Subsea Cold Flow System for Hydrocarbon Slurry Transport
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Solution Overview
Problem
Existing cold-flow systems for subsea hydrocarbon transport are complex, unstable, and fail to effectively control the formation of solids in hydrocarbon production fluids, leading to buildup and flow reduction in flow lines.
Innovation Solution
A cold flow system that cools hydrocarbon production fluids below the temperature at which hydrates and other substances precipitate, using sensors and an instrumentation and control system to establish and control the characteristics of solid particulates, such as size and number, and employs a discharge pressure controller to manage the formation of a stable slurry, with a cooling gas for additional sub-cooling and a macerator pump to reduce particle size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If production fluid is cooled to precipitate solids for slurry formation, then solids buildup in flow lines is reduced, but controlling solid particle characteristics becomes difficult
Solution Approach 1:
The patent implements a feedback control system where sensors continuously monitor solid particle characteristics (size, concentration) in the production fluid, and the control system adjusts cooling parameters accordingly to maintain optimal slurry formation and prevent solids buildup in flow lines
Solution Approach 2:
The system dynamically adjusts temperature parameters during cooling to control the nucleation and growth of solid particles, transforming the uncontrolled precipitation process into a controlled slurry formation process with desired particle characteristics
2Temperature
If existing cold-flow systems are used to cool production fluid, then solids precipitation is achieved, but system stability is poor
Solution Approach 1:
The control system continuously monitors temperature, pressure, and solid particle characteristics, comparing actual values with target values and automatically adjusting cooling rate and other parameters to maintain system stability during the cooling and slurry formation process
Solution Approach 2:
The system incorporates sensors and control mechanisms that detect deviations from optimal operating conditions before they lead to system failure or excessive solids buildup, allowing preventive adjustments to be made to maintain stable operation
3Quantity of substance
If solids are allowed to precipitate without control, then slurry formation occurs, but particle size and distribution are uncontrolled
Solution Approach 1:
The system controls solid particle characteristics by precisely managing temperature parameters during cooling, including cooling rate, minimum temperature, and temperature holding periods, which directly influence nucleation rate and crystal growth to achieve desired particle size and distribution
Solution Approach 2:
The patent replaces mechanical particle size control methods with a thermodynamic control approach, using controlled cooling curves and temperature profiles to dictate particle formation and growth, thereby achieving precise particle characteristics without mechanical intervention
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 system effectively prevents the buildup of solid particulates in subsea flow lines, enabling stable transport of hydrocarbon slurry over long distances without adhesion, reducing the need for extensive remediation efforts and improving flow efficiency.
Implementation Method 1
The cooling gas is compressed and cools the production fluid as the gas expands via Joule-Thompson expansion.
Implementation Method 2
A partial volume of the production fluid is recycled through a cooling loop.
Implementation Method 3
The production fluid is cooled to a temperature below the temperature at which hydrates and other substances precipitate from the production fluid and form solid particulates.
Implementation Method 4
The solids may be formed from several different substances. For example, the solids may be hydrates formed from a mixture of gas and water
Data Source
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AI summary
A technique is provided for producing a slurry of solid particulates and hydrocarbon production fluid for transport via a subsea flow line. The technique utilizes a cold flow system that cools production fluid to a temperature below the temperature at which hydrates and other substances precipitate from the production fluid and form solid particulates. An instrumentation and control system is used to receive and process data from sensors in the system. The instrumentation and control system then provides control signals to one or more components of the cold flow system to produce a slurry having solid particulates with desirable characteristics. In addition, a cooling gas may be used to facilitate sub-cooling of the production fluid. The cooling gas is compressed and cools the production fluid as the gas expands via Joule-Thompson expansion. Furthermore, a discharge pressure controller may be used to control flow through the cold flow system.