Tapered Bowl Elevator Slips for Tubular Handling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing elevators used in oilfield operations face challenges in handling heavy tubular strings, particularly in deep sea applications, where slip-type elevators risk crushing the tubular due to excessive gripping force, and load-bushing-type elevators may fail under heavy loads, leading to higher make-up torques and potential damage.
Innovation Solution
The design of an elevator with a tapered bowl and movable slips featuring both radial and tapered engaging surfaces, which distribute the weight of the tubular string across a larger area, reducing the risk of damage and failure by applying frictional forces without marking the tubular.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If slip-type elevators are used to handle heavy tubular strings, then the gripping force increases to support the weight, but the tubular may be crushed or damaged due to excessive gripping force
Solution Approach 1:
The elevator system is divided into multiple slips (typically three or more) that distribute the gripping force around the tubular circumference. Each slip engages a portion of the tubular outer diameter, segmenting the total gripping force into multiple contact points. This segmentation prevents concentration of force at any single location, reducing the risk of tubular crushing while maintaining adequate total gripping force to support heavy tubular strings.
Solution Approach 2:
The engagement mechanism transitions from purely radial gripping force to a combination of radial and axial force components. The slips are configured with engagement surfaces that contact the tubular at angled orientations, introducing an axial dimension to the force application. This dimensional change allows the slips to grip the tubular more gently while still providing sufficient holding force through the combined vector components.
2Force
If load-bushing-type elevators are used to support heavy loads, then the weight capacity increases, but the upset or tool joint may fail under excessive load
Solution Approach 1:
The slips are designed with differentiated engagement surfaces: a first engagement surface contacts the tubular body at a location optimized for distributing load, while a second engagement surface contacts the tubular at a different location or orientation optimized for minimizing stress on the tool joint. This local quality differentiation allows the system to support heavy loads while protecting the vulnerable tool joint region from excessive stress concentration.
Solution Approach 2:
The slip configuration and engagement geometry are designed to cushion the load transmission path before it reaches the tool joint. The angled engagement surfaces and distributed contact points create a load-distributing mechanism that softens the impact of heavy weights on the tool joint, preventing sudden or concentrated loads that could cause failure.
3Force
If higher-grade tool joints are used to support heavy weights, then the load capacity increases, but the make-up torque increases presenting additional challenges
Solution Approach 1:
The slip-type elevator design serves multiple functions: it provides gripping force to support tubular weight, distributes load to prevent tool joint failure, and minimizes make-up torque requirements through its engagement geometry. By making the elevator system multi-functional, the solution addresses load capacity needs without requiring higher-grade tool joints that would increase make-up torque, thereby resolving the contradiction through a single integrated mechanism.
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
This solution effectively supports and lifts heavy tubular strings without causing damage, distributing the weight to prevent slipping or failure, while maintaining a non-marking engagement, thus enhancing safety and operational efficiency in oilfield operations.
Implementation Method 1
applying frictional forces without marking the tubular
Data Source
AI summary
An elevator, apparatus, and method for handling a tubular, of which the apparatus includes a body defining at least a portion of a tapered bowl. The apparatus also includes a plurality of slips disposed at least partially within the bowl and configured to slide along a surface of the bowl. Each of the slips includes a radial engaging surface configured to engage an outer diameter of a tubular, and a tapered engaging surface configured to engage a tapered section of the tubular.