Quantitative Identification of Breakthrough Channel in Water Flooding Reservoirs at Later Stage

Water breakthrough is one of the main barriers for EOR of reservoirs by water flooding at later stage.In order to enhance oil recovery in water flooding reservoirs,and to identify the breakthrough channels precisely,a method to study the water breakthrough channels quantitatively with dynamic data has been shown in this paper.First,water breakthrough wells can be identified through curves of dynamic data,and then,breakthrough relations can be determined according to the correlation factors between injection and production wells under different conditions.Lastly,breakthrough channel volumes can be obtained by building a model between breakthrough volume and injection-production rates.Well 57217 in Block 57220 in Karamay Oilfield has been analyzed by this method systematically.The distribution of water breakthrough channels of the whole block has been further analyzed and the volumes of the water breakthrough channels have been calculated.According to study,water breakthrough may be found not only inside a well group limitedly,but also can be found between wells in different injection-production well groups.The quantitative identification of water breakthrough channels provided a theoretical basis for measures of formation section control and water shutoff.