Low Molecular Weight Polyacrylate Nanoparticles for Delayed Gelation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current polymer-based solutions for enhanced oil recovery face challenges such as rapid gelation at high temperatures and toxicity issues, which limit their effectiveness in blocking 'thief zones' and optimizing oil extraction efficiency.
Innovation Solution
Development of polyelectrolyte complex (PEC) nanoparticle systems using low molecular weight polyethylenimine and sodium polyacrylate or sodium polyvinyl sulfonate, which delay gelation and reduce toxicity, allowing for more efficient and cost-effective hydrocarbon recovery by gradually releasing multivalent cations to crosslink polymers at target reservoir zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If viscous polymers are used to block thief zones, then sweep efficiency is improved, but gelation occurs too quickly preventing deep placement in reservoir
Solution Approach 1:
The polymer is injected in a pre-gelled or partially gelled state with delayed crosslinking mechanism, allowing it to be placed deep in the reservoir before full gelation occurs. This preliminary placement ensures the polymer reaches the target zone before becoming too viscous to move effectively.
Solution Approach 2:
A delayed crosslinking agent or catalyst is used as an intermediary that triggers gelation only after the polymer has been transported to the desired location. This mediator controls the timing of gelation, separating the transport phase from the gelling phase.
2Strength
If common crosslinking agents such as chromic acetate are used, then crosslinking effectiveness is improved, but gelation occurs too quickly and toxicity increases
Solution Approach 1:
The patent employs biodegradable or environmentally benign crosslinking agents that provide effective crosslinking during the operational period but decompose into harmless substances afterward, reducing long-term toxicity concerns in the reservoir environment.
Solution Approach 2:
The crosslinking mechanism is modified by changing parameters such as pH, temperature sensitivity, or catalyst requirements, allowing crosslinking to occur only under specific conditions that are achieved after polymer placement, thereby delaying gelation and reducing premature toxicity effects.
3Reliability
If polymer concentration is increased to improve blocking capability, then thief zone blocking is improved, but viscosity increases making pumping difficult
Solution Approach 1:
The polymer is injected at lower concentrations in a pumpable state, and the blocking capability is achieved through delayed crosslinking that increases viscosity and gel strength only after the polymer has been successfully placed in the thief zone, separating the injection phase from the blocking phase.
Solution Approach 2:
The system transitions from a low-viscosity pumpable state during injection to a high-viscosity gel state after crosslinking, dynamically adjusting the physical properties to match the requirements of each operational phase.
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 PEC nanoparticle system achieves extended gelation times at higher temperatures, reduces toxicity, and improves sweep efficiency in oil recovery by ensuring the polymer gelation occurs only after deep penetration into the reservoir, enhancing the overall recovery factor.
Implementation Method 1
delayed gelling or crosslinking reaction
Implementation Method 2
crosslinking of polymers at target reservoir zones
Implementation Method 3
polyelectrolyte complex (PEC) nanoparticle systems using low molecular weight polyethylenimine and sodium polyacrylate or sodium polyvinyl sulfonate
Implementation Method 4
gradually releasing multivalent cations to crosslink polymers
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
The disclosure is directed to low molecular weight polyelectrolyte complex nanoparticles that can be used to deliver agents deep into hydrocarbon reservoirs. Methods of making and using said polyelectrolyte complex nanoparticles are also provided.