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一、引言在水压致裂应力测量中,最小水平主应力值(S_b)是根据关井时间的裂缝瞬间闭合压力(Ps)确定的,即: S_h=P_s 而最大水平主应力值(S_H)则依据下面方程求得: S_H=3S_h-P_r-P_0 (2) 式中,P_r是裂缝重新张开时的压力,它可以在压裂记录中取得;P_0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,而且也会对测量技术和压裂工艺方面带来极大的
I. INTRODUCTION In the hydraulic fracturing stress measurement, the minimum horizontal principal stress (S_b) is determined by the instantaneous closure pressure (Ps) at the time of shut-in, ie: S_h = P_s and the maximum horizontal principal stress (S_H) Is calculated according to the following equation: S_H = 3S_h-P_r-P_0 (2) where P_r is the pressure at which the fracture is reopened and can be obtained in the fracturing record; P_0 is the pore pressure in the formation. In general, Put it approximately as hydrostatic pressure into the above formula. But for the deep strata, you can not simply replace it. Especially at thousands of meters, the pore pressure is often higher than the hydrostatic pressure, which not only complicates the analysis and interpretation of hydrofracturing stress measurement data but also greatly contributes to the measurement technique and fracturing process of