把深部灰岩富水性问题转化为灰岩孔隙度问题,通过Willie时间平均方程构建孔隙度与波阻抗关系,利用递推反演得到波阻抗,并转换为孔隙度,孔隙度分布特征与已知裂隙展布特征相符,得到钻孔验证.结果表明:波阻抗值呈近似高斯分布,两端为波阻抗误差,通过滤去高、低值端消除误差;孔隙度公式对于灰岩适用,波阻抗值增大时,孔隙度值单调递减;由于计算面积小,灰分对孔隙度的影响可以不考虑.钻孔验证表明相对孔隙度值在0.162以上为灰岩富水区域,单孔最大出水量达到90m^3/h.
On the basis of analyzing the matter of water-rich region in the deep limestone, a relation between porosity and impedance was derived by the Willie time-average equation. The impedance was calculated by recursive inversion and translated into the porosity, which coincided with the crack distribution characteristics and was verified by actual drilling. The results show that the impedance approximately obeys Gaussian distribution, errors inclined to high- and low-value are eliminated by a filter. The relation between porosity and impedance is suitable for limestone. When the impedance is increasing, the porosity is monotonously decreasing. The effect of pelitic sediments on porosity is neglected because of so small exploration area. According to the drilling verification, the limestone water-rich region exists while the porosity value above 0. 162 and the maximum inflow of water is more than 90 m^3/h.