Epoxidized Fatty Acid Methyl Esters for HPHT Invert Mud Stability

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Solution Overview

Problem

Water-based drilling fluids are not viable for high pressure and high temperature wellbore sections, leading to the use of oil-based muds for stability and shale inhibition, but these may not provide optimal emulsion stability.

Innovation Solution

Invert oil-based muds with an oleaginous continuous phase, an aqueous internal phase, and emulsifiers such as epoxidized methyl oleate, epoxidized methyl linoleate, and epoxidized methyl α-linolenate are used to enhance emulsion stability and rheological properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If water-based drilling fluids are used, then environmental friendliness is improved, but stability and shale inhibition in high pressure and high temperature sections deteriorate

Engineering Contradiction:

Improveenvironmental friendlinessVSAvoidstability in HPHT sections

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the drilling fluid by using invert emulsion technology with specific emulsifiers (epoxidized fatty acid methyl esters) to achieve both environmental compatibility and HPHT stability. The emulsifier structure and concentration are optimized to maintain stability under high pressure and temperature while reducing environmental harm compared to traditional OBMs.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite fluid system combining oil and water phases in an invert emulsion configuration, where the continuous oleaginous phase provides HPHT stability and the dispersed aqueous phase reduces environmental impact. The emulsifier acts as a binding component creating a stable composite structure that leverages the advantages of both fluid types.

Inventive Principle:

Principle #40Composite materials

2Reliability

If oil-based muds are used for stability in HPHT sections, then stability is improved, but emulsion stability may not be optimal

Engineering Contradiction:

Improvestability in HPHT sectionsVSAvoidemulsion stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces epoxidized fatty acid methyl esters as intermediary emulsifier molecules that mediate between the oil and water phases. These emulsifiers have amphiphilic structures with hydrophobic tails that interact with the oleaginous phase and hydrophilic heads that interact with the aqueous phase, creating stable interfacial films that prevent emulsion breakdown under HPHT conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes specific parameters of the emulsion system including emulsifier concentration (0.5-5 wt%), water-to-oil ratio (30-70 wt%), and epoxidation level of the fatty acid esters to achieve optimal emulsion stability. These parameter adjustments ensure the emulsion remains stable under the specific HPHT conditions encountered during drilling operations.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If traditional emulsifiers are used in invert oil-based muds, then ease of manufacture is maintained, but carrying capacity and solids suspension ability deteriorate

Engineering Contradiction:

Improveemulsifier availabilityVSAvoidcarrying capacity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical parameters of the emulsifier by using epoxidized fatty acid methyl esters with specific molecular structures (containing epoxide groups at positions 9,10; 12,13; and/or 15,16 of the carbon chain). These structural modifications enhance the emulsifier's ability to form stable emulsions with improved solids suspension capacity while maintaining ease of manufacture through established epoxidation and transesterification processes.

Inventive Principle:

Principle #35Parameter changes

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 these emulsifiers in invert oil-based muds improves the stability and carrying capacity of drilling fluids, particularly in high pressure and high temperature conditions, and enhances their ability to suspend solids and maintain electrical stability.

Implementation Method 1

Invert emulsion OBMs may be formulated to include additives, such as emulsifiers, which aid in the formation of a stable water-in-oil (W/O) emulsion

Methodology Applied

Scientific EffectEmulsion: Emulsion

Implementation Method 2

emulsifiers, which aid in the formation of a stable water-in-oil (W/O) emulsion

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 3

rheology modifiers, which allow for tuning the rheological properties of the fluid

Methodology Applied

Scientific EffectRheology modification:

Data Source

PatentUS11560508B2Epoxidized fatty acid methyl ester as primary emulsifier for invert emulsion oil based mud

Publication Date: 2023.01.24 SAUDI ARABIAN OIL CO

AI summary

An invert oil-based mud (OBM) may include an oleaginous continuous phase, an aqueous internal phase, and an emulsifier. The emulsifier may include one or more of the group consisting of epoxidized methyl oleate, epoxidized methyl linoleate, and epoxidized methyl α-linolenate. The invert OBM may contain the emulsifier in an amount of the range of 0.1 to 10 wt. % (weight percent), relative to the total weight of the OBM.