西安─咸阳地热田异常地层压力初步研究

A prelim inary study on abnorm al form ationpressures in Xi′an┐ Xianyang geotherm al field

简述了西安—咸阳地热田地质背景，对近年来部分地热井提供的地层压力显示做了初步总结。首次提出，该地热田在较大范围内存在高压或异常高压地层压力，流体动力系统具双层结构特征。初步认为其成因是由于沉积盆地快速沉降，储存在地层中的孔隙流体在基本密封条件下，因欠压实作用而导致压力异常增高的结果，进而推论该地热田属“地压型”地热系统。

The geological setting of Xi′an Xianyang geotherm al field is discussed and m eanw hile the infor m ation of abnorm alform ation pressures from geotherm alw ells com pleted in recent years is sum m arized. Itis the first tim e to indicate that there are high and supernorm al high abnorm al form ation pressures in them ost part of the geotherm al field characterized by the double layers structures of fluid dynam ic system s,w hich is considered prelim inarily being resulted from quick subsidence of sedim entary basin and from poreliquid pressures abnorm alincreasing due to undercom paction of strata in a basically seal condition. It fol low s that the Xi′an Xianyang geotherm al field belongs to the geopressured geotherm alsystem .