| In.order.to.keep.the.long-term.development.of.oil-field,.the.pre-experiment of steam stimulation was conducted in Block Jin-45 in September 1991. The water-out reservoir resulted in the serous imbalance of injection recovery factor, the oil-gas factor was very low, and the cost of oil recovery increased too. The test was terminated as the above reasons. The regular test of water flooding was done in Block Jin-90 in September 1992. The recovery efficiency only increased 5%-7% owing to the big ratio of oil-water viscosity and water breakthrough. Many kinds of oil flooding tests were conducted to compared in Block Jin-45, such as regular water flooding, nitrogen gas + water flooding, nitrogen gas + chemical reagents +water flooding, and nitrogen gas flooding. And the oil flooding mechanism was probed into as well. The test result indicated the best means is the non-hydrocarbon miscible flooding of hot water + nitrogen gas + chemical reagents. The pre-test of non-hydrocarbon miscible flooding was conducted in Block Jin-90 in June 1996. The fairly good result of oil increasing, water decreasing and pressure increasing was achieved.The test was expanded in the central Block Jin-90 in September 1999. The good result of non-hydrocarbon miscible flooding had been achieved up to December 2005 after the technical reformations.The oil recovery rate increases evidently, the water production decreases too.The stratigraphic pressure of block rises evidently. The water injectivity profile was obviously controlled. The test result indicates the non-hydrocarbon miscible flooding is very effective to the recovery of viscous oil, which resulting in the evident increase up to 15% of recovery efficiency and raising economic efficiency as well.
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