| Natural gas. a kind of high quality and clean energy, is playing a more and more important role in satisfying domestic gas supply and promoting economic development. Meanwhile, the demands for natural gas exhibit a significant seasonal non-balance and fluctuation, which has exerted great pressure upon gas supply. It is necessary to speed up the construction of underground natural gas storage (UNGS) to keep the balance between gas supply and demand. This paper takes underground natural gas storage from depleted gas reservoir as a study subject, and deals with forecasting city gas load, and numerical simulation of natural gas injection/production dynamic circulation, and also parameter sensitivity analysis through the application of nodal analysis.The main contents this paper discusses as following:(1) analyzing the characteristics of kinds of models of forecasting city gas load to obtain their application conditions.and selecting out the optimal model for each forecasting city gas load through example calculation.(2) establishing a natural gas flow equations by the law of mass conservation and replacing the non-linear partial differential flow equation with linear algebra equations through oil-gas reservoir numerical simulation of finite-difference method, and then researching the changes of formation pressure with time and space after solving the equations by using the Crout decomposition technique.(3) optimizing the relevant parameters based the influence of reservoir physical property and gas injection/production on the injection-production process of Underground Natural Gas Storage respectively.(4) based on the natural gas flow equation, building up a mathematical model which can obtain a accurate solution for gas leakage through trial method and numerical simulation of finite-difference method.(5) deducing a new pressure-temperature coupling calculation model, presenting a subsection solution to pressure and temperature distribution of a vertical well integrating the coupling influence between pressure and temperature in the wellbore.(6) letting the gas injection-production under maximum gas production to avoid erosion corrosion, carrying out the sensitivity analysis of the tubing inside diameter parameter, well-head injection pressure and average reservoir pressure through the application of nodal analysis.(7) programming for all mathematical models mentioned above using the object-oriented programming technique and VB.Net programming language, outputting the graphs and data through Tee-Chart, and then finishing the practical software of underground natural gas storage from depleted gas reservoir. |
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