Identification of Low-Efficiency and Invalid Injected Water Circulation Channels in an Oilfield in Qaidam Basin

The oil field being studied in the Qaidam Basin is currently one of the main oil fields in Northwest China. It has a long oil-bearing interval, a thin reservoir thickness, a small sand body size, and a high degree of heterogeneity. It is characterized with “thin, multiple, scattered, and miscellaneous” features. As water flooding progresses, the water cut of the oil producers increases, which results in intensify(adj) interlayer and intralayer conflicts, and low-efficiency and invalid oil displacement. It is challenging to implement measures to enhance production. Accurately and quickly identifying the layers with low-efficiency and invalid circulation is crucial for solving this issue and improving the development efficiency. The study uses the grey correlation method to establish an interwell low-efficiency and invalid circulation channel identification model based on eight dynamic and static parameters, such as average porosity, effective perforation thickness, maximum permeability of the perforated layer, maximum monthly liquid production in 12 months, etc. The sresults has been validated by production profile and tracer analysis, which proved that the model can effectively identify the target channels with low-efficiency and invalid circulation. This method provides a comprehensive solution of the challenge and effectively contribute to the better development of target oil fields.