Microwave-Activated Filter Cake for Wellbore Strengthening

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing methods for strengthening wellbores during drilling operations are limited in widening the mud window, leading to increased costs and stability issues like lost circulation and stuck pipes, as they require frequent casing and narrow wellbore diameters, restricting access to deeper reservoirs.

Innovation Solution

A method involving a drilling fluid with a chemical system that accumulates on the wellbore wall and is irradiated with microwave radiation to polymerize or cross-link, forming a strengthened filter cake using methacrylate-based systems and crosslinkers like dimethyldiallylammonium chloride, facilitated by a tool with a microwave antenna for targeted irradiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequent casing is used to strengthen wellbore, then wellbore stability is improved, but drilling costs increase and wellbore diameter is reduced

Engineering Contradiction:

Improvewellbore stabilityVSAvoiddrilling efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The drilling fluid is pre-formulated with polymer and crosslinking agents that remain dormant during drilling but activate upon microwave irradiation. This preliminary preparation allows the wellbore to be strengthened in advance without interfering with the drilling process, eliminating the need for frequent casing while maintaining stability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical system of frequent casing installation with a chemical system activated by microwave radiation. The chemical crosslinking of polymers in the filtercake creates a strengthened wellbore wall without requiring mechanical intervention through casing strings, thereby improving drilling efficiency and maintaining wellbore diameter.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If high hydrostatic pressure is used to prevent pore fluid entry, then formation protection is improved, but formation fracturing risk increases

Engineering Contradiction:

Improveformation protectionVSAvoidformation fracturing

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical-chemical parameters of the drilling fluid by incorporating microwave-activatable crosslinking agents. When microwave radiation is applied, the polymer crosslinks and forms a strengthened filtercake, effectively changing the mechanical properties of the wellbore wall to withstand higher pressures without fracturing the formation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The drilling fluid is prepared in advance with crosslinking agents that remain inactive during normal drilling operations. Upon microwave activation, these agents quickly crosslink and strengthen the filtercake, providing formation protection before pressure issues arise, allowing safer operation within the mud window.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If chemical modification of filtercake is used to strengthen wellbore, then wellbore stability is improved, but process control complexity increases

Engineering Contradiction:

Improvewellbore stabilityVSAvoidprocess control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces microwave radiation as an intermediary energy source that triggers the chemical crosslinking process. This external energy input provides precise and controllable activation of the crosslinking agents, simplifying process control compared to direct chemical addition or other activation methods, while achieving reliable wellbore strengthening.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This approach effectively strengthens the wellbore wall, reducing the need for casings, minimizing stability issues, and allowing deeper drilling by creating a durable filter cake through rapid and controlled polymerization, thereby extending casing intervals and reducing construction costs.

Implementation Method 1

irradiating at least part of the filter cake with microwave radiation so as to cause the chemical system to polymerise or cross-link

Methodology Applied

Scientific EffectMicrowave radiation: Microwave Radiation

Implementation Method 2

cause the chemical system to polymerise or cross-link and so strengthen the filter cake

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS8122950B2Microwave-based downhole activation method for wellbore consolidation applications

Publication Date: 2012.02.28 SCHLUMBERGER TECH CORP

AI summary

Wellbore strengthening during drilling may be achieved by including chemicals in the drilling fluid that can be polymerised when exposed to microwave energy. Selected chemicals are mixed with the drilling fluid but do not react with it. The chemicals concentrate in a filter cake on the borehole wall during drilling-fluid circulation. A tool, which comprises a microwave source, is used to trigger polymerisation or crosslinking reactions within the filter cake. The polymerisation or crosslinking reactions cause the formation of a film or gel that strengthens the wellbore.