Downhole Formation Imaging via Multi-Frequency Current Inversion
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Solution Overview
Problem
Current techniques for measuring downhole parameters in wellbore operations lack accuracy and flexibility, particularly in handling conductive and non-conductive muds, and do not effectively correct for mud effects, limiting their operational range in high temperature and pressure conditions.
Innovation Solution
A formation imaging unit that collects data from currents with different frequencies, determines drilling mud parameters, and inverts formation parameters to determine properties, using a system with a downhole tool equipped with sensors to image subterranean formations, accounting for mud properties and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current measurement techniques are used, then operational simplicity is maintained, but measurement precision deteriorates due to inability to correct for mud effects
Solution Approach 1:
The measurement system is segmented into multiple independent measurement circuits, each dedicated to measuring a specific parameter (resistivity, capacitance, inductance). This segmentation allows each circuit to be optimized for its specific measurement function while collectively providing comprehensive formation characterization and mud effect correction capabilities.
Solution Approach 2:
Multiple measurement circuits act as intermediaries between the drilling mud environment and the formation properties. These circuits measure different electrical characteristics (resistivity, capacitance, inductance) that are affected differently by mud properties, enabling mathematical separation of mud effects from formation properties through inversion algorithms.
2Adaptability or versatility
If single-frequency current measurement is used, then device complexity is reduced, but adaptability deteriorates in handling conductive and non-conductive muds
Solution Approach 1:
The measurement system dynamically adapts to different mud conditions by using multiple measurement circuits that respond differently to conductive and non-conductive muds. Each circuit provides frequency-dependent measurements that allow the system to adjust its interpretation algorithms based on the actual mud electrical properties, enabling operation across a wide range of mud types.
Solution Approach 2:
The system changes measurement parameters by utilizing multiple electrical characteristics (resistivity, capacitance, inductance) measured by different circuits. These parameter variations enable the system to distinguish between mud and formation effects, providing adaptability to handle both conductive and non-conductive muds effectively.
3Measurement precision
If traditional imaging techniques are used, then operational simplicity is maintained, but measurement precision deteriorates in high temperature and pressure conditions
Solution Approach 1:
The measurement system is designed with universal multi-functionality, where the same set of measurement circuits serves multiple purposes: characterizing formation properties, correcting for mud effects, and adapting to varying downhole conditions (temperature, pressure, mud type). This multi-functionality maintains measurement precision across diverse harsh conditions without requiring separate specialized systems.
Solution Approach 2:
The system incorporates feedback through inversion algorithms that use measurements from multiple circuits to continuously refine the separation of mud effects from formation properties. This feedback mechanism adjusts the interpretation based on the actual measured electrical characteristics, maintaining measurement precision even in varying high temperature and pressure conditions.
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
Enhances the accuracy and flexibility of downhole fluid and formation measurements, enabling effective imaging and analysis in various downhole conditions, including high temperatures and pressures, and corrects for mud effects, improving operational efficiency.
Implementation Method 1
A formation sensor positionable on a downhole tool deployable into the wellbore, a controller for controlling the formation sensor, wherein the formation imaging unit comprises a current management unit for collecting data from at least two currents injected into the at least one subterranean formation
Implementation Method 2
a drilling mud data unit for determining at least one drilling mud parameter
Implementation Method 3
an inversion unit for determining at least one formation property by inverting the at least one formation parameter
Data Source
AI summary
A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter.