Abstract:

In viewing the serious injection-production contradictions and highly-dispersed residual oil distribution in the late stage of development of E₃¹ reservoir in Kuergasi oilfield in Qinhai Province, we performed deep profile correction technology laboratory study and pilot test in the high-temperature and high-salinity reservoirs.Based on detailed analyses of the reservoirs, a well pattern with 15 injectors and 30 producers were selected for the pilot test.A technological process with water-plugging and profile correction integrated is established based on identification of preferential water pathways.Flooding characteristic curve shows an incremental recovery factor of 2.1% was achieved during the pilot.During the process, mechanisms of profile correction were further explored and various combinations of injection parameters were tried.Comparing the water-intake profiles and producing profiles before and after the pilot shows that the post-development syndrome was greatly improved by successfully tapping the producing potential of both major and minor oil producing layers.The study indicates that the procedure works effectively in increasing flooding sweep efficiency and the ratio of total producing interval thickness to total perforated interval thickness of producers. For brown reservoirs who have suffered from the similar problem to the one concerned, the procedure may be applied to solve certain technological problems.

Key words: secondary development, deep flooding, enhanced oil recovery, Gasikule oilfield