Sealing Collar for Subterranean Rock Sample Simulation

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Solution Overview

Problem

In simulating subterranean drilling processes, the existing methods fail to prevent drilling fluid from traversing the rock sample/end cap interface, leading to unintended stress distribution and potential rupture of the impermeable sleeve, especially when simulating depleted formations where wellbore pressure exceeds the compressive axial stresses.

Innovation Solution

A sealing collar of complementary geometry is inserted and adhesively bonded into a cut-out cavity in the rock sample, spanning the rock sample/end cap interface and sealed with a suitable sealing element to prevent fluid flow, ensuring the integrity of the rock sample and end cap contact under increased pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wellbore pressure is raised to exceed compressive axial stresses to simulate depleted formations, then the simulation accuracy for depleted formations is improved, but the end caps separate from the rock sample causing fluid leakage

Engineering Contradiction:

Improvesimulation accuracyVSAvoidinterface integrity

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The end cap is segmented into two functional parts: a load application portion that maintains contact with the rock sample under compression, and a sealing collar portion that protrudes into the wellbore to prevent fluid leakage. This segmentation allows each part to specialize in its function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A sealing collar acts as an intermediary element between the end cap and the rock sample interface. This collar protrudes into the wellbore space and creates a fluid barrier that prevents drilling fluid from traversing the interface, while allowing the load application portion to maintain mechanical contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If vertical stress is increased to prevent end cap separation, then the interface integrity is improved, but the stress distribution on the rock sample becomes excessive and detrimental

Engineering Contradiction:

Improveinterface integrityVSAvoidvertical stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The sealing function is segregated from the load application function. The sealing collar handles fluid prevention while the end cap handles mechanical loading, allowing the minimum necessary stress to be applied without excessive vertical stress.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The high wellbore pressure that would normally cause end cap separation is converted into a beneficial sealing force. The sealing collar utilizes the pressure differential to press against the rock sample interface, turning the harmful separation tendency into a beneficial sealing mechanism.

Inventive Principle:

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

3Measurement precision

If drilling fluid pressure exceeds compressive axial stresses, then the simulation of depleted formations is more accurate, but fluid flows across the interface into the sleeve space causing sleeve inflation or rupture

Engineering Contradiction:

Improvesimulation accuracyVSAvoidfluid flow

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sealing collar serves as an intermediary barrier between the high-pressure wellbore environment and the sleeve space. It prevents fluid from traversing the rock sample interface while allowing the high-pressure simulation conditions to be maintained.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing collar creates a flexible fluid barrier at the interface that can accommodate pressure differentials and minor movements while maintaining the seal, preventing fluid from reaching the sleeve and causing inflation or rupture.

Inventive Principle:

Principle #30Flexible shells and thin films

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 configuration effectively prevents fluid flow between the rock sample and end cap, allowing for accurate simulation of drilling in depleted formations without premature termination due to sleeve inflation or rupture, enabling a wider range of testing scenarios by maintaining desired stress distribution.

Implementation Method 1

A suitable sealing element is disposed between the walls of the aperture in the end cap and the impermeable collar

Methodology Applied

Scientific EffectMechanical sealing:

Implementation Method 2

An impermeable collar of a complementary geometry is inserted and adhesively bonded into the cut-out cavity in the rock sample

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentUS10133832B2System and methodology for subterranean process simulation

Publication Date: 2018.11.20 SCHLUMBERGER TECH CORP

AI summary

A technique enables simulation of a process performed on an underground formation. The technique comprises forming a cut-out portion in a rock sample and placing a jacket around the rock sample. A sealing collar is inserted into the cut-out portion, and the rock sample is capped between the sealing collar and the jacket. Simulation testing can then be performed on the rock sample through the sealing collar while applying pressure to the rock sample. The sealing collar may be affixed in the cut-out portion.