Core Catcher Membranes for Unconsolidated Sediment Sampling

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Solution Overview

Problem

Conventional coring methods, especially sidewall coring, face challenges in sampling unconsolidated sediments as they often disturb the sediment, result in small sample sizes, and struggle to retain core samples due to limited space and frictional forces, leading to incomplete or lost data in geological formations.

Innovation Solution

A core sampler with membranes and metal wires that facilitate cutting and separating sediments, providing a bottom seal to preserve in-situ fluids, and a method involving a rotating mechanism to collect and retain core samples without disturbing the sediment, using flexible and durable materials like acetate cellulose or polycarbonate films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If sidewall coring is used to sample unconsolidated sediments, then the sampling process can be performed in limited borehole space, but the sediment is disturbed and sample integrity is compromised

Engineering Contradiction:
Improveborehole spaceVSAvoidsediment integrity
Core Design Contradiction:
Area of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent employs flexible membranes made of materials like acetate cellulose or polycarbonate film that can conform to unconsolidated sediment surfaces without disturbing them. These thin films are inserted into the borehole and allowed to wrap around the sediment, capturing the sample in its natural state while adapting to the limited borehole space.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The core catcher incorporates a rotating mechanism that allows the membranes to dynamically adjust and wrap around the sediment sample. This dynamic action enables the membranes to conform to the sediment shape and secure the sample without applying excessive force that would disturb the unconsolidated material.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If conventional coring methods are used, then core samples can be obtained from the formation, but the sample size is limited and retention is difficult due to limited frictional forces

Engineering Contradiction:
Improvecore sample sizeVSAvoidsample retention
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The flexible membranes envelop the core sample completely, providing continuous contact and retention surface area. This allows larger sample quantities to be retained reliably without depending on frictional forces alone, as the membranes physically constrain the sample within the core catcher structure.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention transitions from relying on one-dimensional frictional forces at the coring bit interface to three-dimensional mechanical constraint through the membrane enclosure. The membranes provide retention in multiple directions, significantly improving sample security for larger core samples.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the coring bit is tilted to fracture the core sample for removal, then the sample can be detached from the formation, but the lower part of the sediment core is disturbed and partly lost

Engineering Contradiction:
Improvesample removalVSAvoidcore sample integrity
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The flexible membranes are inserted into the borehole before coring and positioned to wrap around the sample in situ. This extracts the sampling function from the coring bit itself, allowing the sample to be captured intact by the membranes without requiring tilting or fracturing actions that would disturb the core.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The membranes are deployed and positioned around the target sediment zone before the coring operation begins. This preliminary positioning ensures that when the core is formed, it is already enclosed by the membranes, eliminating the need for subsequent tilting or fracturing to retrieve the sample.

Inventive Principle:
Principle #10Preliminary action

4Area of stationary object

If sidewall coring is performed with small sample sizes, then the limited borehole space is utilized, but there is insufficient frictional force to remove the sample by simple withdrawal

Engineering Contradiction:
Improveborehole space utilizationVSAvoidfrictional force
Core Design Contradiction:
Area of stationary objectVSForce

Solution Approach 1:

The flexible membranes provide a large surface area in contact with the sample relative to the small borehole diameter. This increases the available frictional and adhesive forces between the membrane and sample, enabling secure retention and controlled removal even in tightly constrained borehole spaces.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The core catcher combines flexible membrane materials with rigid structural elements to create a composite system. The membranes provide flexible contact and retention surfaces, while the rigid framework maintains structural integrity and provides mechanical advantage for sample removal without requiring excessive frictional forces.

Inventive Principle:
Principle #40Composite materials

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

Enables undisturbed sampling of unconsolidated sediments, maintaining sample integrity and fluid preservation, and effectively collecting larger core samples with improved retention, addressing the limitations of conventional coring methods.

Implementation Method 1

The membranes hold both the sediment and part of any fluids in the sampler

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 2

The metal wires facilitate cutting through sediments once the coring/sampling has been finished, and separate the sediments inside and outside of the corer

Methodology Applied
Scientific EffectMechanical cutting: Mechanical Force

Implementation Method 3

a rotating mechanism to collect and retain core samples without disturbing the sediment

Methodology Applied
Scientific EffectMechanical rotation: Friction

Data Source

PatentEP3737829B1Core catcher for unconsolidated sediment samples
Publication Date: 2022.03.02 SAUDI ARABIAN OIL CO
  • EP3737829B1 patent drawingFigure 1A~1B
  • EP3737829B1 patent drawingFigure 2A~2B
  • EP3737829B1 patent drawingFigure 3A~3B

AI summary

A core sampler including an inner wall, an outer wall, a plurality of membranes disposed between the inner wall and outer wall, the plurality of membranes attached to the inner wall and outer wall at one or more attachment points, and a rotating knob attached to the inner wall or outer wall, the rotating knob configured to rotate the inner wall relative to the outer wall when the rotating knob is attached to the inner wall and to rotate the outer wall relative to the inner wall when the rotating knob is attached to the outer wall, wherein the membranes reside between the inner wall and the outer wall when the core sampler is fully open, and wherein the membranes come together and fully close the core sampler when the rotating knob is rotated 180 degrees or more.