沉积盆地深井孔隙压力测量

Pore Pressure Measurements in the Deep Wellholes of Depositional Basins

一、引言在水压致裂应力测量中,最小水平主应力值(Sb)是根据关井时间的裂缝瞬间闭合压力(Ps)确定的,即: Sh=Ps 而最大水平主应力值(SH)则依据下面方程求得: SH=3Sh-Pr-P0 (2) 式中,Pr是裂缝重新张开时的压力,它可以在压裂记录中取得;P0是地层中的孔隙压力,在一般情况下,把它近似地当作静水压力代入上式计算。但对于深部地层来说,则不能简单地取而代之。特别是在数千米之下,孔隙压力常高于静水压力,它不但使水压致裂应力测量资料的分析和解释工作复杂化。

In this paper, we discussed the method of the measurement of pore pressure in deep wellholes of depositional basins and the interpretation of recording curves. By analysing more than 20 curves of pore pressure measurements from the Puyang area of Henan Province, we find that there is pore pressure anomaly from the depth of 2000m downwards where the value is obviously higher than normal one and increases with depth. Finally, we discussed the influence of the anomalistical phcnomina of pore pressure based on the data of hydraulic fracture stress measurements.