抄録
Due to the recent soaring of oil and gas price, the exploration activities to seek new oil and gas fields has dramatically accelerated. At the same time, the application of the secondary and the tertiary recovery scheme to the existing oil fields has been drawing industry's keen attention.
The Enhanced Oil Recovery (EOR) based on gas injection is not necessarily a new technology but it has more than 80 years of history since its inception during 1920s. The U.S. Department of Energy (DOE) has recently announced that the EOR based on the gas injection technology has been recognized as proven technology and they have started re-evaluation of the national oil reserves taking the gas injection technology into consideration to re-assess some of major onshore fields.
In the early days, gas injection operations were conducted in the purpose of reservoir pressure maintenance, however, it has been recognized as time that the gas injected into reservoir has other benefits, such as improving recovery factor of heavy crude by means of improving its mobility, improving recovery factor of crude in general under miscible condition by means of improving sweep efficiency, etc. Miscible gas flooding has a huge potential to dramatically improve crude recovery factor, therefore, more gas injection projects that are currently on-going are targeting this scheme.
On the other hand, proffessor Dandina Lao, et al. at Louisiana State University (LSU) are proposing a new method based on a new concept, Gas Assisted Gravity Drainage (GAGD) process. They have been continuously obtaining good results in their investigation and research, which has been making the expectation to GAGD process even higher.
In this paper, the author anticipates to compare the features of conventional immiscible gas flooding such as WAG (Water Alternate Gas Injection), currently-remarked miscible gas flooding and the latest GAGD process, as well as, to introduce an example of preliminary study conducted on the field located U.S. GoM offshore deep water where a gas injection EOR has been planned to implement.
