HISTORY OF A COMMERCIALLY SUCCESSFUL GAS-BASED IOR IN JAPAN: 12 YEARS' CHALLENGE ON MAXIMIZING THE PROFIT OF OFFSHORE OIL AND GAS FIELD BY OPTIMIZING ALLOCATION OF GAS VOLUME BETWEEN SALE AND INJECTION

摘要

Iwafune-Oki Oil and Gas Field located at shallow offshore in Japan was discovered in 1983, and has been producing from multiple oil and gas reservoirs since 1990. After 8 years of plateau production, the field oil started to decline whereas the recovery factor of gas reservoirs still grew sluggish due to the constraints of the local gas demand. There was an incentive to arrest the oil decline by utilizing the potential abundant gas effectively.