Linear Pressure Reducer for Polymer Injection
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Solution Overview
Problem
Existing pressure reduction systems in enhanced oil recovery systems cause mechanical degradation of polymers due to varying injection pressures, leading to reduced viscosity of the injection solution, especially at high pressure drops, which limits oil recovery.
Innovation Solution
A linear pressure reducer composed of modules with varying tube lengths, allowing adjustable pressure drops without substantial degradation of the polymer viscosity, by using tubes of different lengths and diameters connected in series, with by-pass valves for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If traditional chokes with single or multiple openings are used to reduce injection pressure, then pressure regulation is achieved, but polymer degradation occurs due to high shear forces and cavitation effects
Solution Approach 1:
The single choke opening is segmented into multiple parallel channels or flow paths. This segmentation reduces the velocity and shear forces in each individual channel while maintaining the overall pressure reduction function, thereby minimizing polymer degradation through cavitation and mechanical shear
Solution Approach 2:
The invention transitions from a two-dimensional planar choke design to a three-dimensional multi-channel structure. By creating multiple flow paths through the choke body, the solution distributes the flow in additional spatial dimensions, reducing the intensity of shear forces and preventing cavitation in any single flow path
2Adaptability or versatility
If pressure drop through choke is increased to regulate pressure in wells with varying pressures, then pressure control flexibility is improved, but viscosity loss of polymer solution accelerates
Solution Approach 1:
The choke incorporates adjustable or dynamically controllable flow paths that can be modified based on operating conditions. This allows the system to adapt the pressure drop distribution across multiple channels, optimizing for minimal polymer degradation while maintaining the required pressure control flexibility for different well conditions
Solution Approach 2:
The invention changes the physical parameters of the flow paths including diameter, length, and configuration of each channel. By optimizing these parameters, the system achieves the necessary pressure reduction while keeping shear forces below the threshold that causes significant polymer degradation, thus maintaining viscosity even at high pressure drops
3Stress or pressure
If feed pump pressure is set 20 bar above the highest well pressure to ensure sufficient pressure in all wells, then pressure sufficiency is guaranteed, but excessive decompression forces cause cavitation and explosive degradation
Solution Approach 1:
The pressure reduction is segmented across multiple channels with progressively varying restrictions. This gradual pressure drop through distributed channels prevents the formation of extreme decompression forces that would cause cavitation, while still achieving the necessary pressure reduction from the pump outlet to individual well requirements
Solution Approach 2:
The multi-channel choke design provides beforehand cushioning by distributing the pressure drop across multiple flow paths with controlled resistance. This prevents sudden pressure drops and cavitation formation by gradually reducing pressure through the structured arrangement of channels before the polymer solution enters the wellbore
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 regulation of injection pressure to match varying well pressures without significant polymer degradation, maintaining high injection speeds and flow rates, and reducing viscosity loss to less than 10%, thus enhancing oil recovery efficiency.
Implementation Method 1
Studies carried out into the mechanical degradation of polymers in solution are all empirical due to the drag, or friction, reduction effect
Implementation Method 2
The pressure of the wells varies according to multiple factors... The choke allows the injection pressure to be reduced to the desired pressure
Implementation Method 3
as extremely high decompression forces cause cavitation effects that are practically explosive
Data Source
Figure 1~2
Figure 3~3b
AI summary
Linear pressure reducer apparatus for regulating injection pressure of a water-soluble polymer solution in injection wellheads, in an enhanced oil recovery system, including modules connected in series to the main injection pipe and each consisting of tubes of identical diameter but variable length, the said apparatus allows variations to be made to pressure drop by adjusting the length of the tube through which the solution flows by closing or opening modules, without substantial degradation to the viscosity of the solution during its passage through the module. Installation for enhanced oil recovery implementing the said apparatus.