声波曲线分层重构反演在岩性预测中的应用

APPLICATION OF SEPARATE LAYER RECONSTRUCTION INVERSION OF ACOUSTIC CURVE IN THE LITHOLOGIC PREDICATION

塔南凹陷属于断、坳叠置盆地，不适合对全井段或大范围数据进行声波曲线重构。为了提高塔南凹陷岩性预测精度，分析了地层岩石物理性质及测井响应、地震响应特征；从反映岩性能力较强的伽马、声波曲线中分别获取高、低频信息，在对其进行融合的基础上获得了拟声波曲线并用于井约束反演。应用结果表明，拟声波曲线提高了岩性分辨能力，声波曲线分层重构反演技术能够提高反演的分辨率和精度，反演成果符合率从78％提高到86％。

South Tamtsag Sag pertains to faulted-downwarped superposed basin, which is not fit for the acoustic curve reconstruction on the whole interval data or large-scale data. In order to improve the lithologic predicated accuracy in South Tamtsag Sag, the formation petrophysical property and characteristics of log response and seismic response are analyzed. The high and low frequency information are obtained from the gamma and acoustic curve that reflects lithology strongly respectively, and based on the fusion of two curves, pseudo-acoustic curve is obtained and used for well-controlled inversion. The results show that, the lithologic resolving ability is improved by using pseudo-acoustic curve, and the separated-layer reconstructed inversion of acoustic curve can enhance the resolution and accuracy, including that coincidence rate of inversion result improves from 78% to 86%.