阵列声波测井在页岩油体积压裂效果评价中的应用

Application of array acoustic logging in shale oil volume fracturing effect evaluation

陈斌,蔺敬旗,李兆春,吴伟,周炬锋,陈华勇

中国石油集团测井有限公司新疆分公司，新疆 克拉玛依 834000 中国石油集团测井有限公司测井应用研究院，陕西 西安 710000

Xinjiang Branch, CNPC Logging Co., Ltd., Karamay 834000, China Research Institute of Logging Application, CNPC Logging Co., Ltd., Xi′an 710000, China

针对页岩油储层非均质性强、传统方法评价压裂效果精度低的问题，利用阵列声波测井资料开展了偶极横波各向异性、纵波速度径向层析和声波远探测等3项技术在体积压裂效果评价中的应用研究。结果表明：体积压裂裂缝呈不规则网状特征，偶极横波各向异性不明显，方法应用受限；纵波速度径向变化不受裂缝产状的影响，能较好地指示人工裂缝的高度及延伸情况，但纵波频率高、衰减快，无法判断远井壁深层压裂效果；声波远探测利用反射纵波对地层成像，可探测井周几十米内的地质异常体，但远探测反射幅度小、信号弱，处理时容易错失有利信号，增强后的信号又存在干扰信息。根据研究结果，为发挥纵波速度径向层析和声波远探测的综合技术优势，开展了页岩油体积压裂效果评价。该方法既可判断裂缝发育位置和延伸高度，又可定性识别远端裂缝发育情况，使得评价结果更为客观、可靠。

Aiming at the problems of high heterogeneity of shale oil reservoir and low accuracy of traditional fracturing evaluation methods, the application of dipole shear wave anisotropy, P-wave velocity radial tomography and acoustic remote detection in volume fracturing effect evaluation was carried out by using array acoustic logging data. The results show that the fractures of volume fracturing have irregular network characteristics and the dipole shear wave anisotropy is not obvious, so the application of this method is limited. The radial variation of P-wave velocity is not affected by fracture occurrence, which can better indicate the height and extension of artificial fractures, but the high frequency and fast attenuation of P-wave can not judge the fracturing effect in deep layer of far wellbore. Acoustic remote detection uses reflected P-wave to image the formation, which can detect geological abnormal bodies within tens of meters around the wellbore. However, the reflection amplitude of the remote detection is small and the signal is weak, so it is easy to miss the favorable signal in processing, and the enhanced signal has interference information. According to the research results, the volume fracturing effect evaluation of the shale oil is carried out by combining P-wave velocity radial tomography and acoustic remote detection. It can not only judge the development position and extension height of fractures, but also qualitatively identify the development situation of fractures at the far end, which makes the fracturing effect evaluation more objective and reliable.

10.6056/dkyqt202104022