Resource-Efficient Model of an Offshore Platform Compressor Station for the Declining Production Period of a Gas-Condensate Field

Under conditions of gradual depletion of gas-condensate field reserves and declining well production rates, one of the key challenges in operating offshore production facilities is improving the energy efficiency and reliability of process equipment, particularly compressor stations used for gas gathering, treatment, and transportation. Resource conservation and the adaptation of operating modes to changing production conditions require flexible compression systems capable of operating efficiently over a wide range of inlet flow rates and pressures. This article examines examples from three key regions where compressor stations have been adapted to declining production rates and reservoir pressures, and analyses the challenges encountered under actual operating conditions. A compressor model is proposed for the late stage of field development, during which the production rate of gas-condensate wells decreases from 5.0 million m³/day to 0.5 million m³/day over a ten-year period. The wellhead pressure and compressor suction pressure decline from 5.0 MPa to 0.1 MPa, while the discharge pressure remains at 5.5 MPa. Calculations were performed for the principal operating parameters, including gas production rate, wellhead and compressor suction pressures, the capacity of a single compressor under different configurations, the required number of compressors, and the total annual capacity of all operating compressors. The proposed compressor-unit reconfiguration scheme makes it possible to compress natural gas for at least nine years without requiring major upgrading or the construction of a new compressor facility. Unlike centrifugal compressors, which become inefficient when operating below 50% of their design capacity, the proposed configuration maintains effective operation at loads as low as 10% of the design capacity.