Microemulsion Composition for Mixed Scale and Carbonate Stimulation
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Solution Overview
Problem
Conventional methods struggle to effectively remove mixed scales and metal naphthenates from subterranean formations, leading to reduced permeability and flow rates in oilfield operations, and stimulation of tight carbonate reservoirs is challenging due to high reactivity and corrosion issues.
Innovation Solution
A microemulsion comprising a compound of Formula (I), a solvent, and a surfactant, optionally with a co-surfactant, is introduced into the subterranean formation to dissolve both inorganic and organic species, including metal naphthenates, and stimulate carbonate reservoirs by optimizing wormholing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional aqueous or organic based formulations are used to dissolve mixed scales, then dissolution of either inorganic or organic species is achieved, but the other species remains deeply embedded and undissolved
Solution Approach 1:
The microemulsion formulation segments the dissolution process into two functional components: an organic phase (containing chelating agents like EDTA or DTPA) that dissolves inorganic metal naphthenates, and an aqueous phase that dissolves organic scales. This segmentation allows each phase to target its specific substrate effectively without interference from the other species.
Solution Approach 2:
The invention uses a composite microemulsion system combining immiscible organic and aqueous phases stabilized by surfactants. This composite structure enables simultaneous presence of both organic solvents (for inorganic deposits) and water-based solutions (for organic deposits) in a single formulation, achieving versatility against mixed scales.
2Productivity
If organic based chemicals are used to treat mixed scales, then organic species are dissolved, but sludge is produced which chokes pipelines and causes reduced flow rates
Solution Approach 1:
The aqueous phase in the microemulsion acts as an intermediary medium that captures and solubilizes dissolved organic species and reaction products, preventing them from aggregating into sludge. The continuous aqueous phase keeps the system homogeneous and prevents pipeline choking.
Solution Approach 2:
The invention changes the physical-chemical parameters of the treatment system by using a microemulsion with controlled droplet size (50-500 nm) and specific surfactant concentrations. These parameter changes prevent sludge formation by maintaining molecular-level dispersion of all components throughout the system.
3Speed
If highly reactive acids are used for acidizing treatment, then carbonate dissolution is fast, but injection rate cannot be achieved in tight reservoirs and corrosion occurs
Solution Approach 1:
The invention changes the reactivity parameter by using weak organic acids (acetic acid, formic acid) instead of strong mineral acids. These weak acids provide sufficient dissolution rate for tight carbonate reservoirs without requiring high injection rates, and their lower reactivity reduces corrosion of downhole equipment.
Solution Approach 2:
The microemulsion formulation provides local quality enhancement by concentrating acidifying agents (formic acid, acetic acid) within the organic phase droplets dispersed throughout the aqueous continuous phase. This localized acid delivery ensures effective carbonate dissolution at the rock-fluid interface while maintaining overall system stability and controllability.
4Speed
If high injection rates are used to achieve optimum wormholing, then acid penetration is improved, but it is impossible in tight reservoirs and long horizontal wells
Solution Approach 1:
The invention changes the viscosity and flow parameters by using a microemulsion system with surfactants that reduce interfacial tension and improve fluid mobility. This allows adequate acid penetration into tight reservoirs and long horizontal wells at lower, economically viable injection rates while still achieving effective wormholing.
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 microemulsion provides stable and efficient removal of mixed scales and metal naphthenates, improving flow assurance and reducing corrosion, while enabling deep penetration into tight carbonate rocks for effective stimulation.
Implementation Method 1
the microemulsion may be efficient in removing deposits in subterranean formations damaged by mixed scale deposits
Implementation Method 2
Metal naphthenate or naphthenic acid deposits are another challenge in the oilfield industry
Implementation Method 3
the acid comes into contact with the carbonate rock, a reaction occurs and the acid dissolves the carbonates on the surface of the carbonate rock
Implementation Method 4
reducing corrosion
Data Source
AI summary
The present invention generally relates to microemulsions comprising a compound of Formula (I), a solvent, a surfactant and optionally a co-surfactant disclosed herein, wherein the ratio of the surfactant to the co-surfactant is about 100:0 to about 20:90. The disclosed microemulsions may be useful in preventing or removing organic deposits, inorganic deposits, metal naphthenates, napthenic acids, and/or mixtures thereof from subterranean formations. The disclosed microemulsions may also be useful in stimulating tight carbonate reservoirs.