Coiled tubing gas lift (CTGL) implementation in cemented monobore completion which uses 3.5 inch tubing has been a breakthrough in VICO Indonesia. This gas lift technique has been successful on arresting decline and even ramping up the oil production in this brown field. CTGL application in VICO uses only orifice as the injection point without any presence of unloader. Thus, it has limitation on the deepest point of injection given the available pressure at surface. Declining in reservoir pressure as an effect of depletion drive reservoir is the main issue which results in early gas blowing around and shorter production life.

Coiled tubing gas lift with unloader has been introduced recently to address the weakness of CTGL by adding unloader(s) to CTGL. The idea is to increase oil production and cumulative production with longer production life. Slight modification is needed on the bottomhole assembly of the CTGL to incorporate the application of the unloader. Designing opening and closing pressure of the valve is very important at this stage. This also includes the design of dome and test rack opening pressure.

The trial of this technology has been installed in Nilam well on 2015 and successfully produced 229 BOPD initially which then increase to 807 BOPD with optimization on the injection pressure. Current cumulative production since the implementation of this technology is 152 MBO. This trial project uses 3 unloaders and one orifice as the injection point. The current issue in this project is on the fluctuation of the injection pressure which affects the production rate.

Coiled tubing gas lift with unloader is the newest technique used in Vico to address the limitation of cemented monobore completion.

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