Polymer Emulsion Drag Reducers for Subsea Flowline Stability
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Solution Overview
Problem
Subsea oil and gas production is hindered by friction losses in flowlines, which traditional drag reducers, even those with high molecular weight polymers, struggle to effectively address without causing issues like plugging in umbilical lines due to high viscosity or particle size limitations.
Innovation Solution
A polymer composition comprising an oil-in-water emulsion with polyglycerol or polyglycerol derivatives, sulfur-containing surfactants, and specific oil-soluble, oil-miscible, or emulsifiable polymers is used, which remains stable under shear and temperature conditions, reducing drag resistance in hydrocarbon fluids without blocking subsea flowlines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If higher molecular weight polymers are used as drag reducers, then the percent drag reduction increases, but the viscosity increases causing the polymer to plug umbilical lines
Solution Approach 1:
The patent segments the polymer system into multiple components: a base polymer providing drag reduction and a gel-forming polymer present at very low concentrations (0.001-10 ppm) that provides viscosity control. This segmentation allows the system to achieve drag reduction benefits without the viscosity problems of high molecular weight polymers alone.
Solution Approach 2:
The invention creates a composite polymer system combining different polymer types with complementary functions. The base polymer (natural or synthetic) provides drag reduction while the gel-forming polymer (xanthan, guar, carboxymethyl cellulose, etc.) provides viscosity stabilization, creating a composite material that overcomes the limitations of individual polymers.
2Loss of energy
If higher molecular weight polymers are used as drag reducers, then the percent drag reduction increases, but the polymer particles become large enough to block subsea flowlines
Solution Approach 1:
The patent divides the drag reduction function from the viscosity control function, allowing the use of high molecular weight base polymers for drag reduction while using trace amounts of gel-forming polymers to maintain operational flow characteristics, thus preventing line blockages.
Solution Approach 2:
The invention changes the concentration parameter of the gel-forming polymer to extremely low levels (0.001-10 ppm), which is sufficient to control viscosity and prevent blockages without sacrificing the drag reduction performance of the base polymer.
3Ease of operation
If low viscosity fluids are injected through umbilical lines, then the chemicals can reach the flowline effectively, but the drag reduction effectiveness is limited
Solution Approach 1:
The patent prepares the polymer composition in advance with the optimal combination of base polymer and gel-forming polymer at low concentrations, ensuring it remains pumpable through umbilical lines while already containing the full drag reduction capability needed upon injection into the flowline.
Solution Approach 2:
The invention optimizes the concentration parameters of polymer components to achieve a viscosity window that allows easy injection through umbilical lines while maintaining high drag reduction effectiveness in the flowline environment.
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 effectively reduces drag resistance in hydrocarbon fluids, maintaining stability and preventing line blockages, allowing for efficient subsea hydrocarbon transport with reduced friction losses and increased flow capacity.
Implementation Method 1
a polymer composition comprising an oil-in-water emulsion that is stable to shear conditions and is storage stable at low temperature conditions
Data Source
AI summary
A polymer composition has been developed that provides low viscosity oil-in-water polymer emulsions that are stable to shear conditions and are storage stable at low temperature conditions (e.g., −6.7° C. or less) or higher temperature conditions (e.g., up to 60° C.). Use of particular additives provides stability to the emulsion and imparts advantageous properties when the polymer composition is contacted with a hydrocarbon fluid. These compositions are particularly useful as drag reducers for delivery to a subsea flowline via an umbilical line.