Surface Gamma Ray Calibration of Cuttings Depth in UBCTD
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In underbalanced coiled tubing drilling (UBCTD), the traditional method for calculating drill cuttings depth based on fluid velocity and measured depth yields inaccurate results due to fluid velocity estimation difficulties when well conditions change from single phase to multiphase, leading to incorrect lateral placement decisions.
Innovation Solution
A system and method using a gamma ray device on the surface to measure drill cuttings gamma ray responses and a bottom hole assembly tool to measure downhole gamma readings, with an operator comparing these readings to validate and calibrate the drill cuttings depth, accounting for potential contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional fluid velocity-based method is used to calculate drill cuttings depth, then calculation simplicity is maintained, but measurement precision deteriorates due to inaccurate fluid velocity estimation in multiphase conditions
Solution Approach 1:
The patent introduces gamma ray readings as an intermediary measurement parameter to validate and calibrate drill cuttings depth. Instead of relying solely on fluid velocity calculations, the system uses gamma ray responses from both surface measurements and downhole BHA tools as a mediator to cross-check and confirm depth accuracy, thereby improving measurement precision without completely redesigning the entire depth calculation system
Solution Approach 2:
The system implements feedback by comparing surface gamma ray measurements with downhole BHA gamma ray readings to validate depth calculations. This feedback loop allows the system to detect discrepancies in depth measurement and adjust calibration accordingly, improving the accuracy of drill cuttings depth determination in multiphase drilling conditions
2Reliability
If gamma ray calibration system is implemented, then measurement precision of drill cuttings depth is improved, but device complexity increases due to additional surface and downhole measurement equipment
Solution Approach 1:
The gamma ray measurement system serves multiple functions: it provides formation evaluation data, validates drill cuttings depth, and detects contamination issues. By making the measurement system multi-functional, the patent reduces the need for separate dedicated calibration equipment, thereby improving reliability while limiting the increase in device complexity
Solution Approach 2:
The system uses the drill cuttings themselves as the measurement target for gamma ray detection, allowing the cuttings to serve their dual purpose of being both the object being transported and the medium for depth validation. This self-service approach eliminates the need for separate calibration standards or reference materials, reducing system complexity while maintaining accuracy
3Measurement precision
If surface gamma ray measurements are taken, then depth validation capability is improved, but loss of time increases due to additional measurement and comparison operations
Solution Approach 1:
The system performs gamma ray measurements and depth validation calculations in real-time during the drilling operation rather than as a separate post-processing step. By conducting the calibration and validation actions preliminarily during the drilling process, the system minimizes additional time loss and maintains continuous operational efficiency
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
Provides accurate calibration and validation of drill cuttings depth, ensuring precise lateral placement decisions by identifying and addressing contamination issues during UBCTD operations.
Implementation Method 1
measuring a gamma ray response for the plurality of drill cuttings at the first point and the second point using a gamma ray device disposed on surface
Implementation Method 2
measuring a plurality of downhole gamma readings at a plurality of depths between the first point and the second point using the BHA tool
Data Source
AI summary
System and method for on surface calibration of cuttings depth in underbalanced coiled tubing drilling including a drill string for drilling a well and collecting drill cuttings at a first point of a depth interval and at a second point of the depth interval, a gamma ray device at the surface for measuring gamma ray response for drill cuttings at the first point and the second point, and a bottom hole assembly tool on the drill string for measuring downhole gamma readings at a plurality of depths between the first point and the second point of the depth interval. The system further includes an operator on surface for determining a calibration and validation assessment related to the depth interval including a comparison between the gamma ray response and an average of the downhole gamma readings to confirm accuracy of the depth interval of the drill cuttings.