Composite shell for protecting an antenna of a formation evaluation tool

摘要

A fiber reinforced, non-metallic, rigid shell 2 for covering the elastomeric layer 38 surrounding the antenna 36 of a measurement-while-drilling borehole formation evaluation tool. The shell may be made of glass-fibre reinforced heat cured epoxy resin or of a silicon carbide whisker reinforced ceramic of alumina or silicon nitride, or of an inner layer of the resin composite and an outer layer of the ceramic composite. It has pressure equalising holes between inner and outer surfaces and is secured in place by bolts 32. The shell 2 protects the elastomeric layer 38 and antenna 36 from wear and abrasion. If damaged during drilling, the shell 2 may be replaced at the drillsite with minimal downtime.