Flexible Riser Tubing for Liquid Surge Mitigation
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Solution Overview
Problem
Liquid surging in hydrocarbon production risers, particularly at late stages of the life cycle, leads to fluid accumulation, unstable flow, and potential overfilling of separators, causing processing issues and potentially necessitating abandonment of flowlines due to severe surge instabilities.
Innovation Solution
A system utilizing flexible tubing with a pressure differential and adjustable length to draw and remove liquid from the riser, using a regulating valve or pump to control liquid intake, and mechanical means to ensure contact with the riser walls, thereby mitigating liquid surging by reducing the cross-sectional area occupied by fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas velocity is reduced at late stage of life cycle, then production rate decreases, but liquid accumulation in riser increases causing surge instability
Solution Approach 1:
The invention extracts liquid from the riser using a separate liquid removal system (suction line or side stream injection) independent of the main gas flow. This allows continuous liquid removal without significantly affecting gas production rate, thereby maintaining flow stability while preserving productivity.
Solution Approach 2:
The invention introduces an intermediary substance (gas injection or suction mechanism) that mediates between the gas flow and liquid accumulation. The injected gas or suction system acts as a mediator to disrupt liquid slug formation and maintain stable two-phase flow without reducing overall production.
2Reliability
If liquid surging is severe, then separator overfilling occurs causing processing problems, but flowline abandonment becomes necessary
Solution Approach 1:
The invention applies preliminary action by continuously or periodically removing liquid from the riser before liquid slugs can form and cause surge instability. This preventive liquid removal prevents separator overfilling and processing problems before they occur, maintaining reliable operation throughout the flowline lifecycle.
3Stability of the object's composition
If flexible tubing is used to remove liquid, then liquid accumulation is reduced, but device complexity increases
Solution Approach 1:
The flexible tubing system is designed to perform multiple functions: liquid removal, riser inspection, and potential flowline rehabilitation. This multi-functionality justifies the added complexity by providing several benefits from a single deployed system, extending flowline lifetime and reducing the need for separate intervention equipment.
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
Effectively reduces the risk of surge wave formation, extends the lifetime of gas-condensate fields, and prevents overfilling of separators by efficiently removing liquid, allowing continued production without abandoning flowlines.
Implementation Method 1
A pressure differential within the flexible tubing is provided such that any liquid in the area where the tubing ends is drawn into the flexible tubing and is transported up
Data Source
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AI summary
A system for surge protection of a riser adapted to transport gas from a hydrocarbon production well or for surge protection in a well, the system comprising: a flexible tubing, wherein a portion of the flexible tubing extends into the riser or into the well and wherein the tubing terminates inside the riser or inside the well; a pressure control system arranged to create a pressure differential within the flexible tubing such that liquid is drawn from the riser or the well into the flexible tubing if liquid is present in the riser or the well; wherein the length of said portion of the flexible tubing is variable depending on the amount of liquid drawn into the flexible tubing