The Study On DSS For Aggregate Adjustment Of Daqing Oil Field Later High Water-cut Stage

Aiming at the development characteristic of Daqing Oil field at high water-cut late stage and the problems in development process, the aggregate adjustment at high water-cut late stage and the decision support system are researched fully. Then, the aggregate adjustment at high water-cut late stage and the decision support system are established.The development behavioral characteristics at high water-cut late stage are analyzed. Based on the method of fuzzy mathematics, establish the dynamic analysis and development status evaluation model, use the method of numerical simulation to forecast pressure field and saturation field. Based on the geologic model, establish the system of partial differential equations which are used to describe fluid percolation rule by law of conservation of mass, law of conversation of energy, darcy's law and state equation. Then, make the time and space discretized. Namely, scale up the grids of time and oil layer to establish system of linear equations which are used to describe average pressure and saturation in grid block. After that, solve this system of linear equations and obtain pressure-saturation field. Make the water injection rate into every grid by method of dynamic split, establish the prediction method of water saturation in every grid block by method of material balance and then forecast the remaining oil saturation. Genetic Algorithms and fuzzy logic reasoning by weight which are used in the decision support system of intelligence calculation are researched deeply. Genetic Algorithms is based on the mechanism of natural selection and population genetics. It's a random, iterative, evolutional and universal searching method. It simulates the phenomenon of procreation, copulation and variance in the process of natural selection and natural heredity. Based on the rule of the survival of the fittest, use the operator of heredity to generate and optimize the unit gradually. At last, obtain the optimum unit. Based on these theories, it provides fracturing, water plugging, reperforating, produced fluid enhancing, well shut-in, converted injection and other stimulation treatments for preferred method. At first, choose the wells which are fit for stimulation treatment according to the measure principle of every well and layer and give the influential factor. Then, use the method of fuzzy set to make first level judge and second level judge, give every factor new grade. Based on theoretical analysis and empirical statistics, determine the preferred level and range of every factor and choose the wells and layers which are best fit to do the measures.