Surfactant Selection via TAN TBN Analysis for Wettability Alteration
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Solution Overview
Problem
Conventional methods for selecting surfactants for subterranean formations, particularly in unconventional reservoirs, are lengthy and inefficient, as they typically focus on limited attributes and require extensive experimental testing to identify suitable surfactants for enhanced oil recovery and hydraulic fracturing operations.
Innovation Solution
The method involves selecting surfactants based on the total acid number (TAN) and total base number (TBN) of an oil sample, limiting the evaluation to cationic, anionic, or zwitterionic surfactants with polarity opposite to the oil, and using these surfactants in treatment fluids for well stimulation and enhanced oil recovery operations, which can alter rock wettability more quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surfactant selection methods using extensive experimental testing are used, then reliable surfactant performance evaluation is achieved, but the selection process becomes lengthy and inefficient
Solution Approach 1:
The patent applies preliminary action by performing quick preliminary tests (interfacial tension measurements and colorimetric TAN/TBN assays) before committing to extensive experimental testing. This preliminary screening based on oil sample characteristics (TAN/TBN ratios) allows the method to identify promising surfactant candidates early, reducing the overall selection time while maintaining reliable performance evaluation through subsequent targeted testing.
2Measurement precision
If comprehensive experimental testing is performed to evaluate surfactant performance, then accurate surfactant selection is achieved, but the complexity and resource requirements increase
Solution Approach 1:
The patent segments the surfactant evaluation process into distinct stages: (1) preliminary oil sample analysis using simple colorimetric TAN/TBN assays, (2) selection of surfactants with appropriate polarity based on oil characteristics, and (3) targeted performance testing only of selected candidates. This segmentation reduces overall process complexity by filtering out unsuitable surfactants early, while maintaining measurement precision through focused testing on promising candidates.
Solution Approach 2:
The patent utilizes parameter changes by measuring oil sample properties (TAN and TBN values) to determine oil polarity characteristics. These parameter measurements guide the selection of surfactants with complementary polarity, allowing the method to predict surfactant-oil compatibility without extensive testing. This parameter-based approach simplifies the selection process while maintaining accurate performance prediction.
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 facilitates the rapid evaluation and selection of surfactants that enhance oil production by altering rock wettability, reducing the need for extensive testing and improving the efficiency of surfactant selection for subterranean treatments.
Implementation Method 1
one or more surfactants or emulsifiers may be injected into the formation, among other reasons, to lower the interfacial tension between oil and water which allows stable emulsions with small drops to be formed
Implementation Method 2
selecting a set of surfactants to evaluate for a treatment in at least a portion of the subterranean formation based on at least one of the TAN and the TBN of the oil sample... which can alter rock wettability more quickly
Data Source
AI summary
Systems and methods for selecting surfactants for use in subterranean formations are provided. In one embodiment, the methods comprise: providing a sample of oil from at least a portion of a subterranean formation; measuring at least one of the total acid number (TAN) and the total base number (TBN) of the oil sample; and selecting a set of surfactants to evaluate for a treatment in at least a portion of the subterranean formation based on at least one of the TAN and the TBN of the oil sample, the set of surfactants selected from the group consisting of: a set of cationic surfactants, a set of anionic surfactants, and a set of zwitterionic surfactants.