水溶气资源富集的主控因素及其评价方法探讨

DISCUSSION ON MAIN CONTROL FACTORS AND EVALUATION METHODS IN THE CONCENTRATION OF WATER SOLUBLE GAS

水溶气是天然气的一种,其主要成份是甲烷。水溶气在地下的富集主要受温度、压力、水矿化度和储层水容量等因素的控制。储水量越大、水介质温压越高,地下可能储集的水溶气资源量越大。在水量和水介质温度压力条件相同的情况下,水的矿化度越低、水的溶气饱和度越高,水的储气量就越大。评价水溶气资源除应考虑地下天然气富集量之外,还应考虑钻探井的水日产量及采出地表后的释放气量。水溶气被采到地表时温压降低的幅度越大,释放出的气量越大。一般说来,每方水在地下含气饱和度在1～10m3之间;在我国东部沉积盆地这一数值为1～6m3。大庆长垣及其以西地区萨尔图、葡萄花和高台子组储层的水溶气量高达4500×108m3,依油气当量计算,相当于一个储量超过4.5×108t的大油田。在我国,水溶气具有广阔的勘探前景。

Water soluble gas is one kind of natural gas which are mainly composed of methane. The concentration of water soluble gas is dominantly controlled by temperature、pressure、water salinity as well as the water capability of the reservoir. The water\|soluble gas resource underground become rich as water storage capacity rises at higher temperature and pressure of the water medium. Both the quantity of natural gas resources underground and the water production of the drilling well per day as well as the quantity of gas released on the surface should be concerned. The more highly decreasing of the water soluble gas producing pressure, the more amount of gas being released. Commonly, gas saturation of water underground varies from 1 m3 to 10 m3, but in east sedimentary basin of china such as Daqing area the figure is highly up to 4 500×108 m3 that equal to a over 4.5×108 t reserve field. The exploration of water soluble gas in our country has good respects.