Monitoring of undesirable fluid ingress into subsea control modules

• US 8,427,336 B2
• Filed: 06/16/2010
• Issued: 04/23/2013
• Est. Priority Date: 06/17/2009
• Status: Expired due to Fees

• Current Assignee: GE Oil & Gas (General Electric Company)
• Original Assignee: Vetco Gray Controls Limited (General Electric Company)
• Inventors: Davis, Julian R., Gill, Simon David, Derrick, Adrian John
• Primary Examiner(s): Gannon, Levi
• Application Number:
  US12/816,734
• Publication Number:
  US 20110018733A1
• Time in Patent Office: 1,042 Days
• Field of Search: 73/40, 732/90.R, 732/91, 733/04.C, 733/04.R, 116/227, 137/81.2, 137/392, 137/551, 137/552, 137/557, 137/558, 166/66, 166/250.03, 166/250.07, 166/250.08, 166/336, 166/337, 340/603, 340/604, 340/626, 340/627, 340/850, 340/852, 340/853.2, 340/856.3, 374/4
• US Class Current: 340/853.2
• CPC Class Codes: E21B 33/0355 Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads
• CPC Class Codes: E21B 47/001 for underwater installation
• CPC Class Codes: E21B 47/113 using electrical indications; using light radiations
• CPC Class Codes: G01V 3/18 specially adapted for well-logging
• CPC Class Codes: Y10T 137/2036 Underwater
• CPC Class Codes: Y10T 137/7306 Electrical characteristic sensing
• CPC Class Codes: Y10T 137/8342 Liquid level responsive indicator, recorder or alarm

Abstract

A subsea control module has a casing (1) inside which there is at least one pair of electrodes, there being electronic means (26-33) connected with the electrodes of the or each pair for monitoring at least one electrical characteristic between the electrodes as a result of a fluid to which the electrodes are exposed, the or each pair of electrodes comprising an array (19) in which each electrode of the pair has finger portions interleaved with finger portions of the other electrode.

Claims

1. A subsea control module comprising:

a casing containing one or more hydraulic components within an interior thereof and configured to prevent ingress of seawater therein when operably deployed;

a pair of electrodes contained within the interior of the casing; and

an electronic circuit operably coupled to the pair of electrodes and configured to detect changes in an electrical characteristic between the pair of electrodes as a result of a change in characteristic of fluid to which the pair of electrodes are exposed, and responsive to the change in characteristic, to detect ingress of seawater into the interior of the casing when so occurring and to detect ingress of hydraulic fluid into the interior of the casing when so occurring,

wherein the electronic circuit includes at least one isolator switch positioned to provide intermittent energization of the pair of electrodes to thereby reduce corrosion of the pair of electrodes.

2. A subsea control module comprising:

a casing containing one or more hydraulic components within an interior thereof and configured to prevent ingress of seawater therein when operably deployed;

a pair of electrodes contained within the interior of the casing; and

an electronic circuit operably coupled to the pair of electrodes and configured to detect changes in an electrical characteristic between the pair of electrodes as a result of a change in characteristic of fluid to which the pair of electrodes are exposed, and responsive to the change in characteristic, to detect ingress of seawater into the interior of the casing when so occurring and to detect ingress of hydraulic fluid into the interior of the casing when so occurring,

wherein the electronic circuit includes a differential amplifier positioned to provide a signal indicative of a resistance change across the pair of electrodes responsive to undesirable fluid ingress within the interior of the casing when so occurring.

3. A subsea control module comprising:

a casing containing one or more hydraulic components within an interior thereof and configured to prevent ingress of seawater therein when operably deployed;

a pair of electrodes contained within the interior of the casing; and

an electronic circuit operably coupled to the pair of electrodes and configured to detect changes in an electrical characteristic between the pair of electrodes as a result of a change in characteristic of fluid to which the pair of electrodes are exposed, and responsive to the change in characteristic, to detect ingress of seawater into the interior of the casing when so occurring and to detect ingress of hydraulic fluid into the interior of the casing when so occurring,

wherein the electronic circuit includes a capacitive bridge circuit positioned to provide a signal indicative of a change in balance of the capacitive bridge circuit responsive to undesirable fluid ingress within the interior of the casing when so occurring.

4. A subsea control module comprising:

a casing containing one or more hydraulic components within an interior thereof and configured to prevent ingress of seawater therein when operably deployed;

a pair of electrodes contained within the interior of the casing; and

an electronic circuit operably coupled to the pair of electrodes and configured to detect changes in an electrical characteristic between the pair of electrodes as a result of a change in characteristic of fluid to which the pair of electrodes are exposed, and responsive to the change in characteristic, to detect ingress of seawater into the interior of the casing when so occurring and to detect ingress of hydraulic fluid into the interior of the casing when so occurring,

wherein the electronic circuit includes a frequency measuring circuit positioned to provide a signal indicative of a capacitance change across the pair of electrodes responsive to undesirable fluid ingress within the interior of the casing when so occurring.

5. A method of monitoring ingress of undesirable fluid into a subsea control module, the method comprising the steps of:

providing a subsea control module having a casing configured to prevent ingress of seawater therein when operably deployed, the casing containing one or more hydraulic components within an interior thereof and a pair of electrodes for detecting ingress of undesirable fluid therein;

performing an intermittent energization of the pair of electrodes to thereby reduce corrosion thereof; and

detecting ingress of an undesirable fluid responsive to exposure of the pair of electrodes to the undesirable fluid, the undesirable fluid comprising one or more of the following undesirable fluids;

seawater entering within the interior of the casing as a result of a leak in the casing, and hydraulic fluid entering within the interior of the casing as a result of a leak in the one or more hydraulic components.

6. A method as defined in claim 5, further comprising the step of:

determining whether the ingress is of seawater or hydraulic fluid.