Wettability Alteration Protocol for Enhanced Oil Recovery
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Solution Overview
Problem
Current methods for determining wettability alteration in rock/brine/oil systems due to changes in brine composition are complex, sensitive to core preparation, and yield inconsistent results, hindering the understanding of interfacial tension and wettability's impact on enhanced oil recovery (EOR) techniques.
Innovation Solution
A method involving the measurement of interfacial tensions, surface tensions, and contact angles in controlled conditions, using a reference fluid system to calculate wettability changes, which simplifies the process and reduces sensitivity to surface preparation, allowing for the determination of wettability alteration due to fluid changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contact angle measurement techniques are used on reservoir rocks at downhole conditions, then measurement capability is achieved, but the process becomes very complicated and highly sensitive to core preservation and preparation
Solution Approach 1:
The patent introduces an intermediary mathematical model (Young-Dupre equation and wettability alteration model) that mediates between simple, accessible measurements (interfacial tension, surface tension, and contact angle in air) and the desired complex downhole condition measurements. This intermediary framework allows calculation of downhole contact angles without directly measuring under those complex conditions, thus resolving the contradiction between measurement accuracy and process complexity
Solution Approach 2:
The patent replaces the mechanical/experimental approach of directly measuring contact angles under complex downhole conditions with a computational/mathematical approach. By substituting physical measurement complexity with mathematical modeling and calculation, the system achieves accurate wettability assessment without the complications of direct downhole measurement
2Measurement precision
If conventional contact angle measurement techniques are used on reservoir rocks, then wettability assessment is achieved, but the results become inconsistent due to sensitivity to core preparation
Solution Approach 1:
The mathematical model acts as an intermediary that decouples the measurement process from the complex rock surface conditions. By measuring contact angle in air (a controlled, simple environment) and using the model to calculate the equivalent downhole contact angle, the system eliminates the inconsistency caused by varying core preparation quality while maintaining assessment accuracy
Solution Approach 2:
The patent creates a simplified copy of the measurement system that operates under controlled laboratory conditions (contact angle in air, interfacial tension measurements) rather than attempting to replicate complex downhole conditions. This copied measurement approach yields consistent results that can be reliably translated to downhole conditions through the mathematical model
3Measurement precision
If detailed conventional measurement procedures are followed, then comprehensive wettability data is obtained, but the process becomes very time-consuming
Solution Approach 1:
The patent extracts only the essential measurements needed for wettability assessment (interfacial tension, surface tension, and contact angle in air) from the complex conventional procedure set. By taking out only the critical measurements and using a mathematical model to derive the remaining information, the system achieves comprehensive wettability characterization with significantly reduced measurement time
Solution Approach 2:
The patent applies partial action by performing only the minimum necessary measurements (contact angle in air rather than under multiple downhole conditions, interfacial tension measurements) and using mathematical relationships to calculate the complete wettability picture. This partial measurement approach, combined with modeling, reduces time investment while maintaining characterization completeness
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 accurate and less time-consuming wettability assessments, demonstrating that surface alteration has a greater effect on contact angles than interfacial tension changes, particularly in carbonate reservoirs, thus improving the understanding and efficiency of EOR methods.
Implementation Method 1
measuring interfacial tensions between a first liquid and a second fluid, and between the first liquid and a third fluid
Implementation Method 2
measuring surface tensions between the second and third fluid and a first reference fluid
Implementation Method 3
measuring contact angle of the first liquid and a first solid surface in a second reference fluid
Data Source
AI summary
A protocol for determining the effect of water composition on surface alteration is described using simple and less preparation sensitive, brine/oil and rock/brine/air systems when compared to conventional rock/brine/oil measurement methods. A model glass/brine/oil system is described and it is demonstrated that experimental measurements of contact angle obtained using a conventional approach agree well with the contact angles predicted using the proposed protocol.