VICO Indonesia is an Oil and Gas company which has operated mature fields located in the onshore part of East Kalimantan which has been on production for over 30 years. The fields are dominated by gas reservoirs with a much lower presence of oil reservoirs. Production mechanisms cover from natural depletion to weak and strong water drive, particularly in some of the shallow areas. Recent well completions include single and dual slimhole monobore.The field is a perfect combination of stratigraphic and structural traps with more than 4000 sandstone reservoirs where around 450 of those are oil reservoirs. The oil recovery factor for these reservoirs is in the range of 10-30%. Oil development in this fields performed using gas lift as the main artificial lift while several wells still flowing naturally. Coiled tubing gas lifted (CTGL) wells contributes to 60-80% of current oil production of 8000 BOPD.Totally, 50 CTGLs have been installed in VICO Indonesia where most of those considered successful. The main problem found related with initial operation after installation. Lesson learned has been summarized including the design and the procedure for initial operation. Coiled tubing gas lift design and troubleshooting are rarely found in literature. Thus, this paper presents the detail step by step design and how to troubleshoot the possible failure during early operation. This approach exhibits a real benefit to recover more untapped hydrocarbon with more aggressive program.

The brown field, Mutiara, has been producing for more than 25 years where its reservoirs consist of thousands of lenses as a result of the deltaic sedimentation. Operated by VICO Indonesia, aggressive drilling program was implemented to arrest production decline and to increase additional oil reserves from existing and newly discovered reservoirs. Current practice of producing natural flow will not be sufficient to recover oil from small lenses reservoir. Therefore, integrated works need to be implemented for the oil development in this field. Splitting focus from gas to oil production is long journey to walk. Major facility upgrading was needed to eliminate gas lift system "blank spot". Additional compressor was also needed to maintain gas lift pressure distribution in southern remote area. A thorough project planning and procedure are established to ensure optimum field production. Oil zones evaluations followed by prioritization are discussed with well intervention and construction team. After perforation is completed, PCTGL was designed with thorough calculation. It is important to accurately measure pressure drop along gas lift line since PCTGL use single unloader valve which is sensitive to injection pressure changes. VICO Indonesia cross function team, consisting of Resource Management, Technical Support and Operation, conducted regular bi-weekly monitor during this development phase. It was important to ensure every team carried out their respective responsibility. Then harvest time is coming; Mutiara oil production delivered average production of 4,981 BOPD in 2016, an increase of average 2,970 BOPD than 2013. The integrated gas lift also managed base production annual decline by delivering above 4,500 BOPD for in 2015. In the last four years, VICO Indonesia also managed to produce cumulative of 5.1 MMBO oil from this project.

Completion type in Vico Indonesia is designed mainly based on the subsurface considerations. Multi-layer reservoir consisting of gas and oil reservoirs related with fluvio-deltaic depositional environment influences the production strategy which will need zone isolation for single or commingled production. Many completion types have been implemented since early development including single or dual selective, monobore, and dual monobore cemented as the most recent completion. There are more than 500 wells drilled and completed using dual monobore cemented completion. This completion type gives constraints on the application of common downhole pump lift. Evolution in the completion type requires a different approach in gas lift technique for oil development. Many gas lift techniques have been applied to address the completion types. The gas lift techniques include the implementation of conventional gas lift with SPM, poor boy, coiled tubing gas lift, and coiled tubing gas lift with unloader. The first two methods are common for selective completions while the last two are fit for purpose for monobore completions. The appropriate modification and selection on the gas lift techniques exhibits a real benefit to optimize oil recovery in these various and evolving completion types in VICO. The contribution is around 70% from total oil production while single year gas lift project contributes to approximately 30% of annual production in respective year. Total cumulative production from the application of these techniques is around 10 MMBO. Modification in gas lift techniques is needed to tackle evolution of completion types. Coiled tubing gas lift with unloader is the newest technique used to enhance the advantage of coiled tubing gas lift application. The modification of gas lift techniques will be described in this paper.

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.

Mutiara is a mature field located in the onshore part of East Kalimantan which has been on production for over 30 years. The field is dominated by gas reservoirs with a much lower presence of oil reservoirs. Production mechanisms range from natural depletion to weak and strong water drive, particularly in some of the shallow areas. High decline rates are very common, which results in a very dynamic and challenging environment. The main artificial lift used in this field is gas lift. However, this method is not efficient for depleted or high water cut wells. Another issue is oil wells which located in remote areas which need high investment for surface facilities including gas lift line network and sufficient pressure to lift the oil up to the surface. Therefore, more and more wells will be idle without implementation of other artificial lift systems techniques.Several downhole pumping types have been assessed to tackle these issues such as Electric Submersible Pump (ESP), Progressive Cavity Pump (PCP), and Linear Rod Pump (LRP). Considering hilly swampy conditions of the field that requires more compact type of surface unit and flexible to match displacement rate to well capability as well declines. It is then decided to use LRP to unlock oil potential in idle wells.The first installation of LRP was on September 2014 in X-1 well, this well is the first well drilled in 1982. This installation succeeds on bringing back the well on production. The application of LRP provides opportunity to unlock oil potential from idle wells in this mature area thus maximizing reserve by gaining a few more hundreds barrels of oil per day during the first year.