Cation-Modified PVA Resin Drilling Fluid Additive

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Solution Overview

Problem

Conventional drilling fluids with bentonite face issues of insufficient resistance to damage, salt- or cement-sensitivity, and instability at varying temperatures, leading to hydration swelling of montmorillonite, which causes damage to the borehole wall and viscosity changes, making them unsuitable for deep drilling operations.

Innovation Solution

A cation-modified polyvinyl alcohol (PVA)-based resin with a specific structural unit is introduced as a drilling fluid additive, which acts as an excellent dispersing agent for clay components and suppresses hydration swelling of bentonite, forming a stable mud wall and maintaining viscosity stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If bentonite is used as a drilling fluid additive to form mud wall and transport cuttings, then viscosity and cuttings transportation are improved, but hydration swelling of montmorillonite causes borehole wall damage and viscosity instability

Engineering Contradiction:

Improvecuttings transportationVSAvoidborehole wall damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a cation-modified polyvinyl alcohol resin as an intermediary substance that mediates between the bentonite and water. This resin adsorbs onto the montmorillonite surface and forms a protective barrier, preventing direct water contact that causes hydration swelling, while still allowing the bentonite to maintain its viscosity and cuttings transportation functions

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite system by combining bentonite with cation-modified polyvinyl alcohol resin. This composite approach leverages the viscosity-enhancing properties of bentonite while the resin component provides swelling inhibition, achieving both cuttings transportation and borehole wall protection simultaneously

Inventive Principle:

Principle #40Composite materials

2Productivity

If bentonite is used to increase viscosity for cuttings transport, then cuttings transportation is improved, but viscosity becomes unstable due to hydration swelling

Engineering Contradiction:

Improvecuttings transportationVSAvoidviscosity stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The cation-modified polyvinyl alcohol resin acts as a mediator that stabilizes the interaction between bentonite and water. By adsorbing on montmorillonite surfaces, it prevents uncontrolled hydration that leads to viscosity fluctuations, ensuring stable rheological properties for reliable cuttings transportation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical parameters of the polyvinyl alcohol by introducing cationic groups, which changes its interaction characteristics with bentonite. This parameter modification enables the resin to effectively control hydration swelling and maintain stable viscosity under varying drilling conditions

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional drilling mud is used for shallow drilling, then simplicity is maintained, but resistance to damage and temperature stability are insufficient for deep drilling

Engineering Contradiction:

Improvedrilling fluid compositionVSAvoiddamage resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent develops a composite drilling fluid system combining bentonite, cation-modified polyvinyl alcohol resin, and other functional additives. This composite formulation provides enhanced damage resistance and temperature stability required for deep drilling operations while maintaining practical compositional simplicity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The cation-modified polyvinyl alcohol resin serves multiple functions simultaneously: it acts as a swelling inhibitor, viscosity stabilizer, and borehole wall protector. This multi-functionality allows the drilling fluid to meet multiple performance requirements without significantly increasing compositional complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 cation-modified PVA-based resin effectively reduces hydration swelling of shale clay, stabilizes the borehole surface, and ensures stable transportation of drill cuttings by preventing mud wall collapse and viscosity changes, enhancing the drilling fluid's performance in deep drilling operations.

Implementation Method 1

cationic group-containing PVA-based resin...acts as an excellent dispersing agent for clay components and suppresses hydration swelling of bentonite

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

bentonite increases viscosity of the drilling fluid, and supports to transport the cuttings to the ground

Methodology Applied

Scientific EffectHydration swelling: Mineral Hydration

Data Source

PatentUS9475900B2Drilling fluid additive

Publication Date: 2016.10.25 MITSUBISHI CHEM CORP

AI summary

The present invention provides a drilling fluid additive comprising a specific cation-modified PVA-based resin and a drilling fluid containing the same. The drilling fluid additive can reduce hydration swelling of inorganic clay mineral such as bentonite, and provide a drilling fluid such as drilling mud capable of forming a thin and tough mud wall on the stratum during drilling operation.