Wellbore Characteristic Determination via Scattered Photon Count Rates
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Solution Overview
Problem
Current methods for determining wellbore characteristics using gamma ray count rates are complex and prone to statistical perturbations, necessitating improvements in accuracy and sensitivity.
Innovation Solution
A system and method that measures gamma rays scattered from the surrounding environment, utilizing different energy ranges and combining count rates from one or more detectors to determine characteristics like formation density, photoelectric factor, mud density, and mud cake density and thickness, enhancing measurement sensitivity through mathematical combinations of count rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current methods for determining wellbore characteristics using gamma ray count rates are used, then characteristics can be determined, but the methods are complex and prone to statistical perturbations reducing accuracy
Solution Approach 1:
The patent transforms the complex mathematical correlation problem into a simpler linear regression problem by changing the parameter representation. Instead of directly correlating multiple energy-window count rates to parameters of interest using complex mathematical representations, the method uses linear regression analysis on transformed parameters (such as logarithmic transformations of count rates) to achieve accurate determination of wellbore characteristics while reducing computational complexity and statistical perturbations
2Measurement precision
If multiple energy-window count rates are correlated to parameters of interest, then wellbore characteristics can be determined, but statistical perturbations reduce measurement accuracy
Solution Approach 1:
The patent applies parameter transformations (such as logarithmic transformations) to the count rate data before performing linear regression analysis. This transformation stabilizes the statistical properties of the data, reducing the impact of statistical perturbations and improving the reliability of the measurement while maintaining accuracy in determining wellbore characteristics
Solution Approach 2:
The patent employs iterative linear regression analysis where the model parameters are continuously refined based on the correlation between transformed count rate data and reference measurements. This feedback mechanism allows the system to adjust and optimize the determination process, reducing statistical perturbations and improving measurement reliability through continuous refinement of the correlation model
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 provides improved accuracy and sensitivity in evaluating wellbore characteristics by exploiting the radial penetration of photons across various energy ranges, allowing for better determination of material properties despite mud cake and wellbore irregularities.
Implementation Method 1
measuring count rates of scattered photons... measuring count rates of photons scattered by material (15) surrounding the wellbore (12)
Data Source
AI summary
A system and method to determine a characteristic of a wellbore based on count rates of scattered photons. The system and method can include determining at least one characteristic of a material surrounding a wellbore by, emitting photons from a photon source at a location in the wellbore, detecting, via one or more detectors, photons scattered by the material, counting the scattered photons based on an energy level, producing count rates of the detected photons for various energy ranges, and calculating a value of the characteristic based on the count rates. The material can be at least one of mud, mud cake, and earth formation.