Downhole Dielectric Tool for Heavy Oil Mobility Assessment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Evaluating heavy oil mobility in subterranean formations is complicated by low salinity formation water, which reduces the contrast between resistivity of water and oil sands, making it difficult to accurately assess oil presence and movement using existing downhole tools.
Innovation Solution
A downhole tool and surface equipment system that obtains dielectric measurements at multiple depths within the wellbore, utilizing dielectric permittivity to determine water-filled porosity and hydrocarbon volume, allowing for the assessment of oil mobility by comparing these measurements with total porosity, thereby identifying oil crossover indicators and mobility levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dielectric measurements are used to evaluate heavy oil mobility, then measurement precision is improved, but device complexity increases due to multiple measurement depths and processing requirements
Solution Approach 1:
The evaluation process is segmented into multiple depths of investigation, with each depth providing specific information about oil mobility at different zones. The system divides the formation evaluation into discrete measurement levels that can be independently analyzed and combined to provide comprehensive mobility assessment.
Solution Approach 2:
The patent adds the dimension of multiple depths of investigation to the traditional single-depth dielectric measurement. By measuring at multiple depths and comparing the results, the system creates a three-dimensional evaluation space (depth × dielectric property × mobility indicator) that provides more comprehensive information about oil mobility while managing complexity through systematic data processing.
2Quantity of substance
If low salinity formation water is present, then resistivity contrast between water and oil sands decreases, but measurement precision for oil detection deteriorates
Solution Approach 1:
The patent uses dielectric permittivity measurements as an intermediary property that provides contrast between water and oil even when resistivity contrast is reduced by low salinity. The dielectric properties serve as a mediator that maintains measurement precision when traditional resistivity-based methods fail due to low formation water salinity conditions.
Solution Approach 2:
The system changes the measurement parameter from resistivity to dielectric permittivity to maintain detection accuracy in low salinity conditions. By measuring at multiple frequencies and analyzing dielectric dispersion characteristics, the system adapts to varying formation water salinity levels and maintains precise oil detection capability regardless of salinity 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
Enables accurate identification of oil mobility by differentiating between immobile and mobile oil zones, providing a quicklook presentation that helps operators adapt completion techniques and optimize reservoir exploitation, even in heavy oil sands with low salinity formation water.
Implementation Method 1
obtain dielectric measurements of the subterranean formation by emitting electromagnetic energy into the subterranean formation and detecting changes in the energy as it exits the formation
Data Source
AI summary
A downhole tool is conveyed within a wellbore extending into a subterranean formation, and then utilized to obtain measurements at multiple different depths of investigation within the subterranean formation relative to the wellbore. The obtained measurements are then compared to assess mobility of oil within the subterranean formation.