Study On Oil Gathering And Transferring System Operation Optimization For Daqing Peripheral Oilfield

In recent years, Daqing oilfield development has already entered high water cut production stage. The load of oilfield surface production system is generally lower, and system operation is unbalanced. Because of the effects of rising surface system loss, oilfield production cost assumes an obvious increasing trend. As one of the primary energy consumers in the oilfield, the conflict between dropping production rate of oil-gas gathering and transferring system and its rising energy loss is more and more conspicuous. As to Daqing peripheral oilfield, because of the great exploitation difficulty and other causes, its cost is even higher. Therefore, the study on oil gathering and transferring system operation optimization for Daqing peripheral oilfield will play an important role in controlling oil production loss rising, cutting down on oil production cost and realizing high efficiency, low loss, orderly regulation and scientific management.Based on oil gathering and transferring system of Daqing peripheral oilfield, the following aspects are studied in this paper: (1) The Least Squares Method and optimization fitting technique is adopted to fit the calculation formula of wellhead temperature. The mathematic model of it, which is solved by DFP algorithm, is also established. And instances indicate that contrasted with the calculation results of original formula, fitting absolute deviation is reduced by 3.52 percent and relative deviation 16.51 percent.(2) According to the configuration and process characteristics of oil gathering and transferring network of Daqing peripheral oilfield, the calculation methods of network hydraulic and thermal analysis, which are based on node flow equilibrium and energy equilibrium principle, are concluded. Meanwhile, a numbering method of nodes and pipeline segments, which is convenient for parameters calculation, is presented. And the calculation formula of node parameters is deduced. (3) An optimization mathematical model for oil gathering and transferring system operation parameters, whose objective function is the minimum system loss, is established. The model is a nonlinear mathematic programming problem that is not convex or concave. Based on configuration characteristics of the model, it is advised to solve it by use of sequential quadratic programming algorithm. (4) Based upon the theoretical research above, an oil-gas gathering and transferring system simulation and optimization operation software is programmed. The software is applied to the simulation and operation parameters optimization for an oil gathering and transferring system of Daqing peripheral oilfield. Contrasted with data before optimization, the temperature of blended water drops by 14℃, total quantity of blended water decreases by 232t per day, electric power consumption of booster station per day decreases by 228 KWh, natural gas 2880m3, natural gas consumption per ton oil decreases by 15.8 m3 per day, and booster station general cost per day drops from 3085yuan per day to 1546yuan per day. Its energy saving effects are obvious.