Gas Lift Optimization within Field Capacity Limitations

Abstract

Optimizing oil production with facility constraints has become a challenge to most E&P companies even as they pursue sustainable resources. The innovative gas lift technique overcomes this challenge. The conventional gas lift well system has long been in use, but the design most times is limited by gas availability and pressure which limits the depth of gas lift injection for improved production rates. This challenge may not be evident in matured producing fields with gas compressors installed with available non-associated gas source wells, but truly such challenges arise in new fields especially owned by indigenous companies where much uncertainties at an early field life unavoidably allows you to be more stringent in expenditures towards development of a field gas lift project. A new gas lift concept was developed and studied in Field A in an offshore field of the Niger delta in the absence of gas compressors. This design has been proven to be suitable because it was used to bring four closed wells online even when those wells were removed from the company annual forecast. The original design consists of a minimum of two unloading valves and an orifice at a deeper depth, but because of the absence of scrubbers and gas compressors in the facility, pressure depletion in the reservoirs caused four flowing wells to be closed. The new design then sets dummy at shallow mandrels and uses a modified size of orifice to optimize available pressure and gas required to open the closed wells and still sustain other gas lifted wells connected to the same gas lift manifold. This campaign resulted to an additional 7000Bopd which is the primary discussion of this paper.