Degradable Particle Sealing Agent for Ball Sealer Leak-Off

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Solution Overview

Problem

Ball sealers used in oilfield applications often fail to effectively seal perforations due to corroded, eroded, or deformed perforation shapes, leading to reduced pressure building and production response, as they are not suited for irregular or altered perforation geometries.

Innovation Solution

A method involving the injection of a sealing agent comprising degradable particles and fibers that form a plug to inhibit fluid flow through gaps between the ball sealers and perforations, improving the sealing efficiency and reducing leak-off through liner cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ball sealers are used to seal perforations, then diversion to target zones is achieved, but sealing effectiveness deteriorates due to corroded, eroded, or deformed perforation shapes

Engineering Contradiction:

Improvesealing effectivenessVSAvoidadaptability to irregular perforation geometries

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The sealing agent composition is designed with local quality differentiation through a multi-component particle system. Different particle sizes (20-40 mesh, 40-60 mesh, 60-80 mesh) and shapes (spherical, irregular, flake) are distributed to different locations and functions: larger particles provide structural support and bridge larger gaps, while smaller particles fill voids and conform to irregular surfaces. This local differentiation of particle properties enables the seal to adapt to varying perforation geometries throughout the treatment zone.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention employs a composite sealing agent comprising multiple particle types with different physical and chemical properties. The combination includes particles of varying sizes, shapes, and densities, along with fibers, creating a heterogeneous composite material that can simultaneously provide mechanical strength, flexibility, and adaptability to irregular perforation shapes. This composite approach allows the sealing agent to maintain reliability across diverse perforation conditions that would fail with uniform ball sealers alone.

Inventive Principle:

Principle #40Composite materials

2Productivity

If ball sealers are used to seal perforations, then fluid diversion is achieved, but pressure building deteriorates due to ineffective sealing and leak-off

Engineering Contradiction:

Improvepressure buildingVSAvoidsealing effectiveness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The sealing agent utilizes parameter changes in particle properties to optimize sealing performance. Particles are selected with specific density ranges (2.0-4.0 g/cm³) to ensure proper suspension and distribution in the treatment fluid. The particle size distribution (20-80 mesh ranges) controls flow characteristics and packing density. These parameter optimizations enable the sealing agent to maintain effective seals under varying pressure conditions, preventing leak-off and maintaining pressure building necessary for productive fluid diversion.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If degradable particles and fibers are used as sealing agent, then sealing efficiency is improved, but complexity of the treatment fluid increases

Engineering Contradiction:

Improvesealing efficiencyVSAvoidcomplexity of treatment fluid composition

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The sealing agent is segmented into distinct particle size fractions (20-40 mesh, 40-60 mesh, 60-80 mesh) and fiber components, each serving specific sealing functions. This segmentation allows the complex multi-component system to be managed through standardized size classifications and injection protocols. The segmented approach simplifies the practical implementation of the complex composition by enabling systematic dosing and distribution of each particle fraction according to established industry practices.

Inventive Principle:

Principle #1Segmentation

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 use of degradable particles and fibers enhances the sealing efficiency of ball sealers, maintaining effective pressure building and reducing fluid leak-off across deformed or irregular perforation shapes, thereby improving the diversion of fluids to target zones.

Implementation Method 1

particles that form a plug that inhibits fluid flow through the gap

Methodology Applied

Scientific EffectPlugging:

Implementation Method 2

The sealing agent may optionally be degradable under downhole conditions

Methodology Applied

Scientific EffectDegradation: Decomposition (biological)

Data Source

PatentUS9212535B2Diversion by combining dissolvable and degradable particles and fibers

Publication Date: 2015.12.15 SCHLUMBERGER TECH CORP

AI summary

In downhole treatments in the oilfield, ball sealers seated in perforations may not fully seal and may leak fluid through gaps and asperities between the balls and the perforations. A method is given for improving the sealing of ball sealers in perforations by adding a sealing agent that forms a plug in the gaps and severely restricts or eliminates fluid flow. The sealing agent is preferably degradable or soluble, malleable fibers slightly larger than the gaps. Optionally, the particles may be non-degradable, rigid, of different shapes, and smaller than the gaps but able to bridge them. Mixtures of sealing agents may be used. The sealing agent may be added with the ball sealers, after the ball sealers, or both.