Miscible Solvent Gravity Drainage Oil Recovery
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Solution Overview
Problem
Conventional enhanced oil recovery (EOR) techniques face inefficiencies due to properties differences between injection materials and reservoir hydrocarbons, leaving significant residual oil untapped.
Innovation Solution
Injecting a miscible unfractionated hydrocarbon mixture, such as Y-Grade natural gas liquids, into fractured carbonate reservoirs to initiate gravity-stable displacement and gas cap expansion, reducing interfacial tension and enhancing oil recovery by using locally sourced, cost-effective components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional EOR techniques use injection materials with properties differing from reservoir hydrocarbons, then the extraction efficiency is reduced, but the available injection materials and methods are limited
Solution Approach 1:
The patent applies homogeneity by using an unfractionated hydrocarbon mixture as the injection fluid that matches the compositional range (C2-C12+) and properties of the reservoir hydrocarbons. This compositional matching eliminates interfacial tension issues and improves displacement efficiency, directly resolving the contradiction between extraction efficiency and material compatibility by making the injection fluid homogeneous with the reservoir fluid.
Solution Approach 2:
The patent changes the key parameter of injection fluid composition from conventional fractionated or non-hydrocarbon materials to an unfractionated hydrocarbon mixture with specific compositional range (C2-C12+). This parameter change ensures the injection fluid has similar density, viscosity, and solubility characteristics to the reservoir oil, thereby improving extraction efficiency while maintaining adaptability to the reservoir conditions.
2Productivity
If miscible injection fluid is injected to initiate gravity-stable displacement, then sweep efficiency is improved, but the process complexity increases
Solution Approach 1:
The patent utilizes gravity-stable displacement where the unfractionated hydrocarbon mixture, being miscible and having similar density to reservoir hydrocarbons, naturally moves through the reservoir following gravity-driven flow paths. This creates equipotential flow conditions that improve sweep efficiency by preventing fluid channeling and breakthrough, while the natural gravity-driven mechanism reduces the need for complex injection control systems.
Solution Approach 2:
The miscible unfractionated hydrocarbon mixture performs self-service by automatically achieving uniform distribution and displacement throughout the reservoir through its inherent miscibility and gravity-driven flow. The fluid self-regulates its movement to maintain stable displacement fronts without requiring complex external control mechanisms, thereby improving sweep efficiency while minimizing process complexity.
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
Improves sweep efficiency and oil recovery by mobilizing and displacing residual hydrocarbons from structurally higher to lower positions within the reservoir, leveraging the miscibility and buoyancy of the injection fluid.
Implementation Method 1
The miscible injection fluid comprises an unfractionated hydrocarbon mixture that is miscible with hydrocarbons in the fractured carbonate reservoir
Implementation Method 2
leveraging the miscibility and buoyancy of the injection fluid
Implementation Method 3
injecting a miscible injection fluid through an injection well into a fractured carbonate reservoir having a high structural relief to initiate gravity-stable displacement
Data Source
AI summary
A method for enhanced or improved oil recovery includes injecting a miscible injection fluid comprising an unfractionated hydrocarbon mixture through an injection well into a hydrocarbon bearing reservoir at a structurally higher position to initiate gravity-stable displacement and gas cap expansion processes. Residual hydrocarbons in the hydrocarbon bearing reservoir are mobilized and displaced by the miscible injection fluid to a structurally lower position within the hydrocarbon bearing reservoir adjacent a production well through which they are produced to the surface.