Data processing: measuring – calibrating – or testing – Measurement system – Orientation or position
Reexamination Certificate
1997-12-23
2001-06-05
Shah, Kamini (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system
Orientation or position
C702S176000, C702S142000, C700S186000, C700S187000, C700S188000, C700S189000, C700S190000, C700S204000, C701S213000, C701S214000, C701S215000, C073S865600, C324S207130, C324S220000
Reexamination Certificate
active
06243657
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
None.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
None.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multi-parameter pipeline measurement device, and more specifically to integrated pipeline defect and anomaly detection, pipeline mapping, and identification of defect/anomaly location.
2. Description of the Related Prior Art
Underground pipelines are widely used in a variety of industries, allowing a large amount of material to be transported from one place to another without disrupting other activity on the surface of the land under which the pipelines run. A variety of fluids, such as oil and/or gas, as well as particulate, and other small solids suspended in fluids, are transported cheaply and efficiently using underground pipelines. Subterranean and submarine pipelines typically carry enormous quantities of oil and gas products indispensable to energy-related industries, often under tremendous pressure and at high temperature and at high flow rates.
Unfortunately, even buried pipelines are not completely protected from the elements. Corrosion of a pipeline can cause small spots of weakness, which if not detected and fixed, could result in a pipeline catastrophe. Subsidence of the soil, local construction projects, seismic activity, weather, and simply wear and tear caused by normal use can lead to defects and anomalies in the pipeline. Also, harsh environments can cause pipelines to move gradually over time, thus making location of the pipeline difficult. Shifts in the pipeline location can also lead to defects, cracks, leaks, bumps, and other anomalies, within the interior of the pipeline.
Defects and anomalies can appear in the surface of the pipeline. Both the internal and external surface of the pipeline can be damaged by environmental factors such as the reactivity of the material flowing through the pipeline, the pressure, temperature and chemical characteristics of various products and contaminants inside and outside the pipeline, corrosion, mechanical damage, fatigue, crack, stress, corrosion cracks, hydrogen induced cracks, distortion due to dents or wrinkles, exposure, and damage to weight coating and free spanning of offshore pipelines. Moreover, submarine pipelines face a hostile environment of ships anchors, troll boards and seabed scouring due to strong currents. Although timely repair or maintenance of pipelines can lengthen the service lifetime of the pipeline, a rupture or serious leak within the pipeline can be difficult and expensive to repair and can be difficult to locate.
PRIOR ART PIPELINE INSPECTION
The resulting cost to industry as well as the potential for damages to human life can be great, as the efficiency of using the pipeline is adversely affected by the anomalies. Consequently, industry has produced various inspection devices for detecting defects and anomalies. For example, U.S. Pat. No. 4,285,242, issued Aug. 25, 1981 and assigned to British Gas Corporation, of London, England, teaches a pipeline inspection apparatus that includes a vehicle capable of moving along the interior of the pipe by the flow of fluid through the pipe to inspect the pipe for location of anomalies.
Such prior inspection vehicles or pigs have also typically included wheels, spring loaded to be urged against the interior of the pipe, and have further included odometers that count the number of rotations of the wheels. Ultrasound receivers have been located within the wheels on an inspection vehicle themselves. Various measurements have been made by the wheels, which have included the ultrasound receivers, the odometer, and calipers that measure the position of the wheels relative to the body of the vehicle as the wheels encounter various curvatures of the pipe in order to allow the inspection vehicle to map the pipeline. The inspection vehicle has been used to record shape of the pipeline according to the ultrasonic signature received by ultrasonic transducers located within the wheels of the inspection vehicle, each data sample associated with an odometer measure.
Other related technologies have included measurement devices such as ultrasonic transducers mounted on an inspection unit within the pig which emit high frequency sound and measure and record the reflected and refracted signals from the walls of the pipe. Such measurement devices have typically been used to examine the interior of the pipe.
Test personnel have loaded pigs into pipelines recorded various signals from emitted magnetic fields, recorded the data within the pig, and then examined the data after completion of the run, extracting also defect and anomaly signatures, as well as the location of such anomalies.
Unfortunately, repairing a detected defect can be a monumental undertaking. Repair teams, equipped with detailed maps showing the location of the buried pipeline beneath the ground from previous surveys, have placed pegs in the ground immediately over the pipeline where shown on the maps. Using the information obtained from the inspection vehicle, repair teams have been able to “walk the pipeline,” following along the pegs to a distance corresponding to an odometer measured distance digging down to the pipeline and then visually identifying and mechanically repairing the pipe.
Minor variations, such as vehicles having multiple interconnected portions, a first portion propelled along the interior of the pipe by the fluid moving through the pipe and a second portion containing the inspection apparatus, are also known and widely used. Such inspection vehicles may be somewhat more flexible, and may report interior characteristics of the pipe with somewhat greater accuracy.
PRIOR ART MAPPING
Not only is the identification of defects and anomalies crucial to pipeline maintenance, but the location of the pipeline itself can be problematic. Many of the environmental stresses on the pipeline that cause defects and anomalies to appear in the pipeline can also shift the pipeline location. This is particularly true of very long pipelines.
Locating or mapping the pipeline has typically been accomplished by inserting a pipeline pig within a pipeline to inspect the interior of the pipeline for the locations of the pipeline, that is, its curvature or profile. For example, U.S. Pat. No. 4,747,317 to Lara, issued May 31, 1988 teaches a pipe survey pig including an onboard inertial reference unit and signal processing units for receiving acceleration and angular velocity signals generated by the inertial reference unit calculating resultant values of angular velocity in accelerations and averaging the calculated result to provide recordable signals related to the position of the pig and curvature of the pipe.
Also, U.S. Pat. No. 4,717,875, also issued to Lara, Jan. 5, 1988, teaches measuring the change in curvature or displacement of a section of submarine of subterranean fluid transmission pipeline. Lara '875 teaches traversing the pipeline with a pig have in onboard instrument package including accelerometers and a longitudinal positioning measuring device comprising a magnetonometer for counting the girth welds or other known magnetic anomalies along the section of pipeline to be measured. The magnetometer is carried by the pig, and determines distance traveled by counting welds of a known distance apart. These systems for measuring the curvature or displacement of the pipeline have allowed mapping of subterranean and submarine pipelines to a generally adequate level of precision.
PRIOR ART USES OF AN IMU TO MAP
The concept of using inertial technology in the pipeline surveying application was recognized in the 1978 time frame where it was identified as an example of “land surveying”. Many examples of land surveying (or “land navigation”) subsequently appeared in the literature which used inertial measurements in combination with odometry and zero-velocity updates available at enforced stops. It is known to use initial guidance technology within a pipeline pig, in conjunction with, post-run software using error minimi
Anderson Donald William
Brayson Gary
Gilman James Michael Alexander
Glen Stephen James
Ignagni Mario B.
Akin Gump Strauss Hauer & Feld & LLP
PII North America, Inc.
Shah Kamini
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