Invert Emulsion for Simultaneous Elastomer Swelling and Filtercake Removal
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Solution Overview
Problem
Current well completion methods require a two-step process to remove filtercakes and swell oil-swellable elastomers, increasing operational time and cost, and existing fluids lack stability during hydrolysis, affecting the efficiency of filtercake removal and elastomer swelling.
Innovation Solution
A dual-functional water-in-oil emulsion treatment fluid comprising a hydrolyzable ester of carboxylic acid and water as the internal phase, and an oil and emulsifier as the continuous phase, which is stable during hydrolysis and can simultaneously break filtercakes and swell oil-swellable elastomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-step process is used to remove filtercakes and swell oil-swellable elastomers, then the effectiveness of filtercake removal and elastomer swelling is improved, but the operational time and cost increase
Solution Approach 1:
The patent combines filtercake removal and elastomer swelling into a single treatment fluid application. The treatment fluid contains both filtercake breaker components (acid, enzyme, or chemical breaker) and elastomer swelling components (oil-based fluid), allowing both functions to be performed simultaneously in one operational step, thereby reducing operational time while maintaining effectiveness
Solution Approach 2:
The treatment fluid is designed with multi-functionality to perform both filtercake removal and elastomer swelling. The fluid comprises a continuous oil phase that swells elastomers while containing hydrolyzable ester compounds that break down filtercakes, making a single fluid system capable of executing multiple functions that previously required separate treatments
2Ease of operation
If existing fluids are used for filtercake removal and elastomer swelling, then the operational process is simplified, but the fluid stability during hydrolysis is compromised
Solution Approach 1:
The patent modifies the chemical composition parameters of the treatment fluid by incorporating hydrolyzable ester compounds (such as esters of carboxylic acid with alcohols or phenols) into the continuous oil phase. These esters are specifically selected to remain stable during initial application but undergo controlled hydrolysis to release active filtercake breaker compounds, thereby maintaining fluid stability during operation while enabling subsequent chemical action
Solution Approach 2:
The hydrolyzable ester compounds act as intermediary substances that bridge the gap between fluid stability and chemical reactivity. The esters remain intact during transport and initial application (maintaining stability), then undergo hydrolysis to release the active filtercake breaker components, serving as a temporary carrier that enables controlled chemical action at the appropriate time
3Loss of time
If a single-step treatment fluid is used for filtercake removal and elastomer swelling, then operational time and cost are reduced, but the breaking time of filtercakes cannot be controlled
Solution Approach 1:
The treatment fluid is designed with dynamic chemical behavior where the hydrolyzable ester compounds undergo controlled hydrolysis over time. The rate of hydrolysis can be influenced by factors such as temperature, pH, and the specific ester compounds used, allowing the filtercake breaking action to occur at controlled rates. This enables the fluid to maintain stability initially, then progressively activate the filtercake breaking function, providing control over the breaking time while maintaining operational simplicity
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 emulsion fluid reduces operational costs by combining filtercake removal and elastomer swelling into a single step, maintaining stability and controlling the breaking time of filtercakes while effectively swelling oil-swellable elastomers without affecting emulsion stability.
Implementation Method 1
A dual-functional water-in-oil emulsion treatment fluid comprising a hydrolyzable ester of carboxylic acid and water as the internal phase
Implementation Method 2
an oil and emulsifier as the continuous phase, which is stable during hydrolysis and can simultaneously break filtercakes and swell oil-swellable elastomers
Data Source
AI summary
A treatment fluid and method for simultaneously swelling an oil-swellable elastomer and breaking a filtercake in a well. The treatment fluid includes an emulsion comprising: (i) a continuous oil phase, wherein the oil phase comprises: (a) an oil; and (b) an emulsifier; and (ii) an internal aqueous phase, wherein the aqueous phase comprises: (a) water; and (b) a water-soluble hydrolyzable ester of a carboxylic acid; wherein the emulsion is stable to hydrolysis of the water-soluble hydrolyzable ester of the carboxylic acid. A method of treating a well includes the steps of: (A) forming the treatment fluid; and (B) introducing the treatment fluid into the portion of the wellbore, wherein: (i) a filtercake has been previously formed in the portion of the wellbore, wherein the filtercake comprises an acid-soluble or an acid-degradable material; and (ii) an oil-swellable elastomer has been previously deposited or positioned in the portion of the wellbore.