Remotely Controlled Drilling Tool for Subsea Flowline Hydrate Blockage Removal
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Solution Overview
Problem
Subsea flowlines often become blocked by gas hydrates, wax, mineral scale, or corrosion products, restricting or preventing the flow of multiphase fluids due to temperature and pressure conditions, and existing methods are inadequate for effectively addressing these blockages.
Innovation Solution
A remotely controlled electrically operated drilling tool with a drill bit, steering means, and propulsion system is introduced into the flowline to locate and drill through blockages, using the fluid to transport cuttings away from the drill bit, and optionally employing heating elements or lasers to prevent re-formation of hydrates or wax.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods (chemical injection, thermal heating, mechanical pigging) are used to remove blockages, then some blockages can be addressed, but they are inadequate for effectively addressing hydrate blockages in subsea flowlines
Solution Approach 1:
The patent replaces conventional mechanical pigging and chemical injection methods with a remotely controlled electrically operated drilling tool that uses a drill bit to mechanically drill through hydrate blockages. This substitution provides more effective blockage removal capability while maintaining operational simplicity through remote control.
Solution Approach 2:
The patent introduces an intermediary drilling tool equipped with a drill bit, steering means, and propulsion system that can be remotely controlled to drill through hydrate blockages. This intermediary device enables effective blockage removal without requiring complex conventional methods.
2Reliability
If a drilling tool is introduced into the flowline to drill through blockages, then pressure communication can be established, but the flowline may become damaged
Solution Approach 1:
The patent applies local quality by using a drill bit with specific cutting surfaces designed to drill through hydrate blockages while minimizing damage to the flowline. The steering means directs the drill bit precisely at the blockage location, and the propulsion system provides controlled movement, ensuring the drilling action is localized to the blockage area rather than damaging the entire flowline.
Solution Approach 2:
The patent incorporates feedback mechanisms through the steering means and propulsion system that allow real-time monitoring and adjustment of the drilling tool's position and movement. This feedback control ensures the drill bit engages with the blockage at the correct orientation and maintains controlled advancement, preventing excessive force that could damage the flowline.
3Reliability
If heating elements or lasers are used to prevent re-formation of hydrates or wax, then re-formation can be prevented, but energy consumption increases
Solution Approach 1:
The patent applies preliminary action by using heating elements or lasers to prevent re-formation of hydrates or wax immediately after drilling through the blockage. The heating action is applied proactively to the freshly drilled area to ensure the blockage does not re-form, providing preventive protection rather than reactive treatment.
Solution Approach 2:
The patent changes physical parameters by applying thermal energy through heating elements or lasers to alter the temperature of the flowline interior surface immediately after drilling. This parameter change (temperature increase) prevents the re-formation of hydrates or wax by maintaining conditions below the formation temperature, while the energy is applied locally and temporarily rather than continuously.
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 method effectively establishes pressure communication through blockages, removes deposits from the flowline walls, and prevents re-formation of hydrates or wax, ensuring the flowline can be re-started with minimal risk of further blockages.
Implementation Method 1
actuating the electrically operated drill bit so that the drill bit engages with and drills through the blockage
Implementation Method 2
actuating the electrically operated pump so that when the drill bit engages with the blockage, fluid that is present in the flowline adjacent the blockage is passed over the cutting surfaces of the drill bit and cuttings from the blockage are transported away from the cutting surfaces of the drill bit suspended in the fluid
Implementation Method 3
optionally employing heating elements or lasers to prevent re-formation of hydrates or wax
Data Source
Figure 1
AI summary
A method of drilling through a blockage in a flowline using a remotely controlled electrically operated drilling tool that comprises a drill bit, a steering means, a pumping means, and a propulsion system wherein the drilling tool is connected either directly or indirectly to an electric cable and the drill bit is mounted on the steering means, the method comprising: introducing the drilling tool into the flowline; actuating the electrically operated propulsion system to move the drilling tool through the flowline to the location of the blockage; actuating the electrically operated steering means so that the drill bit is aligned with the blockage; actuating the electrically operated drill bit so that the drill bit engages with and drills through the blockage; and actuating the electrically operated pump so that when the drill bit engages with the blockage, fluid that is present in the flowline adjacent the blockage is passed over the cutting surfaces of the drill bit and cuttings from the blockage are transported away from the cutting surfaces of the drill bit suspended in the fluid.