RF Solvent Vaporization for SAGD Startup
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Solution Overview
Problem
The existing steam-assisted gravity drainage (SAGD) process for recovering viscous hydrocarbons is inefficient in establishing thermal communication between injection and production wells, requiring a lengthy start-up phase and relying heavily on water and steam generation, which is costly and environmentally challenging.
Innovation Solution
The method involves pre-soaking wellbores with a solvent and using radio frequency (RF) energy to vaporize the solvent, increasing pressure and accelerating thermal communication between the wells, thereby reducing the pre-heating time and improving the efficiency of the SAGD process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional steam injection is used to establish thermal communication between wells, then the SAGD process can be initiated, but the start-up phase requires three to four months which is excessively long
Solution Approach 1:
The patent applies preliminary action by pre-soaking the formation with solvent before steam injection to reduce hydrocarbon viscosity in advance. This pre-treatment prepares the formation for faster thermal communication during the subsequent steam injection phase, reducing the overall start-up time from 3-4 months to approximately 1 month.
Solution Approach 2:
The patent changes physical parameters by introducing solvent to alter the viscosity of viscous hydrocarbons before steam injection. This parameter change (viscosity reduction) enables faster thermal communication and accelerates the start-up phase significantly.
2Reliability
If water and steam generation is used for the SAGD process, then thermal communication can be established, but the process becomes costly and environmentally challenging
Solution Approach 1:
The patent introduces solvent as an intermediary substance that facilitates thermal communication between wells. The solvent acts as a mediator that reduces hydrocarbon viscosity and enhances heat transfer, replacing part of the water/steam function and thereby reducing environmental impact and operational costs.
Solution Approach 2:
The patent changes the physical and chemical parameters of the injection medium by using solvent instead of pure water/steam. This parameter change reduces the environmental footprint and cost associated with water generation, handling, and disposal while maintaining effective thermal communication.
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 the start-up time for SAGD operations from three to four months to one month, enhancing the cost-effectiveness and environmental sustainability by minimizing water usage and steam generation costs.
Implementation Method 1
heating the soaked wellbore of the well pair with radio frequency energy to produce a vapor
Implementation Method 2
The vaporized solvent will increase the pressure in the wellbore, thus squeezing the formation around the wellbore
Implementation Method 3
The heated, mobilized hydrocarbons (and steam condensate) drain under the effects of gravity towards the bottom of the steam chamber
Data Source
AI summary
The method begins by forming a gravity drainage production well pair within a formation comprising an injection well and a production well. The pre-soaking stage begins by soaking at least one of the wellbores of the well pair with a solvent, wherein the solvent does not include water. The pre-heating stage begins by heating the soaked wellbore of the well pair to produce a vapor. The squeezing stage begins by introducing the vapor into the soaked wellbore of the well pair, and can thus overlap with the pre-heating stage. The gravity drainage production begins after the squeezing stage, once the wells are in thermal communication and the heavy oil can drain to the lower well.