Hydrostatic Tubular Lifting System for BOP Safety
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Solution Overview
Problem
There is a need for an apparatus and method to safely remove a tubular from a blowout preventer (BOP) stack without damaging the BOP, particularly in situations where lateral movement of the rig or riser occurs, requiring quick removal to prevent interference with blind rams during high-pressure operations in deep-water oil and gas production.
Innovation Solution
A tubular lifting system comprising an outer and inner tubular with an annular chamber and a tubular piston, where the tubular piston is selectively movable to lift the wellbore tubular, utilizing a pressure differential between the hydrostatic pressure in the riser and the annular chamber to facilitate the lifting of the tubular portion severed from the BOP, with retaining members to ensure the piston remains in the retracted position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tubular is quickly removed from the BOP to prevent damage during lateral movement, then the reliability of the BOP is improved, but the device complexity increases due to the need for specialized lifting apparatus
Solution Approach 1:
The lifting system employs nested tubular structures where the inner tubular is disposed within the outer tubular, creating a compact integrated assembly that can be quickly deployed to remove severed tubular sections from the BOP while maintaining system reliability
Solution Approach 2:
The tubular piston acts as an intermediary mechanism between the hydraulic pressure system and the severed tubular, transferring force to lift the tubular out of the BOP without direct mechanical intervention, thus improving reliability while managing complexity
2Speed
If a tubular piston is used to lift the severed tubular, then the speed of removal is improved, but the device complexity increases due to additional moving parts
Solution Approach 1:
The tubular piston is actuated by hydraulic pressure applied through the annular chamber, enabling rapid vertical movement to lift the severed tubular from the BOP at high speed without complex mechanical actuation mechanisms
Solution Approach 2:
The piston mechanism transforms the static tubular structure into a dynamic lifting system where the piston can selectively move between retracted and extended positions to quickly remove the tubular when needed
3Force
If the piston surface area is increased to improve lifting force, then the lifting capability is improved, but the device complexity increases due to asymmetric piston design
Solution Approach 1:
The piston is designed with non-uniform cross-sectional areas where the first portion has a larger surface area than the second portion, concentrating the lifting force where needed while maintaining structural integrity and managing overall complexity
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 system effectively lifts the severed tubular portion out of the BOP, preventing damage and allowing the BOP to close safely, thereby enabling safe operation during lateral movements of the rig or riser.
Implementation Method 1
utilizing a pressure differential between the hydrostatic pressure in the riser and the annular chamber to facilitate the lifting of the tubular portion severed from the BOP
Data Source
AI summary
In one embodiment, a tubular lifting system for lifting a wellbore tubular includes an outer tubular; an inner tubular disposed in the outer tubular; an annular chamber defined between the inner tubular and the outer tubular; and a tubular piston selectively movable in the annular chamber, wherein the wellbore tubular is connected to the tubular piston and movable thereby.