Gas-Assisted Gravity Drainage (GAGD) Process for Improved Oil Recovery

Water Alternating Gas injection (WAG) or Simultaneous Water and Gas Injection (SWAG) floods have been proposed as very<br>good solution to overcome gravity segregation and better EOR performance in compare to conventional continuous gas<br>injection (CGI). However WAG-Based processes cause some problems associated with increased water saturation including<br>diminished gas injectivity. As an effective alternative for WAG, Gas Assisted Gravity Drainage (GAGD) for conventional<br>reservoirs has been developed (US Patent 2006/0289157) that takes advantage of the natural segregation of gas from liquid<br>hydrocarbon during injection. The GAGD process consists of placing a horizontal producer near the bottom of oil column and<br>injecting gas through existing vertical wells. As the injected gas rises to form a gas zone, oil and water drain down to the<br>horizontal producer. Application of GAGD for IOR in naturally fractured reservoir is discussed here based on some facts and<br>figures.