| Geopressured-geothermal waters are a subset of geopressured reservoirs. As a potential resource,energy contained in the geopressured-geothermal aquifer takes three forms: mechanical energy as excesspressure at the wellhead, thermal energy, and methane dissolved in the aquifer pore water. It is also animportant carrier of water-rock reaction and deep geological power. Geopressured reservoir of Xianyangurban area is a typical of geopressured-geothermal waters, its characteristics are: high pressure, longretention time, strong water-rock reaction, complex buried conditions, with the sedimentary water isotopehydrogeochemical characteristics, easy development but difficult to recharge, different from the generaltypes of geothermal water, it bring considerable difficulties in sustainable development and utilization ofgeopressured-geothermal water, so far, study of geopressured-geothermal water is still rare domestic andoverseas.This paper is preliminary demonstrates the characteristics of geopressured reservoirs in Xianyangurban area, based on the space distribution of isotopic and hydrogeochemical of geopressured reservoirs inXianyang urban area, using the method of isotopic hydrogeochemical and in combination with theoreticalsimulation method. We have a basic understanding on space distribution of isotopic and hydrogeochemicalof geopressured reservoirs in study area, and based on this we demonstrates the basic types, supplies originand genetic types of geopressured reservoirs in study area. This mainly known of this research as follows:The chemical characteristics of geothermal water in Xianyang urban area are widely different. The watertype in the north of the Weihe river north shore fault is all Cl-Na, while in the south of the fault it isclassified into HCO3-Na and SO4Cl-Na. The TDS and the content of Sr of the geothermal water in thenorth of the fault are greater than in the south, which indict that the water in the north of the fault is saltwater and Sr is its main scaling ion while the water in the south of the fault is brackish water. The supplysource of Xianyang urban area is mainly Holocene precipitation which has some what a bad circulationenvironment, so carrying out hot water reinjection research is quite urgent. Nearby the the Weihe rivernorth shore Fault the geothermal water is somehow supplied by a little modern precipitation from the North,Northwest and the West direction. In the flow path of the Northwest direction, chalcedony, calcite, dolomite,kaolinite is precipitate and halite, gypsum, celestite, albite, mica, fluorite is dissolution. The geothermalwater in the Xianyang urban area is basically sealed retention fossil water; there may be some remnant connate water in the deep stratum. |
