Downhole Positioning System Using Sub-Hertz Electromagnetic Signals
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Solution Overview
Problem
Positional uncertainties along a well bore trajectory lead to costly and hazardous situations, including well bore collisions, drilling decision errors, and inefficiencies in petroleum production, due to inaccuracies in formation property measurements and geologic models.
Innovation Solution
A downhole positioning system comprising a downhole source that transmits an electromagnetic positioning signal, received by an array of receivers, with a data hub collecting amplitude and phase measurements to determine the source's position, using geometric analysis and sub-hertz frequency signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional positioning methods are used, then device complexity is reduced, but measurement precision deteriorates leading to positional errors
Solution Approach 1:
The positioning system is segmented into multiple independent components: a downhole source, an array of surface receivers, and a data hub. This segmentation allows each component to perform a specific function (signal generation, signal reception, data processing) independently, improving overall measurement precision while keeping individual components relatively simple.
Solution Approach 2:
An electromagnetic positioning signal serves as an intermediary between the downhole source and surface receivers. This intermediary carrier wave enables precise position measurement without requiring direct mechanical or optical connections between all components, thereby reducing overall system complexity while maintaining high measurement precision.
2Measurement precision
If higher resolution position measurement is achieved, then measurement precision improves, but the resolution gap with LWD sensors increases
Solution Approach 1:
The positioning system merges position measurement functionality with formation evaluation capabilities by integrating the downhole source with LWD sensors. This merging ensures that position data and formation property data are collected simultaneously and can be directly correlated, eliminating the resolution gap and improving overall measurement precision without losing information.
Solution Approach 2:
The downhole source serves multiple functions: it acts as both a positioning signal generator and a formation evaluation tool. This multi-functionality allows the system to achieve high measurement precision for position while simultaneously obtaining formation property data, thereby reducing the resolution gap between positioning and formation evaluation measurements.
3Reliability
If positional accuracy is improved, then reliability improves, but productivity may decrease due to more frequent monitoring
Solution Approach 1:
The positioning system enables continuous monitoring of well bore trajectory throughout the drilling process. By maintaining continuous measurement and feedback, the system improves reliability through real-time position correction while actually improving productivity by preventing costly rework from positional errors, rather than requiring intermittent monitoring.
Solution Approach 2:
The system incorporates feedback mechanisms where position measurements from the downhole source and surface receivers are continuously processed to provide real-time trajectory information. This feedback loop improves reliability by allowing dynamic adjustment of drilling parameters while maintaining productivity through automated correction rather than manual intervention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively tracks the downhole source's position and path, reducing positional errors, preventing collisions and drilling missteps, and enhancing the accuracy of formation evaluations, thereby optimizing well completions and petroleum production efficiency.
Implementation Method 1
The downhole source transmits an electromagnetic positioning signal that is received by the array of receivers
Data Source
AI summary
Downhole positioning systems and associated methods are disclosed. In some embodiments, the system comprises a downhole source, an array of receivers, and a data hub. The downhole source transmits an electromagnetic positioning signal that is received by the array of receivers. The data hub collects amplitude and/or phase measurements of the electromagnetic positioning signal from receivers in the array and combines these measurements to determine the position of the downhole source. The position may be tracked over time to determine the source's path. The position calculation may take various forms, including determination of a source-to-receiver distance for multiple receivers in the array, coupled with geometric analysis of the distances to determine source position. The electromagnetic positioning signal may be in the sub-hertz frequency range.