Liquid Phase Additive Asphaltene Mobilization SAGD
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Solution Overview
Problem
The challenge in heavy oil production is the deposition of asphaltenes, which reduces permeability and hinders fluid flow in the near wellbore region, leading to decreased production rates and efficiency in steam-assisted gravity drainage (SAGD) operations, particularly when using light hydrocarbon solvents.
Innovation Solution
A method involving the injection of steam and a liquid phase additive into a steam chamber at specific temperatures and pressures to mobilize asphaltenes, maintaining them in a liquid phase and preventing deposition, thereby enhancing heavy oil recovery and maintaining high production rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If light hydrocarbon solvents are used for in situ deasphalting, then the API gravity of produced oil increases, but asphaltenes deposit in the near wellbore region reducing permeability
Solution Approach 1:
A liquid phase additive is introduced as an intermediary substance between the light hydrocarbon solvent and the asphaltenes. This additive selectively interacts with asphaltenes to prevent their deposition in the near wellbore region while allowing the light solvent to continue its deasphalting function. The additive acts as a mediator that resolves the conflict between asphaltene mobilization and deposition, maintaining permeability while enabling API gravity enhancement.
Solution Approach 2:
The invention changes the physical state parameter of the additive by maintaining it in the liquid phase under steam chamber conditions (temperature and pressure). By controlling the additive to remain liquid rather than vaporizing, it can effectively interact with asphaltenes in the near wellbore region. The steam injection temperature and pressure are specifically controlled to ensure the additive remains liquid while still allowing light solvent to function.
2Productivity
If steam injection temperature and pressure are increased to maintain steam as vapor, then heavy oil mobility improves, but light solvent may condense reducing its effectiveness
Solution Approach 1:
The invention carefully controls the steam injection temperature and pressure parameters to achieve a balance: high enough to maintain steam as vapor for heavy oil mobility, but controlled enough to prevent complete condensation of the light solvent. The additive is also maintained in liquid phase under these same conditions, creating a stable multi-phase system where each component performs its intended function.
3Reliability
If light solvent is injected to prevent asphaltene deposition, then fluid flow improves, but steam may short circuit through the steam chamber
Solution Approach 1:
The liquid phase additive serves as an intermediary that addresses asphaltene deposition issues without requiring increased light solvent injection. By having the additive selectively interact with asphaltenes in the near wellbore region, the system maintains fluid flow while avoiding the steam short-circuiting problem that would result from excessive light solvent injection. The additive provides a more efficient mechanism for preventing deposition.
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 effectively reduces asphaltene deposition, increases the mobility of asphaltenes in solution, and maintains high heavy oil production rates by keeping over 90% of the additive in the liquid phase, thus preventing steam short-circuiting and ensuring efficient fluid flow.
Implementation Method 1
The liquid phase additive serves to interact with asphaltenes in the steam chamber and mobilizes them for fluid production from the chamber
Implementation Method 2
injecting steam into a subterranean reservoir and generating a steam chamber in the reservoir, such that the injection tubing is in fluid communication with the production tubing within the steam chamber
Data Source
AI summary
A method is provided for producing upgraded heavy oil from a subterranean reservoir by producing a steam chamber within the reservoir by the action of steam and flowing a liquid phase additive into a near wellbore region of the steam chamber to control asphaltenes mobility within the near wellbore region. Build-up of asphaltenes, which derive from the heavy oil, in the near wellbore region has the potential of affecting heavy oil production rates from the reservoir. The additive is formulated to mobilize the asphaltenes within this region.