STEPHEN GERLEK
Architects at Mnr, Anchorage, AK

5533572, Jul 9, 1996

Jan 10, 1995

8/370689

Jerry L. Brady - Anchorage AK
Stephen Gerlek - Anchorage AK
David L. Lagerlef - Eagle River AK
Raymond Wydrinski - Lewisville TX

Atlantic Richfield Company - Los Angeles CA

E21B 4700

16625005

Corrosion in well tubing strings, pipe and similar conduits may be determined by a circuit which includes a current sensitive meter and a known voltage source which is placed at selected intervals in the tubing string to make current flow measurements and voltage drop measurements between spaced apart contactors engaged with the tubing string at the selected intervals. The current flow measurements from the known source are used to determine resistance of the measured interval and voltage drop from a second source imposed on the tubing string at the surface is measured at the selected intervals to determine current flow from the second source. The differences in current flow at the selected intervals at a first measurement are compared with the differences in current flow at the same intervals at a later time to indicate any changes in current flow which may be related to corrosion in the tubing string between the intervals of measurement. The circuits may be placed in gas lift valve assemblies at spaced apart gas lift mandrels in the tubing string and signals related to current flow and voltage transmitted to the surface by stress wave telemetry or electromagnetic waves transmitted through the earth, for example. The circuits may also be interposed in selected sections of tubing spaced apart in the tubing string or on an instrument carrier apparatus which may be selectively positioned in the tubing string by a coiled tubing conveyed or wire line conveyed running tool.

5458200, Oct 17, 1995

Jun 22, 1994

8/263594

David L. Lagerlef - Eagle River AK
Jerry L. Brady - Anchorage AK
Stephen Gerlek - Anchorage AK
Charles M. Hightower - Plano TX

Atlantic Richfield Company - Los Angeles CA

E21B 3416, E21B 4312

166372

Multiple gas lift valves interposed in a well tubing string are each configured to have gas flow ports adapted to emit a predetermined acoustic signal for transmission through the well to a microphone or similar acoustic signal receiver whereby a determination may be made of which gas lift valves are open or operating properly. One or more of the gas lift valves may also include fluid pressure, temperature and viscosity sensors as well as a valve opening sensor and/or valve pressure setting control and an associated signal controller/generator arrangement for generating signals for transmission to the surface. The signal generators may be of the acoustic or so-called stress wave type.