Study On The Reservoir System And Well Pattern Adjustment Of Complex Fluvial Facies

Due to complex and variable sedimentary environment, the complex fluvial facies reservoir has multiple sedimentary microfacies on the plane and many oil small layers in the longitudinal direction, the heterogeneity of which is very strong. In the early stage of development, because of lacking geological data, this kind of reservoir uses wide spacing horizontally and utilizes one set of development system. When the reservoir is developed in a certain stage, planes problem and layers problem becomes severe, and the well pattern and the layers system adjustment must be carried out in order to improve oil recovery efficiency. For layers system adjustment and well pattern adjustment in the complex fluvial facies reservoir, the following work is done in this paper:(1) Numerical simulation model which is built in the conventional approaches can not reflect the distribution of sedimentary microfacies. To solve this problem, according to distribution characteristics of sedimentary microfacies and permeability, the numerical simulation models which can reflect the distribution of sedimentary microfacies are built. And these models are divided to multiple regions on basis of different of relative permeability curves, which reflects that sedimentary microfacies impact on the formation of remaining oil. The analysis of numerical simulation examlpe shows that this modeling method can reduce significantly the workload and uncertinty of adjusting parameters in history matching.(2) Three distribution types of remaining oil are obtained by numerical simulation model reflecting sedimentary microfacies. The reasons for the formation and the measures for well pattern adjustment are annlyzed. The research results show that the model can reflect the ramaining oil by the incompletion of injection-production pattern and the heteogeneity of reservoir.(3) The optimum time of water injection were studied in the well pattern infilling and adjustment. The wells injected after 3 yeras have the best effect through the comparison of different water injection plan(4) The layer system subdivision and adjustment are studied, mainly based on the change of interlayer interference. The formula of interlayer interfernce variation is detived from the gap increases of liquid production between high and low permeability layer. In the mechanism, the reason of the increase of interlayer interference is that the increase of water saturation in the high permeability layer is greater than that of the low permeability layer.(5) The interlayer interference variation coefficient is defined for describing the variation of interlayer interference quantitatively. Based on field test data, the chart of layers subdivision and adjustment is calculated in commingled production.