Drill Bit Strain Gauge Pressure Offset Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Drillstrings and drill bits experience deformation due to hydrostatic and hydrodynamic pressures, making it challenging to accurately measure drilling forces without accounting for pressure contributions to strain measurements, which affects the accuracy of weight on bit (WOB), torque on bit (TOB), and bit bending calculations.
Innovation Solution
A system that uses strain gauges to measure forces on drillstrings and drill bits, calculates pressure-effect offsets during off-bottom events, and separates hydrostatic and hydrodynamic pressure contributions from other drilling forces, allowing for accurate determination of drilling forces by subtracting pressure contributions from strain measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauge measurements are used to determine drilling forces, then force measurement capability is provided, but measurement precision deteriorates due to pressure-induced deformation of the drill bit
Solution Approach 1:
The patent extracts and removes the pressure-induced strain component from the total strain measurement. By calculating the pressure effect on the drill bit and subtracting it from the measured strain, the system isolates the drilling force component, thereby improving measurement precision despite the presence of pressure-induced deformation
Solution Approach 2:
The patent introduces pressure calculations as an intermediary step between the strain gauge measurement and the final drilling force determination. By computing the pressure effect based on drilling parameters and subtracting it as an intermediate correction, the system achieves accurate force measurement while accounting for the harmful pressure effect
2Measurement precision
If pressure contributions are removed from strain measurements, then measurement precision improves, but device complexity increases due to additional calculations and monitoring
Solution Approach 1:
The system uses readily available drilling parameters (weight on bit, rotational speed, flow rate, mud weight) that are already being monitored during drilling operations to calculate the pressure effect. This self-service approach allows the pressure correction to be computed using existing operational data without requiring additional complex measurement devices
Solution Approach 2:
The patent performs preliminary calculations of the pressure effect using standard drilling parameters before finalizing the drilling force determination. By pre-computing the pressure contribution based on known operational conditions, the system simplifies the overall measurement process while maintaining high precision
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 enhances the accuracy of drilling force measurements, improves the robustness of strain gauge data, and enables better monitoring and control of drilling operations by accounting for changes in mud weight, flow rate, and wellbore conditions.
Implementation Method 1
Strain gauges downhole measure forces experienced by various types of drilling equipment
Implementation Method 2
Drillstrings and drill bits in a wellbore experience hydrostatic pressure—as a result of drilling fluid density and gravitational forces
Implementation Method 3
Drillstrings and drill bits in a wellbore experience hydrodynamic pressure—as a result of drilling fluid circulation and movement
Data Source
AI summary
As a wellbore is extended into a formation, hydrostatic and hydrodynamic pressures change due to variations in drilling mud weight, fluid density, etc. Strain gauges downhole measure forces experienced by drilling equipment also experience strain due to hydrostatic and hydrodynamic pressures. In order to measure strain due to drilling, hydrostatic and hydrodynamic pressure contributions are removed from strain measurement by removal of a pressure-effect offset, which zeroes or tares the strain measurements. Values of the pressure-effect offset can also be monitored to check that strain measurements are accurately zeroed or to monitor wellbore operations and conditions.