U.S. patent application number 12/174166 was filed with the patent office on 2009-03-05 for subsea structure load monitoring and control system.
Invention is credited to Richard W. McCoy, JR..
Application Number | 20090056936 12/174166 |
Document ID | / |
Family ID | 40260059 |
Filed Date | 2009-03-05 |
United States Patent
Application |
20090056936 |
Kind Code |
A1 |
McCoy, JR.; Richard W. |
March 5, 2009 |
Subsea Structure Load Monitoring and Control System
Abstract
A system for monitoring for loads in a subsea structure
comprises one or more sensors disposed proximate a subsea structure
such as a blow-out preventer. The sensors are configured to detect
an induced load on a subsea structure. The detected load is
communicated to a sensor data processor operatively in
communication with the strain sensor. Using the detected load data,
a load generator such as a remotely operated vehicle or other
source of thrust has its thrust output adjusted to induce a load
equal in force, but opposite in direction, to the detected induced
loads.
Inventors: |
McCoy, JR.; Richard W.;
(Cypress, TX) |
Correspondence
Address: |
DUANE MORRIS LLP - Houston
3200 SOUTHWEST FREEWAY, SUITE 3150
HOUSTON
TX
77027
US
|
Family ID: |
40260059 |
Appl. No.: |
12/174166 |
Filed: |
July 16, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60950184 |
Jul 17, 2007 |
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Current U.S.
Class: |
166/250.01 |
Current CPC
Class: |
E21B 43/013 20130101;
E21B 19/002 20130101; E21B 41/04 20130101 |
Class at
Publication: |
166/250.01 |
International
Class: |
E21B 47/00 20060101
E21B047/00 |
Claims
1. A system for monitoring for loads in a subsea structure,
comprising: a. a sensor disposed proximate a subsea structure, the
sensor configured to detect an induced load on a subsea structure;
and b. a sensor data processor operatively in communication with
the strain sensor.
2. The system of claim 1, wherein the induced load is at least one
of a current-induced load or a load induced by lateral displacement
of a vessel.
3. The system of claim 1, wherein the sensor comprises a strain
sensor.
4. The system of claim 1, further comprising a load generator
operatively in communication with the sensor data processor, the
load generator operative to exert a force on the subsea structure
in a direction opposed to a direction of a force detected by the
strain sensor and in proportion to a load sensed by the strain
sensor.
5. The system of claim 4, wherein the load generator is selected
from the group of load generators consisting of a remotely operated
vehicle or a thrust package.
6. The system of claim 1, wherein the sensor is a plurality of
operatively interconnected strain sensors.
7. The system of claim 6, wherein the plurality of strain sensors
are disposed radially about the subsea structure.
8. A method of monitoring and counteracting subsea environmentally
induced loads, comprising: a. deploying a strain sensor proximate a
subsea structure; b. detecting an induced load on the subsea
structure; c. communicating the detected induced load to a load
processor; and d. using the detected load data to adjust thrust
output of the load generator to induce a load equal in force, but
opposite in direction, to the detected induced loads.
9. The method of claim 8, wherein the induced load is selected from
the group of induced loads comprising a current-induced load or a
load induced by lateral displacement of a vessel away from a
wellhead.
Description
RELATION TO PRIOR APPLICATIONS
[0001] The present application claims priority in part through U.S.
Provisional Application 60/950,184 filed Jul. 17, 2007.
FIELD OF THE INVENTION
[0002] Loop currents impart loads and deflections onto subsea
structures such as blow-out preventors (BOPs) and risers such that
the ability to connect and disconnect a BOP to and from a wellhead
is hampered. The current may deflect the hanging riser and BOP
system away from vertical to a degree that the BOP cannot be
latched to the wellhead.
[0003] If the BOP is already latched when the current loads are
induced, there is no way of knowing what effect those forces will
have on the BOP and riser once the connector is unlatched and the
BOP is lifted off the connector. If the forces are sufficient, then
the current may sweep the BOP and the riser into other equipment
installed on the seafloor.
[0004] At the current time, drilling operations are halted in
strong loop current conditions.
FIGURES
[0005] The attached figures illustrate various aspects of exemplary
embodiments of the BOP Current Load Monitoring and Control
System.
[0006] FIG. 1 is an unscaled, side view of a remotely operated
vehicle which has engaged a subsea structure to which a sensor
array has been mounted;
[0007] FIG. 2 is an unscaled, side view of a remotely operated
vehicle which has been deployed to engage a subsea structure to
which a sensor array has been mounted where the subsea structure is
veering off of its intended deployment path; and
[0008] FIG. 3 is an unscaled, side view of a remotely operated
vehicle which has engaged a subsea structure to which a sensor
array has been mounted.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0009] In its various embodiments, the subsea structure load
monitoring and control system described herein below allows the
running of a subsea structure, e.g. a blowout preventer (BOP), in
strong loop currents or other induced loads such as current-induced
loads or loads induced by lateral displacement of a vessel away
from a wellhead. In the following exemplary embodiments, a system
for monitoring loads in such structures, e.g. BOP connectors or
risers, allows induced loads such as environmentally induced loads
resulting from currents, vessel drift, and the like, or a
combination thereof to be monitored and, once the loads are known,
counteracted by inducing equal forces in the opposite
direction.
[0010] Referring now to FIG. 1, one or more sensors 20 is placed
proximate a subsea structure, e.g. BOP connector 11, preferably
radially. When subsea structure 10 is connected with no induced
loads, sensors 20 simply measure the loads that are due to
internal, normally-seen connector forces. However, once subsea
structure 10 is subjected to a lateral load, sensors 20 will detect
additional shear and bending loads superimposed upon the normal
loads. Sensors 20 are typically strain sensors such as foil strain
gauges manufactured by Vishay Intertechnology, Inc. of Malvern, Pa.
or fiber optic strain gauges manufactured by Micron Optics Inc. of
Atlanta, Ga.
[0011] Sensors 20 interface with and are read by appropriate sensor
electronics 22. Sensor electronics 22 may be located on subsea
structure 10, lower marine riser package 14, a remotely operated
vehicle (ROV) 12, a thruster package (not shown in the figures), or
the like, or a combination thereof. In any embodiment, load
information obtained from sensors 20 is used to adjust the thrust
output of ROV 12 or a thruster package so as to induce a load equal
in force, but opposite in direction, to the induced loads such as
current-induced loads.
[0012] In the operation of a preferred embodiment, referring now to
FIG. 2, currents, e.g. water currents, apply force on subsea
structures such as subsea structure 10, causing subsea structure 10
to move off of desired path 30. ROV 12 is positioned to interface
with coupler 5.
[0013] Referring now to FIG. 3, once ROV 12 has mated to coupler 5,
sensors 20 detect additional shear and bending loads on subsea
structure 10. Sensor electronics 22 communicates with ROV 12, which
then applies appropriate counter-forces to move subsea structure 10
back onto desired path 30.
[0014] Once the current load and the externally applied
counter-force have been applied, an operator can release subsea
structure connector 11 and raise subsea structure 10 off of the
wellhead without fear of subsea structure 10 or its associated
riser, if any, being swept into other equipment. For example,
subsea structure 10 may stay vertical during the release and raise
operation.
[0015] The foregoing disclosure and description of the inventions
are illustrative and explanatory. Various changes in the size,
shape, and materials, as well as in the details of the illustrative
construction and/or a illustrative method may be made without
departing from the spirit of the invention.
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