Wellbore Survey Tool Orientation via Remote GPS Reference
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Solution Overview
Problem
Wellbore survey tools face accuracy issues at high latitudes and on moving platforms due to reduced horizontal component of the Earth's rate and platform rotational motion, leading to degraded directional reference alignment and increased survey errors.
Innovation Solution
A method and system that utilize a directional reference system, such as GPS, in conjunction with an inertial navigation system to determine the orientation of a wellbore survey tool by receiving signals indicative of its orientation relative to the reference direction and relative orientation to the directional reference system, allowing for precise initialization and continuous surveying, even at high latitudes and on moving platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gyro-compassing is used for static surveying, then the survey tool can determine orientation with respect to the horizontal component of Earth's rate, but the accuracy degrades rapidly at high latitudes where the horizontal component becomes small
Solution Approach 1:
The patent introduces a remote reference system (such as a GPS-based directional reference system) as an intermediary to provide orientation data at a second location, which is then used to determine the orientation at the first location. This intermediary system is not affected by high latitude conditions in the same way as local gyro-compassing, allowing accurate orientation determination even when the horizontal component of Earth's rate is small.
2Adaptability or versatility
If static surveying is conducted from a moving platform, then the survey can be performed in locations with limited access, but the platform rotational motion corrupts the directional reference and makes precise orientation determination difficult
Solution Approach 1:
The patent uses a remote reference system as an intermediary that provides a stable directional reference independent of platform motion. By receiving orientation data from a fixed reference location rather than relying on local gyro-compassing from the moving platform, the system maintains measurement precision even when operating from moving platforms with rotational motion.
3Ease of operation
If gyro-compassing is used at high latitudes, then the survey tool attempts to align with the horizontal component of Earth's rate, but the reduced magnitude of this component leads to rapidly degrading accuracy
Solution Approach 1:
The patent introduces a remote reference system as an intermediary that provides orientation information without being subject to the same high latitude limitations. The system receives directional data from a reference location where the horizontal component of Earth's rate is sufficient, thereby maintaining measurement precision while enabling survey capability at high latitudes.
Data Source
AI summary
A method and an apparatus are provided for determining an orientation of a tool with respect to a reference direction. At least one first signal is indicative of an orientation of a directional reference system with respect to the reference direction. The directional reference system is positioned spaced from the tool. At least one second signal is indicative of a relative orientation of the tool with respect to the directional reference system. The orientation of the tool at the first position is determined in response at least in part to the at least one first signal and the at least one second signal.