35% Oil Increase for Gas Lift Platform Using Transient Modelling Approach

Abstract

In the oil and gas industry, gas lift is a widely used artificial lift method to boost the oil wells production, particularly when the reservoir pressure is low enough to lift the fluid to the surface. Nevertheless, this application used to face several challenges which affected its processes and led to investing more costs to keep its operations running successfully. This paper summarizes a comprehensive study aimed at optimizing the gas lift operations for one of the crucial offshore oil platforms in the Gulf of Suez Petroleum Company (GUPCO) in Egypt, at minimal costs through the application of a holistic transient modeling approach. While the steady state modeling approach is useful to many engineering processes in the O&G industry, it is not suitable for modeling the gas lift systems as it can experience many transient phenomenon such as transferring of the gas injection point to different levels across the well different operations, changing of the valves setting pressure to accommodate the variation in the temperature happened at the well's different production phases, pressure surging incidents that might occur due to the sudden closure of valves, and the presence of slug flow which can be attributed to improper gas lift design or due to the change of the formation fluid characteristics causing drastic changes in the production rates. Accordingly, a transient modeling approach had been applied to resolve all these gas lift dynamic issues. The findings provide valuable insights into the design, operation, and troubleshooting of the overall gas lift systems using multiple scenarios, including redesigning the valves operating pressures, adjusting the gas injection rates, recommending deeper points of injection, exchanging some types of the installed operating valves, advising a cleanup program for both the wellbores & the gas lift mandrels, and detecting the plugged valves that need to be exchanged in the next intervention plans. The project resulted in increasing the net oil gain for the platform under study by 1500 BOPD (35% Gain) after applying some wellbores interventions as recommended by such a holistic modeling approach. The study also includes the cost measures of such services with a focus on finding the most cost-saving method, thus it helped GUPCO reach its production target with minimal efforts & costs. This paper marks an exceptional solution for perfecting the gas lift applications in GUPCO by allowing the simulation of all the dynamic operations of the gas lift systems which helped in solving all the unstable production incidents & the unloading failures that cannot be captured using the customary steady state gas lift modeling approach, thus, it encouraged GUPCO to consider the gas lift transient modeling as a fundamental element in the optimization of all the future gas lift operations.