Coring Shaft Static Sleeve Layout for Fragile Core Recovery

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Solution Overview

Problem

Mechanical sidewall coring tools face challenges in recovering fragile or friable core samples due to damage during extraction, with issues like core cutting, extraction, and deposition, and inefficient removal of cuttings leading to reduced core recovery and tool degradation.

Innovation Solution

The sidewall coring tool assembly includes a coring shaft with scoops and a static sleeve, along with features like cutting pads, passage areas, and scoops to facilitate the directed flow of drilling mud and cuttings, reducing parasitic torque and enhancing core extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If mechanical sidewall coring tools are used to extract core samples from fragile formations, then core extraction is achieved, but core damage occurs during cutting, extraction, and deposition

Engineering Contradiction:

Improvecore recoveryVSAvoidcore integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The coring tool is divided into separate functional modules: a coring bit for cutting, a coring shaft for extraction, and a core catcher for deposition. This segmentation allows each component to be optimized independently, with the coring shaft designed to minimize damage during extraction while the core catcher provides a safe deposition zone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The core catcher is positioned to receive the core sample before it is fully extracted from the formation, providing a cushioning effect that prevents damage during the extraction process. The gradual transition from the coring shaft to the core catcher minimizes mechanical stress on the fragile core.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If cuttings are not efficiently removed from the coring shaft, then core cutting time increases, but tool wear increases due to rubbing action

Engineering Contradiction:

Improvecore cutting speedVSAvoidtool service life

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

Scoops are added to the coring shaft that actively extract and remove cuttings from the internal diameter during rotation. This continuous removal prevents cuttings accumulation, reduces parasitic torque, and eliminates the rubbing action that would otherwise increase tool wear.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The scoops operate continuously during coring operations, maintaining a constant flow of cuttings removal. This continuous action ensures that the coring shaft internal diameter remains clear throughout the operation, preventing the buildup that would lead to increased tool wear and reduced cutting efficiency.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If a core catcher ring rotates with the coring bit, then core cutting is facilitated, but unevacuated debris causes grinding action on the core

Engineering Contradiction:

Improvecore cutting efficiencyVSAvoidcore damage from debris

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Instead of having the core catcher rotate with the coring bit, the design inverts this approach by having the core catcher remain stationary or rotate independently. The scoops on the coring shaft perform the cutting action while the core catcher provides a protected deposition zone, eliminating the grinding action caused by debris accumulation during rotation.

Inventive Principle:

Principle #13The other way round (Inversion)

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 solution provides effective core recovery by minimizing cutting and extraction damage, improving core extraction efficiency, and reducing tool wear by facilitating the directed flow of cuttings and cooling the coring bit, thereby enhancing drilling performance.

Implementation Method 1

scoops to facilitate the directed flow of drilling mud and cuttings

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

cooling the coring bit, thereby enhancing drilling performance

Methodology Applied

Scientific EffectCooling: Cooling

Data Source

PatentUS20260036046A1Coring tools having coring shafts with associated internal static sleeves

Publication Date: 2026.02.05 SCHLUMBERGER TECH CORP

AI summary

The systems and methods presented herein include a sidewall coring tool assembly that includes a coring shaft having an internal cavity and configured to be coupled to a coring motor shaft of a coring motor at a first axial end of the coring shaft. The coring shaft includes a plurality of scoops disposed circumferentially on a first external surface of the coring shaft. Each scoop of the plurality of scoops forms a conduit from an exterior of the coring shaft to an interior of the coring shaft. The sidewall coring tool assembly also includes a coring bit coupled to the coring shaft at a second axial end of the coring shaft. The sidewall coring tool assembly further includes a static sleeve coupled to the coring motor and disposed radially within the internal cavity of the coring shaft.