Particulate Surface Modification for Delayed Acid Release
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Solution Overview
Problem
Particulates used in subterranean operations, such as sand or synthetic proppants, often have acidic sites on their mineral surfaces that catalyze the premature hydrolysis of hydrolysable coatings like esters, orthoesters, and polyorthoesters, leading to undesirable degradation of fluids and filter cakes, undermining their intended delayed release functionality.
Innovation Solution
Modifying the mineral surface of particulates with surface modification agents, such as sodium hydroxide or organosilicon compounds, to neutralize or make acidic sites more basic, thereby reducing their catalytic effect on hydrolysable coatings, allowing them to degrade at a slower rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If particulates are coated with hydrolysable materials (esters, orthoesters, polyorthoesters), then delayed acid release functionality is achieved, but premature hydrolysis occurs due to acidic sites on the mineral surface
Solution Approach 1:
A surface modification agent is introduced as an intermediary substance between the mineral surface and the hydrolysable coating. This agent neutralizes or masks the acidic sites on the mineral surface, preventing them from catalyzing premature hydrolysis of the coating, thereby ensuring the coating only hydrolyzes at the intended time
Solution Approach 2:
The acidic sites on the mineral surface are neutralized or masked before the hydrolysable coating is applied or before hydrolysis is intended to occur. This preliminary anti-action prevents the harmful catalytic effect of the acidic sites, ensuring the coating remains stable until the desired moment for acid release
2Reliability
If surface modification agents are used to neutralize acidic sites, then premature hydrolysis is prevented, but additional processing steps are required
Solution Approach 1:
The surface modification step and the coating application step are combined into a single integrated process. The surface modification agent is applied to the particulate, and then the hydrolysable coating is applied in sequence, creating a streamlined two-step process that reduces overall complexity while maintaining reliability
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 modification of particulate surfaces delays the hydrolysis of coatings, ensuring they hydrolyze at a slower rate, maintaining the intended functionality of delayed acid release and preventing premature degradation of fluids and filter cakes.
Implementation Method 1
treating a particulate with a surface modification agent
Implementation Method 2
neutralize or make acidic sites more basic
Implementation Method 3
degrade at a slower rate
Implementation Method 4
reducing their catalytic effect on hydrolysable coatings
Data Source
AI summary
Methods comprising: providing a treatment fluid that comprises a base fluid and a least a plurality of coated particulates, the coated particulates having been treated with a surface modification agent and coated with a hydrolysable coating; placing the treatment fluid into a subterranean formation via a well bore. Also provided are methods comprising: treating a particulate with a surface modification agent; coating the particulate with a hydrolysable coating that has an initial degradation rate to produce a coated particulate; placing the particulate in a subterranean formation; and allowing the hydrolysable coating to degrade at a second degradation rate that is slower than its initial degradation rate.