Distributed Temperature Sensors for Subsurface Estimation
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Solution Overview
Problem
Elevated temperatures downhole pose a harsh environment for equipment and are indicative of formation properties, necessitating effective temperature measurement methods and apparatus for oil and gas exploration.
Innovation Solution
A method and system for estimating sub-surface temperatures using temperature sensors distributed along a drill string, calculating an overall heat transfer coefficient, and determining a geothermal gradient to infer formation temperatures, which is essential for pore pressure prediction and cementing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are distributed along the drill string to measure temperature at multiple locations, then temperature measurement capability is improved, but device complexity increases
Solution Approach 1:
The drill string is segmented into multiple zones with temperature sensors distributed at different locations along its length. This segmentation allows temperature measurements at multiple discrete points, enabling the detection of temperature gradients and variations without requiring a single complex measurement system.
Solution Approach 2:
The distributed temperature sensor system serves multiple functions: measuring temperature at various depths, determining geothermal gradients, monitoring drilling fluid temperature, and providing data for both real-time drilling operations and post-drilling analysis. This multi-functionality justifies the added complexity by delivering comprehensive thermal information from a single integrated system.
2Measurement precision
If multiple temperature measurements are taken and processed to calculate heat transfer coefficients and geothermal gradients, then estimation accuracy of formation temperature is improved, but calculation complexity increases
Solution Approach 1:
Temperature measurements are collected and preliminary processing is performed during the drilling operation itself. The system pre-calculates heat transfer coefficients and geothermal gradients from the measured temperature data, so that when formation temperature estimation is needed, the foundational calculations are already complete, reducing real-time computational complexity.
Solution Approach 2:
The system uses measured temperature data to calculate geothermal gradients, which then feed back into the temperature estimation model. This feedback loop allows the system to continuously refine its estimates by comparing calculated temperatures with actual sensor readings, improving accuracy while the computational framework remains established and manageable.
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 estimation of far-field formation temperatures and gradients, improving pore pressure prediction and cementing operations by providing reliable temperature data in real-time, thus enhancing drilling efficiency and equipment durability.
Implementation Method 1
obtaining temperature data from a plurality of measurements of temperature taken within the wellbore
Implementation Method 2
calculating an overall heat transfer coefficient from the measurement data
Data Source
AI summary
A method for estimating a temperature within sub-surface materials traversed by a wellbore includes: obtaining temperature data from a plurality of measurements of temperature taken within the wellbore; calculating an overall heat transfer coefficient from the measurement data; calculating a geothermal gradient from the overall heat transfer coefficient; and using the geothermal gradient to estimate the temperature within the sub-surface materials. A system and a computer program product are provided.