Graphite-Coated Soft Particles for Deep Water Shutoff Sealing

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Solution Overview

Problem

Existing rubber particles used in high-temperature and high-salt oil reservoirs are prone to oxidation failure, agglomerate quickly, and lack sufficient sealing strength, making them ineffective for deep injection and sealing in complex geological structures.

Innovation Solution

A modified graphite-coated soft particle with a surface coating of hydroxyl and carboxyl groups, combined with antioxidants and density regulators, is prepared to enhance thermal stability, slow agglomeration, and improve viscoelasticity, allowing for effective sealing in high-temperature and high-salt environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rubber particles are used in high-temperature and high-salt oil reservoirs, then they provide sealing capability, but they are prone to oxidation failure and lack sufficient thermal stability

Engineering Contradiction:

Improvesealing capabilityVSAvoidthermal stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses composite rubber particles combining nitrile rubber and styrene-butadiene rubber with antioxidants and modified graphite coating to achieve both sealing capability and thermal stability in high-temperature high-salt environments

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent employs inexpensive antioxidants and modified graphite coatings that provide temporary protection against oxidation and thermal degradation, extending the service life of rubber particles in harsh reservoir conditions

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If rubber particles are injected into deep formations, then they can seal water channeling pathways, but they agglomerate quickly and are difficult to inject

Engineering Contradiction:

Improvesealing effectVSAvoidinjectability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent modifies particle density and surface properties through graphite coating and antioxidant addition to control agglomeration timing, enabling particles to remain dispersed during injection and only agglomerate after reaching the target formation zone

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses modified graphite and antioxidants as intermediary substances that prevent premature agglomeration of rubber particles, allowing them to be injected deep into formations and only seal after reaching the intended location

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If rubber particles are used for water shutoff, then they can block water channeling, but they lack sufficient viscoelasticity and particle stacking effect

Engineering Contradiction:

Improvewater shutoff capabilityVSAvoidviscoelasticity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent creates composite rubber particles with nitrile rubber and styrene-butadiene rubber to enhance viscoelasticity and improve particle stacking effects for better water shutoff performance

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies modified graphite coating specifically on the particle surface to enhance local viscoelasticity and stacking properties where they are most needed for sealing, while maintaining the bulk rubber properties for structural integrity

Inventive Principle:

Principle #3Local quality

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 modified graphite-coated particles maintain stability for 90 days, agglomerate slowly, and provide strong sealing, ensuring long-term effectiveness in deep formations with high temperatures and salinity, facilitating deep injection and reducing reservoir damage.

Implementation Method 1

Methodology Applied

Scientific EffectThermal stability:

Implementation Method 2

The modified graphite-coated particles maintain stability for 90 days, agglomerate slowly, and provide strong sealing

Methodology Applied

Scientific EffectAgglomeration: Coagulation

Implementation Method 3

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentUS20260028521A1Modified Graphite-Coated Soft Particle and Method for Preparing Same, and Profile Control and Water Shutoff Agent and Application Thereof

Publication Date: 2026.01.29 CHINA UNIV OF PETROLEUM (EAST CHINA)

AI summary

The present disclosure relates to the technical field of chemical profile control and water shutoff in oilfields, and discloses a modified graphite-coated soft particle and a method for preparing the same, and a profile control and water shutoff agent and an application thereof. The modified graphite-coated soft particle includes a soft particle and first modified graphite coating a surface of the soft particle. The soft particle includes one or more of a rubber main agent, an antioxidant, an auxiliary antioxidant, a density regulator, and second modified graphite. The first modified graphite and the second modified graphite are the same or different and each are modified graphite with a surface rich in hydroxyl groups and carboxyl groups. The profile control and water shutoff agent can mutually agglomerate after aging for a period upon entering a deep formation zone, and can form effective sealing of a water channeling pathway.