Performance analysis of gas lifted wells with injection pressure operated valves in the Ekofisk field

Abstract

Gas lift design featuring several gas lift valves in a well is common in the industry. The sequence of valves in the tubing string allows for gradual well unloading and injection through the deepest valve (operating point). Gas injection as deep as possible, in turn, results in maximized production rate. Moreover, the unloading sequence is intended to bring well back on production after shut-in periods. There are several gas lifted wells with unloading sequences in the Ekofisk field employing injection pressure operated valves. The primary objective of this study is to investigate the performance of aforementioned wells in order to identify the under-performing wells and possible reasons for lifting issues.