Hydraulic Release Module for Pipe String Suspension
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Solution Overview
Problem
Existing heave compensator systems in floating installations can lead to overloading or failure, causing pipe strings to become loose and potentially hazardous, as they do not effectively manage vertical motion induced by waves or currents, resulting in components falling and posing a risk to personnel.
Innovation Solution
The implementation of a release module with multiple single-acting hydraulic cylinder units connected between a load-bearing, heave-compensated unit and a pipe string, utilizing a pressure accumulator and safety valve system to regulate hydraulic pressure, prevent overloading, and ensure the pipe string remains stationary relative to the well during heave motion, while a mechanical piston lock secures the pipe string in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a weak link with shear pin device is used to prevent pipe string breaking, then the pipe string is protected from breaking, but heavy components may come loose and fall down on the deck hurting personnel
Solution Approach 1:
A controlled weak link mechanism is introduced as an intermediary between the pipe string and top drive. This weak link is designed to fail in a controlled manner at a predetermined load, redirecting the failure mode from uncontrolled component detachment to a controlled release mechanism that directs debris away from personnel areas while still protecting the pipe string from breaking
Solution Approach 2:
The potential harm of component failure is converted into a beneficial controlled release mechanism. The weak link is intentionally designed to fail first, but its failure mode is engineered to be safe - the controlled breakage prevents more catastrophic pipe string failure while directing debris in a safe manner, thus converting the harmful aspect of component failure into a protective function
2Strength
If rigid suspension links are used to suspend the workover riser, then the connection is strong and stable, but the system cannot accommodate heave motion without transferring stress to the pipe string
Solution Approach 1:
The suspension system transitions from rigid to dynamic by introducing hydraulic cylinder units with movable pistons. These cylinders allow relative motion between the top drive and pipe string, absorbing heave-induced stresses through controlled piston movement while maintaining strong connection when needed. The system dynamically adapts its rigidity based on operational conditions
Solution Approach 2:
The mechanical properties of the suspension connection are changed by introducing hydraulic elements. The hydraulic cylinders provide variable stiffness and damping characteristics, allowing the system to change its mechanical parameters in response to heave motion, thereby maintaining strength while accommodating motion and reducing stress transmission to the pipe string
3Reliability
If the heave compensator moves with the rig, then it effectively compensates for heave motion, but the pipe string may become overloaded or buckled during sudden pressure changes
Solution Approach 1:
A feedback control system is implemented through the hydraulic circuit connecting the compensator to the cylinder units. Pressure sensors and control valves monitor the state of the pipe string and adjust the hydraulic pressure in the cylinders accordingly, providing active feedback control that prevents overloading and buckling while maintaining effective heave compensation
Solution Approach 2:
The hydraulic cylinder units act as cushioning elements that are pre-positioned to absorb sudden pressure changes and load variations. The hydraulic fluid and accumulators in the circuit provide beforehand cushioning by storing energy and providing damping, preventing shock loads from reaching the pipe string while maintaining the compensator's 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
This solution effectively manages heave motion-induced stress on pipe strings, preventing overloading and buckling, ensuring the pipe string remains stationary and secure, thereby reducing the risk of components falling and enhancing safety by allowing the top drive to move relative to the pipe string within the hydraulic cylinder's stroke.
Implementation Method 1
A hydraulic pressure through a fluid port in said downward facing cylinder end causes a cylinder piston to pull the piston rod into the cylinder
Implementation Method 2
The pressure accumulator is preferably provided as a lengthy, cylindrical body, alternatively several cylindrical bodies connected in parallel by means of an accumulator manifold
Implementation Method 3
The safety valve is arranged to be able to hold the hydraulic fluid circuit closed, i.e. close for fluid communication between the hydraulic cylinder unit and the accumulator unit as long as the pressure in the hydraulic cylinder unit is within defined limits. If the pressure exceeds said limit, the safety valve opens
Implementation Method 4
two or more hydraulic cylinder units form an extendable connection between the heave compensated, load bearing unit and a portion of the pipe string
Implementation Method 5
A hydraulic pressure through a fluid port in said downward facing cylinder end causes a cylinder piston to pull the piston rod into the cylinder
Implementation Method 6
a mechanical piston lock secures the pipe string in place
Data Source
AI summary
A device is for a release module for attaching a pipe string to a heave compensated, load bearing unit arranged on a floating installation, where two or more hydraulic cylinder units form an extendable connection between the heave compensated, load bearing unit and a portion of the pipe string.