The Optimization Research Of Xifeng Oilfield's Surface Gathering System Scheme

The region where Xifeng Oilfield locates is the steep topography, and Xifeng Oilfield is the kind of oilfield that is low permeable, and has high gas/oil ratio. Considering these distinguishing features, Xifeng Oilfield adopted a new and creative gathering mode to adapt itself to the features, such as advancing water flood, enlarging the gathering diameter, decreasing the number of stations, and oil-water-gas three phase transportation.The introduction of new gathering mode into Xifeng Oilfield is to fulfill its own needs. Although the mode is creative and innovative, it will also inevitably influenced by man-made influence when it is designed. So some optimization theories should be introduced and used to evaluate the new gathering scheme on the basis of not interrupting the main gathering mode. Firstly, a new mathematical model was established. The design variables of the new model include the site of all stations and the inner diameters of all pipelines and the object function of this model is the total cost of the gathering system when it is in the period of design ending, besides, all kinds of constraint conditions were also considered. However, before solving this model, well cluster should be classified using the gathering diameter. The following step is to use fuzzy cluster analysis to judge the presence of pressured point. Finally, Genetic algorithm and penalty function were applied to solve this model. Change the gathering diameter, and obtain the minimum total cost corresponding to the gathering diameter. The final choice of optimum planning scheme is based on the one which has minimum total cost. C++Builder6.0 was used to develop a software which is used to determine the optimal planning scheme, and in order to be precise and vivid, three-dimensional terrain data were gained and three-dimensional topographical map was generated.