Drill String Vibration Simulation Device for Deepwater Riser-Free Drilling
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Solution Overview
Problem
There is a lack of a testing system to simulate the longitudinal-transverse-torsional coupled vibration responses of a drill string in riser-free offshore drilling under varying conditions such as rotating speeds, ocean flow rates, drilling fluid flow rates, and torsional and longitudinal excitations.
Innovation Solution
A testing device comprising a pool, motor, hook load adjustment device, vibration exciter, displacement sensors, strain gauges, and a computer system that simulates these conditions by adjusting drilling fluid flow, load, and platform movement to measure and record longitudinal and transverse displacements and stress responses of a plastic tube mimicking a drill string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional drilling with a riser system is used, then the drilling operation can be performed in deep water, but the system becomes increasingly complex and costly with water depth, and the formation pressure window becomes excessively narrow
Solution Approach 1:
The invention extracts and removes the riser system from the deep-water drilling configuration, replacing it with a riser-free drilling approach that uses a drill string extending directly from the platform to the wellbore, thereby eliminating the complex riser, tensioner, and associated systems while maintaining deep-water capability
Solution Approach 2:
The invention segments the drilling system into distinct functional components: the drill string for wellbore access, the dual-gradient mud circulation system for pressure control, and the platform system for support, allowing each segment to be optimized independently without the constraints of a integrated riser system
2Temperature
If a riser system is used in conventional drilling, then deep-water drilling is enabled, but the platform carrying capacity and mooring system requirements increase significantly
Solution Approach 1:
The invention extracts the heavy riser system and its associated tensioning and mooring requirements from the platform load, reducing the moving weight that the platform must support while maintaining deep-water drilling capability through the simplified drill string configuration
3Temperature
If a riser system is used in conventional drilling, then drilling operations can be performed, but the usage amount of casing becomes excessively large
Solution Approach 1:
The invention extracts the need for extensive casing usage by eliminating the riser system that would require additional casing strings for suspension and pressure control, reducing the total quantity of casing required while maintaining wellbore integrity in deep water
4Force
If wave forces act on the platform causing heave motion, then the axial tension of the riser changes with time, but this leads to parametric resonance and large transverse vibration causing damage
Solution Approach 1:
The invention extracts the riser from the system, eliminating the mechanism by which platform heave motion translates into parametric resonance and transverse vibration, thereby preventing the reliability issues associated with riser fatigue and failure while retaining the ability to perform deep-water drilling operations
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
Enables the simulation and measurement of longitudinal-transverse-torsional coupled vibration responses of a drill string under different operating conditions, providing insights into dynamics, stability, and vortex-induced vibrations, thus aiding in the structural design and optimization of deep-water drilling systems.
Implementation Method 1
a circulating pump (17), and a flowmeter (16) are connected to the other end of the drilling fluid inlet tube (15) in sequence
Implementation Method 2
a vibration exciter (11) is fixed on the left extension end
Implementation Method 3
torsional excitations and longitudinal excitations at the bottom of the formation section
Implementation Method 4
the right extension end is connected with an output shaft of the motor (2) through a coupling
Implementation Method 5
the hook load adjustment device (3)... simulate the vibrations by controlling drilling fluid flow, platform movement, and torsional excitations
Implementation Method 6
a three-way displacement sensor (18), a computer (19), a resistance strain gauge (20), a charge amplifier (21), a signal acquisition instrument (22) and a plurality of strain foils (23)
Implementation Method 7
the strain foils (23) are connected to the resistance strain gauge (20) through a signal line B (25)
Implementation Method 8
when the ocean current flows around the riser, the vortex shedding will occur to generate a vortex exciting force on the riser
Data Source
AI summary
The present invention discloses a testing device and method for simulating longitudinal-transverse-torsional coupled nonlinear vibration of a drill string in deep-water riser-free drilling. The testing device comprises a pool (1), a motor (2) and a hook load adjustment device (3), wherein a guide wheel (4) is provided on the top of the pool (1); a support seat A (5) and a support seat B (6) are fixed on the bottom surface of the pool (1); an organic glass tube (8) is fixed between the support seat A (5) and the support seat B (6); a casing (9) is respectively provided on the top surface of the support seat B (6) and the top surface of the trailer (7); the left end of the plastic tube (10) extends into the organic glass tube (8) along the axis of the organic glass tube (8). The present invention further discloses a simulation method. The present invention has the following beneficial effects: the structure is compact; the longitudinal-transverse-torsion coupled vibration responses of the drill string under different rotating speeds of the drill string, ocean flow rates, flow rates of the drilling fluid, torsional excitations and longitudinal excitations at the bottom of the formation section is simulated, thereby filling up the blank in the riser-free drilling system.