EFFECT OF SUB-OPTIMAL PRODUCTION OF A GAS LIFTED WELL (Case of not injecting from the Orifice)
Production of crude oil is a major requirement to sustaining the wellbeing of any petroleum company. Wells that cannot produced liquids to the surface under their own pressure and in some cases wells that are producing to the surface require lift technologies to enable enhanced oil production. Some oil wells require lift assistance from the beginning and almost all require it sooner or later. Gaslift method is one of the most common artificial lift methods applied in the oil industry in order to boost oil production. Its main principle is the injection of gas into the well to reduce the effective density of the fluids produced from the reservoir, hence the weight of the fluid column. As a result, the declined reservoir pressure is sufficient to lift the fluids up to the surface. In this study, PROSPER software was utilized to case study wells J-J1 and J-J2. Well J-J1 is a dead well at 50% water-cut and well J-J2 is producing at an oil rate of 892.148STB/day at 40% water-cut. An optimization plan and continuous gaslift system design was carried out on wells J-J1 and J-J2 to ascertain the maximum production rate, optimum gas injection rate and the effect of injecting liftgas at shallower depths. The results of this work suggests that; The oil production rates increased from 0STB/day and 892.148STB/day to about 668.589STB/day and 1272.23STB/day at an optimum gas injection rate of 2.92MMscf/day and 2.19MMscf/day for wells J-J1 and J-J2 respectively.