Study On Flow Units Of Shan 2 Reservoir Of Zizhou Gas Field

Flow unit is the most basic unit of description and characterization of the gas reservoir.The study of reservoir flow unit is helpful for a better understanding of the underground reservoir,providing a set of reasonable and effective technical methods for the study of reservoir heterogeneity.Zizhou Gas Field belongs to tight gas reservoir,in which Shan 2 reservoir is the most favorable development zone of the Upper Paleozoic of Ordos Basin,and many gas reservoirs of Shan 2 have been detected.This paper mainly studies the flow unit of tight gas reservoir taking Shan 2 reservoir of Zizhou gas field as an example.This paper chooses the combination of geological and mathematical method to divide flow units of Shan 2 reservior by the summary contrast of division method at home and abroad,and the basic division solution is as follows: to divide small layer division vertically by geological method firstly;to divide flow units in the layer by mathematical method finally.To divide the Shan 2 reservoir to four small layers by mie cycle theory firstly,and to verify the validity of the division results through the classification compared with previous results.Then to cluster analyze by selecting the parameters stangding for permeability and sedimentation: porosity,permeability,gas saturation,effective thickness and storage coefficient.To divide the flow units into A,B,C three categories,and to define the reservoir below the lower limit of effective thickness as D category.To establish the discriminant function of flow unit that is suitable for the study area,to establish the corresponding relationship of flow unit contribution index and open flow capacity through the introduction of flow unit contribution index and to verify the applicability of the division results of flow units.Then to study the distribution of flow units.The first step is to establish the distribution of flow units.To establish the model of sedimentary phase,mainly applying the multi-point phase simulation in the process of modeling.To establish the attribute model based on the phase control modeling.Then to establish 3D distribution model of flow unit through the properties of superposition in the space combined discriminant function that is suitable for the study area with attribute model.Finally,this paper calculates the contribution index of each grid unit,and makes the distribution graph of gas well category in the plane according to the relationship of contribution index with gas well categories,which has certain guiding significance for detecting the position of high yielding wells.