Petroleum has long been the main fuel for power generation and transportation. However, mature oil wells are experiencing high water cut production with the crude oil resulting in high production and processing costs, as well as environmental impacts. Co-current hydrocyclonic technique has been adopted to solve oil/water separation in the downhole, but this process has some limitations. This paper introduces a compact axial inlet conical hydrocyclone to resolve the high water cut problem in mature fields. Experimental investigation results are presented to evaluate the separation of the newly introduced hydrocyclone. An experimental test loop was designed and fabricated. The flow loop was calibrated to manipulate and control various operational variables, namely, the oil/water mixture flow rate (1.5�4.0 m3/h), mixture temperature (50 and 80 °C), and water-to-oil ratio (70/30, 80/20, and 90/10). A gear pump is used to circulate the mixture. The droplets were measured and found to be within 35�38 µm with a mean droplets size of 37 µm. The results showed that mixture inlet flow rate, water cut, and temperature were influencing the separation efficiency and the pressure drop. The pressure drop of the water part was larger than the pressure drop of the oil part. Optimal separation efficiency was observed when the inlet flow rate is 4 m3/h with 80:20 water cut at 80 °C. A general trend of increase in separation efficiency with increased temperature was also observed. © 2019 Elsevier Ltd