Steam-Solvent-Gas Process for Heavy Oil Recovery
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Solution Overview
Problem
Current steam-assisted gravity drainage (SAGD) processes for heavy oil and bitumen recovery face inefficiencies, particularly in maintaining thermal efficiency and achieving high production rates, due to heat loss and steam condensation, which can lead to reduced oil flow rates and increased steam consumption.
Innovation Solution
The process involves initiating steam injection in a SAGD configuration, followed by solvent injection and optional co-injection of non-condensable gas (NCG) to maintain reservoir temperature and pressure, allowing for reduced steam usage and enhanced oil mobilization, with additional producers aiding in pressure-driven oil extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If steam injection is used in SAGD process to heat heavy oil and bitumen, then oil viscosity is reduced and oil becomes mobile, but heat loss to overburden increases and thermal efficiency decreases
Solution Approach 1:
A non-condensable gas (NCG) intermediary is introduced between the steam chamber and the overburden. The NCG acts as a thermal barrier that reduces heat loss to the overburden while allowing the steam chamber to maintain high temperatures for oil mobilization. The NCG accumulates at the top of the chamber and provides insulation without condensing, thereby improving thermal efficiency.
Solution Approach 2:
The process changes the compositional parameter of the chamber contents by introducing NCG alongside steam. This creates a gas mixture where the NCG portion does not condense and provides thermal insulation. The partial pressure of steam is reduced by NCG accumulation, which lowers the temperature in the top portion of the chamber and reduces heat loss to overburden.
2Temperature
If steam is continuously injected to maintain high temperature in the steam chamber, then oil remains mobile for production, but steam consumption increases and operational costs rise
Solution Approach 1:
The NCG serves as a pressure-supporting intermediary that reduces the need for continuous steam injection. The NCG travels large distances without condensing and conveys the pressure of the chamber, providing pressure support that facilitates gravity drainage of oil. This allows reduced steam rates while maintaining operational conditions.
Solution Approach 2:
The NCG provides continuous pressure support and thermal insulation throughout the production phase, allowing the system to maintain oil mobility and production rates with reduced steam injection. The NCG remains in the chamber and continuously performs its insulating and pressure-support functions.
3Productivity
If additional producers are added to increase oil production rates, then recovery efficiency improves, but well complexity and operational difficulty increase
Solution Approach 1:
The production system is segmented into multiple independent producer wells rather than relying on a single complex well configuration. Each producer well operates independently to drain oil from specific regions of the reservoir, allowing for modular expansion and simplified individual well operations while achieving high overall productivity.
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 improves thermal efficiency, accelerates oil production rates, reduces steam consumption, and maintains high recovery rates similar to SAGD, while minimizing heat loss and optimizing viscosity for efficient solvent interaction with the oil phase.
Implementation Method 1
steam is injected into the oil reservoir continuously from the top horizontal well and the heated oil in the reservoir drains by gravity
Implementation Method 2
the heated oil in the reservoir drains by gravity from the reservoir into the bottom horizontal producer well
Implementation Method 3
The NCG accumulates near the top of the chamber and reduces the partial pressure of steam. This results in temperature reduction (as compared to SAGD) in the region of NCG accumulation.
Implementation Method 4
This NCG and steam mixture provides some insulation near the top of the reservoir which in turn reduces heat losses to the overburden.
Implementation Method 5
solvent injection into the reservoir from surface is initiated, the solvent mixing with the mobilized reservoir Oil for production as an oil phase liquid
Data Source
AI summary
A system and method of production of hydrocarbons, such as heavy oil or bitumen, by injection of steam, solvent and NCG is provided, which combines the benefits of SAGD, VAPEX, and the use of an additional producer, with specific timing specifications for the initiation of solvent injection prior to inter-chamber fluid communication.