In Western Siberia major reservoirs of oil fields with traditional geological structure were entering later and closing phase of development. It poses new challenges to Rosneft Oil Company and opens prospects for exploration and production of hydrocarbons in reservoirs with a complex geological structure and the poorly understood productive formations of the Achimov complex and Tyumen suite. Achimov deposits confined to the fundoform area of the X oil field’s clinoform complex are one of such productive formations. These deposits are characterized by sufficient net pay, a large number of permeable intervals, low permeability, weak connectivity and also both lateral and vertical reservoir heterogeneity, which is primarily associated with the conditions of formation of these sediments. Oil of Achimov deposits is classified as tight oil.
This paper presents the results of an integrated approach to the analysis of geophysical data, geological structure and defines development plan for Achimov deposits. The key issues are a high degree of reservoir heterogeneity, a low degree of predictability, saturation determination and, high water-cut as well as rapid decrease of production rates. Based on results of geology and petrophysics analysis and production data, geological model of the productive formation was detailed with intra-layer correlation taking into account the clinoform structure of the reservoir. Petrophysical dependencies were corrected, the saturation model was refined, which made it possible to construct a predictive map of the water cut, assess the risks and optimize the purpose and order of well drilling. This approach in using a two-dimensional geological model and forecasting the initial parameters was translated to other Company's oil fields with a similar geologic structure, which made it possible to improve the predictive ability of productive formations models.
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