Borehole measurement while drilling systems and methods

Claim 1

Apparatus for use in making measurements in conjunction with a drilling system for drilling a borehole in the earth, the drilling system including a drill string suspended in a borehole, the drill string including a plurality of lengths of drill pipe some of which may be lengths of drill collars, a drilling means affixed to the lower end of the drill string, a mud pump connected to the upper end of the drill string for circulating drilling fluid therethrough, the apparatus comprising sensor means and instrumentation means for generating electric signals representative of the magnitude of one or more downhole parameters, pulser means for producing pressure pulses in the drilling fluid in response to the electric signals received from said instrumentation means, a pulser sub threadably secured at its upper and lower ends to length of drill pipe in the drill string, said pulser means being mounted within said pulser sub, an elongated housing supported by said pulser sub, said housing having an outside diameter less than the internal diameter of the adjacent drill pipe and being slideably received in the drill pipe adjacent in the drill string to said pulser sub, said pulser and said housing permitting the flow of drilling fluid therepast, said housing containing at least a portion of said instrumentation means.