Economic Analysis And Application Of Single Point Gas Lift Systems For Marginal Fields Of The Niger Delta

ABSTRACT 

The purpose of this study is to develop an innovative technique for optimized gas lift design for marginal fields of the Niger Delta. This study used well data from mature fields located southwest of the Niger Delta to develop optimized gas lift design techniques using the single point continuous gas lift approach. A total of fifty-nine (59) wells from the fields were selected for preliminary screening as potential gas lift candidates. The screening process involved; reviewing well test histories/data, completion status, reservoir parameters, and surface facilities conditions/constraints. Thereafter, a nodal systems analysis tool was used to build and calibrate/match well models with past well test data for each individual well. Potential gas lift candidate well models were used to design for continuous gas lift for both the conventional and single point techniques. When the gas lift models were tested for deliverability and sensitized for optimum production, a total production rate gains of twenty-four thousand, three hundred and nine (24, 309) barrels of oil per day (BOPD) were obtained by design from the single point technique. The single point technique/approach when compared with the conventional continuous gas lift design was observed to be only 1422BOPD less than the convention (i.e. 5.5% reduction in production rate) but with substantial project cost reduction resulting to 8 - 21% increase in net present value (NPV). Following these findings/results, the author then developed a new objective function for net present value (NPV) optimization suitable for economic evaluation of continuous gas lift design in marginal fields of the Niger Delta. The method of solutions for this model provided the algorithm for the further development of a stand-alone computer program that simulates production and reservoir parameters to optimize project net present value (NPV).