Abstract: In practices of oil fields by waterflooding process, a great number of equations of the type-curves have been put forward, among which A, B and C type-curves are widely adopted. However, all these curves would warp upward in mid-late stage of production, resulting in significant differences in recoverable reserves calculation. In this paper, a new set of type-curves are proposed for prediction of the production performance of such a stage, which can be applied to more accurate estimation of the reserves. The case study indicates that the results from the new type-curves are more accurate than those from conventional curves.

Key words: waterflood, characteristic curve, type-curve, recoverable reserves, prediction, production index