Inventors:
Harold P. Adams - Oil City PA
David R. Hill - Oil City PA
Lee M. Richey - Franklin PA
Andrew B. Maitland - Cranberry PA
William E. Banton - Derry NH
David C. Taylor - Slippery Rock PA
Assignee:
Oil Well Automation, Inc. - Oil City PA
International Classification:
E21B 4300, E21B 4704, F04B 4906
Abstract:
A system for controlling production in an oil well comprises a first level sensor mounted upon the outer surface of the tubing near the lower end of the tubing and a second level sensor mounted upon the outer surface of the tubing above the first level sensor. The first level sensor is tuned to a first electrical signal frequency. The second level sensor is tuned to a second electrical signal frequency. A control device at spaced intervals transmits electrical signals of the first and second frequencies down the oil well and senses the liquid level by detecting impedance.