Downhole Steam Generator Combustion Chamber
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Solution Overview
Problem
Current methods for recovering heavy oil face challenges such as wellbore heat loss, decreased steam quality with depth, and issues like material failures and thermal instabilities in downhole steam generation systems, particularly in reservoirs under permafrost layers.
Innovation Solution
A downhole steam generator system comprising a burner head with a sudden expansion region, a water-cooled combustion sleeve, and a vaporization sleeve, optimized for acoustic isolation and efficient fluid flow, which includes multiple injectors and cooling mechanisms to enhance combustion stability and steam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If steam is injected from the surface into deep reservoirs, then heating of heavy oil is achieved, but wellbore heat loss increases and steam quality decreases with depth
Solution Approach 1:
The patent applies preliminary action by generating steam downhole at the reservoir location rather than injecting it from the surface. The downhole steam generator creates steam in-situ, eliminating the long steam pathway through the wellbore and preventing heat loss during transit. This resolves the contradiction by performing the steam generation action at the target location, avoiding the energy loss that would occur during surface-to-depth transport.
2Loss of energy
If downhole steam generators are used to eliminate wellbore heat loss, then steam quality improves, but excessive temperatures and material failures occur
Solution Approach 1:
The patent applies segmentation by dividing the steam generation process into distinct functional zones within the downhole device. The combustion chamber is separated from the steam generation zone, and water injection points are strategically positioned to create localized cooling zones. This segmentation allows temperature control at different locations, preventing excessive temperatures in critical material areas while maintaining high steam quality in the output zone.
Solution Approach 2:
The patent uses water as an intermediary substance that serves dual purposes: it is the feedstock for steam generation and simultaneously acts as a cooling medium. Water is injected into the combustion zone to absorb excess heat and control temperatures, preventing material failures while still producing high-quality steam. This intermediary approach resolves the contradiction between achieving high temperatures for steam generation and preventing excessive temperatures that cause material failure.
3Productivity
If combustion is intensified to improve steam generation efficiency, then energy conversion improves, but combustion instabilities and thermal instabilities increase
Solution Approach 1:
The patent applies local quality by creating different combustion intensity zones within the device. The combustion process is optimized locally in the combustion chamber while the steam generation zone maintains controlled, stable conditions. Water injection points are strategically positioned to provide localized cooling and stabilization without compromising overall combustion efficiency. This local optimization allows high productivity in the steam generation zone while maintaining combustion stability in the fuel combustion zone.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting water injection rates and combustion air supply to maintain optimal operating conditions. The system modifies combustion parameters (temperature, pressure, flow rates) to balance steam generation productivity with combustion stability. By changing these parameters in response to operating conditions, the system achieves both high productivity and stable combustion without the instabilities that would result from fixed, intensified combustion.
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 improves steam quality and efficiency, reducing wellbore heat loss and material failures, enabling effective heavy oil recovery even in deep, permafrost-laden reservoirs by maintaining high combustion efficiency and flame stability.
Implementation Method 1
The combustion sleeve may be a water-cooled liner having one or more water injection arrangements
Implementation Method 2
a burner head, a combustion sleeve... The DHSG may be configured to acoustically isolate the various fluid flow streams that are directed to the DHSG
Implementation Method 3
The DHSG may be configured to acoustically isolate the various fluid flow streams that are directed to the DHSG
Implementation Method 4
a vaporization sleeve... maintaining high combustion efficiency and flame stability
Data Source
AI summary
A downhole steam generation system may include a burner head assembly, a liner assembly, a vaporization sleeve, and a support sleeve. The burner head assembly may include a sudden expansion region with one or more injectors. The liner assembly may include a water-cooled body having one or more water injection arrangements. The system may be optimized to assist in the recovery of hydrocarbons from different types of reservoirs. A method of recovering hydrocarbons may include supplying one or more fluids to the system, combusting a fuel and an oxidant to generate a combustion product, injecting a fluid into the combustion product to generate an exhaust gas, injecting the exhaust gas into a reservoir, and recovering hydrocarbons from the reservoir.