Fishbone Well Preheating for SAGD Plugging
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Solution Overview
Problem
The multilateral well configuration for steam-assisted gravity drainage (SAGD) in oil sands faces challenges such as increased complexity, risk of accidents, sand control difficulties, and uncertainty in maintaining communication with steam chambers, leading to potential plugging issues due to cold bitumen, which reduces performance compared to conventional SAGD processes.
Innovation Solution
The implementation of preheating fishbone wells using additional heat sources like microwave/radio-frequency heating, resistive heating, or chemical heating during the steam circulation period to prevent plugging and ensure consistent flow, combined with optimized well configurations and steam distribution to enhance bitumen recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fishbone well configuration is used to improve bitumen recovery and reduce water consumption, then productivity increases, but the risk of plugging due to cold bitumen increases
Solution Approach 1:
The patent applies preliminary heating action by installing electric heating cables in the fishbone conduits before steam injection begins. The heating cables are activated during the steam circulation period to preheat the conduits and prevent cold bitumen from plugging the laterals, ensuring reliable fluid communication when production starts.
Solution Approach 2:
The patent changes the temperature parameter of the conduits by applying external heat sources (electric heating cables or microwave/radio-frequency heating) to raise the conduit temperature above the bitumen pouring point, thereby changing the physical state of bitumen from solid/pluggy to mobile, ensuring reliable flow.
2Reliability
If additional heat sources are installed in fishbone conduits to prevent plugging, then reliability improves, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical heating systems with electrical heating cables that can be easily installed and controlled. The electric heating system substitutes for more complex mechanical heat generation equipment, reducing overall device complexity while maintaining reliable conduit heating.
Solution Approach 2:
The heating system is designed to be self-regulating, where the heating cables automatically maintain conduit temperature above the bitumen pouring point without requiring complex external control systems. The system serves itself by using the temperature differential between heated conduits and surrounding formation to maintain reliability.
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 reduces the risk of plugging, improves fluid communication, and enhances bitumen recovery by maintaining the fishbone conduits open, leading to increased oil production efficiency and reduced water and energy consumption.
Implementation Method 1
preheating fishbone wells using additional heat sources like microwave/radio-frequency heating
Implementation Method 2
preheating fishbone wells using additional heat sources like microwave/radio-frequency heating
Implementation Method 3
preheating fishbone wells using additional heat sources like microwave/radio-frequency heating, resistive heating
Implementation Method 4
preheating fishbone wells using additional heat sources like microwave/radio-frequency heating, resistive heating, or chemical heating
Implementation Method 5
steam condenses and heat is transferred to the surrounding oil
Implementation Method 6
heat is transferred to the surrounding oil
Implementation Method 7
heated oil becomes mobile and drains, together with the condensed water from the steam, into the production well due to gravity segregation
Data Source
AI summary
The present disclosure relates to a particularly effective well configuration that can be used for SAGD and other steam based oil recovery methods. Fishbone multilateral wells are combined with SAGD, effectively expanding steam coverage, but the fishbones are preheated to mitigate plugging problems, with e.g., resistive heating, EM heating or chemical heating.