Abstract: A method and apparatus for filling a jacketed signal conduit with a blocking material are provided. The blocking material is injected into the jacketed signal conduit such that the blocking material occupies space within the jacketed signal conduit not occupied by the signal conduit. The injected blocking material inhibits fluid intrusion and migration between the signal conduit jacket and the signal conduit.

Abstract: A neoprene plug boot is secured to an electrical connector and to portions of a polyurethane-jacketed conduit adjacent the electrical connector. The method of the present invention includes bonding neoprene to a polyurethane surface by etching the polyurethane surface, coating the etched surface with a bonding agent, applying to the coated surface a neoprene film and contacting the neoprene film with a quantity of neoprene under suitable temperature and pressure.

Abstract: A method and apparatus for detecting the orientation of downhole geophones are provided. A gamma ray source is secured to a casing enclosing a geophone such that the location of the gamma ray source with respect to the orientation of a geophone is known. The geophone is secured to tubing such that the orientation of the geophone with respect to the tubing is known. The tubing, with attached geophone, is secured downhole. A gamma ray logging tool is run the length of the tubing. The orientation of the downhole geophone is determined from the gamma ray log.

Abstract: A metallic down hole seismic sensor cable for operating at temperatures up to about 400.degree. F. and pressures up to about 5000 psig is provided. The seismic sensor cable includes a flexible metallic conduit sized for receiving a seismic sensor, and means for transmitting output generated by the seismic sensor. The cable is preferably constructed of stainless steel. An inert curable heat resistant material substantially fills the unoccupied spaces of the assembled seismic sensor cable.