Method and apparatus for determining location of characteristics of a pipeline

A system for inspecting a pipeline and for mapping a defect within the pipeline, the system comprising:

• a fixed location sensor in proximity to the pipeline, the fixed location sensor for providing a reference location in a terrestrial coordinate frame;
• a pipeline pig vehicle having a defect sensor device for determining the location of defects in the pipeline in a second coordinate frame;
• a kinematic device mounted with the defect sensor device, the kinematic device for measuring the relationship between the second coordinate frame and the terrestrial coordinate frame, the kinematic device having an initially unknown orientation in the second coordinate frame;
• a computer system configured to receive the reference location, to receive the location of defects in the pipeline, and to receive the relationship between the second coordinate frame and the terrestrial coordinate frame, the computer system further configured to transform the location of defects in the pipeline into the terrestrial coordinate frame with respect to the reference location using signals from global positioning satellites.

A pig for insertion into a fluid-carrying pipeline, the pig comprising:

• a pig body;
• a defect sensor, the defect sensor configured to receive an assertable signal and further configured to generate data when the signal is asserted;
• and
• an odometer apparatus, having a wheel rotatably mounted on the pig body, the wheel configured to be urged against the interior of the pipeline, the wheel having a fine-pitch castillation, the odometer apparatus configured to assert the signal when the wheel is in any of a first set of predefined orientations with respect to the pig body and further configured not to assert the signal when the wheel is in any of a second set of predefined orientations with respect to the pig body, such that the assertion of the signal is substantially dependent on the distance traveled relative to the pipeline and substantially independent of pig speed relative to the pipeline.

A method for inspecting a pipeline and for mapping a defect within the pipeline, the method comprising steps of:

• inserting a pig within the pipeline, the pig having a kinematic property sensor generating kinematic property sensor data and a defect/anomaly inspection unit generating defect/anomaly inspection data, such that the pig is carried along with the fluid in the pipeline;
• placing a maglogger at a known location external to and in close proximity with the pipeline, the maglogger containing a device for detecting the passage of the pig along the pipeline, the maglogger generating maglogger data;
• while the pig is being carried along with the fluid in the pipeline, recording within the pig both the kinematic property sensor data and the defect/anomaly inspection data;
• when the pig is within a predetermined distance from the maglogger or has a predetermined speed with respect to the maglogger, recording maglogger data within the maglogger;
• recovering data from the pig;
• downloading kinematic property sensor data from the pig and maglogger data from the maglogger to a computer system;
• determining an initial orientation of the kinematic property sensor from the kinematic property sensor data downloaded in the downloading step;
• combining the maglogger data with the kinematic property sensor data to derive an improved estimate of the location of the pig;
• combining the defect/anomaly inspection data with the improved estimate of the location of the pig to determine an improved estimate of the location of detected defects.

A system for inspecting a pipeline and for mapping a defect within the pipeline, the system comprising:

• a pig insertable within the pipeline, the pig having an on-board real-time sensor generating on-board real-time sensor data during a traversal of the pipeline, the on-board real-time sensor data indicative of instantaneous pig location;
• a first off-board real-time sensor located external to the pig and to the pipeline, the first off-board real-time sensor configured to measure data pertaining to the pig during the traversal of the pipeline;
• a computer system for receiving data from the on-board real-time sensor and the off-board real-time sensor, the computer system configured to combine the data to produce improved data;
• and
• a second off-board real-time sensor, the first and the second off-board real-time sensors being within a set of off-board real-time sensors, such that each of the set of off-board real-time sensors uses global positioning satellite-derived position data, the computer system configured to allow on-board sensor data to be corrected by comparison with the off-board real-time sensor data and further configured to determine pig position between the first and the second off-board real-time sensors according to a dead-reckoned positioning process.

A method for determining the location of a pipeline pig within a pipeline, the method comprising the steps of:

• measuring a direction of travel over a period of time;
• measuring incremental distance traveled over the period of time;
• and
• integrating the distance and the direction of travel to determine the location of the pipeline pig,
• the step of integrating the distance and the direction including steps of:
• multiplying a scalar quantity representing incremental distance traveled by a vector quantity representing direction to provide an incremental directed change in position over the period of time;
• and
• integrating the incremental directed change in position, with respect to an initial position of the pig, to provide the position of the pig within the pipeline.