Fiber-optic cable as integral part of a submersible motor system

• US 7,208,855 B1
• Filed: 03/12/2004
• Issued: 04/24/2007
• Est. Priority Date: 03/12/2004
• Status: Expired due to Term

• Current Assignee: Baker Hughes ESP Inc (Baker Hughes Company)
• Original Assignee: Wood Group ESP, Inc. (John Wood Group PLC)
• Inventors: Floyd, Raymond E.
• Primary Examiner(s): TAMAI, KARL I
• Application Number:
  US10/800,171
• Time in Patent Office: 1,138 Days
• Field of Search: 310/71, 310/87, 310/216, 851/01, 851/35, 85/97, 85/98, 85/651, 166/66.4, 166/65.1, 385/101, 385/135, 385/97, 385/98
• US Class Current: 310/71
• CPC Class Codes: E21B 43/128 Adaptation of pump systems with down-hole electric drives
• CPC Class Codes: E21B 47/135 using light waves, e.g. infrared or ultraviolet waves
• CPC Class Codes: G02B 6/4416 Heterogeneous cables
• CPC Class Codes: G02B 6/4427 Pressure resistant cables, e.g. undersea cables
• CPC Class Codes: H02K 11/00 Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection casings, enclosures or supports H02K5/00
• CPC Class Codes: H02K 11/22 Optical devices
• CPC Class Codes: H02K 5/132 Submersible electric motors H02K5/128 takes precedence
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132

Abstract

Apparatus, systems and methods are provided for transmission of optical signals through a wellbore whereby optic fibers are protected from exposure to harsh downhole fluids and conditions. The system comprises a power cable assembly running down hole from the surface and comprising both electrical leads and at least one fiber-optic lead, an electric submersible motor apparatus having optic fibers and optic fiber leads as an integral part of the motor and internal to the motor casing, and a connection(s) between the optic fibers internal to the motor casing and downhole sensors and other equipment requiring optical communication.

Claims

1. A system for providing transmission of optical signals through a wellbore, the system comprising:

a surface cable assembly comprising electrical conductors and at least one optic fiber running into the wellbore from the surface;

an electric submersible motor having a motor casing, and having one or more optic fibers disposed therein;

a motor lead cable assembly comprising electrical conductors and at least one optic fiber, the electrical conductors and the at least one optic fiber terminating in a plug at an end of the motor lead cable assembly, the motor lead cable being connectable to the electric submersible motor by inserting the plug in a receptacle defined in the motor casing, thereby connecting the at least one optic fiber in the motor lead cable to the one or more optic fibers in the electrical submersible motor, wherein the electrical conductors in the power cable are connected to the electrical conductors in the motor lead cable; and

a splice for connecting the at least one optic fiber in the surface cable assembly to the at least one optic fiber in the motor lead cable assembly, wherein the at least one optic fiber in the motor casing is adapted to be connected to the at least one optic fiber in the motor lead cable assembly to transmit a signal representative of a sensed parameter, the splice for connecting the end of the surface cable assembly to the end of the motor lead cable assembly comprising;

first and second compression barrels, each having first and second ends, the first end having an opening for receiving an optic fiber;

first and second connector bodies threadedly connected to the first and second compression barrels, respectively; and

a first compression seal positioned between the first compression barrel and the first connector body, and a second compression seal positioned between the second compression barrel and the second connector body, wherein the at least one optic fiber from the surface cable assembly is inserted into the first compression barrel and the at least one optic fiber from the motor lead cable is inserted into the second compression barrel to form a butt splice when the first and second connector bodies are connected to each other and to the first and second compression barrels, respectively.

2. The system of claim 1, the first and second compression barrels each having a taper at the first end thereof, wherein the first and second compression seals each have a tapered end to mate with the taper at the first ends of the first and second compression barrels.

3. The system of claim 2, wherein the first and second connector bodies each have a passage defined therein, the passage in the first connector body being adapted to receive the at least one optic fiber from the surface cable assembly, and the groove in the second connector body being adapted to receive the at least one optic fiber from the motor lead cable, wherein ends of the at least one optic fiber from the surface cable assembly and from the motor lead cable assembly form a butt junction.