Rotatable Plate Rig Safety Device for Catching Dropped Tubulars
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Solution Overview
Problem
During wellbore operations, tubulars often drop uncontrolled into the wellbore, leading to delays due to the hydraulic spider's inability to quickly catch and restrain them, resulting in extensive fishing operations.
Innovation Solution
A rig safety device featuring a rotatable plate with spring-loaded arms and rollers made of carbon steel, designed to catch dropped tubulars by interfering with a removable safety clamp, utilizing a coiled metal spring for bias and a rough textured surface to prevent rolling, allowing for controlled retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a hydraulic spider is used to restrain tubulars, then the tubulars can be supported during wellbore operations, but the hydraulic spider cannot quickly catch and restrain dropped tubulars
Solution Approach 1:
The arms are made movable rather than fixed, allowing them to dynamically respond to dropped tubulars. The arms can swing from a retracted position to an extended position to intercept falling tubulars, providing both rapid response and reliable restraint through mechanical motion rather than static structure
Solution Approach 2:
The arms are pre-positioned in a retracted state ready to deploy. When a tubular drops, the arms swing outward to catch it, performing the catching action in advance of the tubular reaching the wellbore bottom, thereby preventing loss without requiring complex active sensing or control systems
2Reliability
If rollers are used to contact the tubular, then the catching mechanism can effectively restrain the tubular, but the rollers may roll on smooth surfaces causing uncontrolled movement
Solution Approach 1:
The roller surfaces are given a specific local property (roughness) only where they contact the tubular. This localized surface treatment provides sufficient friction to prevent uncontrolled rolling while maintaining the roller's ability to effectively restrain the tubular through contact force
Solution Approach 2:
The surface characteristics of the rollers are modified by changing the roughness parameter. This parameter change increases the coefficient of friction between roller and tubular surface, transforming the roller behavior from slippery to grippable, thereby enabling controlled restraint without sacrificing effectiveness
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 device effectively catches dropped tubulars before they fall fully into the wellbore, preventing delays in operations and ensuring the components can withstand multiple drops.
Implementation Method 1
The arms are biased away from the passage
Implementation Method 2
A surface of the roller includes a rough texture
Data Source
AI summary
A rotatable plate is configured to be coupled to a rotary table of a rig floor. The rotatable plate defines a central passage through which a tubular can be passed. Multiple arms each have a first end rotably coupled to the rotatable plate. The arms are hinged such that a distal end of the arms, away from the rotatable plate, are configured to move towards or away from the passage. Each of arms extends away from the rotatable plate towards the passage. The arms are biased away from the passage. Rollers are rotably coupled to one of the distal ends of the arms.