Method and Apparatus to Provide Electrical Connection in a Wellhead for a Downhole Electrical Device

A hot electrical connection assembly in a wellhead for providing a power connection to a tubing string extending to a downhole electrical device, comprising:

• a. one or more pressure-containing wellhead body members enclosing a vertical wellbore extending there through, the one or more body members supporting, in sealed relationship in the vertical wellbore, an isolated tubing hanger, the isolated tubing hanger suspending therefrom a conducting tubing string electrically connected to the downhole electrical device;
• b. the isolated tubing hanger having an outer housing which seats in the vertical wellbore of the one of the one or more wellhead members, an inner electrically conducting portion supported by the outer housing operative to provide electrical connection to, and suspend, the conducting tubing string, and insulation between the housing and the conducting portion to electrically isolate the housing portion from the conducting portion;
• c. a hot electrical connection for making an electrical connection to the conducting tubing string or to the conducting portion of the isolated tubing hanger;
• and
• d. electrical isolation associated with the hot electrical connection and the one or more wellhead members for sealing and electrically isolating the hot electrical connection such that the one or more wellhead body members remain electrically isolated from the hot electrical connection.

An isolated tubing hanger for suspending a conducting tubing string within a pressure-containing tubing head, the isolated tubing hanger comprising:

• a. an outer housing which seats in the tubing head, an inner electrically conducting portion supported by the outer housing operative to provide electrical connection to, and suspend, the conducting tubing string, and insulation between the housing and the conducting portion to electrically isolate the housing portion from the conducting portion;
• b. the housing forming a central bore with an inwardly extending circumferential landing seat at its lower end, and carrying outer circumferential seals to seal with the tubing head;
• c. the conducting portion of the isolated tubing hanger including a landing shoulder to seat on the landing seat, and a conducting neck portion connected to, or integral with, the conducting portion extending upwardly relative to the housing, said conducting neck portion providing the electrical connection to the conducting tubing string;
• d. the insulation including load supporting insulation plates located above and below the landing shoulder, and a plurality of insulation sleeves between the housing and the conducting portion;
• e. one or more seals between the landing shoulder and the landing seat to seal the conducting portion of the isolated tubing hanger with the housing;
• and
• f. a retainer ring at the top of the housing around the conducting neck portion to retain, seal and energize the insulation and the one or more seals.

A method for providing a power connection from a source of current located at a wellhead to a downhole electrical device, wherein the wellhead includes one or more pressure-containing wellhead body members forming a vertical wellbore extending there through, the one or more wellhead body members being operative to support, in sealed relationship in the vertical wellbore, a first and a second tubing hanger, each tubing hanger being operative to suspend therefrom a tubing string such that a first and a second tubing string are concentrically spaced from each other, the method comprising:

• a. providing electrical isolation to the first of the tubing hangers such that an outer housing of the first tubing hanger is electrically isolated from an inner, electrically conducting portion of the first tubing hanger;
• b. suspending the first tubing string from the electrically conducting portion of the first tubing hanger;
• c. providing insulation between the outer housing and the inner conducting portion of the first tubing hanger to electrically isolate the outer housing portion from the inner conducting portion;
• d. connecting the source of current in a sealed and electrically isolated manner to the inner electrically conducting portion of the first tubing hanger or to the first tubing string, such that the one or more wellhead members are electrically isolated from the first tubing string;
• and
• e. connecting the source of current to the one or more wellhead body members so as to provide a grounding connection to the second tubing string.