Restorable antennae apparatus and system for well logging

摘要

An apparatus includes a sub with recesses along an exterior wall to receive inserts, an antennae case including a coil surrounded by a sacrificial wear portion of a material through which signals between the coil and a formation of interest may pass. An eroded outer wall of the sacrificial wear portion is restorable by application of an uncured restorative material to the antennae case. A method includes securing an antennae case having a coil there within onto a sub, surrounding the coil with a metal sleeve shield, and radially receiving and securing a multi-piece sacrificial wear member intermediate the antennae case and a retainer ring having a threaded bore. The multi-piece sacrificial wear member is replaceable after use by unthreading the retainer ring to release the sacrificial wear member for radial removal from the sub.

主权项

1. An apparatus, comprising:
a sub with a first end having a connector, a second end having a connector, a bore therebetween, and an exterior wall having a plurality of recesses; an antennae case having a non-metallic body, an exterior wall surrounding a sacrificial portion of the antennae case, a first end having a first shoulder, a second end having a second shoulder, a bore receivable onto the exterior wall of the sub, and a coil of conductive wire within the sacrificial portion of the antennae case, the coil having a first end and a second end, winding about the bore and encased within the non-metallic body; a first metal wear ring having a bore receivable onto the first shoulder of the antennae case; a second metal wear ring having a bore receivable onto the second shoulder of the antennae case; a first set of curved inserts received within a first set of recesses in the exterior wall of the sub and having an outer surface with threads and an inner surface generally conforming to the exterior wall of the sub within the first set of recesses; a second set of curved inserts received within a second set of recesses in the exterior wall of the sub, spaced apart from the first set of recesses, and having an outer surface with threads and an inner surface generally conforming to the exterior wall of the sub within the second set of recesses; a first retainer ring threadably receivable onto the first set of inserts received into the first set of recesses adjacent to the first end of the antennae case; and a second retainer ring threadably receivable onto the second set of inserts received into the second set of recesses adjacent to the second end of the antennae case; wherein threadably receiving the first and second retainer rings onto the first and second sets of inserts received within the first and second sets of recesses in the exterior wall of the sub secures the antennae case on the sub; and wherein the exterior wall of the sacrificial portion of the antennae case is restorable after erosive damage by application of an uncured restorative material to the antennae case to restore the exterior wall of the sacrificial portion of the antennae case to surround and protect the coil of the antennae case and to enable reuse of the antennae case for investigation of geologic formations drilled using a well logging assembly including the sub.