Method for calculating recovery ratio under secondary-tertiary combination development mode

Abstract

The present disclosure relates to the field of oil recovery technologies in an oilfield, and discloses a method for calculating recovery ratio under a secondary-tertiary combination development mode. The method includes: obtaining a sweep efficiency of water used in the process of a primary oil recovery EV1 and an oil displacement efficiency of the primary oil recovery ED1; performing a secondary development of water flooding using injection-production conditions of the primary oil recovery, and obtaining an increment percentage of the EV1, ω, caused by the secondary development of water flooding; directly performing a tertiary oil recovery using injection-production conditions of the primary oil recovery, and obtaining an increment percentage of the EV1, ε, caused by the tertiary oil recovery and an oil displacement efficiency of the tertiary oil recovery ED2; establishing a calculation model of a sweep efficiency of displacement media used in the process of the secondary-tertiary combination development EV2+3 according to EV1, ω and ε; and calculating an increment in a recovery ratio under the secondary-tertiary combination development mode relative to a recovery ratio of the primary oil recovery ΔER2+3. The increment in the recovery ratio ΔER2+3 as determined in the present disclosure takes the advantage of the secondary development of water flooding that has an integrated well network and the advantage of the tertiary oil recovery that can increase the oil displacement efficiency, and thereby can be used for theoretically understanding the increased value of the recovery ratio under the secondary-tertiary combination development mode.

Dependencies are inferred from the claim text.