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本文推导了关于射线参数的横波(SS)反射系数近似及横波射线弹性阻抗(SREI)表达式。SREI可以写成S-波入射角或者P-波反射角的表达式,分别记作SREIS和SREIP。由井资料计算得到的弹性模型表明SREIP比SREIS及一般的横波弹性阻抗(SEI)具有更强的储层岩性和流体识别能力。Castagna和Smith(1994)收集的25种样本表明大角度SREIP比一般流体因子具有更好的流体识别能力。每个样本包含一组泥岩、含水砂岩和含气砂岩。实际应用也表明,由纵横波阻抗计算得到的大角度SREIP能有效识别致密含气砂岩储层。
This paper derives the approximation of the transverse wave (SS) reflection coefficient and the expression of transverse wave elastic impedance (SREI) for the ray parameters. SREI can be written as either the S-wave angle of incidence or the P-wave angle of reflection as SREIS and SREIP, respectively. The elastic model calculated from well data shows that SREIP has stronger reservoir lithology and fluid identification ability than SREIS and general shear elastic impedance (SEI). Twenty-five samples collected by Castagna and Smith (1994) show that high-angle SREIPs have better fluid identification capabilities than typical fluid factors. Each sample contains a set of mudstone, water-bearing sandstone and gas-bearing sandstone. The practical application also shows that the SREIP calculated by the S-wave impedance can effectively identify the tight gas-bearing sandstone reservoirs.