| Cha 30-fauotblock lies in northern Chaheji oilfield Its current production rate is below 0.46%, the water cut above 54.99%, the recovery percentage of reserves only arriving at 22.5%. Two thirds of oil wells produce little or have been closed because of high water cut and 50 percent of injection wells stop injecting because of low efficiency. For studying the methods of improving the water-flooding efficiency and the ultimate recovery of Cha 30-faultblock, the following four aspects are studied in this paper:First, how much is the water-flooding potential of the oil field? That is to say what is the ultimate maximal water-flooding recovery by all the current home and abroad techniques and technologies.Second, how to evaluate the current development efficiency? How much does the present development thought and level fit the oil field?Third, which artificial factors imposed during the previous course of development, are correct and have gotten good results? Which factors are unfavorable for the development or do not fit for the oilfield?Fourth, the improvement in water flooding efficiency of Cha30 fault-block by taking integrated measures is analyzed and evaluated.Firstly, this paper selects the index systems which reflects the above four aspects and summarizes the calculation methods of each index. After accurate analyzing and evaluating each single factor, by means of principle of AFIP, the weight of each index is calculated. Then according to corresponding principles of fuzzy mathematics and the evaluation standard of each index, the evaluation vector is calculated for each index. At last, according to the weight and evaluation vector of each index and the index system, the potential of water flooding, water-flooding efficiency, the artificial factors and the approachable improvement of water-flooding efficiency of Cha 30-block are evaluated.Through heavy studies this paper indicates that the maximum recovery of cha30 fault-block is 25%, the main current problems are the low degree of water-flooding control and serious interference between layers due to the geological complexity. Byfurther study in this paper, the next main area to be adjusted should focus on the well groups of Cha201, 83-16, 83-14, 83-12, 83-5, 207, 203, 30-7, 30-6, and the adjusting method should focuses on the reasoning of drilling infill wells. By the aid of reservoir roiling map, profile-logs of production and injection well, analyze and do contrast and between layers in detail, re-recognize the geological condition, do utmost to improve the flooding pattern on the whole, overcome the interference between layers, seek possible potential layers and tapped by single layer if found. |
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