Core Annular Flow Stability with Polynuclear Aromatic Sulfonic Acid Additives
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Solution Overview
Problem
The production of heavy oil is hindered by high viscosity, leading to increased friction and pressure drops in fluid flow systems, with existing core annular flow methods facing challenges in maintaining stability under shear forces and requiring large quantities of water.
Innovation Solution
The use of sodium salts of polynuclear aromatic sulfonic acids (PASS additives) to enhance the shear stability of high-viscosity fluid-water flow systems, particularly in core annular flow systems, by maintaining separation of fluids and reducing shear-induced destabilization at the oil-water interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If core annular flow is used to transport heavy oil, then pressure drops are reduced, but the flow stability under shear forces deteriorates
Solution Approach 1:
A surfactant is introduced as an intermediary substance at the oil-water interface to stabilize the core annular flow. The surfactant reduces interfacial tension and prevents emulsion formation, allowing the biphasic flow to maintain its structure under shear forces while continuing to reduce pressure drops through the pipeline.
Solution Approach 2:
The patent changes the physical-chemical parameters of the fluid system by adjusting surfactant concentration and molecular structure. This modifies the interfacial properties of the oil-water mixture, enabling stable core annular flow at lower shear rates and improving flow stability without sacrificing the pressure drop reduction benefits.
2Loss of energy
If large quantities of water are used in core annular flow, then friction is reduced, but the system complexity and resource consumption increase
Solution Approach 1:
The patent optimizes the water-to-oil ratio and adjusts surfactant concentration to achieve effective friction reduction with minimized water usage. By changing these parameters, the system maintains low friction characteristics while reducing the large quantities of water that would otherwise be required to sustain core annular flow.
3Device complexity
If conventional tubing is used for heavy oil transport, then the system is simple, but adhesion of heavy oil to pipe walls increases friction
Solution Approach 1:
The surfactant acts as an intermediary that prevents direct adhesion between heavy oil and pipe walls. It forms a protective interface that reduces friction without requiring complex pipe coatings or modifications, maintaining system simplicity while addressing the friction problem.
Solution Approach 2:
The patent replaces mechanical solutions (such as rough pipe interiors or specialized coatings) with a chemical approach using surfactants. This substitutes the mechanical interaction between oil and pipe walls with a chemical interface management system, achieving reduced friction without increasing mechanical complexity.
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
The PASS additives improve the stability of the oil-water interface, allowing for more efficient and stable core annular flow, reducing friction and pressure drops, and enhancing the flow of heavy oils through pipelines and subterranean environments.
Implementation Method 1
The biphasic fluid is introduced into the fluid flow system... maintaining separation of fluids and reducing shear-induced destabilization at the oil-water interface
Implementation Method 2
The method employs a family of demulsifier additives used in maintaining separation of the fluids in the biphasic flow system
Data Source
AI summary
A method is provided for enhancing the shear stability of a high-viscosity fluid-water flow system, such as a core annular flow system. The method employs a family of demulsifier additives for maintaining separation of the fluids in biphasic flow. The additive family is sodium salts of polynuclear aromatic sulfonic acids. In one aspect, the high-viscosity fluid is heavy oil. A method to flow oil through a biphasic flow system is also provided. The method includes locating an oil in the biphasic flow system; placing water within the biphasic flow system; flowing the oil through the biphasic flow system within an annular flow of water; and subjecting the water in the biphasic flow system to a salt of a polynuclear aromatic sulfonic acid additive so as to improve shear stability of the oil and water.