Polymeric Acid Precursor Emulsion for Subterranean Wellbore Treatment
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Solution Overview
Problem
Current acid treatments for subterranean formations face challenges such as corrosion issues with iron-containing wellbore components, difficulty in accurately delivering acid to distant formation locations, and rapid reaction of acid with materials, leading to inefficiencies and stability problems.
Innovation Solution
Development of a composition involving a polymeric acid precursor dissolved in a polymer dispersing solvent, which forms an emulsion with a substantially immiscible liquid, using surfactants and stabilizers to control the release of acid, allowing for controlled hydrolysis and acid generation at specific conditions, reducing molecular weight through transesterification or ester hydrolysis, and introducing the solution or emulsion into the wellbore for treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional acid is used for treating subterranean formations, then the acid can react with the formation to etch differential flow paths, but the acid causes corrosion to iron-containing wellbore components and requires additional additives and specialized equipment
Solution Approach 1:
The acid is bound in advance within a biodegradable polymer matrix before injection. The polymer-acid complex is injected as a stable formulation that remains inert during transport and storage, then degrades in-situ at the target formation location to release the acid for etching. This preliminary encapsulation prevents premature reaction and eliminates the need for complex corrosion inhibition systems.
Solution Approach 2:
The biodegradable polymer acts as an intermediary carrier between the acid and the wellbore components. It protects the acid from contacting iron-containing wellbore components during pumping and storage, preventing corrosion. The polymer serves as a temporary vehicle that delivers the acid to the formation where it then reacts with the formation rock rather than the wellbore equipment.
2Productivity
If acid is pumped from the surface down the wellbore, then the acid can reach the formation, but the acid reacts with materials closer to the wellbore before reaching the desired position
Solution Approach 1:
The acid is pre-bound within the polymer matrix before injection, creating a stable polymer-acid complex that remains inert during transport. The complex is designed to degrade at specific depths or under specific conditions (such as temperature changes or contact with formation water), ensuring the acid is released at the precise target location rather than reacting prematurely near the wellbore.
Solution Approach 2:
The polymer serves as an intermediary carrier that transports the acid through the wellbore and into the formation without allowing premature reaction. It acts as a protective vehicle that maintains the acid in a non-reactive state during transport, then releases it at the desired location where it can effectively etch the formation rock.
3Productivity
If the acid is placed in the internal phase of an emulsion, then the acid can be transported, but the friction pressure associated with pumping is relatively high
Solution Approach 1:
The biodegradable polymer serves as an intermediary carrier that encapsulates the acid, creating a stable polymer-acid complex. This complex has favorable rheological properties that reduce friction pressure during pumping compared to conventional emulsified acids. The polymer matrix maintains acid stability while allowing for smoother flow characteristics, reducing the pumping pressure required to deliver the acid to the formation.
4Productivity
If solid polymeric acid precursors are injected into the formation, then the acid can be released at controllable rates, but the location and timing of release may be difficult to control
Solution Approach 1:
The polymer formulation parameters (molecular weight, composition, crosslinking density) are designed to provide controlled acid release rates. By adjusting these parameters, the release characteristics can be tuned to match specific treatment requirements. The polymer-acid complex was designed to remain stable during transport and then degrade at controlled rates once in the formation, providing both rate control and location precision.
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
This approach minimizes corrosion, allows precise acid delivery and release, and enhances the stability and effectiveness of acid treatments by controlling the generation of monomeric acids, thereby improving the treatment of subterranean formations.
Implementation Method 1
the solid polymeric acid precursor is injected into the formation and is allowed to hydrolyze so that 'monomeric acids' are released at controllable rates
Implementation Method 2
the solvent includes an ester that degrades to at least one of carboxylic acids, dicarboxylic acids and polycarboxylic acids
Implementation Method 3
the composition further includes at least one of a surfactant and a steric stabilizer
Implementation Method 4
the surfactant has a hydrophile-lipophile balance of from about 6 to about 35
Implementation Method 5
reducing molecular weight through transesterification or ester hydrolysis
Implementation Method 6
introducing the solution or emulsion into the wellbore for treatment
Data Source
AI summary
A composition is formed from a polymeric acid precursor, such as polylactic acid (PLA), that is a least partially dissolved within a polymer dispersing solvent. An emulsion may be from polymeric acid precursor that is at least partially dissolved within a solvent and a liquid that is substantially immiscible with the solvent. In certain cases, the molecular weight of the polymeric acid precursor may be reduced in forming the solution. The solution may be used in treating a formation penetrated by a wellbore.