PIPE SYSTEM WITH ELECTRICAL CONDUCTORS

Abstract: A drill pipe member has screw threaded and regions (11, 12) for mechanical connection of the member to like or co-operating members in end-to-end relationship, electrical conductors (22) extending along the pipe member between pin and socket connector assemblies (30, 31) at its ends and carrier tubes (25) containing the conductor means and extending between the connector assemblies, the carrier tubes and the electrical connector assemblies providing isolation for the electrical conductors from the pipe member interior.

Description: PIPE SYSTEM WITH ELECTRICAL CONDUCTORS DESCRIPTION The invention relates to a pipe system incorporating one or more electrical conductors, and more specifically to a pipe system in hic a plurality of pipe members or sections are connected together in end-ro-end relationship, and in which the pipe sections include one, or usually more, electrical conductors, which are also connected together to provide for electrical po er supply a /or communication along the pipe system. The invention is thus concerned with the provision of a pipe member or section of a kind having electrical conductor means and at least one fluid passage extending therealong, means whereby the section can be mechanically connected with a like or a co-operating section in a pipe system, and means for effecting connection of the electrical conductor means and the at least one fluid passage with an electrical conductor means and a fluid passage of the like or co-operating section respectively. The invention provides a pipe section of this kind including means for isolating the electrical conductor means from the fluid in the fluid passage. The invention can thus provide one or more carriers or carrier tubes, for containing the conductor or conductors, which are located in the fluid passage, or are exposed to the pressure of fluid in the passage, and which extend between appropriately sealed electrical connector assemblies at the ends of the pipe section. The electric conductor or conductors can comprise for example, conventional electrical cables. The pipe section thus contains within it a conductor assembly comprising electrical conductor means protected by reception withhin a sealed compartment provided by the conductor carrier means and the connector assemblies sealed off to the ends of the pipe section. The invention has particular reference to a drill string and can be embodied as a drill pipe section comprising a drill pipe defining within it a passage for drilling mud, and including the carrier tube or tubes. The mud passage can be defined by an internal mud liner to ensure smooth flow of the mud and the carrier tube or tubes can be located between the drill pipe and the mud liner. The carrier tube or tubes can thus be received in a groove or grooves defined outwardly of the mud liner wall, as by deformation of a tubular liner of substantially uniform wall thickness. The carrier tubes accommodated in the grooves can be exposed to the pressure of the drilling mud by way of perforations in the mud liner wall so as to experience substantially uniform ambient pressure. The pressure protection for the conductors is then provided by the carriers, not by the mud liner. In this way, good protection, total pressure balancing and pressure resistance is obtained. Usually, there will be a plurality of conductors, typically three conductors, and the mud liner will accordingly be provided with plural, typically three, such grooves equi-angularly spaced around longtudinal axis of the drill pipe section. The invention also provides a pipe section of the kind described having hollow pin and box type conductor connection means at respective ends of the pipe section, the connection means providing reliable electrical connections independent of angular orientation and permitting a substantially unobstructed fluid flow from and into adjacent pipe sections. The ends of a drill pipe section can thus receive within them hollow detachable conductor connector assemblies the interiors of which communicate with the mud liner to provide a continuous fluid passage along the drill string. The pin type assembly can provide contact elements protruding from the pipe section end and the box type assembly can provide co-operating contact elements within a socket portion providing controlled contact in the radial direction. The contact elements of both assemblies can be constituted as contact rings. When embodied as a drill pipe section with the conductor arrangements described above, the conductor carriers can extend between the assemblies which can be sealed to the pipe section wall inwardly of the contact elements and/or to each other as by a sealing portion projecting beyond the contact elements for reception in a socket portion inwardly of the contact elements of the box-type assembly. Seal means can be arranged to wipe clean the contact areas of the contact elements during assembly. The invention can thus be readily embodied in a drill string including electrical conductors, in which the conductor carriers provide protection from pressure for the conductors and their insulation. The carriers can compensate also for the elongation experienced by the conductors under tension. The conductor carriers can have fixed ends, at the conductor connection assemblies, so no dynamic seals are required. The conductor assembly means as a whole can be axially and/or rotationally movable relative to the pipe section, and can have low torsional stiffness so as to follow torsional displacement of the drill pipes. The conductors are also free to expand thermally without transmitting adding load to the insulation when the drill string is under high tension. The conductors themselves can be of conventional form, capable of providing excellent signal and power transmission. Assembly of the drill string can be effected conventionally by means of stabbing guides, after cleaning of the conductor contacts or contact rings. The electrical components of the pipe section can be easily disconnected and retrieved from the drill pipe for replacement of any damaged parts, and for any repair of the drill pipe separately. The invention is further described, by way of example, with reference to the accompanying drawings, in which: Figure is a perspective view with parts removed in order to show the interior of the upper end of a drill pipe section embodying the invention; Fig. 13 is a like view of the lower end of the drill pipe section of the invention; Figures 2 & 3 are sectional side views of the upper and lower ends of the pipe section respectively; and Figure 4 is a sectional side view of the end regions of two of the drill pipe sections embodying the invention, assembled together. The illustrated drill string comprises a plurality of like drill pipe sections 10 of appropriate length mechanically connected together in end-to-end relationship. The mechanical connections are effected by co-operating screw-threaded portions at the ends of the sections, comprising an externally threaded downwardly and inwardly tapering pin portion 11 at the lower end and a correspondingly tapered internally threaded box or socket portion 12 at the upper end for receiving the pin portion of the section immediately above. Internally, the drill pipe sections 10 have a substantially uniform internal diameter, except near the upper end as will be described, but the end regions are mechanically reinforced by portions of enlarged external diameter. From the main length of the pipe section, the external surface tapers outwardly to upper and lower intermediate portions 14 and 15, from which it tapers further outwardly to upper and lower end portions 16 and 17. The lower end portion 17 has an inward step 18 at its free end and the pin porrion 11 extends downwardly from this step. The upper end portion 16 is of greater length than the lower end portion 17 to accommodate within it the box portion 12. An 0-ring seal 19 received in a circumferential slot in the pin portion 11, adjacent the step 18, establishes a secondary seal with the inner surface of box portion at its upper end when the adjacent sections are connected together, the primary seal being a metal-to-metal seal between the step 18 and the upper end of the pipe section below. The pipe sections 10 are thus externally more or less conventional, except for somewhat increased dimensions at the end regions, and can be releasably connected together in conventional manner to provide a mechanical connection between the sections capable of meeting typical structural and strength requirements. Each pipe section 12 provides internally a passage by which drilling mud can be conveyed to the drill bit. This passage is defined along most of the length of the pipe section by a perforated liner 20 received within i . Three electric conductors 22 for conveying electrical power and/or communication signals along che drill string are located between the mud liner and the pipe section. To accommodate and position the electrical conductors 22, the mud liner wall is formed with three equi-angularly spaced grooves 24 extending along its length. Within the grooves are received tubular conductor carriers 25 not necessarily of circular cross-section and, if of other cross-section, conveniently one corresponding to that of the mud liner grooves 24. Each conductor carrier 25 extends between the end regions of the section 10 and receives therein a respective one of the electric conductors, constituted by a conventional insulated cable. The carriers 25 protect the conductors 22 against pressure of the mud, which is transmitted to the exteriors of the carriers through the perforations in the mud liner wall and balanced within the grooves 24. It is of course necessary to arrange for continuity of the conductors 22 along the drill string and the pipe sections 10 contain co-operating upper and lower electrical connector assemblies 30 and 31 of the pin and box type by which electrical continuity between the conductors 22 of adjacent sections is reliably and conveniently ensured. The assemblies provide anchoring for the ends of the carriers 25 and also access to the terminations of the conductors 22. The assemblies incorporate seals against internal mud pressure and can be readily removed from and replaced within the sections 10. As appears from Figures 1A & 2, the box or female connector assembly 30 comprises a connector sleeve 32 received within the upper end portion of the pipe section, below the threaded connector portion 12. At its lower end, the sleeve 32 has a sealing portion 34 stepped inwardly at its lower end to rest on a matching internal step 36 provided in the pipe section interior. The sealing portion 34 has annular grooves around it receiving axially spaced seal rings 40, for sealing to the pipe section interior. Above the sealing portion 34, the sleeve 32 has three equi-angularly spaced axially extending grooves or recesses 42 each of which communicates with a passage 44 through the sealing portion. The lower end of each passage 44 provides an upper seating for one of the conductor carriers 25. Beneath the connector assembly 30, the mud liner 20 is tapered inwardly and upwardly to match the interior of the sleeve 32, except in the regions at which are formed the axial grooves 24 containing the conductor carriers 25. At the upper end of the sleeve 34, the interior is enlarged to provide a socket 46 for reception of the lower end of the male or pin connector assembly 31. Above the sleeve 34, the assembly 30 includes a conductor sleeve 50 of electrically insulating material mounting axially spaced conductor rings 54 received in internal annular grooves. The electrical conductors 20 extend upwardly from the carriers 25 through the passages 44 into the grooves 42, the conductors having outwardly inclined portions in these grooves because of the socket 46. Jumper portions 56 at the ends of the conductors 22 connect to leads 60 in axial passages within the wall of the conductor sleeve, by which connection is made to the conductor rings 54. As shown in Figures 1B & 3, the male or pin connector assembly 31 comprises a tubular connector sleeve 33 received within and projecting from the lower end of the section 10. At its upper end, the sleeve 33 has a sealing portion 35, delimited below by an annular inward step resting on a matching step 37 in the pipe section interior. The sealing portion 35 engages axially spaced seal rings 39 in annular grooves in the pipe section wall. Equi-angularly spaced passages 41 in the sealing portion 35 provide seatings for the lower ends of the conductor carriers 25 and communicate with external grooves 43 which extend downwardly to a portion 45 of the sleeve, at the lower end of the pipe section pin portion 11, which reverts to a complete circular cross- section externally but which includes apertures 47 in alignment with the grooves 43. Slightly below the lower end of the pin portion 11, the sleeve exterior is inwardly stepped, and below the step, the sleeve 33 is surrounded by a connector sleeve 51 , of electrically insulating material, and a sealing sleeve 53 the lower end of which has an internal flange of which the inner diameter matches that of the connector sleeve. The conductor sleeve 51 is externally grooved to receive three axially spaced conductor contact rings 55 each electrically connected to a respective one of the electrical conductors and the sealing sleeve 53 is externally grooved to receive two axially spaced seal rings 57. The conductors 22 extend downwardly from the carriers 25 through the sealing portion passages 41 and the grooves 43. Jumper portions at the conductor ends connect to leads 59 in axial passages in the wall of the conductor sleeve 51 , to make connection to the conductor rings 55. At the upper end of the connector sleeve 33, the wall of the mud liner tapers inwardly and downwardly from a position in the region of the join between the intermediate and end portions of the pipe section 10, between the portions forming the grooves, so as to communicate with the sleeve interior. Assembly together of two of the pipe sections 10 to reach the condition of Figure 4 is effected by stabbing, after cleaning of the contact rings 54 & 55. As the mechanical connection is completed the sealing sleeve 53 is received in the socket 46 and the conductor sleeve 51 is received in the sleeve 50, with electrical contact established between the rings 54 & 55. The invention can be embodied in a variety of ways other than as specifically described.

Claims: CLAIMS 1. A pipe member having electrical conductor means (22) extending between respective contacts (54,55) of a first connector assembly (30) at one end of the pipe member and a second connector assembly (31) at the other end of the pipe member, and carrier means (25) containing the electrical conductor means and extending between the connector assemblies, the connector assemblies and the carrier means co-operating to isolate the conductor means from the pipe member interior. 2. A pipe member as claimed in claim 1 wherein the carrier means comprises at least one carrier tube (25) within the pipe member interior. 3. A pipe member as claimed in claim 2 having a tubular liner (20) in the pipe member interior, the at least one carrier tube being between the liner and the pipe member and the liner being perforated to expose the at least one carrier tube to fluid within the liner. 4. A pipe member as claimed in claim 3 wherein the liner (20) is provided with at least one longitudinally extending groove (24) accommodating the at least one carrier tube (25) therein. 5. A pipe member as claimed in claim 1, 2, 3 or 4 wherein the connector assemblies comprise inner sleeve portions providing seatings for the carrier means (25), outer sleeve portions carrying the contacts (54,55), and passage means for the electrical conductor means extending between the seatings and contacts. 6. A pipe member as claimed in any preceding claim wherein the connector assemblies (30,31) are removably received in the pipe member, and the connector assemblies and the pipe member have co-operating configurations (36,37) defining the received position of the connector assemblies within the pipe member. 7. A pipe member as claimed in any preceding claim having sealing means (39,40) operative between each of the connector assemblies (30;31) and the pipe member. 8. A pipe member as claimed in any preceding claim having mechanical connection means (11,12) at its end regions and wherein the connector assemblies comprise a pin connector assembly (30) having a portion protruding outwardly of one end of the pipe member beyond the connection means and a socket connector assembly (30) received in the other end of the pipe member inwardly of the connection means. 9. A pipe member as claimed in claim 8 having sealing means (57) operative between the connector assemblies beyond the free end of the pin connection assembly (30). 10. A pipe member as claimed in any preceding claim constituted as a drill pipe member, wherein the carrier means (25) is capable of movement in use relative to the drill pipe member.

Inventors: MOHN FRANK, MOHN, FRANK
Applicants: FRAMO DEV LTD, FRAMO DEVELOPMENTS (UK) LIMITED
Application year: 1991
Main classification: E21B17
IPC codes: E21B17, G07F7