Consider Convex Obstacles Natural Gas Transportation Pipeline Network System Planning Studies

Natural gas gathering and transferring engineering is a very important stage in production after oil-gas accumulation exploration, exploitation and oil-gas recovery. Generally speaking, its investment occupies 60%-70% of oil field ground projects system and 40% of the whole oil field engineering. Therefore, the optimal design of the system will greatly reduce the disbursement. Considering the complexity of the whole system in structure and technology, the mathematical model established can only to a certain extent get close to the actual situation. How to improve the precision of the mathematical model has been the aim of the pipeline researchers all the time, the research purpose of this paper is to make mathematical model get much closer to the practical situation.Obstacle dose exist during the optimal process of gathering and transferring natural gas pipeline network, and the effect of it to the plan and design, especially to the distribution of the project is so great that it can't be ignored. During the course of optimization, if we can't reasonably take the effect of obstacle into consideration, it will so surely reduce the effectiveness of the whole project as to make it less perfect. Therefore, it has a very important practical meaning to consider the effect of obstacle during the whole optimal process of gathering and transferring natural gas pipeline network.Regarding the two-step stations Natural gas gathering and transferring pipeline network as the research object and considering the effect of convex-surface shape obstacle and line-shape obstacle to the optimal design, the paper put emphasis upon topological optimization of pipeline network, and based on this, optimal topology parameter optimization of pipeline network was also studied.According to the relationship between pipeline investment and the construction investment of gas gathering stations, gas wells partition mathematics model was set up. The greatest advantage of mathematics model is that it could complete the optimization of network allocation at a time in specific condition. During the course of optimal partition of gas wells, it could determine the best way to pass the obstacles through calculation, and add the positional evaluation of temporary gas gathering station.In this paper, the process of select gas gathering stations' location was divided into two parts: optimize location and positional evaluation. On the basis of optimal partition of gas wells, Tabu Search algorithm and simplex algorithm is adopted. The topological optimization of the main and lateral gas network was divided into the determination of Joint Station's station and the optimization of pipeline connecting way. During the course of determination of Joint Station's station, considering the salience of changing weight and referring the ideas of progressively growth method, the optimization connecting way with minimum cost was determinedafter determining the Joint Station's position.Aiming at the mathematics model's characteristics of pipeline parameter optimization, Tabu searching algorithm was adopted to solve the model which was widely used in combinatorial optimization algorithm, succeeding in solving two critical problems: the establishment of the both discrete solution space and neighborhood solution. This algorithm has brought discreteness into effect.Based on the theoretical research mentioned above, homologous calculation procedure was developed; the results of the procedure demonstrate that it has directive significance for planning and design work of new exploitationed natural gas field.