Gas-Cap Air Injection for Thermal Oil Recovery
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Solution Overview
Problem
Current bitumen recovery methods from oil sands overlain by a gas zone often result in suboptimal performance when steam injection intersects the gas zone prematurely, disrupting in situ combustion and reducing efficiency in both gas and bitumen recovery.
Innovation Solution
A combined thermal recovery process using cyclic steam stimulation in the oil sands reservoir and in situ combustion in the overlying gas zone, where the timing and pressure of steam injection are coordinated to ensure the rising hot zone intersects the gas zone only after the combustion front has moved beyond that area, thereby preventing interference and enhancing energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam injection is used to heat the oil sands reservoir, then bitumen recovery is improved, but the rising hot zone may intersect the gas zone prematurely, disrupting in situ combustion and reducing gas displacement performance
Solution Approach 1:
The combustion front is advanced into the gas zone before steam injection begins. This preliminary action ensures that the combustion front is already positioned ahead of where the rising hot zone from steam injection will reach, preventing interference between the two processes and maintaining both bitumen recovery and gas displacement performance
Solution Approach 2:
The timing and pressure of steam injection are dynamically coordinated with the combustion front position. Steam injection is controlled to ensure the rising hot zone intersects the gas zone only after the combustion front has moved beyond that area, creating a dynamic balance between heating the oil sands and preserving gas zone integrity
2Productivity
If steam injection is used to mobilize bitumen, then bitumen production increases, but the steam-oil ratio increases, reducing energy efficiency
Solution Approach 1:
The in situ combustion process and steam injection process are merged into a coordinated system where combustion provides supplemental heat to the oil sands reservoir. This combination allows bitumen mobilization through both combustion heating and steam injection, reducing the amount of steam required and thereby lowering the steam-oil ratio and energy consumption
Solution Approach 2:
The combustion front acts as an intermediary heat source between the steam injection system and the oil sands reservoir. By positioning the combustion front to overlap with the rising hot zone, the system uses combustion heat as an intermediate energy source to supplement steam heating, reducing steam requirements and improving energy efficiency
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 steam-oil ratio, improves bitumen recovery efficiency, and maintains gas displacement performance by ensuring the thermal recovery process operates in the depleted gas zone behind the combustion front, providing additional energy to the oil sands reservoir.
Implementation Method 1
Steam is injected into the oil sands reservoir to heat the bitumen, creating a rising hot zone
Implementation Method 2
Air is injected into the gas zone to initiate and sustain in situ combustion, creating a combustion front
Implementation Method 3
The combustion front moves through the gas zone, heating and displacing gas toward production wells
Implementation Method 4
Heated bitumen flows under the influence of gravity to the production well for recovery
Data Source
AI summary
A method for producing bitumen or heavy oil from a subsurface oil sands reservoir, the subsurface oil sands reservoir and an overlying gas zone in fluid communication, the method includes providing an in situ combustion process in the overlying gas zone, to create or expand a combustion front within the overlying gas zone, providing a thermal recovery process in the oil sands reservoir, to create or expand a rising hot zone within the oil sands reservoir, and selectively operating the thermal recovery process or the in situ combustion process or both such that the rising hot zone does not intersect the overlying gas zone until the combustion front has moved beyond that portion of the overlying gas zone at the intersection.