Polyvinyl Alcohol Diverting Agents for Wellbore Fluid Distribution
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Solution Overview
Problem
Current diverting agents used in subterranean wellbore operations face challenges in evenly distributing servicing fluids across intervals with varying permeability and injectivity, and they often leave residues that hinder hydrocarbon production after degradation, necessitating improved solubility and degradability profiles.
Innovation Solution
A particulate composition comprising a blend of polyvinyl alcohol resin with a plasticizer and fibers, designed to provide a broad range of solubility and ease of degradability, allowing for effective fluid management and post-servicing cleanup in subterranean formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If polyvinyl alcohol compositions are used as diverting agents to evenly distribute servicing fluids across intervals with varying permeability, then fluid distribution is improved, but the compositions may leave residues that hinder hydrocarbon production after degradation
Solution Approach 1:
The patent modifies the chemical structure of polyvinyl alcohol by incorporating acid-functional comonomers (acrylic acid, methacrylic acid, itaconic acid) to create compositions with controlled solubility and degradability parameters. This allows the diverting agent to perform its function during servicing operations and then degrade completely without leaving harmful residues that would hinder hydrocarbon production.
Solution Approach 2:
The invention creates composite diverting agent compositions by blending polyvinyl alcohol with acid-functional comonomers and optional additives. This composite structure provides both the desired fluid distribution properties during servicing operations and the ability to degrade without residue formation after treatment, resolving the contradiction between operational effectiveness and post-treatment productivity.
2Productivity
If polyvinyl alcohol compositions are designed with high solubility for easy degradation, then cleanup is facilitated, but the compositions may lose effectiveness as diverting agents during servicing operations
Solution Approach 1:
The patent creates dynamically adjustable solubility and degradability characteristics by selecting specific acid-functional comonomers and their proportions. The compositions are designed to maintain stability and effectiveness during servicing operations, then progressively degrade after treatment. The acid functional groups provide controlled hydrolysis rates that enable the material to serve its diverting function reliably while ensuring complete degradation for rapid cleanup.
Solution Approach 2:
By modifying the degree of hydrolysis, molecular weight, and comonomer composition, the patent tailors the solubility and degradation kinetics of the polyvinyl alcohol compositions. These parameter adjustments ensure the diverting agent maintains its structural integrity and effectiveness during servicing operations while enabling controlled degradation afterward for efficient cleanup without compromising either performance or productivity.
3Loss of substance
If conventional diverting agents are used to plug high-permeability zones, then fluid loss is reduced, but the agents may not degrade completely and require additional cleanup operations
Solution Approach 1:
The patent designs polyvinyl alcohol compositions with self-degrading capabilities through incorporated acid-functional comonomers that hydrolyze under downhole conditions. These compositions automatically degrade after performing their fluid loss control function, eliminating the need for additional cleanup operations. The acid functional groups (carboxylic acid, carboxylate, or amine) enable the material to self-digest and break down into soluble products, providing self-service degradation that reduces both fluid loss and cleanup time.
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 composition effectively reduces fluid loss into formations, ensures even distribution of servicing fluids, and facilitates quick cleanup, maintaining formation permeability for hydrocarbon production while being environmentally friendly and non-toxic.
Implementation Method 1
The vinyl alcohol polymers and fibers can also be used with equally good results as separate members of a kit... a broad range of solubility and ease of degradability
Data Source
AI summary
Disclosed are compositions and kits of fibers and acid-functional vinyl alcohol polymers, wherein such compositions and kits are useful for wellbore remediation as applied to a subterranean formation traversed by the borehole of an oil or gas well.