In-Situ Electric Heating for Shale Oil Lightening
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Solution Overview
Problem
Current methods for shale oil in-situ development, such as radiation heating and thermal conduction, face challenges like low energy replacement ratio, poor economic benefits, complex equipment, and are not suitable for deep shale oil deposits, limiting large-scale economic development.
Innovation Solution
A method that determines effective shale intervals based on total organic carbon content and favorable regions for in-situ lightening development, optimizing well arrangement and heating procedures to improve oil and gas output, using vertical and horizontal well sections with specific completion modes and heating sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If radiation heating or thermal conduction heating is used for shale oil in-situ development, then heating can be achieved, but energy replacement ratio is low and economic benefits are poor
Solution Approach 1:
The patent replaces traditional thermal conduction heating and radiation heating methods with in-situ electric heating technology. Electric heating elements are directly inserted into the shale formation to generate heat through resistive heating, eliminating the need for external heat sources and improving energy conversion efficiency. This substitution of heating mechanism directly addresses the low energy replacement ratio issue while reducing operational costs and improving economic benefits.
Solution Approach 2:
The patent employs self-service by using the shale formation's own electrical conductivity to generate heat in-situ. The heating elements utilize the natural properties of the shale formation to convert electrical energy directly into thermal energy within the target zone, eliminating energy losses associated with external heating methods. This self-heating mechanism improves energy replacement ratio and reduces dependency on external energy sources.
2Quantity of substance
If existing in-situ lightening technology is used, then oil and gas can be produced, but downhole process equipment is complex and cost control is difficult
Solution Approach 1:
The patent extracts and eliminates complex downhole processing equipment by implementing a simplified electric heating system. Instead of using complex thermal conduction or radiation heating equipment downhole, the invention uses straightforward electric heating elements that can be easily deployed and controlled from the surface. This extraction of unnecessary complexity directly reduces equipment costs and simplifies the overall system while maintaining oil and gas production capabilities.
Solution Approach 2:
The patent applies universality by using multi-functional electric heating elements that serve both as heating sources and as part of the production system. The same downhole infrastructure is used for both heating and production purposes, eliminating the need for separate complex processing equipment. This multi-functional approach reduces device complexity and improves cost control while maintaining effective oil and gas output.
3Ease of operation
If shallow oil shale in-situ development is performed, then development can proceed, but it is not suitable for deeper shale oil deposits
Solution Approach 1:
The patent applies parameter changes by modifying the heating method to be suitable for deep shale oil deposits. Electric heating elements can be deployed to greater depths compared to traditional thermal conduction or radiation methods. The electrical parameters (voltage, current, power) can be adjusted to match the specific conditions of deep formations, enabling the technology to adapt to various depths while maintaining operational feasibility. This parameter adjustment resolves the depth adaptability issue.
Solution Approach 2:
The patent transitions from surface-level or shallow heating methods to deep-in-situ electric heating by moving the heating function into the subsurface dimension. Electric heating elements are directly placed within the deep shale formation, enabling heating at depths that were previously inaccessible to conventional methods. This dimensional transition from surface to subsurface heating resolves the depth limitation while maintaining ease of operation through centralized surface control.
4Adaptability or versatility
If conventional horizontal well volume pressure technology is used for low maturity shale (Ro < 0.95%), then technology can be applied, but scaled economic development cannot be realized
Solution Approach 1:
The patent replaces conventional horizontal well volume pressure technology with in-situ electric heating technology specifically tailored for low maturity shale formations. The electric heating method directly converts organic matter in the shale to oil and gas in-place, eliminating the need for complex pressure management and horizontal well infrastructure. This substitution enables scaled economic development by simplifying the technology while maintaining broad applicability to low maturity shale resources.
Solution Approach 2:
The patent applies parameter changes by adjusting the thermal and electrical parameters to optimize conversion of organic matter in low maturity shale (Ro < 0.95%). The electric heating parameters (temperature, duration, power density) are specifically calibrated for low maturity formations, enabling effective conversion where conventional pressure-based methods fail. This parameter optimization achieves both technology applicability and scaled economic development by making the process efficient and scalable.
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 approach increases the recovery rate of shale oil to 65% or more, enhances energy replacement ratio, and facilitates scaled economic development by optimizing well placement and heating processes.
Implementation Method 1
a heater disposed in the horizontal section of the heating well... converts the unconverted organic matters and the generated hydrocarbons in the shales with medium and low maturities into light oil and natural gas through an in-situ electric heating method
Implementation Method 2
the practices of exploration and development have proved that when the shale vitrinite reflectance (Ro) is less than 0.95%, the existing horizontal well volume pressure technology cannot realize a scaled economic development. The shale oil can be developed by adopting the in-situ lightening technology, which converts the unconverted organic matters and the generated hydrocarbons in the shales with medium and low maturities into light oil and natural gas through an in-situ electric heating method
Data Source
AI summary
Embodiments of the present disclosure disclose a shale oil in-situ lightening development method, apparatus and system, wherein the method comprises: determining an effective shale interval according to an interval with a total organic carbon greater than a first lower limit value in a target stratum; determining a favorable region for shale oil in-situ lightening development according to a thickness of the effective shale interval and an effective layer thickness ratio, wherein the effective layer thickness ratio includes a ratio of the thickness of the effective shale interval to a thickness of a shale section, and the shale section includes the effective shale intervals and interlayers therebetween. By utilizing the embodiments of the present disclosure, the benefit of the shale oil in-situ lightening development can be improved.