Downhole Steam Generator Cascade Control System
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Solution Overview
Problem
Downhole steam generators lack a means to optimize performance based on real-time measured process parameters, leading to inefficiencies in steam injection into heavy oil, extra heavy oil, or bitumen reservoirs.
Innovation Solution
A control system comprising a local well master controller, sensors to measure operational characteristics, and flow control loops that adjust fluid flows to achieve a predetermined injection rate and steam quality, with communication between the local and regional master controllers to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If surface-based fuel, oxidant, and feedwater supply systems are used for downhole steam generators, then the basic steam generation function is achieved, but the system cannot optimize performance based on actual measured process parameters
Solution Approach 1:
The patent implements feedback control by installing sensors (temperature, pressure, flow meters) that continuously measure process parameters and transmit data to the well master controller. The controller automatically adjusts fuel, oxidant, and feedwater flow rates based on real-time measurements, creating closed-loop feedback that enables performance optimization without requiring complex manual intervention
Solution Approach 2:
The downhole steam generator is equipped with an autonomous control system that independently monitors its own operational parameters and self-regulates fluid flows. The well master controller and downhole controller work together to automatically maintain optimal combustion conditions and steam generation efficiency without external intervention, enabling the system to serve and optimize itself
2Productivity
If remote surface systems supply fuel, oxidant, and feedwater, then basic operational requirements are met, but real-time control and optimization are not achievable
Solution Approach 1:
The control system is segmented into multiple independent components: surface control system, downhole controller, local well master controller, and individual flow control loops. This segmentation allows each component to operate autonomously and respond to local conditions in real-time, improving overall system responsiveness and steam injection efficiency without requiring centralized control
Solution Approach 2:
The control system continuously monitors process parameters and proactively adjusts fluid flows before deviations from optimal performance occur. The well master controller maintains setpoints for fuel, oxidant, and feedwater flows based on predetermined optimal combustion conditions, preventing efficiency losses rather than reacting to them after they occur
3Manufacturing precision
If no local control system is installed at the downhole steam generator, then device complexity is reduced, but the ability to adjust fluid flows for optimal injection rate and steam quality is lost
Solution Approach 1:
The control system implements local quality control by installing sensors and control components specifically at critical locations within the downhowe steam generator. Temperature sensors measure combustion chamber and steam generator temperatures, pressure sensors monitor system pressure, and flow meters measure fluid flows at precise points, enabling targeted control of steam quality and injection rate where it matters most
Data Source
AI summary
A control system for controlling the operation of a Downhole Steam Generator (DHSG) system includes a cascade control strategy for control of individual final control elements in communication with a local well master controller. The final control elements may control fuel, oxidant, feedwater, and/or carbon dioxide flow to the downhole steam generator. The local well master controller may monitor and adjust the flows to the DHSG to control the operating performance of the DHSG.