| Dating back to middle and late 80 s of 20 th century, Daqing Oilfield had set on the path to the research on the technology of ASP flooding, which was a long process of indoor evaluation, pilot field test and industrial field test. Both indoor and field tests proved that ASP flooding could enhance the oil recovery efficiency by 20% on the basis of water flooding. The increment of oil recovery efficiency of weak base ASP flooding was almost equal to that of strong base ASP flooding. However, weak base ASP flooding can eliminate the scaling problem of strong base in production end. In recent years, weak base ASP flooding has been wide-spread in Daqing Oilfield, and has gradually become the primary method to promote the application of ternary compound flooding.In the process of weak base ASP flooding, influenced by geology and development factors, there existed apparent difference of injection-production performance, effect laws and adjustment method between well groups. Therefore, the adjustment law should be concluded to find out a comprehensive adjustment method which is suitable for different well groups. Theoretically guided by reservoir engineering and enhancing oil recovery technology, by means of numerical simulation, taking reservoir geology and fluids from Xing 12 Block in the 5th production plant in Daqing Oilfield as research object, the thesis created the elaborate geological and numerical model of the target reservoir. The history matching water flooding and chemical flooding on pilot field was carried out. According to static and dynamic data of wells, 3 type wells of A, B and C were confirmed. Aiming at injection parameters, subsequent profile controlling, fracturing and water plugging of 3 type wells, further optimization study was conducted. Results show that the original oil in place in Xing 12 Block is 649.70×104 m3, and the oil in place in PI3 oil formations for compound flooding is 114.36×104 m3. The oil recovery efficiency after water flooding in the block for compound flooding only gets 35.21%, and that after ternary compound flooding in which the injection parameters are optimized rises by 22.01% on the basis of water flooding. The adjustment methods that are applied to different well types are:(1) for type A, concentration and injection rate of main and auxiliary slug were enhanced to balance injection pressure. On initial stage and during the period when the water cut decreases, fracturing is implemented to enhance the injection-production capacity. When the water cut increases, profile controlling and water plugging are implemented to control the rise of water cut.(2) For type B, we reduce the injection rate to balance the injection pressure. When the water cut decreases or it is lower, fracturing is implemented to enhance the injection-production capacity. When the water cut increases, profile controlling and water plugging are implemented to control the rise of water cut in parts of wells.(3) For type C, due to its thin growth, poor connection and low injection-production capacity of oil formations, polymer and alkali concentration in main slug, the size of auxiliary slug and injection should all be reduced to control injection pressure. When the water cut decreases, fracture is implemented to enhance the employment of oil formations. When the water cut is lower, we also enhance the injection-production capacity by fracturing. Compared with original plan, the increment of oil production through the optimization of injection parameters and adjustment measures reaches 3.37×104 m3. And the oil recovery efficiency is enhanced by 2.95%. Oil recovery efficiency of target formation gets 59.09%. The effect of enhancing oil production is better. Therefore, the method the thesis present to classify the wells to optimize injection parameters in ternary flooding and the time of adjusting measures has important guiding significance on the application of ternary compound flooding. |
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