基于Xu-White模型TZ地区致密砂岩弹性波速测井解释

Logging Interpretation of Tight Sandstone Elastic Wave Velocity in TZ Area Based on Xu-white Model

深层致密砂岩储层是TZ地区油气勘探、开发的重点,纵横波弹性波速精细解释对地震、测井及钻完井施工均具有重要意义。由于该地区大部分井缺少密度及横波测井资料,而这些资料往往是弹性波速反演或进行预测效果验证所必须的。本文首先利用常规中子、泥质等测井资料对声阻抗进行反演,对各井岩石密度进行精细解释。利用基质矿物模量自提取方法及Xu-White模型对致密砂岩基质矿物体积模量及剪切模量、干岩样体积模量及剪切模量进行表征,最后利用Gassman方程对岩石纵横波波速进行预测。结果表明,AC与自适应提取的基质矿物各模量间存在较好的二次多项式相关性,因此可以利用AC对基质矿物各模量进行定量表征,从而简化自适应提取方法,提高计算效率;利用该方法预测的纵波及横波波速平均相对误差分别小于0.8%和2%,明显好于常规经验法,因而对于该地区深层致密砂岩储层地质结构精细解释具有参考价值。

The tight sandstone reservoir in depth is the key point of oil and gas exploration and exploitation in TZ area. The detailed interpretation in longitudinal wave, shear wave and elastic wave means a lot to the execution of earthquake experiment, logging, drilling and completion. Due to the lack of the data, including the density logging and shear wave logging of most of the wells, which is necessary to the inversion of the speed of the shear wave and conducting the validation of prediction. The author does the inversion of wave impedance at first, utilizing the data of ordinary neutron logging and mud logging, in order to get the detailed interpretation on density of the rocks to all wells. Bulk modulus and shear modulus of the matrix mineral of tight sandstone and the dry core sample are represented, using the method of matrix mineral and Xu-White method, and then the speed of the longitudinal wave and shear wave of the stone is predicted through Gassman equation. It shows that there is good correlation between AC and the extracted mineral matrix modulus, so if we use AC to quantitative mineral matrix modulus, the extraction method is simplified;the average relative error of the speed of longitudinal wave and shear wave, predicting through this method mentioned above, is lower than 0.4% and 2%, which is obviously better than ordinary methods in experience, which possesses the reference value to the detailed interpretation on geology construction of sandstone reservoir in detail in that area.