Pressure Exchange Control for Stable Hydraulic Fracturing Flow
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Solution Overview
Problem
High-pressure fluid exchange systems used in hydraulic fracturing face challenges in regulating and controlling fluid pressures and rates, which are highly variable and sensitive to changes in wellbore resistance and fluid composition, requiring constant adjustments to maintain optimal operation and prevent reduction in well production.
Innovation Solution
An integrated control system coordinates multiple high-pressure positive displacement pumps with pressure exchange valves to actively regulate the supply and timing of fluid exchange, matching demand requirements and ensuring precise control of fluid properties, using real-time data from the well to adjust pump rates and valve operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If high-pressure positive displacement pumps are used to supply fluid to the pressure exchange system, then the fluid can be delivered at the required high pressure for hydraulic fracturing, but the system becomes highly sensitive to changes in wellbore resistance and fluid composition, requiring constant adjustments to maintain optimal operation
Solution Approach 1:
The patent implements a control system that continuously monitors wellbore resistance and fluid composition changes, and automatically adjusts pump operations and pressure exchange valve timing in response. This feedback mechanism allows the system to maintain optimal performance despite varying conditions, resolving the contradiction between delivering high pressure and adapting to changing wellbore conditions
Solution Approach 2:
The system dynamically adjusts the timing and sequencing of pressure exchange valves based on real-time wellbore conditions and fluid properties. This dynamic adaptation allows the high-pressure pump system to respond to changing resistance and composition without requiring constant manual intervention, maintaining optimal operation across varying conditions
2Ease of operation
If pressure exchange valves are used to regulate fluid flow in the pressure exchange system, then fluid exchange can be controlled, but instantaneous pressure transients occur during valve opening and closing cycles, causing system instability
Solution Approach 1:
The control system prepares for valve transitions by pre-positioning adjacent valves and adjusting pump operations before pressure transients occur. This preliminary action minimizes the magnitude and duration of pressure fluctuations during valve opening and closing, maintaining system stability while preserving valve control functionality
Solution Approach 2:
The system uses accumulators and damping elements positioned strategically in the fluid lines to cushion against instantaneous pressure transients generated by valve operations. This beforehand cushioning absorbs pressure shocks and smooths out fluctuations, allowing valve control to function effectively without compromising pressure stability
3Device complexity
If the pressure exchange system operates with stable pressures and constant resistance, then system control is simplified, but the system cannot adapt to variable wellbore conditions and fluid compositions, reducing productivity
Solution Approach 1:
The control system automatically monitors wellbore conditions and adjusts pressure exchange parameters without external intervention. This self-service capability allows the system to adapt to variable wellbore conditions and fluid compositions autonomously, maintaining productivity while managing complexity through automation rather than manual control
Solution Approach 2:
The system dynamically changes operating parameters such as valve timing, pump rates, and pressure exchange ratios in response to detected changes in wellbore resistance and fluid composition. These parameter adjustments enable the system to adapt to variable conditions and maintain optimal productivity without requiring overly complex control architecture
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 solution enables precise control of fluid exchange processes at high pressures, maintaining optimal conditions and preventing contamination, ensuring efficient hydraulic fracturing operations and maximizing well production.
Implementation Method 1
the high-pressure fluid of the second system is energized by at least one positive displacement pump
Implementation Method 2
The first system energizes the low-pressure fluid from the third system with the high-pressure fluid from the second system to form a high-pressure fracking fluid
Data Source
AI summary
A method for optimizing pressure exchange includes providing a first pressure exchange system comprising an energy recovery device (ERD). A second system supplies high-pressure fluid, energized by a positive displacement pump, to the ERD. A third system supplies low-pressure fluid to the ERD. The first system energizes the low-pressure fluid with the high-pressure fluid to form a high-pressure fracking fluid, which is delivered from the first system to a well-head. A rate of required flow is input into a control system, which determines a rate of flow of the high-pressure fluid, a rate of flow of the low-pressure fluid, and an actual rate of flow of the fracking fluid at the well-head. The control system then adjusts to equilibrium: the rate of flow of the high-pressure fluid based on the actual rate of flow; and the rate of flow of the low-pressure fluid based on the actual rate of flow.