Loading...

Macroscopic recovery mechanisms of in-situ combustion process in heavy oil fractured systems: Effect of fractures geometrical properties and operational parameters

Fatemi, S. M ; Sharif University of Technology | 2012

1436 Viewed
  1. Type of Document: Article
  2. DOI: 10.2118/154839-MS
  3. Publisher: SPE , 2012
  4. Abstract:
  5. The In-Situ Combustion (ISC) as a thermal EOR process has been studied deeply in heavy oil reservoirs and is a promising method for certain non-fractured sandstones. However, its feasibility in fractured carbonates remained questionable. The aim of the present work was to understand the recovery mechanisms of ISC in fractured models and to evaluate the effect of fractures geometrical properties such as orientation, density, location and networking on the ISC recovery performance. Combustion parameters of a fractured low permeable carbonate heavy oil reservoir in Middle East called KEM; applied to simulation study. Simulator has been validated with KEM combustion tube experimental data and validated model modified to 3D semi-scaled combustion cells. It was found that in fractured models oxygen first flows into the fractures and then diffuses from all sides into the matrix. Combustion of the oil in the fractures produces water ahead of fracture combustion front which prohibits oxygen from early breakthrough through fractures into producer. Water imbibes into matrix and causes further oil drainage. Part of this oil imbibes into downstream matrices and the other part produces into producer through fractures. The oxygen diffusion/water imbibition based recovery mechanism is slower in production rates compare to conventional model recovery mechanism, and also results in lower quality of produced oil. It was found that ISC recovery was higher in the presence of networked fractures (presence of both longitudinal and traversal fissures) compare to the case of presence of either longitudinal or traversal fracture systems. Results show that ISC is more feasible in the case of densely fractured reservoirs such as those in the Middle East. Further, sensitivity analysis on air injection rate, formation thickness, injection well depth of perforation and also feasibility of water alternating gas (air), WAG, process for fracture model have been studied
  6. Keywords:
  7. Air injection ; Combustion fronts ; Combustion parameters ; Combustion tubes ; Conventional models ; Experimental data ; Fracture model ; Fracture systems ; Fractured carbonates ; Fractured reservoir ; Fractured systems ; Geometrical property ; Heavy oil ; Heavy oil reservoirs ; In-situ combustion process ; Injection wells ; Middle East ; Operational parameters ; Oxygen diffusion ; Production rates ; Recovery mechanisms ; Recovery performance ; Simulation studies ; Water alternating gas ; Combustion ; Enhanced recovery ; Fracture ; Geometry ; Heavy oil production ; Injection (oil wells) ; Oxygen ; Petroleum reservoirs ; Recovery ; Sustainable development ; Three dimensional ; In situ combustion
  8. Source: Society of Petroleum Engineers - SPE EOR Conference at Oil and Gas West Asia 2012, OGWA - EOR: Building Towards Sustainable Growth ; Volume 2 , 2012 , Pages 593-617 ; 9781622760473 (ISBN)
  9. URL: https://www.onepetro.org/conference-paper/SPE-154839-MS