Perpustakaan Digital ITB

Gas lift is an artificial lift technique used to increase oil wells flow rate. In this method, high pressure gas is injected into the oil column in the wellbore to reduce its density and make it easier to flow. But, during its application in the field, determining the optimum gas lift rate is crucial, because excessive gas will block the oil flow and reduce its rate, whilst injecting less gas won’t be able drive the production to the maximum limit. Field X, which is an offshore field, has been producing oil since December 1989. After producing for more than 30 years, the oil rate production has declined drastically due to the pressure drop, from 1503 to 301 Psig. This phenomena is inevitable, but there a lot of methods to solve this problem and one of them is by using artificial lift. The main objective of this paper is not only to improve the current oil rate, but also to forecast and optimize the oil production in the future by using artificial method which is selected first on the beginning of the study. Hence, several steps must be done, starting from artificial lift screening. After that, model construction and history matching is done by using Material Balance software. Then, the suitable wells for continuous gas lift are selected based on its reservoir and fluid properties by using the Vertical Lift Performance software. Finally, optimization and prediction of this field’s production is accomplished by Surface Facilities software in order to establish the optimum scenario for Field X. By applying the reinjection continuous gas lift, oil production optimization in X field is done. This can be seen by comparing the oil rate and cumulative oil production on 10 years of production forecasting, where production increment occured. By using reinjection continuous gas lift method, the selected wells (Well 1 and Well 2) produce 0.031 MMSTB (36.47 % increment) and 0.025 MMSTB more (5.76 % increment) than the cumulative oil production without any artificial lift applied for the 10 years production forecasting. Those increment is very essential for mature field, such as X field.