Empirical Compressor Performance Maps for High-Speed Multi-Stage Compressors
High-speed compressor packages used in natural gas gathering applications have not historically been subject to the scrutiny of field performance mapping and equation development. In recent years the criticality, size, and volume moved by such compressors has made it economically justifiable and profitable for operators to have more and more accurate maps. Experience with a tried and true field methodology used in natural gas transmission applications and the changes needed for gas gathering are discussed here. The results of this activity show that theoretically generated curves can predict horsepower and flow, either low or high by as much as 20%. Several fundamental differences in control and operation required special attention and changes to the testing protocol. Although more challenging than transmission applications, empirical methods do work in field gathering high speed, multi-stage applications. Given the cost of gas and value of gathering contracts, small improvements in the operation of high speed field compressors makes empirical mapping not only viable, but desirable. High speeds present some different challenges to the field engineer but with persistence and proper tools these challenges can be met.