High temperature wellbore monitoring method and apparatus

• US 7,862,228 B2
• Filed: 07/27/2006
• Issued: 01/04/2011
• Est. Priority Date: 07/28/2005
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Wiese, Jacques, Veneruso, Anthony, Cadere, Dimitri, Ostiz, Jean-Claude, Popilian, Constantin
• Primary Examiner(s): VERBITSKY, GAIL KAPLAN
• Application Number:
  US11/460,270
• Publication Number:
  US 20070032957A1
• Time in Patent Office: 1,622 Days
• Field of Search: 374/135, 374/136, 374/137, 374/141, 374/143, 374/208, 731/523.3, 731/521.8, 731/520.1, 702/6, 702/14, 702/1, 166/378, 166/277, 166/129, 340/870.17
• US Class Current: 374/136
• CPC Class Codes: E21B 47/06 Measuring temperature or pressure
• CPC Class Codes: G01K 1/12 for preventing damage due to heat overloading

Abstract

The invention provides an apparatus for use in high temperature conditions, constituted of a downhole element and a master element connected together via a sealed connection; wherein the downhole element comprises a temperature sensor and a pressure sensor without any electronics and is embedded in a sealed housing resistant to high temperature; wherein the master element comprises electronics needed for function of the temperature sensor and the pressure sensor; and wherein the sealed connection is resistant to high temperature.

Claims

1. An apparatus comprising a downhole element and a master element connected together via a sealed connection;

wherein the downhole element consists of a temperature sensor and a pressure sensor without any electronics and is embedded in a sealed housing resistant to high temperature;

wherein the master element comprises electronics that control the temperature sensor and the pressure sensor;

wherein the sealed connection is resistant to high temperature;

wherein the sealed connection is a cable; and

wherein the master element comprises further a controlled current source supplying a current to the downhole element via the sealed connection and said current being alternatively switched in polarity.

2. The apparatus of claim 1, wherein the apparatus operates in temperature conditions such that the high-temperature is below 250 degrees Celsius.

3. The apparatus of claim 1, wherein the sealed housing and the sealed connection comprise metal without elastomeric and/or polymeric seals.

4. The apparatus of claim 1, wherein the master element is at surface and the cable has a seven-wire cable configuration.

5. The apparatus of claim 1, wherein the controlled current source is switched using a pseudo-random code sequence.

6. The apparatus of claim 5 wherein the controlled current source is switched using a maximal-length pseudo-random code sequence of polarity plus one and/or minus one times of the current.