Downhole Coils
In one aspect of the invention, a downhole tool string component comprises a tubular body with at least one end adapted for threaded connection to an adjacent tool string component. The end comprises at least one shoulder adapted to abut an adjacent shoulder of an adjacent end of the adjacent tool string component. An annular magnetic coupler is disposed within an annular recess formed in the at least one shoulder, and the magnetic coupler comprises a coil in electrical communication with an electrical conductor that is in electrical communication with an electronic device secured to the tubular body. The coil comprises a plurality of windings of wire strands that are electrically isolated from one another and which are disposed in an annular trough of magnetic material secured within the annular recess.
1 . A downhole tool string component, comprising:
a tubular body with at least one end adapted for threaded connection to an adjacent tool string component;
the end comprising at least one shoulder adapted to abut an adjacent shoulder of an adjacent end of the adjacent tool string component;
an annular magnetic coupler disposed within an annular recess formed in the at least one shoulder;
the magnetic coupler comprises a coil in electrical communication with an electrical conductor in electrical communication with an electronic device secured to the tubular body; and
the coil comprises a plurality of windings of wire strands that are electrically isolated from one another and disposed in an annular trough of magnetic material secured within the annular recess.
2 . The component of claim 1 , wherein the wire strands are interwoven.
3 . The component of claim 1 , wherein the coil comprises the characteristic of increasing less than 35° C. when 160 watts are passed through the coil.
4 . The component of claim 1 , wherein the coil comprises the characteristic of increasing less than 20° C. when 160 watts are passed through the coil.
5 . The component of claim 1 , wherein the adjacent shoulder of the adjacent downhole tool string comprises an adjacent magnetic coupler configured similar to the magnetic coupler and these couplers are adapted to couple when the downhole components are connected together at their ends, wherein the magnetic coupler and the adjacent magnetic coupler are adapted to induce magnetic fields in each other when their coils are electrically energized.
6 . The component of claim 5 , wherein the magnetic coupler comprises a characteristic of transferring at least 85% energy from the magnetic coupler to the adjacent magnetic coupler when 160 watts are passed through the coil.
7 . The component of claim 1 , wherein the electronic device is a power source.
8 . The component of claim 7 , wherein the power source comprises a battery, generator, capacitor, motor, or combinations thereof.
9 . The component of claim 1 , wherein the electronic device is a sensor, drill instrument, logging-while-drilling tool, measuring-while-drilling tool, computational board, or combinations thereof
10 . The component of claim 1 , wherein the magnetic material comprises a material selected from the group consisting of ferrite, a nickel alloy, a zinc alloy, a manganese alloy, soft iron, a silicon iron alloy, a cobalt iron alloy, a mu-metal, a laminated mu-metal, barium, strontium, carbonate, samarium, cobalt, neodymium, boron, a metal oxide, rare earth metals, and combinations thereof.
11 . The component of claim 1 , wherein the magnetic material comprises a relative magnetic permeability of between 100 and 20000
12 . The component of claim 1 , where in the coil comprises between 5 and 30 wire strands.
13 . The component of claim 1 , wherein the coil comprises a gauge between 36 and 40 AWG.
14 . The component of claim 1 , wherein the coil comprises between 1 and 15 coil turns.
15 . A method of transferring power from a downhole tool string component to an adjacent tool string component, comprising:
providing a downhole tool string component and an adjacent tool string component respectively comprising an annular magnetic coupler and an adjacent annular magnetic coupler disposed in an annular recess in a shoulder of an end of the component;
adapting the shoulders of the downhole tool string component and the adjacent tool string component to abut one another when the ends of the components are mechanically connected to one another;
mechanically connecting the ends of the components to one another;
driving an alternating electrical current through the magnetic coupler at a frequency of between 10 and 100 kHz.
16 . The method of claim 15 , wherein the frequency is between 50 and 70 kHz.
17 . The method of claim 15 , wherein the magnetic coupler and the adjacent magnetic coupler are respectively disposed within annular troughs of magnetic material that are disposed within the respective annular recess of the downhole and adjacent components.
18 . The method of claim 15 , wherein at least one of the magnetic coupler and adjacent magnetic coupler comprise a coil that comprises a plurality of windings of wire strands, the wire strands each being electrically isolated from one another.
19 . The method of claim 18 , wherein at least 85% of energy comprised by the alternating electrical current being driven through the annular magnetic coupler is inductively transferred to the adjacent magnetic coupler when 160 watts are passed through the coil.
20 . The method of claim 18 , wherein at least 95% of energy comprised by the alternating electrical current being driven through the annular magnetic coupler is inductively transferred to the adjacent magnetic coupler when 160 watts are passed through the coil.
21 . The method of claim 15 , wherein the alternating electrical current is a square wave.