Drill String Electrode System for Relief Well Ranging
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Solution Overview
Problem
Drilling relief wells is time-consuming and costly due to the uncertainty in positioning the drill bit with respect to the mother well, especially in regions with a steeply inclined Earth's magnetic field, leading to deviations from the desired trajectory.
Innovation Solution
A method and apparatus that inject electrical current into the subsurface using a drill string with electrodes and sensors to detect the magnetic field generated in the mother well's casing, allowing for real-time data processing to determine the proximity and direction, enabling accurate advancement of the drill bit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional ranging tool measurements are used intermittently to determine drill bit position, then the equipment complexity is reduced, but the measurement precision and drilling trajectory accuracy deteriorate due to time delays and position deviations
Solution Approach 1:
The patent replaces the mechanical ranging tool with an electrical field-based measurement system. Electrodes inject electrical current into the subsurface, and sensors detect the resulting magnetic field to continuously determine drill bit position relative to the mother well casing, eliminating the need for intermittent mechanical ranging tools.
Solution Approach 2:
The patent enables continuous measurement of drill bit position by maintaining constant electrical current injection and magnetic field detection throughout the drilling process. This continuous action eliminates the interruptions and time delays associated with intermittent ranging tool measurements, providing real-time position data for accurate trajectory control.
2Measurement precision
If the drill string is pulled out and ranging tool is run in on wireline for measurement, then the measurement can be performed, but the drilling time increases and productivity decreases
Solution Approach 1:
The patent allows drilling and measurement to occur simultaneously and continuously. The electrical current injection and magnetic field detection systems operate while the drill string remains in place, eliminating the need to pull out and reinsert ranging tools, thereby maintaining continuous drilling productivity without sacrificing measurement accuracy.
Solution Approach 2:
The drill string is equipped with both drilling functionality and measurement functionality integrated into a single system. The electrodes and sensors are incorporated into the drill string itself, allowing it to serve both as the drilling tool and the measurement instrument, thereby eliminating separate measurement operations and improving overall productivity.
3Ease of operation
If drilling is performed based on previously collected ranging tool data at increasing distance from actual drill bit position, then the measurement process can be completed, but the manufacturing precision of the borehole trajectory deteriorates
Solution Approach 1:
The patent implements real-time feedback by continuously detecting the magnetic field generated by electrical current injection and using this information to determine the current drill bit position. This real-time feedback allows for immediate correction of trajectory deviations, ensuring high borehole trajectory precision without the delays inherent in using previously collected ranging tool data.
4Device complexity
If compasses are used for directional drilling, then the device complexity is low, but the measurement precision deteriorates in regions with steeply inclined Earth's magnetic field
Solution Approach 1:
The patent replaces magnetic compasses with an electrical field-based directional determination system. By injecting electrical current into the subsurface and detecting the resulting magnetic field, the system determines drill bit direction relative to the mother well casing independently of the Earth's magnetic field conditions, providing accurate directional control in regions with steeply inclined magnetic fields.
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
This approach significantly reduces the need for intermittent ranging tool measurements, improving the accuracy and efficiency of drilling by allowing continuous data collection and real-time correction, thereby enhancing the precision of intersecting the mother well's casing.
Implementation Method 1
injecting current into the subsurface using at least one electrode disposed on the drill string, thereby generating current in a casing of another well, e.g. a mother well, which is located a distance away from the borehole of the well
Implementation Method 2
detecting at least one component of a magnetic field which is associated with the current generated in the casing, using at least one sensor disposed on the drill string
Data Source
AI summary
A method, drill string, bottomhole assembly, drill bit, and insert are for extending a borehole for a relief well in a subsurface. The rotary drill string is provided in the borehole and includes a bottomhole assembly. The bottomhole assembly includes a drill bit. Current is provided into the subsurface using at least one electrode on the drill string, thereby generating current in a casing of a mother well located a distance away from the borehole of the relief well. At least one component of a magnetic field associated with the current generated in the casing is detected using at least one sensor disposed on the drill string. Data is obtained from the sensor for determining either or both the proximity and direction to the mother well. The drill string is advanced into the subsurface based upon the obtained data to extend the borehole.