Formation Temperature Estimation Using Thermal Conduction
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Solution Overview
Problem
Existing methods for determining formation properties in subsurface formations, such as hydrocarbon presence and rock characteristics, face challenges due to temperature sensitivity issues, particularly when drilling fluid temperature differs from the actual formation temperature, leading to errors in measurements like NMR data.
Innovation Solution
A method and apparatus that estimate the actual formation temperature by calculating the elapsed time since drilling, fluid temperature over time, virgin formation temperature, thermal conductivity, and heat capacity, allowing for accurate computation of formation properties using these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If drilling fluid temperature is used as the formation temperature for measurements, then the measurement process is simple, but measurement precision deteriorates due to temperature differences between drilling fluid and formation
Solution Approach 1:
The system performs preliminary temperature estimation by calculating the elapsed time since drilling and using thermal conduction models to predict the current formation temperature before actual measurements are taken. This preliminary action corrects the temperature parameter proactively, ensuring measurement accuracy is maintained without complicating the measurement process itself.
2Measurement precision
If the actual formation temperature is determined through complex thermal conduction calculations, then measurement precision improves, but device complexity increases
Solution Approach 1:
The system uses readily available data already present in the drilling operation - specifically the elapsed time since drilling and drilling fluid temperature - to perform self-service temperature estimation. By leveraging existing operational parameters and applying thermal conduction principles, the system achieves accurate formation temperature determination without requiring additional complex measurement devices or external data sources.
3Measurement precision
If temperature correction is performed using elapsed time and thermal conduction parameters, then measurement accuracy improves, but loss of time increases due to additional calculation steps
Solution Approach 1:
The temperature estimation is performed as a preliminary calculation that leverages the already-measured elapsed time parameter. By using the natural thermal conduction process occurring during the elapsed time as the basis for correction, the system achieves accurate temperature determination without requiring additional time-consuming measurement or waiting periods.
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 enables precise estimation of actual formation temperatures and properties, reducing measurement errors caused by drilling fluid temperature differences, thereby improving the accuracy of formation evaluation measurements.
Implementation Method 1
a thermal conduction model to estimate an actual temperature of the selected region using the estimated elapsed time, temperature of the fluid over time, a virgin formation temperature, a thermal conductivity of the earth formation, and a heat capacity of the earth formation
Data Source
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AI summary
Apparatus, methods and computer programs disclosed herein, in one aspect, estimate a temperature of a selected region of an earth formation using a virgin formation temperature of the earth formation, a downhole fluid temperature measured over time, an elapsed time between drilling proximate the selected region and making of a formation evaluation measurement of the selected region, an estimate of thermal conductivity of the earth formation, and a heat capacity of the earth formation. In another aspect, the apparatus, methods and computer programs utilize the estimated temperature and the formation evaluation measurement to estimate a property of interest of the selected region.