Drag-Reducing Additive Emulsion Stability in Brine
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drag-reducing additives for aqueous treatment fluids in oil and gas wells are limited by low inverting surfactant levels, leading to incomplete emulsion inversion, poor brine tolerance, and potential formation damage, especially when encountering acidic or high salt conditions.
Innovation Solution
A drag-reducing composition is formed by mixing a dispersion polymer with a high HLB surfactant and a solvent, increasing the surfactant level to enhance stability and inversion rate, thereby reducing friction and minimizing polymer usage, which includes a polymer emulsion combined with a terpene solvent and a nonionic surfactant, forming a stable emulsion that can withstand brine and acidic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inverting surfactant is added to achieve complete emulsion inversion, then emulsion inversion is improved, but the surfactant may adversely interact with the emulsifier and destroy the emulsion
Solution Approach 1:
The patent introduces a specific inverting surfactant (nonionic surfactant with HLB 8-16) as an intermediary that mediates between the emulsion and aqueous treatment fluid. This surfactant acts as a bridge that enables complete emulsion inversion while minimizing adverse interactions with the emulsifier, thus maintaining emulsion stability during the inversion process
Solution Approach 2:
The patent changes the HLB parameter of the inverting surfactant to be greater than 7 (specifically 8-16), which is higher than conventional inverting surfactants. This parameter change allows the surfactant to be more water-soluble and effective at lower concentrations, reducing adverse interactions while achieving complete emulsion inversion in brine and acidic conditions
2Loss of energy
If high molecular weight polymer is used to reduce friction, then drag reduction is improved, but formation permeability damage increases
Solution Approach 1:
The patent changes the molecular weight parameter of the polymer to be in the range of 100,000 to 10,000,000 g/mol, optimizing it to achieve sufficient drag reduction while minimizing formation damage. This parameter optimization allows the polymer to be effective at lower concentrations, reducing the harmful effects on formation permeability
Solution Approach 2:
The patent uses a copolymer structure (acrylamide-acrylic acid copolymer) that combines the drag reduction properties of high molecular weight polymers with the benefits of lower polymer concentration requirements. The copolymer structure effectively 'copies' the essential drag reduction function while reducing the amount of polymer needed, thus minimizing formation damage
3Ease of manufacture
If conventional emulsion formulation is used, then manufacturing cost is reduced, but brine and acid tolerance is poor
Solution Approach 1:
The patent changes the HLB parameter of the inverting surfactant to be greater than 7 (specifically 8-16), making it more water-soluble and effective in brine and acidic conditions. This parameter change enables the emulsion to tolerate brine and acid environments while using conventional polymer emulsions, maintaining cost-effectiveness
Solution Approach 2:
The patent creates a composite formulation combining conventional polymer emulsion with a specific inverting surfactant (nonionic surfactant with HLB 8-16). This composite material combines the cost advantages of conventional emulsions with the enhanced brine and acid tolerance provided by the specialized inverting surfactant
Data Source
AI summary
A method begins with the step of preparing a drag-reducing additive by mixing a dispersion polymer with a surfactant and a solvent. The method continues with the step of forming a drag-reducing composition by combining the drag-reducing additive with an aqueous treatment fluid. The method further involves the step of injecting the drag-reducing composition into a subterranean formation, a pipeline or a gathering line.