Top Drive Elevator Support Decoupling for Drilling
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Solution Overview
Problem
Existing top drive well drilling installations face challenges in designing a robust elevator support system that is independent of the top drive unit, leading to complex and costly designs, and requires mechanisms to prevent pivotable arms from being entrained in rotary motion during drilling.
Innovation Solution
The elevator support assembly is designed as a direct drill string load-bearing connection between the elevator and the trolley, independent of the top drive unit, allowing for a detachable top drive unit and incorporating two pairs of pivotal elevator arms that can move between operative and parking positions, enabling efficient switching between different types of elevators and simplifying the design by removing the need for the top drive unit to support the elevator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the elevator is suspended from the rotatable tubular stem of the top drive unit, then the elevator can be positioned on the drill string axis, but the pivotable arms holding the elevator are entrained in the rotary motion of the tubular stem during drilling
Solution Approach 1:
The system is divided into independent functional segments: the top drive unit with its rotatable tubular stem for drilling operations, and the elevator support assembly with pivotable arms for elevator positioning. The elevator support assembly is suspended from the trolley rather than the top drive unit, creating functional independence that prevents rotational interference while maintaining positioning capability.
2Reliability
If the top drive unit is designed to support the elevator, then the elevator can be held during drilling operations, but the design becomes more complex and costly
Solution Approach 1:
The elevator support function is extracted from the top drive unit and transferred to the elevator support assembly, which is suspended from the trolley. This separation allows the top drive unit to be designed solely for drilling operations without the added complexity of supporting the elevator, while the elevator support assembly provides dedicated support capability through its pivotable arms and actuator system.
3Strength
If robust pivotable arms are designed to absorb the load of the entire drill string, then the elevator can be supported during tripping, but mechanisms are required to prevent the arms from being entrained in rotary motion
Solution Approach 1:
The trolley acts as an intermediary suspension point between the hoisting device and the elevator support assembly. The pivotable arms are connected to the trolley rather than the rotatable tubular stem, creating a mechanical decoupling that allows the arms to bear the full load of the drill string during tripping operations while being naturally protected from rotational entrainment by the independent suspension geometry.
Data Source
AI summary
A top drive well drilling installation comprising a drilling tower, vertical rails supported by the drilling tower, a trolley guided along said one or more vertical rails, and a hoisting device for moving the trolley up and down. The installation further comprises a tubular stem which is to be connected to the upper end of a drill string for rotation therewith about an axis of the drill string, and a top drive unit including a motor adapted to rotate the tubular stem and thereby the connected drill string to drill a well, wherein the top drive unit is supported by the trolley. Furthermore an elevator is provided which is adapted to—in an operative position—suspend the drill string, e.g. during tripping, and an elevator support assembly is provided which is adapted to absorb the load of the suspended drill string and adapted to move the elevator between an operative position on the drill string axis and a retracted position. According to the present invention, the elevator support assembly is embodied as a direct drill string load bearing connection between the elevator and the trolley, independent from the top drive unit.