Nitrogen Foam Plugging Walls for Heavy Oil Reservoir Water Encroachment
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Solution Overview
Problem
Heavy oil reservoirs with edge and bottom water experience significant water encroachment and steam channeling issues during cyclic steam stimulation, leading to reduced formation energy and impaired development efficiency.
Innovation Solution
Implementing an integral profile control and plugging method using high-intensity nitrogen foam systems and nitrogen foam systems injected at different positions in the oil reservoir to form effective plugging walls, slowing down water encroachment and steam channeling by optimizing well row arrangements and steam injection volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cyclic steam stimulation is performed in heavy oil reservoirs with edge and bottom water, then heavy oil recovery is improved, but water encroachment and steam channeling occur leading to reduced formation energy
Solution Approach 1:
The patent introduces nitrogen foam as an intermediary substance injected into the reservoir to control water encroachment and steam channeling. The foam acts as a mediator that occupies pore space, redirects fluid flow paths, and maintains pressure distribution, thereby preserving formation energy while allowing cyclic steam stimulation to continue effectively
Solution Approach 2:
The patent changes the physical and chemical parameters of the injection fluid by using nitrogen foam instead of conventional water or steam alone. The foam's unique properties (gas-liquid mixture, adjustable bubble size, controlled mobility) alter the flow dynamics in the reservoir, enabling better energy management during heavy oil recovery operations
2Productivity
If multiple cycles of cyclic steam stimulation are performed, then more heavy oil is extracted, but steam channeling channels form between huff-puff wells
Solution Approach 1:
Nitrogen foam serves as an intermediary that stabilizes steam flow distribution by occupying preferential flow paths and forcing steam to distribute more uniformly across the reservoir. This prevents the formation of stable steam channeling channels between wells while maintaining effective heavy oil extraction over multiple cycles
Solution Approach 2:
The patent employs periodic injection of nitrogen foam followed by cyclic steam stimulation cycles. This periodic action allows the foam to reset the flow regime before each steam cycle, preventing cumulative steam channeling effects that would otherwise develop over multiple consecutive steam injection cycles
3Productivity
If steam injection volume is increased to enhance heavy oil recovery, then oil production increases, but pressure difference causes water encroachment into the oil layer
Solution Approach 1:
Nitrogen foam acts as a pressure buffer and flow mediator that allows increased steam injection volumes to be used for enhancing oil production without creating excessive pressure differences. The foam's compressibility and mobility control characteristics absorb pressure fluctuations and redistribute stress, preventing water encroachment while maintaining high oil recovery rates
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 method reduces moisture content by 10%-15% and increases the oil-steam ratio by 0.2%-0.5%, thereby enhancing the development effect of multi-cycle cyclic steam stimulation in heavy oil reservoirs.
Implementation Method 1
injecting a high-intensity nitrogen foam system and a nitrogen foam system to well rows at different positions in the oil reservoir to form effective plugging walls
Implementation Method 2
injecting a high-intensity nitrogen foam system and a nitrogen foam system to well rows at different positions in the oil reservoir to form effective plugging walls, thereby slowing down the water encroachment and steam channeling
Data Source
AI summary
Disclosed is a method for performing integral plugging control on water invasion and steam channeling of an edge-bottom water heavy oil reservoir. The method for performing integral plugging control on water invasion and steam channeling of an edge-bottom water heavy oil reservoir comprises the following steps: (1) selecting an oil reservoir; (2) arranging a huff-puff well; (3) performing steam huff-puff development; and (4) performing integral plugging control. An integral plugging control technology is used for the method, a high-strength nitrogen foam system is injected by means of well rows at different positions in the oil reservoir, and effective plugging walls are formed at different positions from the edge-bottom water to reduce water invasion and steam channeling.