application for geo-steering

Key words:  electromagnetic wave resistivity (EWR)  measurement while drilling (MWD)  tilted antenna  geo-steering  anisotropic formation  dyadic Green's functions

Abstract:

The response of a kind of electromagnetic wave resistivity measurement while drilling (MWD) tool with tilted antennas was computed via the dyadic Green s functions produced by magnetic dipoles in horizontally stratified anisotropic media. The influence of the relative dip angle of the borehole and the angle of the tilted receiver antenna on the amplitude ratio and phase difference of the received signal were analyzed. The characteristics of the horns appearing in the responses of the conventional and renovated MWD tool were analyzed. Numerical illustration results show that the electromagnetic wave resistivity MWD tool with tilted antennas can provide an indication of the existence of bed boundary much earlier than conventional tool during a directional drilling operation，thus the drilling apparatus can be easily adjusted to maintain the borehole in a desired geological bed，which shows that the new tool has a higher capability of geo-steering.