Solvent-Based Mobilizing Fluid and Loss Circulation Material for Heavy Oil Recovery
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Solution Overview
Problem
Current thermal recovery methods for heavy oil and bitumen, such as steam-assisted gravity drainage, are energy-intensive and face challenges in solvent-recovery processes for efficient and effective commercial application, particularly in preventing solvent vapor from escaping during well workovers.
Innovation Solution
Incorporating a loss circulation material and fluid into the well to maintain a hydrostatic pressure column, inhibiting solvent vapor and gas from exiting during workovers, and using a solvent-based mobilizing fluid to enhance hydrocarbon recovery, with specific materials like PolyBLOK™ C and EnerCure™ degrading to allow well reactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solvent is injected into the hydrocarbon-bearing formation to reduce viscosity and improve mobility, then production efficiency is improved, but solvent vapor may escape during well workover operations creating safety hazards
Solution Approach 1:
A loss circulation material is introduced as an intermediary substance between the solvent-containing formation and the wellbore during workover operations. This material creates a temporary barrier that prevents solvent vapor from migrating to the surface while allowing work operations to proceed safely. After the workover is complete, the material degrades and disappears, restoring normal production without leaving harmful residues.
Solution Approach 2:
The physical and chemical parameters of the wellbore environment are temporarily altered by introducing the loss circulation material, which changes the pressure and compositional parameters to prevent solvent vapor escape. The material's ability to degrade over time provides a dynamic parameter change that transitions from a closed state during workover to an open state for production.
2Productivity
If thermal processes are used to heat the reservoir to mobilize hydrocarbons, then hydrocarbon mobility is improved, but energy consumption and water usage increase significantly
Solution Approach 1:
The patent replaces the thermal field (steam heating) with a chemical field approach by injecting solvent that reduces hydrocarbon viscosity through solvation and swelling mechanisms. This substitution eliminates the need for large-scale steam generation, thereby reducing energy consumption and water usage while achieving the same goal of improving hydrocarbon mobility for production.
Solution Approach 2:
Instead of changing the temperature parameter through steam injection, the patent changes the compositional parameter by introducing solvent that chemically interacts with the hydrocarbons to reduce viscosity. This parameter change from thermal to compositional provides an alternative pathway to improve mobility with lower energy input.
3Reliability
If loss circulation material is injected to prevent solvent vapor escape, then well safety during workover is improved, but the material must be degraded before production can resume adding process complexity
Solution Approach 1:
The loss circulation material is designed with self-degrading properties that allow it to break down automatically after serving its protective function during workover operations. This self-service characteristic eliminates the need for complex manual intervention or additional equipment to remove the material, as it naturally degrades through exposure to formation conditions or microbial activity, simplifying the overall process.
Solution Approach 2:
The loss circulation material functions as a temporary, disposable barrier that is intentionally designed to have a limited lifespan. It performs its safety function during the workover period and then degrades without requiring recovery or removal operations. This disposable approach reduces long-term complexity compared to permanent barriers that would require maintenance and removal systems.
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
Facilitates safe and efficient workover operations by preventing solvent vapor and gas from escaping, allowing for the continued production of hydrocarbons and reducing energy consumption by reusing solvents, while maintaining well integrity and operational safety.
Implementation Method 1
after degradation of the loss circulation material, injecting the mobilizing fluid and producing the produced fluids is commenced
Implementation Method 2
Hydrocarbon solvent is generally utilized to reduce viscosity and improve mobility in the hydrocarbon reservoir
Data Source
AI summary
A process includes injecting mobilizing fluid, including a solvent, through an injection well and into a hydrocarbon-bearing formation. Fluids are produced from the hydrocarbon-bearing formation to a surface through a well, and injection of the mobilizing fluid is discontinued. Gas flow to the surface from the well is inhibited by injecting a loss circulation material that inhibits solvent-vapor flow from exiting the formation through the well such that a fluid column that includes the well kill fluid, the loss circulation material, or a combination thereof is maintained within the well. The well is opened to perform work thereon After degradation of the loss circulation material, injecting the mobilizing fluid and producing the produced fluids is commenced.