LAUSR

Abstract This review focuses on the overall development and applications of the electrical imaging logging in oil-based mud (OBM) with the aims to help researchers learn more from past and extend more relevant study. Because of the normally larger resistivity of OBM than that of water-based mud (WBM), the imaging quality of conventional electrical imaging logging method is poor in OBM, resulting in the imperative requirement of the electrical imaging logging method and technology in OBM. The electrical imaging logging in WBM is initially summarized. Then, the emphasis is on the attempt to acquire clear imaging in OBM. The main methods include the development of conductive OBM, the mudcake-scrapped method, the four-terminal measurement method, the capacitive coupling method and inversion processing etc. On the perspective of imaging results, the clear and quantitative resistivity imaging is more popular than the only qualitative results, and furthermore, more information can be obtained to uncover additional formation features, such as the formation dielectric permittivity image and the standoff image between the imaging pad and formation, which extends the interpretation and applications of electrical imaging logging in OBM. This study will contribute to the development of electromagnetic logging technique in OBM. The sufficient verification and interpretation of the imaging results in OBM and artificial intelligence-based data processing may be the improvement direction in the future.