Field B is undergoing implementation of an accelerated development plan and around 40 wells have been drilled so far. Due to the volatile nature of the crude and high GOR, gas recycling was identified as the reservoir pressure maintenance strategy. There are 4 gas injectors in the field injecting into two reservoirs. As per the original development plan, no artificial lift was envisaged and model results showed sustained natural flow from the well. However, after drilling and completing the wells, it was found that sand connectivity and continuity were far more complicated than expected. This resulted in depleting the reservoirs in certain compartments thus requiring some form of artificial lift. Further, this field will be undergoing a gas blow down project from 2015 onwards, and the challenge to the Well & Reservoir Management Team was to maximize recovery before gas blow down.
A series of options were considered and gaslift was selected as the most viable artificial lift mode. Lead time for the conventional gaslift and the cost associated with special piping materials were adversely impacting the plans and an innovative idea of auto gaslift was proposed as an alternate to conventional gaslift. Accordingly, Well #XX was selected for application of this technology. Auto gaslift uses high pressure gas from a gas reservoir admitted into the tubing using an intelligent completion & special ICV with gas trim and straddle packers. A down hole pressure gauge installed on top of the packer will assist in tuning the choke settings during auto gas lifting. Based on the success of this well, 5 more wells were re-completed with Auto gaslift technology resulting in increasing the production by 50% from the field. Currently, this technology is being evaluated for other fields in the company's assets.
This paper explains the technology of Auto gaslift, details of intelligent completion used in the wells, results obtained, gaslift optimization, lessons learned and way forward for artificial lift in other fields with similar reservoir conditions.