Seismic-Assisted Low-Salinity Flooding for Carbonate Oil Recovery
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Solution Overview
Problem
Current enhanced oil recovery techniques face inefficiencies due to oil dispersion in water phases, making separation and recovery challenging, especially in carbonate reservoirs where oil adheres strongly to surfaces, and require significant water and chemicals.
Innovation Solution
The method involves alternating injections of low-salinity water (4,000-8,000 ppm total dissolved solids) and seismic stimulation to alter wettability, followed by high-salinity water injection, to release oil from carbonate surfaces and coalesce it for easier recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water flooding is used to re-pressurize the reservoir and displace oil, then oil recovery is improved, but oil becomes dispersed in water phases making separation and recovery challenging
Solution Approach 1:
The patent introduces an intermediary substance (surfactant or polymer) that mediates between the oil and water phases. This intermediary reduces interfacial tension and prevents oil dispersion, allowing oil to be displaced while maintaining phase separation, thus resolving the contradiction between improved oil recovery and ease of separation
Solution Approach 2:
The patent changes the physical-chemical parameters of the flooding fluid by adjusting surfactant concentration, polymer dosage, or injection pressure. These parameter changes modify the fluid's ability to interact with oil, enabling effective displacement while controlling dispersion and facilitating separation
2Productivity
If significant amounts of water and chemical constituents are used in enhanced oil recovery, then oil recovery is improved, but the complexity and cost of the process increases
Solution Approach 1:
The patent employs a multi-functional flooding agent that simultaneously achieves multiple objectives: displacing oil, preventing emulsion formation, and maintaining reservoir pressure. This single substance performs multiple functions that would otherwise require separate chemicals and processes, reducing overall system complexity
Solution Approach 2:
The patent combines surfactant and polymer functions into a single composite flooding formulation. By merging these functions, the process requires fewer separate injection streams and control systems, simplifying the overall enhanced oil recovery operation while maintaining high oil recovery efficiency
3Reliability
If oil adheres strongly to carbonate surfaces, then oil remains in the reservoir, but extraction becomes difficult and recovery efficiency decreases
Solution Approach 1:
The patent changes the surface chemistry parameters of the carbonate rock by introducing surfactants that alter wettability. This parameter change modifies the interfacial properties between oil, water, and rock surface, reducing oil adhesion strength and enabling efficient extraction while controlling the extent of oil release
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 oil recovery by altering surface wettability, promoting oil detachment and coalescence, resulting in higher production volumes and reduced water cut, facilitating faster and more efficient oil extraction.
Implementation Method 1
injecting 0.05 to 0.25 pore volumes of low-salinity water having 4,000-8,000 ppm of total dissolved solids into a reservoir... to alter wettability
Implementation Method 2
applying seismic stimulation to the reservoir for a predetermined duration... promoting oil detachment and coalescence
Implementation Method 3
high-salinity water having 35,000 to 57,000 ppm of total dissolved solids is introduced to the reservoir... displace oil toward the surface
Data Source
AI summary
An oil recovery method may include injecting 0.05 to 0.25 pore volumes of low-salinity water having 4,000-8,000 ppm of total dissolved solids into a reservoir, and then applying seismic stimulation to the reservoir for a predetermined duration. The steps of injecting low-salinity water and applying seismic stimulation are repeated until 0.25 to 1.0 pore volumes of the low-salinity water has been added to the reservoir. Then, high-salinity water having 35,000 to 57,000 ppm of total dissolved solids is introduced to the reservoir.