Steam assisted gravity drainage (SAGD) made great success in developing super-heavy oil or oil sands projects. However, steam chamber growth and the performance may be impaired when shale laminae with high frequency exist. Inspired by the successful application of vertical-horizontal offset well pair combined steam drive and gravity drainage (VH-SDGD) process in Liaohe super-heavy oil projects, the feasibility study of VH-SDGD process in a shallow oil sands project was conducted using numerical simulations. The application conditions and performance of steam drive and gravity drainage process in Liaohe super-heavy oil and other oil sands projects were evaluated. Their common point is that they have undergone a period of CSS or SAGD process, and the newly deployed vertical or horizontal wells often need to implement steam stimulation. Inspired by this, the conditions for establishing thermal communication between the vertical and horizontal wells were explored by numerical simulation based on the dilation-recompaction model. On the basis, the performance of VH-SDGD process and SAGD process based on a typical pad sub-model in a shallow oil sands project was compared by using numerical simulations. Under the condition of vertical-horizontal well spacing of 30 m and operating pressure of 2.6 MPa, it takes 5–6 years of steam stimulation to achieve thermal communication between the vertical injector and horizontal producer, corresponding to a heating radius expansion rate of 2.5–3 m/year at 80 °C. Furthermore, the comparison results indicate that VH-SDGD process can achieve higher oil production rate than SAGD process, but it also has limitations such as difficulties in deploying vertical wells under the limitations of surface swamp environment and slow preheating of vertical wells, and a significant increase in SOR. This paper first evaluated VH-SDGD process by systematic numerical simulation and proved important reference in Alberta oil sands projects, Canada. With the help of the early evaluation wells, it can improve the SAGD performance of adjacent horizontal producer to some extent.

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Potential Evaluation of Vertical-Horizontal Offset Well Pair Combined Steam Drive and Gravity Drainage Process in Oil Sands Project

  • Guang-yue Liang,
  • Yang Liu,
  • Hong-jun Wang,
  • Yu Bao,
  • Jiu-ning Zhou,
  • Jixin Huang

摘要

Steam assisted gravity drainage (SAGD) made great success in developing super-heavy oil or oil sands projects. However, steam chamber growth and the performance may be impaired when shale laminae with high frequency exist. Inspired by the successful application of vertical-horizontal offset well pair combined steam drive and gravity drainage (VH-SDGD) process in Liaohe super-heavy oil projects, the feasibility study of VH-SDGD process in a shallow oil sands project was conducted using numerical simulations. The application conditions and performance of steam drive and gravity drainage process in Liaohe super-heavy oil and other oil sands projects were evaluated. Their common point is that they have undergone a period of CSS or SAGD process, and the newly deployed vertical or horizontal wells often need to implement steam stimulation. Inspired by this, the conditions for establishing thermal communication between the vertical and horizontal wells were explored by numerical simulation based on the dilation-recompaction model. On the basis, the performance of VH-SDGD process and SAGD process based on a typical pad sub-model in a shallow oil sands project was compared by using numerical simulations. Under the condition of vertical-horizontal well spacing of 30 m and operating pressure of 2.6 MPa, it takes 5–6 years of steam stimulation to achieve thermal communication between the vertical injector and horizontal producer, corresponding to a heating radius expansion rate of 2.5–3 m/year at 80 °C. Furthermore, the comparison results indicate that VH-SDGD process can achieve higher oil production rate than SAGD process, but it also has limitations such as difficulties in deploying vertical wells under the limitations of surface swamp environment and slow preheating of vertical wells, and a significant increase in SOR. This paper first evaluated VH-SDGD process by systematic numerical simulation and proved important reference in Alberta oil sands projects, Canada. With the help of the early evaluation wells, it can improve the SAGD performance of adjacent horizontal producer to some extent.