부산대학교 도서관

Predicting formations ahead of the drill bit at low angles can have a significant impact on drilling operations. Due to low sensitivity and a scarcity of useful measurements, solving this inverse problem is extremely difficult. Current techniques for look-ahead applications are limited to 1D inversions based on ultra-deep electromagnetic measurements. Realistic formations, on the other hand, may have complex structures such as unconformity or fault. As a result, this paper looks into the 2D inversion method for look-ahead applications and investigates the look-ahead capability of an ultra-deep electromagnetic logging tool. Because prior knowledge is important for improving inversion performance, a reference model extracted from the shallow resistivity sensor is incorporated into the cost function. It has been discovered that the reference model can significantly improve the look-ahead capability. Furthermore, several synthetic examples are used to demonstrate the efficacy of the 2D inversion algorithm. It also demonstrates that the look-ahead ability is strongly related to resistivity contrast.