Multiphase gas compression to boost unconventional production and reserves

Abstract

Hydraulic fracturing has significantly increased well inflow performance in unconventional reservoirs, enabling their economic development. This improved inflow performance has opened up the possibility of leveraging further reserves and production gains through artificial lift or similar production enhancement techniques. A ‘multiphase compressor’ has been developed with differentiating characteristics:compression ratios of up to 40:1 (an order of magnitude greater than conventional compressors), ability to handle a broad range of multiphase conditions, and significant operational flexibility. This makes it very well suited for deployment in unconventional reservoirs at the wellhead, either on its own in a multiphase boosting capacity or in conjunction with other forms of artificial lift (such as gas lift, plunger lift, and potentially downhole pumping). The multiphase compressor has been deployed in the field on naturally flowing wells, and wells with plunger lift. Production rate increases of up to 300% were achieved, and production was maintained in wells that would have otherwise loaded up and died. Wells were unloaded by reducing wellhead flowing pressures to atmospheric pressure at the compressor suction – similar to flowing the well into an ‘open topped’ tank. The multiphase compressor demonstrated a very broad operating range and the ability to handle slug flow conditions. Further applications to be tested include gas lift and downhole pumping in shale wells, gas wells that have received fracture hits and require clean up from invaded fracture fluids, and coal seam gas production. Multiphase compression has significant potential to increase both production and reserves from unconventional reservoirs and wells.