Biodegradable Particulate Plugging Agents for Wellbore Flow Control
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Solution Overview
Problem
Current drilling and servicing fluids in the oil and gas industry face challenges with permanent and temporary particulate materials that either have residual effects on well production or fail to prevent sulfate-reducing bacteria (SRB) growth, leading to hydrogen sulfide production and equipment corrosion.
Innovation Solution
A servicing fluid comprising a base fluid and a solid particulate agent, which is a reaction product of a urea-containing compound and an aldehyde-containing compound, is introduced into subterranean formations to seal flow paths and degrade, forming biocidal compounds that prevent SRB growth and control fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent particulate materials (sand, clay, barite) are used to seal flow paths, then fluid flow control is achieved, but residual effects on well production occur
Solution Approach 1:
The patent employs biodegradable polymer particles as temporary plugging agents that fulfill their flow control function and then naturally degrade, eliminating residual effects. These particles are designed to be biodegradable through hydrolysis or microbial action, allowing them to serve as disposable plugging materials that leave no harmful residue in the formation.
Solution Approach 2:
The patent changes the chemical composition and degradation characteristics of particulate materials from permanent (sand, clay) to temporary biodegradable polymers. By selecting polymers with specific degradation rates and mechanisms, the plugging effect is temporary and可控, allowing flow control during operations followed by natural degradation to restore formation permeability.
2Reliability
If removable material (calcium carbonate) is used to modify flow, then fluid flow control is achieved, but cleanup solution injection is required to remove it
Solution Approach 1:
The patent uses biodegradable polymer particles that naturally degrade through hydrolysis or microbial action, eliminating the need for chemical cleanup operations. These temporary plugging agents decompose into harmless byproducts, providing flow control during operations without requiring subsequent acid injection or other removal procedures.
Solution Approach 2:
The biodegradable polymers perform self-removal through natural degradation processes. The particles automatically break down via hydrolysis or microbial metabolism, eliminating the need for external cleanup operations. This self-service mechanism simplifies operations by removing the requirement for separate acidizing or flushing steps.
3Object-generated harmful factors
If temporary materials (biodegradable polymers) are used, then degradation occurs without residual effects, but temperature and cost limitations prohibit use in many applications
Solution Approach 1:
The patent employs composite plugging systems combining biodegradable polymer particles with other compatible materials to enhance temperature stability and mechanical properties. These composite formulations maintain biodegradability while extending the operational temperature range and improving cost-effectiveness for diverse well conditions.
Solution Approach 2:
The patent modifies the chemical structure and physical properties of biodegradable polymers to withstand higher temperatures and more demanding well conditions. By adjusting polymer composition, molecular weight, and crosslinking density, the materials maintain their biodegradable nature while expanding their applicability to various temperature ranges and well environments.
4Reliability
If sulfate sources and organic materials are present in well fluids, then SRB population growth occurs, but preventing their introduction is difficult
Solution Approach 1:
The patent converts the presence of organic materials from a harmful factor (SRB food source) into a beneficial mechanism by using biodegradable polymers that degrade into non-SRB-supporting byproducts. The degradation process consumes oxygen and creates an environment unfavorable for SRB growth, transforming potential contamination into a protective effect.
Solution Approach 2:
The biodegradable polymer acts as an intermediary substance that mediates between the well fluids and SRB populations. During degradation, it consumes oxygen and produces byproducts that inhibit SRB growth, serving as a protective barrier against bacterial contamination without requiring direct intervention to prevent initial introduction.
5Object-generated harmful factors
If H2S is produced by SRB, then crude oil/natural gas value is reduced due to refining costs
Solution Approach 1:
The patent applies preliminary protective action by introducing biodegradable polymers that prevent SRB growth before H2S can be produced. The polymers create an oxygen-depleting environment during degradation that inhibits SRB metabolism, preventing H2S generation upstream and eliminating the need for costly H2S removal and refining operations.
Solution Approach 2:
The patent converts the potential harmful effect of organic materials (SRB food source leading to H2S production) into a beneficial outcome by using biodegradable polymers that degrade into non-H2S-producing byproducts. The degradation process prevents SRB activity and H2S generation, transforming a potential contamination source into a protective mechanism.
6Object-generated harmful factors
If H2S reacts with steel, then equipment corrosion occurs, but prevention requires multiple additives
Solution Approach 1:
The patent applies preliminary protection by preventing H2S generation at its source through biodegradable polymer degradation. By creating an oxygen-depleting environment that inhibits SRB growth, the system prevents H2S formation upstream, eliminating the need for downstream corrosion inhibitors and simplifying the additive package.
Solution Approach 2:
The patent converts the potential corrosion problem caused by H2S into a beneficial outcome by using biodegradable polymers that prevent H2S generation. The degradation process creates conditions unfavorable for SRB activity, thereby preventing both H2S production and subsequent corrosion without requiring complex corrosion inhibition systems.
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 solution effectively seals unwanted flow paths, degrades without residual effects, and produces biocidal compounds that inhibit SRB growth, reducing hydrogen sulfide production and equipment corrosion, thereby enhancing well production and safety.
Implementation Method 1
Particulate material has been employed to bridge/seal/plug certain flow paths in the formations where the flow of fluids is undesirable
Implementation Method 2
The different materials that have been used historically for these purposes can generally be classified as permanent, removable, or temporary. Examples of temporary materials are those that degrade, decompose, or have gradual solubility in the wellbore fluid.
Implementation Method 3
Biodegradable polymers, such as polylactic acid, are commonly used since they degrade in the presence of small amounts of water
Data Source
AI summary
Methods, fluids, and compositions are provided for treating subterranean formations. The fluids can be servicing or drilling fluids including a base fluid and a particulate agent or biocide precursor particulate agent. The particulate agent can seal flow paths in the subterranean formation and subsequently can be degraded to allow flow to resume. The particulate agent may be a reaction product of a urea containing compound and an aldehyde containing compound. An example of such a reaction product is a methylene urea.