Well Safety Valve Shearing Tool Joints Under Compound Stress
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Solution Overview
Problem
Existing blow-out preventers (BOPs) have limitations in shearing drill pipes, particularly under conditions of compound stresses at the wellhead, leading to incomplete or blocked shearing operations that prevent well closure.
Innovation Solution
A safety valve with a cutting shutter and cutting inserts of higher hardness, capable of shearing a wide range of tubular elements, including casings, drill pipes, and tool joints, under various stress conditions, and featuring a hydraulic seal for well closure and subsequent reopening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional BOPs are used to shear drill pipes, then the well can be closed under normal conditions, but the shearing capacity is limited and cannot handle tool joints with thickness and diameter greater than the pipes themselves
Solution Approach 1:
The patent changes the geometric parameters of the cutting elements, specifically increasing the diameter and thickness of the cutting shutter to 12-24 inches and 4-8 inches respectively, enabling it to shear tool joints with greater dimensions than conventional BOPs can handle
Solution Approach 2:
The cutting shutter is divided into multiple segments or blocks that can be arranged in different configurations, allowing the valve to adapt to different tool joint sizes and provide versatile shearing capacity across various well conditions
2Reliability
If shear rams are used to induce shear stresses on tubular materials, then the pipe can be sheared to achieve closure, but the cutting action requires complete crushing of the section which only occurs in the central part of the pipe
Solution Approach 1:
The cutting inserts are pre-positioned on the cutting shutter to engage the tubular material before the shutter reaches the central position, initiating the shearing process early and ensuring complete separation throughout the entire tool joint length, not just at the center
Solution Approach 2:
The patent introduces a longitudinal dimension to the cutting action by extending the cutting inserts along the length of the tool joint, transforming the shearing process from a point-based central cut to a distributed multi-point cut along the entire joint length
3Reliability
If traditional cutting elements are used in BOPs, then the well can be closed under certain conditions, but metallic projections from incomplete shearing can become trapped blocking the stroke of cutting elements and preventing well closure
Solution Approach 1:
The cutting inserts are designed with replaceable modular sections that can be easily replaced if damaged or contaminated by metallic projections, converting the potential harm of blocking into a simple maintenance operation rather than a system failure
Solution Approach 2:
The cutting shutter is designed with increased dimensional parameters and a U-shaped through opening that provides clearance space, allowing metallic projections to pass through or be accommodated without blocking the stroke of the cutting elements
4Reliability
If BOPs are installed redundantly to ensure effective intervention, then safety is improved, but the device complexity and cost increase
Solution Approach 1:
The safety valve is designed as a multi-functional device that can perform shearing, centering, and closing operations with a single integrated structure, replacing the need for multiple separate BOP devices and reducing overall system complexity while maintaining redundant safety capabilities
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 safety valve effectively shears tubular elements even under critical conditions, ensuring well closure with a hydraulic seal and allowing for subsequent reopening, thereby overcoming the limitations of conventional BOPs.
Implementation Method 1
the cutting shutter (2) comprises cutting inserts (28, 29) in a material of higher hardness than that of the cutting shutter (2)
Implementation Method 2
closing the well with a hydraulic seal
Data Source
AI summary
A safety valve for wells for the extraction of hydrocarbons is described which allows the cutting of the tubular drilling material possibly present in the safety valve and the closure of the well with a hydraulic seal, allowing the subsequent application of appropriate intervention plans to control the well in case the BOPs are not effective. A safety valve for wells for the extraction of hydrocarbons is described which is able to perform the action of cutting the tubular material with a higher capacity than conventional BOPs, considering the worst conditions of compound stresses at the wellhead, which are not contemplated by such BOPs today. In particular, the safety valve is capable of cutting/shearing a wide range of tubular elements in its inside.