be retrieved from the well.




When in the releasing position of

FIGS. 3A-3D

, tension may be applied to coiled tubing


62


. Because wireline tool


218


is stuck, the tension on the coiled tubing will result in the substantially simultaneous shearing of shear pins


164


and the engagement of chamfers


184


on lugs


178


with chamfer


174


at the top of lug recess


172


in lug housing


42


. This chamfered engagement will force lugs


178


to be moved radially inwardly to their unlocked position in which inner surfaces


180


thereof are directed toward lug saddle


128


.




Referring now to

FIGS. 4A-4D

, cablehead


10


is shown with upper housing


16


completely detached from lower housing


18


. Shear pins


164


are completely sheared, and lugs


178


are shown to be moved fully radially inwardly. That is, during the application of tension, lugs


178


are moved from their locked position to their unlocked position wherein inner surfaces


180


of the lugs engage lug saddle


128


so that the lugs are completely retracted within lug windows


176


and no longer prevent relative longitudinal movement between upper housing


16


and lower housing


18


. Once upper housing


16


and lower housing


18


are thus separated, coiled tubing


62


and upper housing


16


, along with the components within the upper housing, may be removed from the well. Wireline tool


218


with lower housing


18


attached thereto remains in the wellbore. Referring to

FIG. 4C

, lug recess


172


and chamfer


174


at the upper end thereof now provide an internal fishing neck in lower housing


18


which may be later engaged by a GS pulling/fitting tool


228


of a kind known in the art.




In summary, three conditions must exist before cablehead


10


can be completely actuated and upper housing


16


and lower housing


18


separated. First, a sufficient flow rate must be established to shift piston


14


from the running position to the sealed position thereof. Second, additional pressure must be applied to shear shear pins


198


to move piston


14


to its releasing position. Third, tension must be applied to coiled tubing


16


to shear shear pins


164


which connect upper housing


16


and lower housing


18


. By requiring these three conditions, a high degree of confidence is maintained that cablehead


10


will not be prematurely released or actuated.




The invention is not intended to be limited to the illustrated embodiment. For example, the drawings show only a single conductor cable. A multi-connector cable could also be utilized by providing additional holes for the wires to run and utilizing multiple electrical connectors. Also, the logging tool connection at the bottom of cablehead


10


can be easily changed to adapt any brand of logging tool.




It will be seen, therefore, that the heavy-duty logging and perforating cablehead for coiled tubing of the present invention is well adapted to carry out the ends and advantages mentioned as well as those inherent therein. While a presently preferred embodiment of the invention has been shown for the purposes of this disclosure, numerous changes in the arrangement and construction of parts may be made by those skilled in the art. All such changes are encompassed within the scope of the appended claims.



Claims
  • 1. A cablehead for use with coiled tubing electric line in well operations, said cablehead comprising:a housing comprising: an upper housing adapted for connection to a length of coiled tubing; a lower housing adjacent to said upper housing; and a shearing means for shearably attaching said lower housing to said upper housing, said shearing means being shearable in response to relative movement between said upper housing and said lower housing such that said upper housing and said lower housing are separated when tension is applied to the coiled tubing; locking means, disposed between said upper and lower housings, for preventing said relative movement and thereby preventing shearing of said shearing means when said locking means is in a locked position and allowing shearing of such shearing means when said locking means is in an unlocked position by said relative movement; and a piston slidably disposed in said housing, said piston having a running position holding said locking means in said locked position and being movable to a releasing position allowing movement of said locking means to said unlocked position.
  • 2. The cablehead of claim 1 wherein said piston has a saddle thereon which is aligned with said locking means when said piston is in said releasing position thereof.
  • 3. The cablehead of claim 1 further comprising biasing means in said housing for biasing said piston toward said running position thereof.
  • 4. The cablehead of claim 3 wherein said biasing means is characterized by a compression spring.
  • 5. The apparatus of claim 1 wherein said housing and said piston define a flow path therein for circulation of fluid therethrough when said piston is in said running position.
  • 6. The apparatus of claim 5 further comprising a nozzle disposed across said flow path for controlling a fluid flow rate therethrough.
  • 7. The apparatus of claim 6 wherein said nozzle is one of a plurality of interchangeable nozzles.
  • 8. The apparatus of claim 5 wherein said flow path is closed when said piston is in said releasing position thereof.
  • 9. The apparatus of claim 8 wherein said housing defines a second flow path for allowing circulation of fluid therethrough when said piston is in said releasing position.
  • 10. The apparatus of claim 1 wherein said piston comprises:an upper piston on which said saddle is located; and a prop attached to said upper piston.
  • 11. The apparatus of claim 1 wherein:said lower housing defines a recess therein; said upper housing defines a lug window therein aligned with said recess; and said locking means is characterized by a lug disposed in said window and extending into said recess when in said locked position and spaced from said recess when in said unlocked position.
  • 12. The apparatus of claim 11 wherein:said piston has a recessed saddle thereon; and said lug extends into said saddle when in said unlocked position.
  • 13. A cablehead for use in well operations on a coiled tubing electric line, said cablehead comprising:a housing comprising: an upper housing adapted for connection to a length of coiled tubing; a lower housing adjacent to said upper housing and adapted for connection to a wireline tool; and a housing shearing means for shearably attaching said lower housing to said upper housing; a lug disposed in said housing, said lug having a locked position engaging said upper and lower housings, said locked position preventing relative longitudinal movement therebetween and thereby preventing shearing of said housing shearing means, and an unlocked position disengaged from one of said upper and lower housings, said unlocked position allowing relative longitudinal movement between said upper and lower housings thereby allowing shearing of said housing shearing means; a spring rest disposed in said housing; a spring rest shearing means for shearably attaching said spring rest to said housing; a piston slidably disposed in said housing and movable between a running position in which said lug is held in said locked position, a sealing position in which said lug is held in said locked position, and a releasing position in which said lug is released from said locked position and free to move to said unlocked position, said housing and piston defining a first flow path therethrough when said piston is in said running position and said housing defining a second flow path therethrough when said piston is in said releasing position, said first and second flow paths being closed when said piston is in said sealed position; and a spring disposed between said spring rest and said piston, said spring biasing said piston toward said running position; wherein: when fluid is pumped down the coiled tubing and through the first flow path when said piston is in said running position, a first operating indication is provided to an operator; when the fluid flow is increased, a differential pressure is created across said piston to compress said spring and move said piston to said sealing position, closing said first flow path and providing a second operating indication to the operator; when additional pressure is applied in said housing to shear said spring rest shearing means, said piston is moved to said releasing position, opening said second flow path and providing a third operating indication to the operator; and when said piston is in said releasing position and tension is applied to the coiled tubing said lug is moved to said unlocked position and said housing shearing means is sheared.
  • 14. The cablehead of claim 13 further comprising a nozzle disposed in said first flow path.
  • 15. The cablehead of claim 14 wherein said nozzle is one of a plurality of interchangeable nozzles connectable to said piston.
  • 16. The cablehead of claim 13 wherein said first flow path comprises:a housing longitudinal opening and a transverse housing flow port defined in said housing; and a piston longitudinal opening and a transverse piston flow port defined in said piston.
  • 17. The cablehead of claim 16 further comprising a replaceable nozzle disposed in said piston flow port.
  • 18. The cablehead of claim 16 further comprising a check valve disposed in said housing longitudinal opening for allowing fluid flow downwardly therethrough and preventing fluid flow upwardly therethrough.
  • 19. The cablehead of claim 13 wherein said second flow path comprises a housing longitudinal opening and a transverse housing vent port defined in said housing.
  • 20. The cablehead of claim 13 wherein said spring rest shearing means shearably attaches said spring rest to said upper housing.
  • 21. The cablehead of claim 20 wherein said upper housing has a shoulder for limiting movement of said spring rest.
  • 22. The cablehead of claim 13 wherein said piston comprises a saddle thereon for receiving said lug when said piston is in said releasing position.
  • 23. The cablehead of claim 13 wherein said lug is one of a plurality of lugs spaced around said housing.
  • 24. The cablehead of claim 13 wherein:said lower housing defines a recess therein; said upper housing defines a lug window therein aligned with said recess; and said lug is disposed in said window and extends into said recess when in said locked position and is retracted from said recess when in said unlocked position.
  • 25. The cablehead of claim 13 further comprising a back check valve disposed in said first flow path.
  • 26. The cablehead of claim 25 wherein said check valve is one of a plurality of ball check valves.
  • 27. A method of releasing a wireline tool in a well comprising the steps of:(a) providing a cablehead for connecting the wireline tool to a length of coiled tubing, said cablehead comprising: a housing having an upper housing connectable to the coiled tubing and a lower housing shearably attached to the upper housing with a shear pin and connectable to the wireline tool, said upper and lower housings being shearably detachable from one another when tension is applied to the coiled tubing; a lug disposed in the housing for preventing shearing disconnection of the upper and lower housings when the lug is in a locked position and allowing shearing disconnection between the upper and lower housings when the lug is in an unlocked position; and a piston disposed in the housing and movable between a running position holding the lug in the locked position and a releasing position allowing the lug to be moved to the unlocked position; (b) when said piston is in said rnning position, running the coiled tubing, cablehead and wireline tool into a wellbore; (c) pumping fluid down the coiled tubing and applying pressure to said piston and thereby moving said piston to said releasing position; (d) applying tension to the coiled tubing such that, substantially simultaneously, said lug is moved to said unlocked position and said upper housing is shearably disconnected from said lower housing as a result of said tension to break said shear pin; and (e) removing said coiled tubing and said upper housing from the wellbore.
  • 28. The method of claim 27 further comprising the step of:(f) fishing said lower housing and said wireline tool from the wellbore.
  • 29. The method of claim 28 wherein step (f) comprises:engaging a fishing tool with a fishing neck defined in said lower housing when said upper housing has been disconnected from said lower housing.
  • 30. A cablehead for use with coiled tubing electric line in well operations, said cablehead comprising:a housing comprising: an upper housing adapted for connection to a length of coiled tubing; a lower housing adjacent to said upper housing; and a shearing means for shearably attaching said lower housing to said upper housing; locking means, disposed between said upper and lower housings, for preventing shearing of said shearing means when said locking means is in a locked position and allowing shearing of said shearing means when said locking means is in an unlocked position by relative movement between said upper and lower housings; a piston slidably disposed in said housing, said piston having a running position holding said locking means in said locked position and being movable to a releasing position allowing movement of said locking means to said unlocked position; a spring rest disposed in said housing; a second shearing means for shearably attaching such spring rest to said housing, said second shearing means being sheared when said piston is moved to said releasing position thereof; and a spring engaged with said piston and said spring rest for biasing said piston toward said running position thereof.
  • 31. A method of releasing a wireline tool in a well comprising the steps of:(a) providing a cablehead for connecting the wireline tool to a length of coiled tubing, said cablehead comprising: a housing having an upper housing connectable to the coiled tubing and a lower housing shearably attached to the upper housing and connectable to the wireline tool; a lug disposed in the housing for preventing shearing disconnection of the upper and lower housings when the lug is in a locked position and allowing shearing disconnection between the upper and lower housings when the lug is in an unlocked position; a piston disposed in the housing and movable between a running position holding the lug in the locked position and a releasing position allowing the lug to be moved to the unlocked position; a spring rest shearably connected to said housing; and a spring disposed between said spring rest and said piston for biasing said piston toward said releasing position; (b) with said piston in said running position, running the coiled tubing, cablehead and wireline tool into the wellbore; (c) pumping fluid through the coiled tubing and cablehead to move the piston from said running position to a sealing position engaging said spring rest, and when said piston is in said sealing position, applying pressure thereto, and thereby shearably releasing said spring rest from said housing and moving said piston to said releasing position; (d) applying tension to the coiled tubing such that, substantially simultaneously, said lug is moved to said unlocked position and said upper housing is shearably disconnected from said lower housing; and (e) removing said coiled tubing and said upper housing from the wellbore.
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