Abstract: This paper analyzed the variation of the fluid productivity index and oil productivity index in Wenmi oilfield and their affected factors in which include the effects of crude viscosity and starting pressure gradient on these two indexes with changes of water-cut. The studies of the variation of the fluid productivity index for different microfacies with increasing production differential pressure show that fluid productivity index of channel sand decreases faster than that of edge sand with the increasement of production pressure differences; the poorer the percolation property of reservoir,the more serious impermeability caused pressure declines; the effect of water-cut on fluid productivity index and productivity index is greater; the decrease of fluid productivity index and productivity index occurs due to formation degassing. The results will be as a guide for fluid-extracting oil recovery in Wenmi oilfield.

Key words: Wenmi oilfield, fluid productivity index, productivity index, starting pressure gradient, production differential pressure