Top Drive Main Shaft Segmentation for Maintenance Access

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Solution Overview

Problem

Existing top drive systems for drilling wellbores face challenges in efficiently managing load transfer and rotation of tubulars, particularly in maintaining a stable connection and efficient lubrication during drilling operations, which can lead to system downtime and maintenance issues.

Innovation Solution

The top drive apparatus incorporates a main shaft with a flow bore, a quill connected to a motor-driven gear system, a ring gear housing with a motor for rotating the link adapter, and a spool arranged about the main shaft, along with a spring cartridge apparatus to maintain a gap between the link adapter and load ring, allowing for selective locking or rotation of the link adapter and efficient load transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the main shaft is permanently connected to the gear system, then structural stability is improved, but maintenance complexity and downtime increase

Engineering Contradiction:
Improvestructural stabilityVSAvoidmaintenance complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The top drive apparatus is divided into separable modules: the main shaft can be disconnected from the gear system and removed independently. This segmentation allows the main shaft to be replaced or maintained without affecting the gear system, reducing maintenance downtime and complexity while maintaining structural stability during operation through secure coupling mechanisms.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the link adapter is continuously locked, then rotational stability is improved, but operational versatility deteriorates

Engineering Contradiction:
Improverotational stabilityVSAvoidoperational versatility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The link adapter incorporates a dynamic locking mechanism that can transition between locked and unlocked states based on operational requirements. During drilling operations, the link adapter is locked to provide rotational stability. During tripping or maintenance operations, it can be unlocked to allow rotation or disconnection, providing operational versatility without compromising stability when needed.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the spring cartridge maintains constant contact between link adapter and load ring, then load transfer efficiency is improved, but mechanical complexity increases

Engineering Contradiction:
Improveload transfer efficiencyVSAvoidmechanical complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The spring cartridge is pre-loaded to maintain a predetermined gap between the link adapter and load ring under normal operating conditions. This pre-cushioning allows the springs to absorb load variations and maintain efficient load transfer without requiring constant mechanical contact. The gap provides a buffer that simplifies the mechanical design while maintaining high load transfer efficiency through the spring mechanism.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2013436B1Top drive apparatus
Publication Date: 2012.02.15 NAT OILWELL VARCO LP
  • EP2013436B1 patent drawingFigure 1
  • EP2013436B1 patent drawingFigure 2A~2B
  • EP2013436B1 patent drawingFigure 2C~4

AI summary

A top drive apparatus for wellbore operations, the top drive apparatus comprising a main body (130), a main shaft (160) having a flow bore (163) therethrough for the passage of drilling fluid, a quill (190) surrounding at least part of the main shaft (160) and drivingly connected therewith, and a motor apparatus (120) for rotating the quill (190), characterized in that a gear system (146) is arranged between the motor apparatus (120) and the quill (190) to rotate the quill (190) and thereby drive the main shaft (160), the main shaft (160) passing through the gear system (146), the main shaft (160) removable from the main body (120) by disconnecting the main shaft (160) from the quill (190) and lifting the main shaft (160) from the quill (190).