Drill Bit Displacement Sensing for Accurate Downhole ROP
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Solution Overview
Problem
Current downhole ROP measurements are not reliable enough for closed loop automated steering routines and downhole imaging tools, necessitating the need for improved, low-cost, and reliable downhole ROP measurement systems.
Innovation Solution
A displacement sensor is deployed in a downhole tool, such as a drill bit, comprising an engagement piston and a position sensor to measure the axial position, allowing for real-time computation of bit depth of cut and rate of penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface ROP measurements are used with driller intervention, then measurement reliability is improved, but automation capability deteriorates
Solution Approach 1:
The patent replaces surface-based mechanical measurement systems with downhole electronic sensors that directly measure ROP at the bit location. The displacement sensor and encoder system eliminate the need for surface block position measurements and driller intervention, enabling automated closed-loop steering while maintaining measurement reliability through direct downhole measurement.
Solution Approach 2:
The patent introduces downhole displacement sensors and encoders as intermediary measurement devices between the drill bit and the surface control system. These sensors act as mediators that directly capture ROP data at the source and transmit it to the surface, eliminating the need for manual surface measurement procedures and enabling automated control.
2Extent of automation
If downhole ROP measurements are implemented, then automation capability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent segments the measurement system into distinct functional components: displacement sensors mounted on individual blades, engagement pistons for each cutting element, and encoders for precise position detection. This segmentation allows each component to be optimized for its specific function, ensuring high measurement precision while enabling automated ROP measurement.
Solution Approach 2:
The patent creates a universal downhole measurement system that can measure ROP for multiple cutting elements simultaneously using identical sensor assemblies. Each blade equipped with the displacement sensor and encoder serves multiple functions: measuring depth of cut, providing engagement status, and enabling automated control, thereby maintaining precision across all measurement points.
3Measurement precision
If complex downhole ROP measurement systems are deployed, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a nested sensor assembly where the displacement sensor, engagement piston, and encoder are integrated within a compact housing mounted on the drill bit blade. The encoder is nested within the displacement sensor assembly, which itself is nested within the blade structure. This nesting reduces overall device complexity while maintaining measurement precision.
Solution Approach 2:
The patent merges multiple measurement functions into a single integrated sensor assembly. The displacement sensor and encoder are combined in one unit, and the engagement piston is integrated with the sensor housing. This merging eliminates the need for separate measurement devices, reducing device complexity while preserving measurement precision through the unified design.
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
Enables accurate, real-time measurement of drilling parameters, facilitating closed loop steering and enhanced downhole imaging, thereby improving drilling efficiency and precision.
Implementation Method 1
an engagement piston deployed in and disposed to translate axially in the sensor housing. The engagement piston includes an inner plunger and an opposing outer engagement element configured to engage a subterranean formation
Implementation Method 2
a position sensor configured to sense an axial position of the engagement piston in the sensor housing
Data Source
AI summary
A drill bit includes cutting elements and a displacement sensor deployed on a drill bit body. The displacement sensor includes an engagement piston disposed to translate axially in a sensor housing. The engagement piston includes an inner plunger and an opposing outer engagement element configured to engage a subterranean formation and is biased outward from the sensor housing. The displacement sensor further includes a position sensor configured to sense an axial position of the engagement piston in the sensor housing. An electronic controller is configured to determine a measured displacement from the sensed axial position of the engagement piston. The displacement sensor may enable depth of cut and rate of penetration measurements to be made while drilling.