Downhole Steam Generator Shear Points
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Solution Overview
Problem
Current methods for recovering viscous hydrocarbons from subterranean reservoirs face challenges such as wellbore heat loss, environmental concerns, and inefficiencies in steam injection, particularly in permafrost regions and deep offshore wells, where steam quality decreases and causes thermal instabilities and material failures.
Innovation Solution
A downhole steam generation system is employed, which includes a packer, a downhole steam generator, and an umbilical device with shear points, allowing for the production of steam closer to the reservoir and minimizing heat loss and environmental impact by using a combustion product to reduce viscosity and enhance hydrocarbon recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If steam is generated on the surface and injected through permafrost layers, then the reservoir can be heated to reduce viscosity, but the heat expands or thaws the permafrost causing wellbore stability issues and environmental problems
Solution Approach 1:
The system performs preliminary action by generating steam downhole at the reservoir location rather than at the surface. The steam generator is positioned within the wellbore below the permafrost layer, so steam is produced directly at the target zone without heating the permafrost during transport, thus maintaining wellbore stability while achieving reservoir heating
Solution Approach 2:
The system segments the steam generation process from surface operations by placing the steam generator downhole. This segmentation allows the heating function to be performed in-situ at the reservoir, separating the thermal process from the surface infrastructure and eliminating the thermal pathway through the permafrost
2Temperature
If steam is generated on the surface and injected through deep wellbores, then the reservoir can be heated, but wellbore heat loss decreases steam quality by the time it reaches the reservoir
Solution Approach 1:
The steam is generated preliminarily at the downhole location where it is needed, eliminating the transport pathway that causes heat loss. The steam generator produces steam in-situ at the reservoir depth, so no heat is lost during wellbore travel, maintaining high steam quality for effective viscosity reduction
Solution Approach 2:
The steam generation function is extracted from the surface facility and relocated to the downhole environment. This extraction removes the thermal process from the surface-to-reservoir pathway, eliminating the source of heat loss that would otherwise occur during steam transport through the wellbore
3Productivity
If surface generated steam is injected into the reservoir, then hydrocarbon recovery can be enhanced, but gases and by-products are produced that are harmful to the environment
Solution Approach 1:
The system uses self-service by utilizing hydrocarbons produced from the reservoir itself as fuel for the downhole steam generator. The combuster burns produced hydrocarbons to generate steam, creating a self-sustaining system where the production process fuels the enhancement process, eliminating external fuel requirements and associated environmental emissions
Solution Approach 2:
The system converts the harmful aspect of produced gases (which would otherwise be flared or vented) into a beneficial fuel source. By using the combuster to burn produced hydrocarbons for steam generation, the system transforms potential environmental pollutants into a useful energy source that drives the enhanced recovery process
4Loss of energy
If a downhole steam generator is used to generate steam in-situ, then thermal efficiency is improved and heat loss is minimized, but the device complexity and material challenges increase due to high temperatures
Solution Approach 1:
The system merges multiple functions into a single integrated downhole assembly: the steam generator, combuster, and steam injection system are combined in one downhole device. This consolidation reduces the number of separate surface-to-downhole connections and control systems needed, simplifying the overall system despite the complex thermal processes involved
Solution Approach 2:
The downhole steam generator performs multiple functions: it generates steam through combustion, heats the reservoir, and injects steam into the formation. The combuster serves both as a heat source and as a means to utilize produced gases. This multi-functionality reduces the need for separate surface facilities and downhole equipment, offsetting the complexity of the high-temperature components
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 achieves improved thermal efficiency and reduced environmental impact by generating steam downhole, maintaining high quality, and increasing hydrocarbon recovery rates while minimizing wellbore instability and leakage risks.
Implementation Method 1
A combustion chamber burns fuel to generate thermal energy
Implementation Method 2
A vaporization chamber vaporizes water to produce steam
Data Source
AI summary
A system for recovering hydrocarbons comprises a downhole steam generator for coupling with a packer in an injector well, an umbilical device coupled to the downhole steam generator for lifting or lowering the downhole steam generator in the injector well, a first shear point disposed between the downhole steam generator and the packer, and a second shear point disposed between the umbilical device and the downhole steam generator, wherein the first shear point has a shear strength that is different than a shear strength of the second shear point.