Optimization of Outflow Control Devices Design in Steam-Assisted Gravity Drainage Models with Wellbore Trajectory Excursions

• Author / Creator

  Anas Khalil Sidahmed

• Canada has giant oil reserves which ranks third worldwide with proven oil reserves of 171 billion barrels. Alberta alone contributes with 165.4 billion barrels found in oil sands. However, those oil sands are extremely viscous and only 10% are recoverable by means of open-pit mining. In-situ thermal recovery methods such as Steam-Assisted Gravity Drainage (SAGD) have been developed and adopted as an efficient mean to unlock the oil sands reserves.
  Different reservoir geological settings and long horizontal wells impose limitations and operational challenges on the implementation of SAGD technology. Well pair trajectory excursions (unintentionally generated trajectory deviations due to suboptimal drilling operations) are some of the complications that lead to non-uniform steam chamber conformance, high cumulative Steam-Oil Ratio (cSOR) and low bitumen recovery.
  Conventional dual-string completion scheme (a short tubing landed at the heel and a long tubing landed at the toe) has been widely adopted in most of the SAGD operations. Such configurations allow steam injection at two points: the toe and the heel sections of the horizontal well. However, these completions have demonstrated poor efficiency when reservoir/well complications exist. Tubing-deployed Flow Control Devices (FCD’s) have been introduced to offer high flexibility in delivering specific amounts of steam to designated areas (such as low permeability zones) and ensure uniform development of steam chamber in the reservoir. The work in this thesis presents the results of a numerical effort for optimizing the design of Outflow Control Devices (OCD’s) in SAGD wells for different scenarios of well pair trajectory excursions.
  A coupled wellbore-reservoir SAGD simulation model was constructed to optimize the placement and number of ports in each single OCD. Three different cases were generated from the constructed basic SAGD model with each case having a certain well pair trajectory which causes variable lateral distances between the well pair.
  Results of the optimized OCD’s cases demonstrate a higher SAGD efficiency compared to their corresponding conventional dual-string cases. Those enhancements were reflected in a higher steam chamber conformance, a higher cumulative oil production, and an improved Net Present Value (NPV).

• Subjects / Keywords

  • SAGD
  • Optimization
  • FCD
  • OCD
  • ICD
  • NPV
  • CMG
  • Bitumen
  • Simulation
  • Thermal
  • cSOR

• Graduation date

  Fall 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R32R3PC88

• License

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