Abstract
AbstractIn order to study the distribution law of residual oil in high water cut old oilfield to further reflect the distribution law of flow units in the later development period and the production rate of different flow units, this paper takes the high water cut sandstone K oilfield which has been developed for 40 years as an example. In this paper, we started by studying the cored wells. The reservoir lithology particles of K oilfield is fine with a weak correlation between porosity and permeability, the heterogeneity is strong, and the waterflooding development effect varies greatly. In this paper, from studying the cored wells, a variety of parameters of reservoir lithology, physical properties and seepage characteristics were obtained by core analysis. By using principal factor analysis and stepwise discriminant analysis, 11 relatively independent parameters such as porosity, permeability, shale content, reservoir quality factor and permeability variation coefficient are selected, which can reflect the flow unit type. Cluster analysis and discriminant analysis methods were used to establish the discriminant functions of various flow units. At the same time, the study area was divided into 8 flow units according to the rhythm of sand body and the characteristics of production and injection profile. Based on the dynamic characteristics in the later development period of K oilfield, combined with the test data of production and injection profile, the type of flow units, the development effect of various flow units, and the distribution law of residual oil were analyzed. It is concluded that the middle and upper part of A1 type flow units and the middle and lower part of B1 type flow units with permeability contrast greater than 5 are main residual oil potential zones.KeywordsSandstone reservoirFlow unitStrong heterogeneityCluster analysisResidual oil distribution
Published Version
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