US 3518608 A
Description (OCR text may contain errors)
June 30, 1970 M. N. PAPADOPOULOS 3,513,603
TELEMETRY DRILL PIPE WITH THREAD ELECTRODE 2 Sheets-Sheet 1 Filed Oct. 28, 1968 FIG. 2A
. M.N. PAPADOPOULOS HIS ATTORNEY June 30, 1970 M. N. PAPADOPOULOS 3,518,608
TELEMETRY DRILL PIPE WITH THREAD ELECTRODE Filed Oct. 28, 1968 2 Sheets-Sheet 2 r f r \5 Q BY: W 7.2-0
HIS ATTORNEY flG 2| INVENTOR M. N. PAPADOPOULOS FIG.
United States Patent O" 3,518,608 TELEMETRY DRILL PIPE WITH THREAD ELECTRODE Michael N. Papadopoulos, Houston, Tex., assignor to Shell Oil Company, 'New York, N.Y., a corporation of Delaware Filed Oct. 28, 1968, Ser. No. 770,063 Int. Cl. E21b 1/06; H01r 3/04 US. Cl. 339-16 7 Claims ABSTRACT OF THE DISCLOSURE Drill pipe constructed of a plurality of pipe sections attachable to one another in an end-to-end manner by means of cooperating threaded connector means. Each section has associated therewith insulated electrical conductor means running along substantially the full length thereof and connected at each end to electrode means which comprise a portion of the threaded connector means. When the pipe sections are attached together, the electrode means of adjacent sections are in cooperative engagement, thereby providing an electrical path along the full length of the drill pipe string.
This invention relates to apparatus for use in drilling oil and gas wells while at the same time being utilized to transmit telemetric data from the bore of the hole being drilled. More particularly, the present invention relates to a drill pipe construction which incorporates electrical conductor means and cooperating electrode means to provide an electrical path along the full length of the drill pipe string.
When drilling a bore hole or otherwise carrying out operations with respect to a well through the use of a pipe string, it is often desirable to send or receive electrical signals between the surface and downhole. It is a known practice in the art to incorporate transducer or other devices at selected locations downhole, such as on the drill bit, to detect such operating conditions as drilling pressure, temperature, resistivity, and the like, and relay such information to the surface by means of electrical signals. In addition, it is often desirable to send signals from the surface to a downhole location for various purposes.
Numerous arrangements have been employed in the past for transmitting these electrical signals between downhole and the surface. One approach has been to in corporate in each pipe section an individual electrical conductor, such as an insulated wire or conduit, with some means for electrically connecting the conductors together as the pipe sections are joined during the course of operations. Such arrangements have been characterized by the fact that they are often complex and prone to mechanical failure after repeated usage. In addition, many arrangements of the prior art type require the use of specially designed drill pipe at great cost and expense to the operator.
SUMMARY OF THE INVENTION It is therefore a primary object of the present invention to provide an improved telemetry apparatus of simple construction which incorporates conventional drill pipe and which is exceedingly rugged in construction whereby it may be used repeadly Without substantially diminishing the effectiveness thereof.
This and other objects have been attained in the present invention by providing a drill pipe constructed of a plurality of conventional pipe sections attachable to one another in an end-to-end manner by means of cooperating threaded connector means. Each pipe section is modified by running lengthwise therealong electrical conduc- Patented June 30, 1970 tor means which is connected at the terminal ends thereof to electrode means comprising a portion of the threaded connector means. The electrode means comprise thin strips of a conductive metal such as copper bonded into position by means of a resinous materal having insulator characteristics in such a manner that the strips form a portion of the connector threads at both the box and pin ends of the pipe section. In addition, the electrical conductor means itself (which may be in the form of a copper wire) is bonded into position along the pipe section by means of the insulating resinous material.
DESCRIPTION OF THE DRAWING Other objects, purposes, and characteristic features of the present invention will be obvious from the accompanying drawing and from the following description of the invention. In describing the invention in detail, reference will be made to the accompanying drawing in which the like reference characters designate corresponding parts throughout several views, and in which:
FIG. 1 is a longitudinal view taken in partial crosssection illustrating a section of telemetry drill pipe with thread electrode means according to the present invention;
FIG. 2 is a cross-sectional view taken along a portion of the drill pipe of FIG. 1;
FIG. 2A is a view similar to that shown in FIG. 2 but illustrating an alternative embodiment of the present invention;
FIG. 3 is a diagrammatic view illustrating portions of cooperating box and pin elements of adjacent pipe sections in the respective positions assumed thereby when the sections are end-connected; and
FIG. 4 is an enlarged cross-sectional View illustrating details of the electrode means utilized in the present invention.
Referring now to FIG. 1, a drill pipe section incorporating elements of the present invention is indicated generally by means of reference numeral 11. As is clearly shown in that figure, drill pipe section 11 has a pin end 12 and a box end 13. The intermediate portion of drill pipe section 11 comprises an elongated tubular element or portion 14 with the inner wall thereof defining a throughbore 15 in the usual manner. As is conventional with respect to drill pipe constructions, internal threads 16 are provided about a portion of the inner peripheral surface of box end 13 while external threads 17 are provided about a portion of the outer periphery of pin end 12. It is of course to be understood that as pipe section 11 is joined in an end-to-end manner with other pipe sections (not shown), the internal threads 16 will cooperate with external threads, similar to threads 17, of one ad joining pipe section while external threads 17 will cooperate with internal threads, similar to threads 16, of the other of said adjoining pipe sections, thereby maintaining said sections in coupled relationship. The drill pipe is constructed of steel material except for those portions thereof which will be described below and constitute modifications to the above-described conventional drill pipe section in accordance with the teachings of the present invention.
As may be seen with reference to FIGS. 1 and 2, running lengthwise along elongated tubular element 14 within throughbore 15 is an electrical conductor means comprising copper wire 21. Wire 21 is maintained in a fixed position relative to the inner peripheral wall of cylinder element 14 by means of an electrically insulating material 22 such as epoxy cement or resin. As may be seen most clearly with respect to FIG. 2, the wire 21 may be imbedded in a pool of epoxy cement or resin formed along the inner wall of tubular element 14. In this manner the Wire will be protected from drilling fluid abrasion and/or from possible impact damage from wire-line or other tools which may be utilized during operations. It is to be understood, of course, that the resulting decreased internal diameter of the pipe section at its minimum is still larger than the undisturbed diameter near the joint, and that it is still large enough to readily carry out drilling operations without substantially impeding the flow of drilling fluid in the pipe, and without impeding at all the passage of tools.
In an alternative embodiment shown in FIG. 2A a channel 23 may be formed lengthwise in tubular element 14 with the wire 21 being substantially centrally maintained in the channel by insulating material 22 which, as stated above, may be epoxy cement or resin, for example. This alternative embodiment has the obvious advantage that the full throughbore of the pipe section is not diminished upon installation of the electrical conductor means. On the other hand, the use of relatively thin-walled drill pipe sections in carrying out the teachings of this embodiment of the invention may be precluded since a channel formed in such pipe may substantially weaken it.
Returning once again to FIG. 1, it may be seen that drill pipe section 11 is drilled in the vicinity of pin end 12 to provide a throughbore 25 into which one end of wire 21 extends. In like manner, a throughbore 26 is provided in the vicinity of box end 13 to accommodate the other end of wire 21. It should be noted that the wire is substantially centrally disposed in the throughbores in an insulated manner by the same above-described electrically insulating material 22 utilized to bond the wire to the inner peripheral wall of the elongated tubular element 14. While the paths of throughbores 25 and 26 may be varied in accordance with the requirements of practice and the exigencies of any given situation, it is of course desirable that the overall strength of the pipe not be compromised. Accordingly, the various holes drilled and channels machined should be in regions of considerable pipe thickness. The throughbore paths shown in FIG. 1 therefore are merely by way of example and illustrative of paths which may be selected.
Wire 21 is connected at its end to electrode or contact means 31 and 32 which are positioned at the pin and box ends, respectively, of the pipe section. It should be noted that one of the contacts (in this instance male contact 31) actually comprises an integral outer portion of external threads 17 at the pin end of the pipe section. Female contact 32, on the other hand is imbedded in the root of box threads 16 to form an integral portion thereof.
Referring now to FIGS. 3 and 4, the construction and placement of the contacts, as well as their cooperative relationship, will be described in detail. As stated above, the pipe sections incorporating the teachings of the present invention are adapted to be placed in an end-to-end manner during actual operations. More particularly, the connector means comprising threads 16 and 17 are adapted to secure adjacent pipe sections together in the well known manner. In addition to performing this securing function, the threads including contacts 31 and 32 cooperate to effect a completed electrical path along the string of joined pipe sections. FIG. 3 illustrates this operation in diagrammatic fashion. In this figure, a portion of the pin end 12 of one pipe section is shown as being positioned in a portion of the box end 13 of an adjoining cooperating pipe section. The pipe sections during drilling or other operations are maintained in this fixed relative relationship by means of threads 16 and 17 in the well known manner. When the pipe sections are engaged in this manner contacts 31 and .32 of the adjoining pipe sections are in communication thereby establishing an electrical path between the wires 21 of the sections. It is of course to be understood that similar couplings are made between adjoining pipe sections throughout the entire pipe string.
FIG. 4 provides an enlarged detailed illustration of a preferred form of contact to be utilized in accordance with the teachings of the present invention. Female contact 32, which is at least one full thread in length, comprises a relatively thin strip of copper embedded in the root of the box end threads 16 by means of insulating material 22 and is secured in any known fashion to wire 21 associated with that particular pipe section. A channel is formed in threads '16 on both sides of female contact 32 and coextensive with the length thereof so that insulating material 22 may be accommodated therein to form a zone of insulation 41 which flares outwardly from the female contact 32 in the manner illustrated.
Male contact 31 also comprises a relatively thin strip of copper at least one full thread in length. In this instance, however, contact 31 is bonded as by means of epoxy cement or resin to a thread 17 on pin end 12 which has been ground down or otherwise decreased in height in the manner illustrated. Male contact 31 is secured in any known manner to the wire associated with the particular pipe section and is positioned so that it is flush with the steel male threads associated with the remainder of the pin end. As is clearly shown in FIG. 4 contact 31 is supported in this position by means of insulating material 22 which is filled in the gap between contact 31 and ground-down thread 17. It should be noted that the sides of the thread '17 associated with contact 31 are ground down and that some of the insulating material 22 is positioned in the void created thereby to form a smooth thread surface as at 42. When contact 31 is in communication with contact 32 the zone of insulation 41 surrounds thread surface 42 thereby insuring that neither contact 31 nor 32 is placed in engagement with the steel portions of pin end 12 and the boxend 13.
The location of contacts 31 and 32 is quite important with respect to the proper functioning of the apparatus according to the present invention. The female copper contact 32 is imbedded in the root of the box end threads, second thread from the top as viewed in FIG. 1. The male copper contact 31 is bonded to form a portion of the corresponding thread on the pin end 12. By locating the contacts in this manner they are located in a region of zero fluid pressure gradient and minimal principal stress. This location precludes contact damage through misalignment during the makeup of the joint, through accidental pin end-to-box end impact, chain impact, or field-handling of the pipe in general.
Adequate electrical contact is assured by making the female copper contact face slightly oversize. If, through long use, copper is abraded from the copper faces of the contacts in sufficient quantities to prevent engagement therebetween, the problem may be corrected merely by coating the face of the male contact 31 with a thin film of a mixture of epoxy cement and copper dust.
Finally, it should be noted that although the root space of some of the box end threads is effectively plugged with copper and/or insulating material, the root space of all of the pin end threads is free. Thus, this latter root space maintains the desired communication of fluid between the inside of the drill pipe, through the threads, and to the annular space above the threads. As a result, no fluid pressure gradient can exist across the contacts.
While this invention has been described with particular reference to preferred embodiments thereof, it should be understood that the particular forms disclosed have been selected to facilitate explanation of the invention rather than to limit the number of forms which is may assume. Further, it should be understood that various modifications, alterations and adaptations may be applied to the specific forms described to meet the requirements of practice without in any manner departing from the spirit of the invention or the scope of the subjoined claims.
I claim as my invention:
1. Apparatus for transmitting electrical signals along a drill string disposed in a well borehole, said apparatus comprising:
a plurality of drill pipe sections detachably interconnected in an end-to-end manner, each pipe section including;
an elongated tubular portion having an inner wall defining a throughbore and terminating at the ends thereof with first and second connector means, said first connector means comprising a box end and said second connector means comprising a pin end, each of said connector means being provided with thread means to effect detachable interconnection 'with adjoining pipe sections;
electrical conductor means extending substantially along the length of said pipe section;
electrically insulating material bonding said electrical conductor means to said pipe sections;
electrical contact means comprising an integral portion of said thread means and being fixedly positioned in an insulated manner with respect to the remainder of said thread means by means of an insulating bonding material; and
said electrical conductor means being end-connected to said electrical contact means to provide an electrical path therebetween which is electrically insulated from the remainder of said drill pipe section.
2. The apparatus according to claim 1 wherein said electrical contact means are in the form of thin strips of copper approximately one full thread in length and said insulating bonding material is epoxy resin.
3. The apparatus according to claim 2 wherein one of said electrical contact means comprises a portion of the male threads on said pin end and another of said electrical contact means is disposed in the root of the threads on said box end.
4. The apparatus according to claim 3 wherein said electrical contact means disposed in the root of the threads on said box end is slightly oversize to ensure engagement between said contact means and a cooperating contact means on an adjoining pipe section.
5. The apparatus according to claim 1 wherein the electrically insulating material used to bond the electrical conductor means to said pipe section is epoxy resin.
6. The apparatus according to claim 5 including a channel formed along the length of said tubular portion, said electrical conductor being centrally fixedly disposed in said channel by means of said epoxy resin.
7. The apparatus according to claim 3 including a zone of insulation formed by said electrically insulating material adjacent said electrical contact means disposed in the root of the threads on said box end.
References Cited UNITED STATES PATENTS 959,977 5/ 1910 Washburn et al. 2,979,142 4/1961 Reid l105 3,170,137 2/1965 Brandt 339-16 RICHARD E. MOORE, Primary Examiner R. A. HAFER, Assistant Examiner US. Cl. X.R. -104