The Study On The Experiment Of Methane Emissions From The Gas Field Water In Shunan Gas Field, Sichuan Basin

Methane, is a principle greenhouse gas and the greenhouse effect of unite mass is21times that of carbon dioxide, and it aggravates the global climate warming. Methane is the bases of the nature gas, as the nature gas has a considerable solution in the formation water with a high pressure, methane exsolution occurs when the temperature and pressure decrease greatly after the formation water is taken to the ground surface. Shunan gas field is a major producing area of nature gas, so it is representative for studying the emissions of methane from the gas field water. We studied the samples from the gas field water by the simulated experiment of two different conditions:the open system and the closed system, and contrasted the emissions process and mechanism of the gas field water in the two different systems, and we get the important conclusions below:(1) The methane concentration in the atmosphere samples from gas field water is obviously higher than that in circumjacent air, which shows the methane release from gas field water has an influence on atmosphere.(2) In the open system of5,15and30Celsius degree conditions, methane emissions decreased gradually with the increasing of time at first, then it rebounded, as higher the temperature, the more methane emissions.(3) In the isothermal closed system, the cumulative emissions of methane increased with the increasing of time. In the closed system with changing temperature conditions, the methane emissions reached maximum at20Celsius degree with the temperature increases, and then showed a decreasing trend.(4) The methane emissions from the gas field water is typically affected by original formation pressure in Maokou formation of Shunan gas field. The methane emissions increases when the formation water was taken to the ground.(5) The experiment shows the methane emissions from the gas field water in the open system is much more than that in the closed system, the closed system is more benefit for reducing the methane emissions, not only it can control the temperature but also it can restrain the methane emissions with the increasing of vapor pressure.