Biodegradable Emulsion for Oil-Based Mud Cake Removal

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Solution Overview

Problem

Existing methods for removing oil-based and synthetic-based mud filter cakes from wellbores often cause formation damage and are not biodegradable, particularly in deepwater and high-temperature, high-pressure applications, and may lead to emulsion blocks that obstruct oil production.

Innovation Solution

A biodegradable synthetic oil base emulsion with a nonionic surfactant is used to break down the interfacial rheological properties of oil-based and synthetic-based mud cakes, effectively removing filter cakes and preventing wellbore adherence, composed of a base oil with 75-99% linear paraffins and 3.5-15% surfactant, which is lighter than water and does not produce a sheen on the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aqueous surfactant based systems are used to remove filter cake, then emulsion breakdown and phase separation are achieved, but additional formation damage occurs due to emulsion block formation from water saturation

Engineering Contradiction:

Improveemulsion breakdown effectivenessVSAvoidformation damage from emulsion block

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of using aqueous-based systems to break oil-based emulsions (conventional approach), the patent inverts the approach by using oil-based emulsion to break oil-based filter cakes. This reversal avoids water saturation issues that cause emulsion blocks and formation damage, while still achieving effective emulsion breakdown and phase separation.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a biodegradable oil-based emulsion as an intermediary substance that facilitates filter cake removal without causing harmful side effects. This intermediary system uses biodegradable surfactants to break down the filter cake emulsion and enables phase separation without creating water saturation problems that lead to emulsion blocks.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If conventional OBMs and SBMs are used for drilling, then penetration rates and lubricity are improved, but filter cake formation and skin development occur requiring cleanup treatments

Engineering Contradiction:

Improvepenetration rateVSAvoidfilter cake formation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful filter cake formation into a beneficial opportunity by developing a cleanup system that uses biodegradable oil-based emulsion. This system effectively removes the filter cake that formed during drilling, transforming the problematic residue into a removable layer that can be cleaned without causing additional formation damage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If solvent-based systems are used for filter cake removal, then removal efficiency is achieved, but environmental and safety concerns arise

Engineering Contradiction:

Improvefilter cake removal efficiencyVSAvoidenvironmental and safety issues

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the cleanup system by using biodegradable surfactants and oil-based emulsion instead of conventional solvents. This parameter change maintains effective filter cake removal efficiency while eliminating the environmental and safety concerns associated with toxic solvent-based systems.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs biodegradable materials that break down naturally after use, replacing persistent solvent-based systems. The biodegradable surfactants and oil-based emulsion serve their purpose of removing filter cake and then degrade harmlessly, eliminating long-term environmental contamination issues.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 emulsion achieves high mudcake removal efficiency, breaking down filter cake cohesion and preventing wellbore adherence, while being environmentally friendly and safe for use in sensitive drilling environments like the Gulf of Mexico, offering a more economical alternative to solvent-based systems.

Implementation Method 1

aqueous surfactant based treatment often creates additional damage by forming an emulsion block in the wellbore due to water saturation

Methodology Applied

Scientific EffectEmulsion breakdown: Emulsion

Implementation Method 2

The emulsion contains an external phase of a surfactant emulsified in the base oil

Methodology Applied

Scientific EffectSurfactant action: Surfactant

Data Source

PatentUS7392845B2Method of treating oil or gas well with biodegradable emulsion

Publication Date: 2008.07.01 BAKER HUGHES CO

AI summary

A biodegradable water-in-synthetic oil base emulsion, effective in the removal of filter cakes, consists of an external phase of a surfactant emulsified in a paraffinic base oil. The emulsion is particularly effective in breaking-down the interfacial rheological properties of oil base mud and synthetic oil base mud filter cakes and acts as a demulsifier to break the water-in-oil emulsions present in such oil base and synthetic oil base muds.