An experimental study of a new vane-type pipe separator (VTPS) was conducted for the possible application in the well-bore for oil-water separation and reinjection. Results by using particle image velocimetry (PIV) reveal a better flow field distribution for oil-water separation, which is formed in VTPS than that in hydrocyclone. The effects of split ratio, the oil content, guide vanes' installation and number of guide vanes on oil-water separation performance have been investigated experimentally. Compared to a traditional single hydrocyclone, VTPS shows a good separation performance as the water content at the inlet of VTPS reaches 79.9%, the oil content at the water-rich outlet is about 400 ppm while the split is near 0.70. These results are helpful to provide a possibly new design for downhole oil-water separation. Crown Copyright (C) 2012 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.