Segmented Heat Exchange for Well Fluid Wax Stabilization
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Solution Overview
Problem
Existing methods for preventing wax deposition in pipelines during long-distance oil and gas transport, such as the cold flow technique, face issues like re-deposition of melted wax, frequent and prolonged heating requirements, and the need for significant conditioner sections, leading to potential blockages and logistical challenges.
Innovation Solution
A system of multiple heat exchange devices arranged in series, where each device alternates between cooling to deposit wax on the pipe wall and heating to release stabilized wax into the fluid, ensuring continuous stabilization and reducing re-deposition, with operational phases controlled to maintain efficient wax management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cold flow technique is used to prevent wax deposition by cooling the fluid and allowing wax to form on the pipe wall, then wax deposits can be released into the fluid, but some melted wax may re-mix with the oil and eventually deposit downstream
Solution Approach 1:
The patent divides the single conditioner section into multiple separate heat exchange devices arranged in series. Each device independently performs cooling and wax deposition, allowing the system to process fluid through multiple stages rather than one long section, thereby improving wax management effectiveness
Solution Approach 2:
The patent introduces a heating device as an intermediary between the cooling devices and the transport pipeline. This heating device stabilizes the wax by melting and re-freezing it, creating a stable wax structure that prevents re-deposition downstream, thus acting as a mediator that transforms unstable wax into stable wax
2Reliability
If heating is applied frequently and for prolonged periods to release stabilized wax, then wax can be effectively removed from the wall, but the pipeline fluid will not be subjected to cooling and wax may deposit downstream
Solution Approach 1:
The patent implements periodic alternating operation between cooling phase (where multiple devices cool and deposit wax) and heating phase (where one device heats to release and stabilize wax). This periodic cycle ensures that wax is continuously managed without prolonged heating that would cause downstream deposition
Solution Approach 2:
While one heat exchange device is undergoing heating to release wax, the other devices continue cooling and depositing wax, ensuring continuous wax management. This parallel operation maintains the useful action of wax stabilization without interruption
3Reliability
If a significant length of conditioner section is used to condition the fluid, then wax can be effectively stabilized, but the equipment size and logistical requirements increase
Solution Approach 1:
The patent segments the conditioner section into multiple discrete heat exchange devices that can be arranged in series over a compact footprint. This segmentation allows effective wax stabilization to be achieved in a shorter overall length compared to a single long conditioner section
Solution Approach 2:
The patent transitions from a single longitudinal conditioner section to multiple devices arranged in series, effectively using the series arrangement dimension to achieve compact conditioning. This dimensional change allows shorter overall equipment length while maintaining stabilization effectiveness
4Reliability
If insulation and electrical heating are applied to keep fluid temperature above wax appearance temperature, then wax deposition is prevented, but logistics and cost increase particularly for long pipelines
Solution Approach 1:
The patent changes the temperature parameter profile by using periodic cooling and heating instead of continuous heating above wax appearance temperature. This parameter change allows wax deposition prevention through controlled deposition and stabilization cycles, reducing the need for continuous energy input and associated costs
Solution Approach 2:
The patent converts the harmful effect of wax deposition into a beneficial process by allowing controlled wax deposition on the pipe wall, then using heating to release and stabilize the wax in the fluid. This transforms what would be a problem (wax deposition) into a solution (wax stabilization), eliminating the need for continuous insulation and heating
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 approach significantly reduces the amount of non-stabilized wax entering the transport pipeline, minimizing fouling, requiring less maintenance, and optimizing logistics and cost by allowing for smaller equipment and reduced power demand.
Implementation Method 1
Each of the heat exchange devices 2a-2d acts to cool the fluid from the well
Implementation Method 2
cooling to deposit wax on the pipe wall
Implementation Method 3
heating to release stabilized wax into the fluid
Implementation Method 4
The heat pulse will melt a very thin layer of the wax at the wax/wall interface
Implementation Method 5
cool by transfer of heat via the walls of the pipe to the surrounding seawater
Data Source
AI summary
Methods and apparatus for processing fluid from a well are described. A first wall portion may define a first region and a second wall portion may define a second region, fluid from said well being let through those regions. Heating of said first wall portion may be performed to release wax from said first wall portion into said fluid at said first flow region. During said heating, cooling of said fluid at said second flow region may be performed to cause wax from said fluid to deposit on said second wall portion.