已固结岩石中不含游离气体的热流体热动力研究

Research on dynamics of geothermal fluid in indurated rocks without free gas

结合地热地质工作所能采集的数据,在假设实验的条件下,推导出流体膨胀压表达式。它适合于一切温、压条件,并揭示了:①流体膨胀压是地热回灌的一个制约因素,在天津地区古近系储层膨胀压是0.53～0.61MPa;②盆地中热源点流体膨胀压是推动流体向热源点、向浅部运移的基本动力;③重力势分压(初压)与流体密度相关,密度越小,重力势分压所占比例越少,当流体密度为初始密度一半时,重力势分压为0MPa,其温度区间是350℃～408℃,与流体的超临界点相关,相当于低阻带深度,在天津地区该深度是8～10km,即这一深度是流体重力循环的最大深度。

A formula of fluid swelling pressure （FSP） has been presented under the conditions of hypothesis testing in combination with the data collection in geothermal-geological fieldwork. The formula is fit for all temperature-pressure conditions. It shows that ① the FSP is a restrictive factor of geothermal injection, which ranges from 0. 53 to 0.61 MPa in Palaeogene reservoir in Tianjin area; ② the FSP of thermal source points in the basin is basic dynamics of liquid towards thermal source points and shallow positions ;③ the differential pressure of gravity potential （DPGP） is closely related to the liquid density. The less of its density is, the less percentage of the DPGP. When the fluid density reaches the half of initial density, DPGP will be 0 MPa, and the temperature range will be 350℃ -408℃, which is related to the super critical point of liquid. The corresponding depth of low resistant zone in studied area is at 8 - 10 kin, which is the maximum depth in fluid gravity circulation.