Methods of making moisture-resistant downhole electrical feedthroughs
A method for making a downhole electrical feedthrough package where the feedthrough package may include a metal shell forming a shell conduit. A metal web may be coupled to the metal shell, and the metal web may form a web conduit. A conducting pin may extend through the shell conduit and web conduit. A dielectric seal may electrically isolate the conducting pin from the metal web. The dielectric seal may be formed by a bismuth glass based dielectric sealing material system having at least two of the four components selected from Bi 2 O 3 , B 2 O 3 , MO, and optionally REO forming a bismuth glass system. MO may be selected from ZnO, BaO, TiO 2 , and Fe 2 O 3 , and their glass making pre-cursors. REO may be selected from CeO 2 , Y 2 O 3 , Sc 2 O 3 , Nd 2 O 3 , Pr 2 O 3 , and lanthanum series oxides. One or more isolators may be disposed within the shell conduit proximate to the dielectric seal and surrounding a portion of the conducting pin.
1. A method of forming a downhole electrical feedthrough package, the method comprising:
combining at least two of the four components selected from Bi 2 O 3 , B 2 O 3 , MO, and optionally REO to form a glass mixture;
heating the glass mixture to approximately 650 to 1400 degrees Celsius;
quenching the heated glass mixture in de-ionized water bath to form glass frits;
sintering the glass frits with hollow cylinder shape and fitted into a conduit of a metal shell to form an electrical feedthrough assembly;
firing the electrical feedthrough assembly at first temperature (T 1 ) for a first time period to form a dielectric seal and to provide a first thermal energy to the dielectric seal;
heating the electrical feedthrough assembly at second temperature (T 2 ) for a second time period to provide a second thermal energy to the dielectric seal;
cooling the dielectric seal of the electrical feedthrough assembly to ambient temperature for a third time period; and
integrating two isolators into the conduit so that the dielectric seal is in contact with at least one of the isolators.
2. The method of claim 1 , wherein B 2 O 3 is between 0 mol % to 40 mol %.
3. The method of claim 1 , wherein MO is selected from the group consisting of ZnO, BaO, TiO 2 , Fe 2 O 3 , and their glass making pre-cursors.
4. The method of claim 1 , wherein MO is between 0 mol % to 35 mol %.
5. The method of claim 1 , wherein Bi 2 O 3 is combined with B 2 O 3 and MO to form the glass mixture, and wherein Bi 2 O 3 is between 20 to 60 mol %.
6. The method of claim 4 , wherein a REO is combined with B 2 O 3 and MO to form the glass mixture.
7. The method of claim 5 , wherein REO is selected from the group consisting of CeO 2 , Y 2 O 3 , Sc 2 O 3 , Nd 2 O 3 , Pr 2 O 3 , and lanthanum series oxides.
8. The method of claim 5 , wherein REO is between 0 mol % to 15 mol %.
9. The method of claim 1 , wherein the first temperature (T 1 ) is approximately 300 to 400 degrees Celsius and the first time period is approximately 30 to 45 minutes, and wherein the second temperature (T 2 ) is approximately 480 to 650 degrees Celsius and the second time period is approximately from 20 to 45 minutes.
10. The method of claim 1 , wherein cooling the dielectric seal in the metal shell is cooled with a quenching process to produce a hydrophobic multi-phase (δ-phase and α-phase) mixed dielectric sealing material.
11. The method of claim 1 , wherein cooling the dielectric seal in the metal shell is heated approximately 480 to 550 degrees Celsius and cooled for approximately 5 to 12 hours to produce a high dielectric and hydrophobic α-phase dominated dielectric sealing material.