Expandable Polymeric Microparticles for Reservoir Conformance Control

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Solution Overview

Problem

In hydrocarbon recovery, the heterogeneity of reservoir rock strata leads to inefficient mobilization and recovery of hydrocarbons due to thief zones with high permeability, where injected fluids bypass lower permeability zones, resulting in poor sweep efficiency and high costs.

Innovation Solution

The use of expandable polymeric microparticles with hydrophobic polymers and labile pendant groups that expand upon activation, allowing for efficient propagation through the reservoir and impeding fluid flow to divert injected fluids into less swept zones, thereby enhancing hydrocarbon recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If injected fluid is used for secondary or tertiary recovery, then hydrocarbon mobilization is enhanced, but fluid follows low resistance routes through thief zones and does not effectively sweep hydrocarbon from lower permeability zones

Engineering Contradiction:

Improvehydrocarbon recovery rateVSAvoidsweep efficiency

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The microparticles undergo a parameter change in their physical state, transitioning from an unexpanded hydrophobic state to an expanded hydrophilic state. This parameter change allows them to first propagate through the reservoir in their compact form, then expand in situ to modify permeability and divert fluid flow, thereby improving sweep efficiency while maintaining productivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The microparticles are designed to be dynamic rather than static, changing their size and wettability in response to environmental conditions. They begin as small hydrophobic particles that can move freely through the reservoir, then transform into larger hydrophilic particles that impede fluid flow and divert it into unswept zones, dynamically adapting to solve the sweep efficiency problem

Inventive Principle:

Principle #15Dynamics

2Reliability

If mechanical seals or cement squeezes are used to block thief zones, then injected fluid diversion is achieved, but these methods are expensive and not amenable when communication exists between layers outside casing reach

Engineering Contradiction:

Improvefluid diversion effectivenessVSAvoidtreatment cost and applicability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts the sealing function from traditional mechanical methods (cement squeezes, mechanical plugs) and implements it through chemical-physical means using expandable microparticles. This extraction allows the treatment to be applied in cases where mechanical methods are not feasible, such as when communication exists between layers outside the casing reach

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The expandable microparticles act as an intermediary substance that bridges the gap between injection and production wells, dynamically blocking thief zones through their expansion mechanism. This intermediary approach is more versatile and cost-effective than direct mechanical sealing methods

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If near wellbore conformance control treatments are applied, then some fluid diversion is achieved, but injected fluids can bypass the treatment and re-enter thief zones having contacted little or none of remaining hydrocarbon

Engineering Contradiction:

Improveconformance control effectivenessVSAvoidhydrocarbon recovery

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The microparticles operate in a different dimensional space by expanding within the pore structure of the reservoir rock rather than forming a near-wellbore barrier. This dimensional change allows them to create distributed blockages throughout the thief zone, preventing fluid bypass and improving both conformance control and hydrocarbon recovery

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 expanded microparticles effectively divert injected fluids into under-swept zones, improving hydrocarbon recovery rates and reducing costs associated with fluid cycling and well maintenance by maintaining unexpanded size until activation, allowing for targeted permeability modification within the reservoir.

Implementation Method 1

exposing the hydrophobic microparticles to an activating event such as a change in temperature and/or at a predetermined pH sufficient to hydrolyze the labile pendant groups

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

the microparticle expands by absorbing the injection fluid (normally water)

Methodology Applied

Scientific EffectFluid absorption and expansion: Absorption (physical)

Data Source

PatentUS7888296B2Composition and method for recovering hydrocarbon fluids from a subterranean reservoir

Publication Date: 2011.02.15 CHAMPIONX LLC

AI summary

This invention is directed to a composition comprising expandable polymeric microparticles comprising hydrophobic polymers having a backbone with labile pendant groups, the microparticles having an unexpanded volume average particle size diameter of from about 0.05 to about 5,000 microns. Labile pendant groups on the backbone are subject to hydrolysis under a change in environmental conditions that results in expansion of the microparticle. The invention is further directed to the use of the composition for modifying the permeability of subterranean formations and increasing the mobilization and/or recovery rate of hydrocarbon fluids present in the formations.