偶极横波远探测典型地质体解释模型研究及应用

Application of forward modeling to typical geological characterization using dipole reflection imaging

偶极横波远探测技术是近年来发展起来的一门重要的地球物理测井技术,它把常规测井技术的测量范围从井周1 m左右提高到几十米,在井旁裂缝和孔洞等地质体的探测中取得了较好的应用效果。本文根据偶极横波辐射声场和接收声场的互易性,提出了一种快速计算井旁地质体反射声场的解析方法——远场渐近解,实现井旁孔洞、裂缝等典型地质体反射声场的快速计算,分析了不同地质体的远探测成像特征,在此基础之上,与已有实际井资料结合建立了偶极横波远探测的解释模型,并将其应用于海上实际井旁地质体评价。应用结果表明,偶极横波远探测解释模型可用于海上缝洞型地层识别、井旁断层或断裂带判断等,效果明显。

Dipole acoustic reflection is important in acoustic logging technology in recent years.It makes themeasurement of the conventional well logging ranging from1meter up to dozens of meters around the welland has achieved good results in the exploration of the fractures and vugs by the side of the well.Based onthe reciprocity between the sound field of dipole shear wave and that of the receive,we have proposed a rapidanalytical method for calculating well reflected acoustic field of geological bodies-far gradual solution.Withthis method,we can implement the fast computation of well holes,fractures and other typical geological bodyreflection field and analyze the different geological bodies far detection imaging characteristics.By combiningthe method with the field data,we have established the dipole shear reflection interpretation models andapplied them to the evaluation of geological body on sea.The application results show that the dipole shearwave detection model can be used to explain the vuggy formation identification,fault or fault judgment on sea.