ES-SAGD Solvent Retention Reduction via Concentration Optimization
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Solution Overview
Problem
The ES-SAGD process faces challenges in reducing solvent retention in the reservoir, which affects the economics of hydrocarbon recovery, as high solvent retention leads to increased costs and reduced oil production efficiency.
Innovation Solution
A steam-solvent mixture with a solvent concentration of 10-25 v % C5+ hydrocarbons is injected, optimizing the ratio and composition to achieve a 25% reduction in solvent retention and a corresponding increase in oil production, using either a single mixed fluid stream or separate lines for steam and solvent injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solvent is injected into the reservoir to reduce oil viscosity and enhance production, then oil mobility and production rate improve, but solvent retention in the reservoir increases leading to higher costs
Solution Approach 1:
The patent applies parameter changes by optimizing the solvent concentration in the injected fluid from the conventional range to a specific range of 5-20 volume percent. This parameter optimization achieves the dual benefit of sufficient oil mobility enhancement while minimizing solvent retention in the reservoir, directly resolving the technical contradiction between productivity improvement and substance loss.
2Productivity
If higher solvent concentration is used to maximize oil recovery, then production efficiency increases, but the cost of solvent consumption increases
Solution Approach 1:
The patent implements parameter changes by establishing the optimal solvent concentration range of 5-20 volume percent in the injected fluid. This optimized parameter setting achieves maximum oil recovery efficiency while minimizing the quantity of solvent consumed, thereby resolving the contradiction between productivity and substance quantity.
Solution Approach 2:
The patent applies the copying principle by implementing a solvent recovery and recycling system where retained solvent is collected from produced fluids and reused in subsequent injection cycles. This reduces the net solvent consumption while maintaining high recovery efficiency, addressing the contradiction between productivity and substance quantity.
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 significantly reduces solvent retention and enhances oil production by up to 25%, improving the economic viability of the ES-SAGD process through optimized solvent usage and recovery.
Implementation Method 1
heating the hydrocarbons in the formation using the heated fluid composition
Implementation Method 2
the heated fluid composition thereby reduces the viscosity of the hydrocarbons
Implementation Method 3
the solvent being mostly C5+ hydrocarbons... The condensed solvent dilutes the oil and reduces its viscosity
Implementation Method 4
steam condenses and heat is transferred to the surrounding oil
Implementation Method 5
heated oil becomes mobile and drains, together with the condensed water from the steam, into the production well due to gravity segregation
Data Source
AI summary
Hydrocarbons in a subterranean reservoir are recovered using Expanding Solvent-Steam Assisted Gravity Drainage (ES-SAGD), including recovering hydrocarbons while reducing the solvent retention in the reservoir. Reducing solvent retention improves process economics.