反射声波成像测井的物理模拟

The physical modeling of acoustic reflection image logging.

反射声波成像测井的分辨率和测量范围介于常规地震勘探和常规测井之间,在当前油气勘探的诸多领域尤其是随钻测井、大斜度井和水平井评价等复杂油气藏勘探和定量解释中具有实际意义。为此,对反射声波成像测井进行了物理模拟,制作了缩小比例的铝质和混凝土模型井,并用于模拟井旁不同倾角的声阻抗不连续界面对声波的反射。在充液环境下对反射声波模型井进行了实验测量,从全波波形上可以清楚地看到沿井壁传播的折射波和来自井旁声阻抗不连续界面的反射纵波。应用偏移叠加技术对物理模拟波形进行了反演处理,从偏移剖面上反演出的反射界面的尺寸、位置和倾角等几何特性与实验参数基本一致。

Acoustic reflection image logging, whose reso- lution and measurement range are situated between seismic survey and well logging, has great potentials in oil and gas exploration. lt can be used in highly deviated or horizontal wells and logging-while-drill- ing. Physical modeling of acoustic reflection image logging is conducted in this paper. Several scale- down model wells are made with aluminium and con- crete materials. Reflections from reflectors of differ- ent dips are investigated in fluid-filled environment. Refracted waves, which propagate along the borehole sidewall, and reflected P-waves, which are from by interfaces near borehole, can be identified undoubt- edly On measured waveforms. The measured wave- forms are then inverted. The inverted geometrical properties of the interfaces are in good agreement with the experimental parameters.