Gelled Acid Matrix Stimulation for Permeability
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Solution Overview
Problem
Current matrix acidizing techniques for increasing permeability in subterranean formations rely primarily on chemical reactions with acids, lacking effective mechanical disruption methods to enhance fluid flow, which limits their efficiency in creating conductive channels.
Innovation Solution
Injecting a treatment fluid with a gelling agent selected from specific chemical formulas into a wellbore at pressures below fracturing pressure, forming voids and increasing viscosity to enhance acid penetration and self-diversion into the formation, thereby creating more effective fluid flow channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If matrix acidizing is used to increase permeability in low permeability formations, then chemical reactions occur between acid and formation, but mechanical disruption is insufficient to create effective conductive channels
Solution Approach 1:
The patent combines chemical acidizing with mechanical disruption by injecting gelled acid that undergoes in-situ gelation to provide mechanical force for creating conductive channels, merging the benefits of both chemical and mechanical stimulation methods
Solution Approach 2:
The patent changes the physical state parameter of the acidizing fluid by using gelling agents that transform the fluid from liquid to gel state in-situ, enabling mechanical disruption capability while maintaining chemical reactivity
2Productivity
If hydraulic fracturing is used to create fissures in the formation, then mechanical disruption and permeability increase are achieved, but proppants and complex equipment are required
Solution Approach 1:
The patent extracts the essential mechanical disruption function from hydraulic fracturing by using in-situ gelation to provide mechanical force without requiring proppants or complex fracturing equipment, retaining only the necessary mechanical action
Solution Approach 2:
The patent replaces the complex mechanical system of hydraulic fracturing (pumps, proppants, high-pressure equipment) with a chemical-based mechanical system where gelling agents provide mechanical disruption through in-situ gelation and expansion
3Reliability
If acidizing fluid is injected at pressure below breakdown pressure, then formation integrity is maintained, but permeability increase is limited without mechanical disruptions
Solution Approach 1:
The patent changes the rheological parameters of the acidizing fluid in-situ by inducing gelation, which provides mechanical disruption capability at lower injection pressures while maintaining formation integrity
Solution Approach 2:
The patent applies preliminary action by injecting the gelled acid that undergoes in-situ gelation to prepare mechanical disruption before the acid reacts with the formation, enabling both integrity maintenance and permeability enhancement
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 method effectively increases permeability by creating conductive channels through both chemical reactions and mechanical disruptions, improving hydrocarbon flow without fracturing the formation, thus enhancing oil production.
Implementation Method 1
a treatment fluid having a first viscosity and including an aqueous acid and a gelling agent
Implementation Method 2
increase in permeability is affected primarily by the chemical reaction of the acid within the formation
Data Source
AI summary
Methods of acidizing a subterranean formation penetrated by a wellbore that include the steps of (a) injecting into the wellbore at a pressure below subterranean formation fracturing pressure a treatment fluid having a first viscosity and including an aqueous acid and a gelling agent selected from the group consisting of Formulas I-XI and combinations thereof; (b) forming at least one void in the subterranean formation with the treatment fluid; and (c) allowing the treatment fluid to attain a second viscosity that is greater than the first viscosity.