Self-Inverting Polymer Emulsions for Subsea Drag Reduction
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Solution Overview
Problem
Subsea oil and gas production is hindered by friction losses in flowlines, which traditional drag reducers fail to adequately address, especially in remote locations where umbilical lines with small diameters are used, leading to inefficiencies and economic losses due to potential blockage and plugging issues.
Innovation Solution
A polymer composition comprising an oil-in-water emulsion with a temperature-sensitive surfactant and high molecular weight oil-soluble polymer that self-inverts upon contact with hydrocarbons, releasing at least 50% of the polymer within 60 minutes without additional surfactants, thereby reducing drag and maintaining stability in umbilical lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high molecular weight polymers are used as drag reducers, then drag reduction effectiveness is improved, but the polymer may block or plug umbilical lines with small diameters
Solution Approach 1:
The high molecular weight polymer is segmented into emulsion droplets dispersed in an aqueous continuous phase. This segmentation allows the polymer to be transported through small-diameter umbilical lines as a stable emulsion without plugging, while maintaining the drag reduction capability of high molecular weight polymers upon release into the hydrocarbon flowline.
Solution Approach 2:
An aqueous continuous phase acts as an intermediary medium to transport the oil-soluble high molecular weight polymer. The polymer is solubilized in this intermediary phase as an emulsion, enabling it to pass through umbilical lines without blockage, and then releases into the hydrocarbon flowline where it performs drag reduction.
2Reliability
If polymer emulsion is used for drag reduction, then the polymer can be delivered through umbilical lines, but the emulsion must remain stable during transport and invert quickly upon contact with hydrocarbons
Solution Approach 1:
The emulsion utilizes temperature-sensitive surfactants whose hydrophilic-lipophilic balance (HLB) changes with temperature. During transport at lower temperatures, the surfactants maintain high HLB values ensuring emulsion stability. Upon contact with warmer hydrocarbon flowlines, the temperature increase reduces HLB values, triggering rapid inversion and polymer release.
Solution Approach 2:
The emulsion system undergoes a phase transition from oil-in-water emulsion stable at lower temperatures to inverted state at higher temperatures. This thermally-induced phase transition enables the emulsion to remain stable during umbilical line transport and automatically invert upon contact with the hydrocarbon flowline at elevated temperature.
3Loss of energy
If traditional drag reducers are used in subsea flowlines, then friction losses can be reduced, but they fail to adequately address the specific challenges of remote locations with small diameter umbilical lines
Solution Approach 1:
The polymer emulsion composition serves multiple functions: it remains stable during transport through small-diameter umbilical lines, inverts automatically upon contact with hydrocarbon flowlines, and provides effective drag reduction. This multi-functionality makes it universally applicable to subsea production systems with umbilical line constraints, addressing both transport and performance requirements.
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 polymer composition achieves significant drag reduction, with up to 95% of the polymer released within minutes, effectively reducing friction losses and preventing plugging in subsea flowlines, thus enhancing hydrocarbon production efficiency and reducing operational costs.
Implementation Method 1
Use of a temperature-sensitive emulsifying surfactant facilitates inversion of the oil-in-water polymer emulsion when applied to a hydrocarbon composition at a temperature sufficiently high to destabilize the emulsion
Implementation Method 2
Ultra-high molecular weight polymers are known to function well as drag reducers; however, drag reducers vary in their effectiveness
Data Source
AI summary
A polymer composition has been developed that provides low viscosity oil-in-water polymer emulsions that release the polymer in the emulsion at a faster rate and without an additional surfactant when the emulsion is added to a hydrocarbon stream. Use of a temperature-sensitive emulsifying surfactant facilitates inversion of the oil-in-water polymer emulsion when applied to a hydrocarbon composition at a temperature sufficiently high to destabilize the emulsion. These compositions are particularly useful as drag reducers for delivery to a subsea flowline via an umbilical line.