Energetics Device for Cement Sheath Leak Sealing

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Solution Overview

Problem

Small cracks (microcavities) in the cement sheath surrounding wellbore tubulars lead to unacceptable surface casing vent flow, which existing tools like hydraulic expanders struggle to effectively seal, especially in smaller diameters and require significant maintenance.

Innovation Solution

An energetics device is used to create a 360° outwardly directed pressure wave within the wellbore tubular, causing plastic deformation and forming a circumferential recess that forces the outer surface into the cement sheath, sealing microcavities and micro annuli.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic expanders are used to seal microcavities in cement sheath, then sealing capability is improved, but device complexity and maintenance requirements increase

Engineering Contradiction:

Improvesealing capabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the essential function of local expansion from complex hydraulic机械设备 and implements it through a simple explosive charge. The explosive charge is placed directly against the wellbore tubular at the target location, eliminating the need for hydraulic actuators, control systems, and mechanical expansion segments, while achieving the same sealing effect through controlled plastic deformation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical hydraulic expansion system with a chemical energy-based explosive system. Instead of using hydraulic pressure to mechanically expand the tubular, the invention uses the rapid gas expansion from detonation to create the same plastic deformation effect, simplifying the device architecture significantly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If hydraulic expanders are used to seal microcavities, then sealing effectiveness is improved, but ease of operation deteriorates due to maintenance requirements

Engineering Contradiction:

Improvesealing effectivenessVSAvoidease of operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invention employs a disposable explosive charge that is set, detonated, and discarded. This eliminates the need for maintenance of complex hydraulic systems, as the explosive device requires no servicing, calibration, or repair. The simplicity of the disposable nature dramatically improves ease of operation while maintaining sealing effectiveness.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Object-affected harmful factors

If local expansion is applied to seal microcavities, then leak rate reduction is achieved, but energy consumption increases

Engineering Contradiction:

Improveleak rateVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The invention uses a pulsed energy delivery method through controlled detonation. Instead of continuous energy input from hydraulic systems, the explosive charge delivers a concentrated burst of energy in milliseconds, creating the necessary plastic deformation and seal. This periodic, impulsive energy application is more efficient than continuous hydraulic pressure maintenance.

Inventive Principle:

Principle #19Periodic action

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 method drastically reduces leak rates through the cement-filled annulus, is more effective than hydraulic expanders, and requires less capital investment due to smaller, disposable energetics tools, maintaining well integrity and preventing surface casing vent flow.

Implementation Method 1

detonating the at least one charge to create an outwardly directed pressure wave over a full 360 radiation angle in a plane transverse to a longitudinal axis of the wellbore tubular

Methodology Applied

Scientific EffectPressure wave: Shock Wave

Implementation Method 2

plastically deforming the wellbore tubular with the pressure wave at the selected depth thereby forming a circumferential recess into an inner surface of the wellbore tubular

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

forcing the outer surface of the wellbore tubular at the selected depth into the surrounding cement sheath

Methodology Applied

Scientific EffectImpact force: Impact Force

Data Source

PatentEP3824157B1Method of remediating leaks in a cement sheath surrounding a wellbore tubular

Publication Date: 2022.11.16 SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV

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AI summary

An energetics device is employed to create an outwardly directed pressure wave at a selected depth within a wellbore tubular cemented into a wellbore. The pressure wave causes the wellbore tubular to plastically deform at the selected depth. This locally expands the wellbore tubular at the selected depth, whereby a circumferential recess is created into an inner surface of the wellbore tubular and whereby the outer surface of the wellbore tubular is forced into the surrounding cement sheath at the selected depth. Microcavities and/or micro annuli in the impacted zone may be sealed as a result.