Study On The Evaluation Methods Of Development Effects Of Waterflooding Typical Blocks In Lasaxing Oilfield

Oilfield development effect evaluation which is an important approach to make sure the production direction and adjustment measures works through the whole oilfield development history. So far, Lasaxing oilfield waterflooding has entered into ultra-high water cut development stage completely, facing more and more production difficulties. How to evaluate oilfield development effects reasonably and correctly so as to excavate the development potential of the high water cut oilfield thoroughly, deepen the knowledge of reservoir development rule and direct oilfield development reasonably and effectively becomes an extremely urgent problem.In this paper, the waterflooding development system and its properties of Lasaxing oilfield have been carried through an overall analysis on application of the theory of systems engineering. At the same time, starting from the structure and property of waterflooding development system, the reservoir sub-system and the token system of its geological condition, the water-injection sub-system and oil-extraction sub-system and their token system were studied. The evaluation index system of geological conditions was established based on the organic integration of the reservoir engineering principles and systems engineering theory, including channel sand proportion, permeability, effective thickness, permeability variation coefficient, reserves abundance, oil viscosity, saturation pressure and initial oil saturation eight indexes. Through fuzzy mathematics method, the geological conditions of waterflooding blocks of Lasaxing oilfield were evaluated comprehensively. According to the evaluation results, thirty six blocks of Lasaxing oilfield were classified to four categories as the first kind, the second kind, the third kind and the fourth kind of blocks. The system efficiency of oilfield development was put forward. The evaluaiton indexes system of oilfield development effect was established, which includes injection-production pressure, well spacing density, oil-water well ratio, injection-production ratio, plane sweep coefficient, vertical sweep coefficient, displacement efficiency, injectivity index, productivity index and cumulative injected water remaining rate ten indexes. A comprehensive evaluation method of development effect of Lasaxing waterflooding oilfield was established. On the base of classified geological condition, thirty six blocks of Lasaxing oilfield were classified to four categories according to the evaluation results of system efficiency. The east of Beisan area was selected as the typical block. From the system efficiency of oilfield development, the main problems and the potential of oilfield development were studied and the major adjustment measures were given. Through the study, the results of this paper provide scientific basis and technical support for establishing the twelfth five-year development planning of Daqing oilfield and adjusting oilfield development of ultra-high water cut stage.