WIRELINE PACKOFF FOR A DOWNHOLE ELECTRICAL TOOL

FIELD

Embodiments herein relate to apparatus and methods for establishing the mechanical and electrical integrity of a wireline to the tool, and more particularly to a fluid sealed termination apparatus and methodology therefor.

BACKGROUND

Wireline operations are carried out in oil and gas wells for conveying tools downhole in the well. A wide variety of downhole tools may be supported on a wireline including tools to perform logging, perforating, and setting and retrieving operations. Logging tools can be electrically coupled to surface through one or more electrical conductors sheathed within armor about the wireline. The wireline armor has a limited operational tensile strength and for deeper or horizontal wells may be combined with a surrounding tubing string such as coil tubing for greater tensile capability.

In either case, a cable head is provided which connects the wireline to the downhole tools both for tensile and electrical connections. For a wireline extending downhole through a tubing string, the cable head also can affect coupling to the tubing string. The wireline cable head connection is also typically provided with a tensile release interface to permit the wireline to be disconnected from the tools, such as when the tools become stuck downhole. Wireline armor comprises strands of individual wires wound about the electrical connector. One or more layers or wires may be provided, determining the operating tensile strength of the wireline. The electrical conductor is typically covered in an elastomeric insulator or cover.

With reference to FIG. 1A through FIG. 2B, in a known prior art technique for making a tensile connection, the wireline is passed through a restricted entrance bore into a packoff bore. The packoff bore is housed in a tool body, typically referred to as a cable head. Some or all of the individual wires of the wireline armor extend through the entrance bore, through a support bushing and are bent back uphole thereabout. The support bushing is sized for the packoff bore but is larger than the entrance bore to prevent return of the bushing and armor therethrough, establishing the tensile connection. The number of wires to bend back uphole predetermines the tensile release interface capability; the more wires, the higher the required release load. The electrical connector passes through the bushing for electrical connection downhole.

A packoff arrangement is fit about the wireline passing through the packoff bore downstream of the bushing in an attempt to exclude well fluids. However, as is the nature of cables and armor for wireline, the annular wound, discrete and axially adjacent individual and cylindrical wires provide a leak path for fluids therealong which is difficult to seal. In downhole settings, with operational pressures, such as in hydraulic fracturing, pressures can reach in the order 15,000 psi, which causes fluid to creep along the small crevices between wires. Thus, while the industry has managed tensile load considerations, it has only been partially successful in mitigating hydrocarbon and drill fluid ingress into the connections of wirelines and tool electrical connections.

The balance of the tool is integrated with the cable head or otherwise removably attached thereto, the tool having a cylindrical structural body for supporting electronics and conducting fluid passages therethrough while bypassing the electronics. The body is fit with a pressure barrel that is a removable tubular housing for covering the electronics and providing connection access thereto. A side port in the body is employed as an access, and connection chamber, for enabling at-surface termination of the wireline tensile connection and the electrical connection. The side port is accessible when the tubular housing is displaced axially for connection, exposing a chamber.

The wireline extends through the restricted entrance bore of an uphole end of the side port to the chamber and out of the packoff bore for fitting of the support bushing, seals and means for electrical connection. The electrical conductor portion of the wireline is trimmed for fitting with an electrical conductor extending into the chamber from a bulkhead fitting at a downhole end of the side port. The bulkhead fitting is sealably secured to isolate the electronics from the chamber. The supported and electrically connected wireline resides in the connection chamber and is sealed by repositioning the tubular housing over the side port. The tubular housing is fitted with seals to exclude well fluids.

Accessed through the side port, the packoff bore receives the wireline support bushing and packoff components for sealing between the wireline and the body. Downstream of the support bushing is the packing or a packoff. The packoff typically comprises a series of seals including cylindrical bushings having circumferential O-rings to seal to the entrance bore, and one or more plastic bushings that, when compressed axially, expand radially to aid in sealing inwardly onto the wireline armor. In operation, the connection chamber is and remains at atmospheric pressure.

The electrical conductor portions extend into and are terminated in the connection chamber.

As a result of the wireline characteristics and pressure differential from the entrance bore and connection chamber, high pressure fluids in the wellbore migrate under differential pressure along the packoff to the low pressure connection chamber. Fluids can flow along the armor strand interfaces of the wireline, penetrating the bulkhead to wireline connection, and result in a failed connection.

Vulnerability to fouling or contamination of the electrical connection is a persistent cause of sensor tool operation and communication failure. Further, the arrangement of the packoff components and electrical conductor termination requires handling of many components and steps requiring skill and time, often resulting in error.

In addition, as previously stated, a wireline cable head connection is also typically provided with a tensile release interface. The restricted bore entrance provides the tensile connection of the wireline and the downhole tool components. With prior technology as shown in published application WO2004046497A1, a commonly accepted safe operational pull of the wireline is a pull which does not exceed one-half the breaking strength of the wireline. When a tension is placed on the wireline which is over 50% of its break point, then problems begin to occur with the electrical conductors in the wireline. Also, there is the danger of breaking the wireline.

A typical wireline release utilizes a mechanical weak point in the connection made between the wireline and the cable head. Typically this is a metal member which is designed to break, like a fuse analog, breakable upon a predetermined pull force on the wireline. The correct conventional mechanical weak point must be calculated and installed prior to running the cable head and tools into the borehole on the wireline.

There are two limitations in using the typical mechanical weak point release, one is the strength of the wireline itself and the other is the strength of the mechanical weak point. For example, when the tool is stuck, the operator will fish for the tool with the wireline still attached to the tool in the hole. The operator lowers a grapple on a separate line, such as a slick line, which grabs the top of the cable head or the tool body. Once the tools are engaged by the grapple, the operator can release the wireline from the tool and remove it from the hole. Removing the wireline makes it easier to pull the tools and pipe out of the well. In order to affect the release, the operator places a large tension on the wireline to activate the typical mechanical release.

There is interest in the industry for a robust and releasable apparatus and methods for coupling wireline and downhole tools, including methods of reliably terminating electrical conductors and sensor tools.

SUMMARY

In an embodiment, the primary electrical connection of a wireline terminates, and thus is wholly enclosed and sealed, within a closed packoff bore of a termination housing. The termination housing can be formed within a cable head, a downhole tool itself or other intermediate packoff or termination sub. The wireline release strength can be selected upon wireline connection.

In any event, the termination sub is sealably coupled or integrated with an uphole end of the downhole tool carrying the electrical components. Such a downhole tool includes a sensor tool. The packoff sub includes the sealed termination housing having an uphole mechanical structure or support for transferring wireline armor tensile loads to the sub, a packoff bore for housing the wireline electrical conductor at a primary electrical connection, and a downhole closure for sealing the packoff bore from fluid flow therethrough.

The wireline conductor, or conductors, extend downhole from the armor and end within the sealed packoff bore. Thus, any wellbore fluid penetration is stopped thereat, including possible seepage or leakage downhole along the wireline and through the otherwise sealed packoff bore.

A secondary electrical connection or interface, such as a hermetically sealed electrical pass-through connector, extends sealably from the packoff bore's downhole closure end. A downhole end of the secondary electrical connection enables releasable electrical coupling with the downhole tool or sensor. An uphole end of the secondary electrical connection enables releasable electrical coupling with the electrical wire of the wireline conductor.

The wireline conductor terminates at an electrical connection within the sealed packoff bore. The only available leak path of well fluids is into the packoff bore at the entrance of the wireline. Under well pressures, well fluids are known to leak along the wireline armor and about components therein and deep into the packoff bore. To prevent well fluid from migrating therealong and to the primary electrical connection, the packoff bore is filled with a fluid pad, such as dielectric grease, to form a substantially incompressible liquid front or barrier that fills the packoff bore from the downhole closure end and at least uphole of the electrical connection. The dielectric grease cannot be displaced by fluid and therefore prevents ingress of well fluids thereto. In embodiments, to minimize or eliminate air pockets, the components can be assembled pre-greased. In further embodiments, to displace air pockets about the primary electrical connection, grease is injected from the downhole ends and displaced uphole to minimize air pockets and voids.

Access for fluid pad to the sealed packoff bore is provided via a closable fluid pad port. The injected grease is directed into the termination housing to flow uphole within the packoff bore from the downhole closure end, about the packoff components, and along the bore, at least to encompass the electrical connection. Where the grease is continuous within the packoff bore, wellbore fluids are excluded. The grease fills the cross-section of the packoff bore from its downhole end and uphole to the extent needed to exclude the ingress of wellbore fluid to the primary electrical connection, despite the possibility of some voidage and grease installation deficiencies.

Uphole of the primary electrical termination, excess injected grease, if any, flows along the packoff bore and wireline leak path and can discharge at the uphole end of the termination housing.

In an embodiment, a boot housing resides in the packoff bore and houses the primary electrical connection and a secondary electrical connection passing through a packoff bulkhead at the downhole end of the boot housing. An elastomeric boot is provided about the electrical insulation of the wireline conductor uphole of the electrical contact and is housed within the boot housing. Dielectric grease can be pre-placed into the boot to minimize air pockets or voids including along the interface of the grooved or impressed insulation jacket about the wire, the impressions resulting from the inner strands of the wireline.

In an embodiment, access to the fluid pad need not be located at the downhole closure end to affect the fluid pad. The boot housing further comprises one or more grease galleries to receive grease injected through the termination housing and direct it firstly to an extreme downhole location within the boot housing before entering the packoff bore to fill voids and displace undesirable bore fluids uphole while being backfilling with the grease. Secondly, grease can be directed along the interface between the packoff assembly and the packoff bore. Circumferential seals, such as O-rings, can be located between the boot housing and the packoff bore at the uphole and downhole ends of the boot housing for preventing the passage of grease and fluids thereby.

The boot housing can receive an uphole source of grease through the packoff housing, distribute it about the circumference through the one or more grease galleries, and controllably direct the grease to an extreme downhole location before discharge into the packoff bore. The downhole end of the boot housing forms the packoff bulkhead at the downhole end of the packoff bore once secured therein. The housing's downhole end also supports the hermetically-sealed secondary electrical connection that projects downhole of the packoff bulkhead of the sealed packoff bore. The injected grease can complete backfilling of any dielectric grease preplaced in the packoff bore and elastomeric boot, thus eliminating any voids in the grease pad.

In one method of installation and termination of the wireline, the wireline is extended downhole through uphole mechanical support of the packoff housing and at least some of the armor is wrapped back uphole about a support bushing fittable within the packoff bore, to bear against the entrance structural support, for transferring wireline armor tensile loads to the uphole support. In embodiments, the uphole support may be integral with the packoff housing, or in alternate embodiments, the uphole support is releasably secured to the packoff housing with an uphole stop imparting fuse characteristics.

The wireline is passed downhole through a restricted entrance bore and through a bore in the support bushing, such as a cone-like bushing. Some or all of the individual wires of the wireline armor extending downhole through the support bushing bore are bent back uphole thereabout. The support bushing is larger than the entrance bore. The wireline, bent wires, and support bushing are secured concentrically within an annular surrounding housing, so that under tension, the support bushing and bent wires are supported radially and prevented from releasing from about the support bushing and thus enabling a tensile connection therebetween. The number or wires to bend back uphole predetermines the tensile release interface capability of the wireline portion; the more wires, the higher the required release load. The uphole stop also provides a means of fused release.

A non-supportive remaining wireline portion, comprising at least the electrical conductor, itself comprised of the wire and insulative or insulating jacket, extends downhole from the support bushing and into the packoff bore. As is the nature of cables and armor for wireline, the individual wires inherently provide a leak path for fluids therealong, that path being difficult to seal. In downhole settings, with operational pressures, such as in hydraulic fracturing, pressures can reach in the order 15,000 psi. Thus, the industry has had to address both the tensile load considerations whilst minimizing hydrocarbon and drill fluid ingress to the connections of wirelines and tool electrical connections.

In the prior art, as described above, a bushing was compressed to minimize the flow path along the radial extent of the interface between the bore of the bushing and the wireline armor wire strands. The use of such a bushing was unsatisfactory, as fluid was still capable of leaking along the wireline armor strands under high pressure due to the small radial spaces that exist between the wireline armor and the bore of the bushing.

Herein, in an embodiment, a compressible packoff sealing bushing may also be installed, as was the case in the prior art, about the remaining wireline portion for restricting the annulus formed between the wireline and packoff bore. While the migration of well fluid is restricted by the packoff bushing, it is not eliminated. However, in the current embodiments, the termination arrangement also incorporates a grease pad to prevent well fluid from contaminating the electrical conductor of the wireline.

The electrical conductor extends from the support bushing and packoff, if so fit, and is fit at its termination with an electrical contact having a female receptacle. A further and hermitically sealed electrical connector is supported at, and through, a downhole electrical bulkhead. An uphole electrical pin, in the packoff bore, is releasably coupled with the electrical contact.

Between the packoff bushing and the downhole electrical bulkhead is a grease recess. The electrical bulkhead or a closure cap secures the bulkhead to the packoff bore, compressing the packoff seal against the uphole support. Grease is injected into the grease recess, at about the downhole electrical bulkhead, for displacement uphole along the packoff bore to form an axial barrier at least at or uphole of the electrical contact. A downhole electrical pin extends from the downhole electrical bulkhead for releasable coupling with the downhole tool. In operation, well fluid at operating pressures can only ingress through the uphole support and along the wireline until reaching the fluid pad formed by the axial fluid barrier formed by the injected grease.

In an embodiment, the packoff seal is a tubular seal assembly that couples with the support bushing, and the downhole bulkhead is a tubular bulkhead component that couples with the packoff seal for forming a tubular packoff assembly that is insertable into the packoff bore for retention against the uphole support, the assembly being retained therein by a downhole closure.

In one embodiment of method of termination, the wireline is over-extended through the packoff bore and the tubular packoff assembly is assembled downhole of the packoff bore. The wireline and assembled packoff assembly is pushed back a short distance uphole into the packoff bore to bear against the uphole support and the closure plug nut secures the assembly therein. The grease port is uncovered, temporarily fit with a fitting and grease is injected to establish the fluid barrier. The balance of the tool is electrically coupled to the downhole electrical pin extending from the closure.

In an embodiment, the packoff assembly includes serially threadable components. To enable threadable coupling of the components, conveniently and temporarily outside of the packoff bore, the downhole end of the packoff bore is compatible with the fitting of a temporary vise for non-rotatable retention of uphole components during assembly of sequential downhole components. The vise is removable thereafter for insertion and securing within the packoff bore.

In a method of assembly, the wireline can be readily connected to a cable head or termination sub in a dependable, reliable, and electrically sound manner. For replacing the packoff bore or installing a new wireline, the termination sub is decoupled from the downhole tool to expose the packoff bore and the packoff assembly is removed from the packoff bore. The packoff bore components are uninstalled from the distal end of the wireline.

Thereafter and for an initial assembly, the wireline is introduced through the restricted entrance of the uphole support of the packoff bore. For convenience of external assembly of the packoff assembly, an anchor slip vise can be secured about the downhole end of the packoff bore.

The wireline is installed through a restricted uphole support of a packoff bore of the cable head and extending the wireline out a downhole opening. The anchor slip is temporarily secured to the packoff bore adjacent the downhole opening. At least an outer armor of the wireline is separated and bent back uphole over the anchor slip, the number of strands predetermined for setting the tensile release force of the wireline to the packoff assembly. The bent strands are trimmed and a tubular cap installed thereover to trap the bent strands in an annulus formed therebetween. The cap is axially secured to the anchor slip. The remaining wireline extends downhole and the remaining armor trimmed adjacent the cap to expose the remaining wireline conductor.

A packoff bushing is fit to the wireline, sandwiched between an uphole conical recess and a downhole conical recess, wherein, when axially compressed therebetween, the bushing compressively engages the remaining wireline, a portion of wireline conductor extending downhole of the packoff bushing.

A primary releasable electrical connector contact is electrically secured to the wireline conductor wire. A secondary electrical connector, sealably secured at a packoff bulkhead, is coupled to the primary electrical connector contact.

The wireline, anchor slip and cap, bushing, and electrical connectors are installed into the packoff bore sealed therein by a closure plug, the packoff bore being fluidly sealed. However, the secondary electrical connector is electrically passed through the downhole end of the packoff bore before electrical coupling with the downhole tool.

In embodiments, and before installation into the packoff bore, any or all of one or more groups of components can be pre-assembled. A first grouping of the anchor slip and cap can be threadably coupled, a second grouping of the uphole conical slip, bushing, and downhole conical slip can be threadably coupled, a third grouping of the secondary electrical connector and bulkhead can form a unitary group, and each of the first, second, and third groups can be threadably coupled to one or several packoff cartridges. Each independent group and the group couplings can be provided with manual inclusion of dielectric grease. Any or all of the groups can be injected with pressurized grease.

After the packoff assembly is installed and sealed within the packoff bore, pressurized grease is injected at the downhole end of the packoff bore, at the secondary electrical connector bulkhead for displacing the bore volume, such as remaining air or other voids, uphole until pad grease backfills the packoff bore at least uphole of the primary electrical connection for forming a barrier to leakage of well fluids from the restricted entrance bore and along the wireline passing therethrough, preventing the well fluids from reaching the electrical connection(s) between the wireline conductor and tool.

In one aspect, a method is provided for sealing a wireline in a cable head located between the wireline and a downhole tool, the wireline having wireline armor and an electrical conductor therealong, the method comprising: inserting the wireline through an uphole stop of a packoff bore of the cable head and out of a downhole opening of the packoff bore; positioning an anchor slip about the wireline; bending one or more wires of the armor over a slip interface of the anchor slip and securing the one or more wires to the anchor slip. Further, a packoff bushing is positioned about the wireline downhole of the anchor slip and electrical contact is established by electrically connecting the conductor of the wireline with a boot contact to form a primary electrical connection; coupling a first contact of a feed-through connector with the boot contact to form a secondary electrical connection; and inserting the first electrical and second electrical connections into a boot housing, the anchor slip, packoff bushing, and boot housing forming a packoff assembly. The packoff assembly is inserted into the packoff bore and further comprises: sealing the downhole opening of the packoff bore with a closure nut; and introducing grease to the packoff bore such that grease fills the packoff bore from the downhole end to encompass at least the primary electrical connection and the secondary electrical connection.

In another aspect, a cable head termination sub comprises: a cable head having a structural body, the body having a packoff bore extending therethrough from an uphole end of the body to a downhole end of the body, the downhole end adapted for releasable coupling with the tool; and the packoff bore being configured to releasably receive a packoff assembly therein and having an uphole stop defining an entrance bore, and a downhole opening, the entrance bore having an entrance diameter smaller than a bore diameter of the packoff bore and sized for receiving the wireline therethrough. A closure plug is provided for sealing the downhole opening and fluidly isolating the packoff bore from the downhole tool; and a grease port located on the body for introduction of dielectric grease to the packoff bore. The packoff assembly comprises: an uphole anchor slip having a slip bore for receiving the wireline therethrough and a slip interface for securing the wireline armor thereto, the anchor slip bearing against the uphole stop; a packoff bushing downhole of the anchor slip having a bushing bore for receiving the wireline therethrough; a boot contact attached to the wireline conductor to form a primary electrical connection; and a feed-through connector having a first contact compatible with the boot contact and coupled thereto to form a secondary electrical connection, and a second contact for electrical connection with the downhole tool; and when the packoff assembly is sealed within the packoff bore with the closure plug, the grease within the packoff bore prevents fluid from reaching the first and second electrical connections.

In a broad aspect, a cable head termination sub is located between a wireline having wireline armor and an electrical conductor therealong, and a downhole tool, the termination sub comprising: a cable head having a structural body, the body having a packoff bore extending therethrough from an uphole end of the body to a downhole end of the body, the downhole end adapted for releasable coupling with the tool; and the packoff bore configured to releasably receive a packoff assembly therein and having an uphole stop defining an entrance bore, and a downhole opening, the entrance bore having an entrance diameter smaller than a bore diameter of the packoff bore and sized for receiving the wireline therethrough; a closure plug for sealing the downhole opening and fluidly isolating the packoff bore from the downhole tool; and a grease port located on the body for introduction of dielectric grease to the packoff bore; and wherein the packoff assembly comprises an uphole anchor slip having a slip bore for receiving the wireline therethrough and a slip interface for securing the wireline armor thereto, the anchor slip bearing against the uphole stop; a packoff bushing downhole of the anchor slip having a bushing bore for receiving the wireline therethrough; a boot contact attached to the wireline conductor to form a primary electrical connection; and a feed-through connector having a first contact compatible with the boot contact and coupled thereto to form a secondary electrical connection, and a second contact for electrical connection with the downhole tool; and when the packoff assembly is sealed within the packoff bore with the closure plug, the grease within the packoff bore prevents fluid from reaching the first and second electrical connections.

In an embodiment, the grease port directs grease to the downhole end of the packoff bore for backfilling the packoff bore with the grease from the downhole end toward the uphole end.

In an embodiment, the packoff assembly first comprises a boot housing having a downhole end sealably supporting the secondary electrical connection at the closure plug, an uphole end for receiving the primary electrical connection, and a boot having an uphole boot end fit concentrically about the wireline conductor and the boot contact and a downhole boot end for releasably receiving the first contact when the first contact is coupled with the boot contact, the boot residing within the boot housing.

In an embodiment, the boot housing has at least a first grease gallery adapted to direct injected grease from the grease port at least downhole to the downhole end of the packoff bore.

In an embodiment, the boot housing further comprises a circumferential seal for creating a seal with the packoff bore uphole of the grease port for preventing grease from travelling uphole between the boot housing and packoff bore.

In an embodiment, the boot housing has at least a second uphole gallery adapted to direct grease toward the uphole end of the packoff bore and along an annulus defined between the packoff assembly and the packoff bore.

In an embodiment, the boot housing further comprises an uphole port for discharging grease along the annulus.

In an embodiment, the uphole stop is removably coupled with the packoff bore.

In another broad aspect, a method is provided for sealing a wireline in a cable head located between the wireline and a downhole tool, the wireline having wireline armor and an electrical conductor therealong, the method comprising: inserting the wireline through an uphole stop of a packoff bore of the cable head and out of a downhole opening of the packoff bore; positioning an anchor slip about the wireline; bending one or more wires of the armor over a slip interface of the anchor slip and securing the one or more wires to the anchor slip; positioning a packoff bushing about the wireline downhole of the anchor slip; electrically connecting the conductor of the wireline with a boot contact to form a primary electrical connection; coupling a first contact of a feed-through connector with the boot contact to form a secondary electrical connection; inserting the first electrical and second electrical connections into a boot housing, the anchor slip, packoff bushing, and boot housing forming a packoff assembly; inserting the packoff assembly into the packoff bore; sealing the downhole opening of the packoff bore with a closure nut; and introducing grease to the packoff bore such that grease fills the packoff bore from the downhole end to encompass at least the primary electrical connection and the secondary electrical connection.

In an embodiment, the method further comprises the step of securing the uphole stop within the packoff bore.

In an embodiment, the step of introducing grease to the packoff bore further comprises directing the grease first to a downhole end of the packoff bore and then toward an uphole end of the packoff bore.

In an embodiment, the method further comprises the step of applying grease to one of the anchor slip, packoff bushing, and boot housing, or a combination thereof, prior to sealing the downhole opening of the packoff bore.

In an embodiment, the step of inserting the first and second electrical connections into a boot housing further comprises inserting the first and second electrical connections into a boot and inserting the boot into the boot housing.

In an embodiment, the step of positioning the anchor slip further comprises securing a vise to the wireline downhole of the downhole opening and coupling the anchor slip to the vise, and step of inserting the packoff assembly into the packoff bore comprises first removing the vise from the wireline.

In an embodiment, grease is introduced to the downhole end of the packoff bore.

In an embodiment, the grease is introduced at an axial location uphole of the downhole end of the packoff bore, the grease flowing toward the downhole end via at least a first grease gallery.

In an embodiment, the method further comprises directing the grease toward the uphole end from the downhole end via at least a second grease gallery.

In another broad aspect, a packoff assembly is provided for use within a packoff bore of a cable head to connect a wireline having wireline armor and an electrical conductor therealong with a downhole tool, comprising: an uphole anchor slip having a slip bore for receiving the wireline therethrough and a slip interface for securing the wireline armor thereto; a packoff bushing having a bushing bore for receiving the wireline therethrough; a boot housing having a feed-through connector sealably supported therein, the feed-through connector having a first contact compatible with a boot contact attached to the wireline conductor and a second contact for electrical connection with the downhole tool; and at least a first grease gallery formed in the boot housing and adapted to receive grease injected into the packoff bore and directed the grease towards a downhole end of the boot housing.

In an embodiment, the boot housing defines an uphole port in communication with at least a second grease gallery and adapted to direct grease toward an uphole end of the packoff bore and along an annulus defined between the packoff assembly and the packoff bore.

In an embodiment, the boot housing comprises a boot having an uphole boot end fit concentrically about the wireline conductor and the boot contact a downhole boot end for releasably receiving the first contact when the first contact is coupled with the boot contact, the boot residing within the boot housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1C illustrate a prior art tool and wireline to tool termination according to Applicant's patent application WO2018137027 published Feb. 8, 2018 from PCT/CA2018/050080, the entirety of which is incorporated herein by reference, the tool having a cable head packoff sub for connection to the wireline and optionally to coil tubing, a sensor tool for electrically and fluidly coupling to the packoff sub, and a sealing tubular or pressure barrel for fluidly sealing the wireline termination connection chamber and sub to the tool coupling;

FIG. 1A is a cross-sectional view of the prior art uphole cable head packoff sub coupled to a downhole sensor tool;

FIG. 1B is an enlarged cross-sectional view of the uphole cable head portion of the tool of FIG. 1A, and illustrating the pressure barrel having been displaced axially downhole for access to the termination connection chamber and a packoff bore in the packoff sub having a wireline extending therethrough prior to termination, the packoff bore being fluidly connected to the connection chamber;

FIG. 1C is a cross-sectional and exploded view of the prior art packoff components as they are installed about the wireline of FIG. 1B;

FIG. 2A illustrates the cross-sectional view of the prior art packoff bore of FIG. 1B with some of the packoff components being guided onto the wireline for installation into the packoff bore about the wireline, the components including an uphole stop, a wireline anchor cap, an uphole packoff bushing, and a grease gallery;

FIG. 2B is a cross-sectional view of the prior art packoff bore of FIG. 2A, the tubular housing having been removed, with all of the packoff components within the packoff bore and compressibly secured therein by a packoff nut, the electrical conductor terminated at an electrical contact and termination arrangement within the termination connection chamber for extending sealably through a pressure bulkhead of the sensor tool of FIG. 1A;

FIG. 3 is a perspective view of one current embodiment of a cable head packoff sub, a packoff assembly, and a packoff-to-sensor tool adapter, the packoff assembly having a simplicity of assembly and having a sealed termination of the wireline electrical conductor within;

FIG. 4 is a perspective view of an embodiment of a sensor tool with a pressure barrel removed to access to the electronic components, the uphole end fit with a target ring (shown displaced uphole from the tool) for enabling coupling of the electrical components between the wireline packoff sub and the sensor tool;

FIG. 5 is a cross-sectional view of a clean packoff sub body, free of wireline packoff components, the body rotationally oriented with the packoff bore shown below the flow passage thereabove, the packoff bore receiving the wireline from the uphole end at the left and is closed and fluidly sealed at the downhole end at the right;

FIGS. 6A, 6B and 6C respectively illustrate a side, uphole, and downhole end view of the packoff sub of FIG. 5, repeated in smaller representation in side view in FIG. 6A, the downhole end view shown in FIG. 6B, and the uphole end view shown in FIG. 6C;

FIG. 7 is a side cross-sectional view of an embodiment of the packoff components, assembled into a packoff assembly or cartridge for installation within the packoff bore of FIG. 5 and for sealing the downhole end of the packoff bore when secured therein, and in this embodiment, the cartridge bearing again an uphole packoff stop installed in the packoff sub from the uphole end thereof and the remainder of the components installed into the packoff bore from the downhole end, the packoff components being sealably and compressed therein by a downhole closure nut or plug;

FIG. 8A illustrates a cross-sectional and exploded side view of the packoff components installed about a wireline, the wireline shown broken periodically therealong to better illustrate the structure of the components;

FIG. 8B is a cross-sectional and exploded side view of the wireline conductor termination to a sealed conductor, the conductor termination having a protective boot thereabout, all of which resides within the packoff bore;

FIG. 8C is an exploded perspective view of the packoff components for installation into the packoff bore including the uphole stop for securing into the uphole end of the packoff bore;

FIG. 8D is a cross-section of an embodiment of a boot housing cut at 90 degrees to illustrate the section through one of two opposing axial structural stringers and one side opening of two opposing side openings, the stringer connecting the uphole end to the downhole packoff bulkhead end;

FIG. 9A is repeat of the body of the packoff sub, rotated about the body axis to present the packoff bore at the top in an orientation convenient for installation and assembly of the wireline packoff, the flow passage arranged therebelow;

FIG. 9B is a repeat of the packoff components of FIG. 7, the components arranged juxtaposed axially from the packoff bore of FIG. 9A, in which they are to be installed;

FIG. 9C illustrates the packoff sub of FIG. 9B with a distal end of a wireline extending through the packoff bore, the wireline shown in its post-packoff installation form with one or more of the wireline armor wires bent back uphole;

FIG. 10 is a cross-sectional side view of the packoff sub with the packoff components installed therein, the uphole stop installed from uphole end of the packoff bore and the balance of the components installed from downhole end, the wireline shown trimmed according to FIG. 9C;

FIG. 11A illustrates an end view of the downhole end of the packoff sub with a temporary wireline vise secured thereto by two diametrically opposed cap screws (not detailed);

FIG. 11B illustrates a cross-sectional side view of the downhole end of the packoff sub with the temporary wireline vise secured thereto;

FIG. 11C is a cross-sectional side view of a wireline anchor slip and wireline securing Allen screw poised thereabove, the anchor slip being spaced axially from the vise shown in FIG. 11B for insertion into the vise and rotationally constrained therein;

FIG. 11D is an uphole end view of the wireline anchor slip for illustrating the hexagonal profile for mating with a hexagonal socket of the vise for locking thereto rotationally and clamped axially when the vise is damped thereto;

FIG. 12A illustrates a cross sectional side view of the packoff sub of FIG. 9B with a distal end of a wireline extending firstly through the uphole stop and then extending through the packoff bore;

FIG. 12B is an exploded perspective view of the remaining packoff components for installation into the packoff bore from the downhole end thereof, the wireline passing through the anchor slip, some or all of the armor wires bent back uphole and thereabout for forming the tensile connection and the balance of the wireline extending through the packoff bore to terminate at the electrical connection;

FIG. 13A illustrates a cross-sectional side view of the packoff sub of FIG. 12A with all components installed and the packoff bore sealed at the closure cap. Further, the path of the pre-charging pad grease is shown via arrows, the grease introduced from a temporary grease nipple and using the boot housing as a grease gallery to conduct the grease to the downhole most location in the packoff bore for displacement uphole along the wireline;

FIG. 13B is a perspective and exploded view of the wireline conductor termination to the sealed conductor, and as shown from the uphole end, the termination having a crimp-on female contact, a protective boot, a plastic boot support sleeve, the sealed electrical connector having a male uphole and downhole ends, an uphole O-ring for the boot housing, the boot housing, and downhole seals, the downhole end of the boot housing forming a packoff bulkhead for sealably passing the secondary and hermetically sealed electrical connector;

FIG. 13C illustrates a cross-section of the wireline with two layers of armor, a conductor wire, and conductor insulating jacket between the armor and the conductor;

FIG. 13D illustrates a cross-section of the protective boot of FIG. 13B installed about the conductor wire and conductor insulating jacket of FIG. 13C, the boot only partially conforming with the scalloped deformations on the outside of the insulation;

FIG. 13E illustrates a cross-section of the protective boot of FIG. 13B over a side view of the conductor wire and conductor insulating jacket of FIG. 13C and illustrating the boot only partially conforming with the scalloped deformations on the outside of the insulation;

FIG. 14 illustrates a cross-sectional side view of the packoff sub of FIG. 13A, with the packoff sub housing extended so as to axially position the grease port corresponding with the downhole-most location of the packoff bore without the need for a grease gallery in the of FIG. 13A;

FIG. 15A illustrates a cross sectional side view of the packoff sub of with an alternate embodiment of the packoff components installed, the components stacking sequentially but not in a self-supporting cartridge format;

FIG. 15B illustrates a cross sectional side view of the packoff components installed in the packoff bore of FIG. 15A, and components not necessarily being secured to one another, but being serially stackable and having full bore diameter, the wireline armor anchor cap being fit to the bore, the uphole and downhole cone stops being full bore diameter and the bushing sized accordingly;

FIGS. 16A through 30A illustrate the steps to terminate a wireline in an embodiment of the cable head according to FIG. 3;

FIG. 30B illustrates a quality control viewing of the resulting incompressible grease filled packoff cartridge resulting therefrom;

FIGS. 31A through 31D illustrate an embodiment of the steps needed to terminate a wireline in a termination sub using apparatus and methods disclosed herein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
General Overview

In embodiments, and as shown in FIGS. 9A to 10, a wireline 10 is supported and terminated in a termination sub 24. With reference to FIGS. 13C to 13E, the wireline 10 comprises wireline armor 12 and at least one electrical conductor 20. The wireline armor 12 comprises numerous armor strands or wires 14, and can be supportably connected to the termination sub 24 to create the tensile connection with the sub 24. The electrical conductor 20 is terminated and sealed within the termination sub 24.

With reference to FIGS. 3, 4, and FIGS. 31A to 31D, one process 200 is shown for termination and electrical connection of a wireline 10 to a sensor tool 22. At step 202, a termination sub 24, such comprising as a cable head 30 and adapter assembly 26, is disconnected from the sensor tool 22, exposing the termination sub 24 for accessing a packoff bore 32 extending through the body thereof. Depending upon the stage at which the termination is performed, whether to affix a wireline 10 in the first instance or for replacement thereof, various additional or fewer steps may apply.

As best shown in FIGS. 5 to 6C, cable head 30 can comprise a generally tubular body having a packoff bore 32 for terminating and electrically connecting the wireline 10 and a flow bore 38 for permitting fluid communication therethrough without interference with the components housed in the packoff bore 32.

As shown in FIGS. 16A and 168, at step 204, in the instance that a cable head 30 and adapter assembly 26 have just been separated from a sensor tool 22, the adapter assembly 26 is exposed and can be separated from the cable head 30. As shown in FIGS. 3 and 4, the adapter assembly 26, and corresponding adapter target ring 28, couples the termination sub 24 to the sensor or other downhole tool 22 as the situation dictates.

Returning to FIG. 16A, fasteners, such as a pair of cap screws, are removed and the freed adapter assembly 26 is removed axially from the downhole end 36 of the cable head 30 for separating the sealed flow passage coupling from the adapter 26, exposing the packoff bore 32, and disconnecting the downhole electrical connection pin of the packoff cartridge 40 from the female electrical connection plug of the adapter assembly 26.

As shown in FIG. 17A, pulling the adapter assembly 26 exposes the packoff bore 32. A previously installed packoff assembly cartridge 40 may already be installed in the packoff bore 32. If so, the closure plug nut 42 of the prior installation is removed and the packoff cartridge 40 is removed. The closure plug nut 42 is engageable with a wrench. The downhole end can be castellated or fit with an array of wrench recesses, such as pin holes 43, for enabling engagement and unthreading of the closure plug nut 42 from the threaded downhole end 36 of the packoff bore 32. The packoff cartridge 40 is then available for extraction from the packoff bore 32 (step 206). A puller tool (not shown) can be threaded onto the downhole end of the boot housing 94 for applying axial removal loads.

Assuming the prior packoff cartridge 40 was removed, or not present, the packoff bore 32 is available for a new or refurbished packoff cartridge 40.

With reference to FIGS. 7 to 8C and 12B, and as will be explained in greater detail below, the packoff cartridge or packoff assembly 40 comprises numerous components for creating a tensile connection between the cable head 30 and wireline 10, establishing an electrical connection with the wireline 10, and preventing wellbore fluids from coming into contact with the electrical connection(s) made with the wireline conductor 20.

As shown in FIG. 12A, an uphole stop 44, which can be integrated with the cable head 30 or removably secured to the cable head 30, such as a threaded uphole stop 44, remains in place or is secured at the uphole end 34 of the packoff bore 32. The uphole stop 44 acts as a fuse, retaining the wireline 10 in the packoff bore 32 as long as the tensile load thereon is below a threshold, and releasing like a fuse if the threshold tensile load is exceeded. The distal end of the wireline 10 is shown in juxtaposition with the cable head 30 as it would look when installed in tensile connection and with electrical termination complete.

The installable and releaseable uphole stop 44 is a fuse having a predetermined failure strength that permits the mechanical weak point release to be selected upon installation of the wireline 10 to the cable head 30. Accordingly, the strength of the mechanical weak point can be adjusted separate and apart from the cable head 30 or wireline 10 themselves.

As shown in FIGS. 8A and 17A, at step 208, a wireline 10 having a new or raw cut end is extended through the restricted entrance 46 of the uphole stop 44 and through the open packoff bore 32 to project from the downhole end 38 thereof.

As shown in FIGS. 11A-11D and 17, at step 210, in order to facilitate assembly of the packoff cartridge 40, for post-assembly insertion of the cartridge 40 the packoff bore 32, a jig or vise 48 is temporarily secured to the downhole end 36 of the cable head 30. The vise 48 is secured to the cable head 30, conveniently using the same fasteners or fastener locations that were used to secure the adapter assembly 26 to the cable head 30. The vise 48 forms a polygonal clamp that grips the polygonal uphole end 52 of an anchor slip 50. The vise 48 is aligned with the packoff bore 32. The vise 48 also establishes the axial location of the wireline relative to the cable head 30 and to the cartridge 40.

As shown in FIG. 18A, at step 212, the anchor slip 50 is slipped over, or fit to, the protruding wireline 10. In the instance of a wireline 10 within coil tubing 8, the coil tubing 8 is secured to the cable head 30 such as through a dimple connector (not shown) uphole of the cable head 30. The wireline 10 extends from the coil tubing 8 and through the cable head 30 and results again as shown in FIG. 17A. The wireline 10, being a flexible cabling, can become serpentine when axially compressed or retracted into the coil tubing 8 and thus has the capability of a limited axial extension when pulled therefrom. To enable hand manipulation of the wireline 10 by personnel, the limited extension and retraction is managed during termination.

At step 214, the protruding wireline 10 is pushed back into the cable head 30 against increasing resistance and the wireline 10 is marked. The wireline 10 is pulled out of the cable head 30 to a working length, being less than a full by-hand extension. The anchor slip 50 can be slid onto the wireline 10 before or after the wireline 10 is cut off. The wireline 10 is cut off at some convenient location greater than the marked location and about 8″ from the end of the anchor slip 50. The wireline 10 can be cut at any other suitable location depending on the requirements of the operation.

As shown in FIG. 18A, at step 216, the anchor slip 50 is secured to the wireline 10 by tightening a set screw 58 once engaged with the vise 48 (FIG. 18B) or with the anchor slip 50 spaced in close proximity to the vise 48. Also detailed in FIGS. 11A through 11D, at step 218, the clamp portion of the vise 48 is tightened to pinch the anchor slip 50 and secure the slip 50 axially and rotationally. Prevention of rotation of the anchor slip 50 and added components is aided by corresponding hexagonal or other irregular profiles in the vise clamp bore 49 and uphole end 52 of the anchor slip 50, here illustrated as a hexagonal profile.

The anchor slip 50 forms the axial tensile connection of wireline 10 and cable head 30. The anchor slip 50, when installed to the packoff bore 32, bears against the uphole stop 44, transferring tensile loads to the cable head 30 and thus to the downhole tool 22 connected downhole thereof. The uphole stop 44 can act as a mechanical fuse, having a pre-determined release or failure load to permit emergency release of the wireline 10 from the cable head 30 and enable retrieval of the wireline 10.

As shown in FIG. 18C, the anchor slip 50 has a small outer diameter tubular slip interface portion 56 about which wireline armor wires 14 can be bent back uphole thereabout.

In FIGS. 19A and 19B, the illustrated wireline 10 has at least two layers of wound wire 14, the outermost wires 14 being separated at the cut end of the wireline 10, and bent back over the slip 50. Depending on the design tensile loading, one can bend back some (lower tensile capability) or many of the armor wires 14 (higher tensile capability), cutting those strands off flush with the end of the slip 50 that were not so manipulated. As shown in FIG. 19B, for each one wire 14 being bent back, two are shown being cut off, only using about ⅓ of the available wires from the outer armor 12 for an embodiment of the anticipated wireline tensile release strength.

As shown in FIG. 20C, at step 220, the wireline outer armor 12 is manipulated to form a slip portion 12a, and inner armor portion 12b is shown projecting downhole thereof and may or may not be used for tensile support over the slip 50, or for sealing by the packoff bushing 70. Downhole of the armor 12 is the electrical conductor 20 portion comprising the wire(s) and a conductor insulation layer or jacket 16.

As shown in FIG. 20A, at step 224, the armor wires 14 can be trimmed to the slip length. The armor wires 14 are stiff and can be more readily bent back to the final position as necessary using a tubular swage tool and hammer to conform the wires 14 to the slip 50 (step 222). The resulting wireline and bent wire profile, in isolation, is shown in FIG. 20C.

As shown in FIG. 20B, at step 226, the slip cap 60 can be forced over the wires 14 and slip 50, securing the wires 14 in an annulus 62 formed between the slip 50 and cap 60, also shown in FIG. 20D. The cap 60 can be prefilled with the dielectric grease G to backfill between bent strand wires 14. The tensile wireline connection is then complete for bearing against the uphole support of the cable head.

In FIGS. 21A and 21B, at step 228, the slip cap 60 is secured using an anchor sleeve 64, which in this embodiment is threaded to the anchor slip 50, sandwiching the slip cap 60 axially therebetween. FIG. 8A illustrates an exploded view of a packoff assembly 40 connected component by component using complementary threaded couplings. Alternatively, as shown in FIGS. 15A and 15B, the components may be independent, non-threaded, and when assembled, butt up against each other and are secured together only once the closure plug nut 42 is threaded into downhole end 36 of the packoff bore 32.

In FIGS. 21C, 22A and 22B, at step 230, the remaining layer or layers of inner armor wires 14 extending from the anchor sleeve 64 can be trimmed off radially down to the insulation layer 16 of the electrical conductor(s) 20. Further, at step 232, the electrical conductor 16 of the wireline 10 can be trimmed to the desired length.

The anchor sleeve 64 also provides a conical recess or uphole cone slip 66 for the packoff bushing 70. With reference to FIGS. 22A and 22C, at step 234 and for filing the uphole cone slip 66 and generally for maximal packoff cartridge fluid padding, a grease fitting or interim injection tool adapter 110 can be temporality threaded to the anchor sleeve 64 and grease G pumped into and through the anchor sleeve 64 and anchor slip 50 assembly, excess grease G discharging from the anchor slip 50 at the vise 48. Fillage is confirmed as needed and visible if the vise 48 is temporarily loosened form the cable head 30 (step 236).

After confirmation of grease fillage, at step 238, the vise 48 can be secured again to the cable head 30 and the slip 50 reset thereto.

As shown in FIG. 23A, at step 240, the packoff bushing 70 can be slid over the wireline 10. In embodiments, the packoff bushing 70 can be made of polytetrafluoroethylene or another suitable material. With reference to FIG. 23C the packoff bushing 70 can be countersunk to accept the diameter of the trimmed inner armor 12, and the remainder of the bushing bore 72 fit to the diameter of the insulation 16 of the electrical conductor portion 20. The downhole end of the anchor sleeve 64 is a concave conical recess or cone slip 66 for receiving the packoff bushing 70. Shown best in FIGS. 23B and 23C, at step 242, a packing sleeve 74, having a downhole conical recess or cone slip 78 at its uphole end 76, is axially engaged with the packoff bushing 70 and can be threadably secured to the anchor sleeve 64. The threadable packing sleeve 74 includes this convex conical receiver 78 intermediate therealong for receiving the downhole end of the packoff bushing 70. The uphole and downhole ends of the packoff bushing 70 are a corresponding convex conical shape or other suitable shape for being axially compressed by the uphole cone slip 66 and downhole cone slip 78 to seal with the wireline 10. Grease G can be liberally provided about the bushing 70, in the bushing bore 72, and within the packing sleeve 74 before installation.

With reference to FIG. 10, when the packoff components are assembled, the bushing 70 is compressed axially between the conical convex faces of the anchor sleeve 64 and packing sleeve 74, compressing the bushing bore 72 into close or compressive engagement with the wireline 10.

As shown in FIG. 24A, the insulated electrical conductor 20 is shown extending from the packing sleeve 74. A short portion of the electrical conductor 20 is shown stripped. In FIG. 24B, at step 246, a crimped contact or boot contact 80 is placed over the conductor 20 and crimped in place for forming primary electrical connection 86 and leaving a socket or female contact portion 84 available at a downhole end 82 thereof for releasable female/male coupling electrical coupling with the hermetically sealed secondary electrical connection 90.

At this point, if unprotected, the electrical connections 86,90 could be vulnerable to high pressure well fluid incursion along the wireline strands 14, as was the prior art. In this embodiment, the inner wireline armor 12 terminates upstream of the primary electrical connection 86.

With reference to FIGS. 25A through 28A, the boot contact 80 is housed wholly within the packoff cartridge 40 that is then sealed within the packoff bore 32, having only a hermetically sealed female contact portion 84 extending therefrom.

In more detail and starting at FIGS. 25A and 25D, the female crimped contact or boot contact 80 is axially coupled with a first male electrical contact 104 of a feed-through connector 100, which extends hermetically through the axial connection of the balance of the cartridge components.

In FIGS. 25B and 25C, at step 248, an elastomeric boot 96 and plastic sleeve 98 are arranged about the contact 80. Also with reference to FIGS. 13D and 13E, the female contact portion 84 is concentric within the boot 96. While the boot 96 is elastomeric and conforms generally to the insulation 16 about the conductor wire 20, the seal may not be perfect due to imperfections such as scalloped indents 18 formed along the insulating jacket 16 of the wireline 10. Accordingly, the success and efficacy of the grease pad is improved by manually adding grease G to the boot 96 during assembly.

In this embodiment, the releasable primary and secondary electrical connections 86,90, contact 80, and boot components are those supplied by Kemlon in various forms, including a feed-through connector 100, shown here as a single pin version. Other multi-pin connectors and similar arrangements can be employed for more detailed and complex electronic environments. The feed-through connector 100 provides an electrical connection through a hermetically sealed body 102 that is sealably fit to a tool bulkhead for fluid sealed, electrical pass through connection. The feed-through connectors 100 include those with differential pressure ratings across the bulkhead of about 20,000 psi. The packoff cartridge bulkhead 41, formed by the closure plug nut 42, separates the wellbore fluids from the downhole tool 22.

Such electrical sealing systems fall under the Duo-Seel™ (Kemlon Products) for “booted feed-through connectors”. As stated by Kemlon, a single pin connector system consists of a feedthrough connector 100 mounted in a bulkhead and a female connector (commonly referred to as a boot) 96 which plugs onto a first male contact 104. Inside the boot 96 is a contact 80 which grips the metal pin on the male bulkhead connector 104. The boot 96 and contact 80 are sold together as a set. An uphole end of the boot 96 is either bonded to the wire cable 20 or slips onto the wire tightly and makes a seal on the cable 20. A downhole end of the boot 96 fits tightly on the dognut of the feed-through connector 100 and makes a seal there also. Inside the boot 96, current passes through the wire 20, through the contact 80, and finally through the first male contact 104. A seal between the feed-through connector 100 and the tool bulkhead 23 is most commonly made with a rubber “O” ring, but can be made with a pipe thread or a metal ring. Kemlon's connector system is covered by one or more of the following U.S. Pat. Nos. 4,077,261, 3,793,608 and 3,898,731. A second male contact 106 of the feed-through connector 100 is positioned opposite the first male contact 104 such that is located on the other side of the tool bulkhead 23 for connecting with electronic components of the tool 22. In embodiments, the contact 106 can be a female contact.

In FIG. 26A, at step 250 and with reference back to FIG. 25D, the primary electrical connection 86 is protectively housed in a boot housing 94 fit with a hermetically sealed secondary electrical connection 90 having at least the first male contact 104 extending uphole, the first male contact 104 being compatible with the female boot contact 80 crimped to the wireline conductor wire 20. As shown, the secondary electrical connection 90 has a downhole electrical connection, in this case the second male contact 106, located outside the packoff bore 32. As stated above, while the contact 106 illustrated as male in this embodiment, the contact could be configured as a female connection depending on the adapter assembly arrangement and downhole tool 22.

Shown also in FIG. 268, the boot housing 94 aligns with the contact(s) 104,106 of the feed-through connector 100. A window in the boot housing 94 enables viewing of the interface of the elastomeric boot 96 and the first male contact 104. The plastic sleeve 98 within the boot 96 guides the first male contact 104 into the crimped boot contact 80 as the boot housing 94 axially approaches the packing sleeve 74 for coupling.

With reference to FIG. 27A, the length of the electrical wire 20 extending from the wireline 10 had been previously trimmed for seating the crimped contact 80 over the first feed-through male contact 104 when the boot housing 94 is axially engaged with the packing sleeve 74. Similarly, the elastomeric boot 96 extends about the feed-through pin interface, providing a protective cover about the primary electrical connection 86. As will be discussed below, the protective cover is not strictly needed for the exclusion of well fluids as the packoff bore 32 is sealed at the downhole end 36 by the packoff closure plug nut 42 and the packoff bore 32 is filled with an incompressible grease G that cannot be displaced despite any attempt by well fluids to encroach along and between the strands of wireline armor 12. As above, to minimize error, the boot 96 can be pre-filled with grease G.

With reference to FIG. 27B, the feed-through connector 100 is sealably fit to and secured to a downhole end of the boot housing 94. In turn, the boot housing 94 is fit with circumferential seals 92, such as at the uphole and downhole ends thereof, for sealable interface with the packoff bore 32. When secured therein by the packoff closure plug nut 42 (FIG. 29A), the feed-through connector 100 is sealed within the packoff bore 32 with the second male contact 106 extending sealably out of the packoff bore 32 to a dry side of the cable head 30.

Turning to FIG. 28A, if the packoff assembly 40 had not already been threadably coupled as each component was added, the entirely of the packoff assembly 40 can be tightened and axially compressed by tightening the boot housing 94 as against the non-rotating anchor slip 50 held in the vise 48. In FIG. 28B, at step 252, the packoff assembly is complete as a packoff cartridge 40.

As shown in FIGS. 8D and 27B, at step 254, the boot housing 94 has a threaded end 95 which can be temporarily adapted to an insertion tool T as shown in FIG. 28A. The packoff assembly 40 can be held securely while the vise 48 is removed as shown in FIG. 28B (step 256). As discussed earlier, and as shown, the wireline 10 has some slack before being installed to the packoff bore 32. There is sufficient axial travel in the wireline 10 for the freed anchor slip 50 to now be axially inserted into the packoff bore 32 and all the way uphole to engage the uphole stop 44. Grease G can be applied to the packoff assembly 40 prior to installation in the packoff bore 32.

As shown in FIG. 29A, at step 260, the closure plug or nut 42 is fit threadably to the downhole end of the packoff bore 32. To avoid the nut 42 from projecting axially from the packoff bore 32, the nut 42 is axially sized for the packoff bore 32. The nut 42 can be fit with a face wrench interface, here shown as an array of pin holes 43 for drivable connection with a comparable pin wrench. As shown in FIG. 29B, the pin wrench permits retention of the packoff assembly 40 within the packoff bore 32.

With reference to FIG. 30A, at step 262, grease G is first provided to the downhole end of the packoff assembly 40. Grease G flows through the cable head 30 and into the packoff bore 32 to fill the packoff bore 32 from the downhole end 36 towards an uphole end 34. To ensure the electrical connections 86,90 are protected from wellbore fluid ingress, the electrical connections 86,90 and surroundings are padded or filled with grease G. As shown in FIG. 301, the boot housing 94 can then be checked to ensure proper grease fillage.

Also with reference to FIG. 14, at step 262, a grease fitting 110 is fit to a grease port 108 of the termination sub 24 at about the downhole end 36 of the packoff bore 32. Alternatively, as shown in FIGS. 80, 13A, and 138, the packoff assembly 40 is fit with grease galleries 112 in stringers 113 for receiving grease G from the fitting 110 into the bore 32 and first directing the grease G at least downhole along a periphery or passages 112 of the assembly 40 to the downhole end 36 of the packoff bore 32 before the grease G proceeds toward the uphole end 34. As a result, in both embodiments, grease G fills the bore 32 from the downhole end 36 and migrates towards the uphole end 34, displacing any remaining voidage and placing the incompressible grease G within the bore 32. As shown in FIGS. 8D and 14, the boot housing 94 can also be fit with an uphole port 114 for discharging grease G along the packoff assembly and bore interface for elimination of voids therealong. A grease gallery 112 can connect the grease port 108 with the uphole port 114. In operation, pressurized well fluid cannot migrate into the packoff bore 32 from the uphole end 34 as the grease G cannot be displaced downhole.

As seen in FIG. 3, a grease plug 109 can be used to fluidly seal the grease port 108 when not in use.

After packoff assembly 40 has been secured inside the packoff bore 32 of the cable head 30, the adapter assembly 26 can be connected to the cable head 30 and the now assembled termination sub 24 can be connected to the sensor tool 22.

WIRELINE PACKOFF FOR A DOWNHOLE ELECTRICAL TOOL

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CROSS-REFERENCE TO RELATED APPLICATIONS

Provisional Applications (1)