The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 04, 1994
Filed:
Jun. 11, 1991
Daniel Codazzi, Missouri City, TX (US);
Anadrill, Inc., Sugar Land, TX (US);
Abstract
Gas influx into a wellbore, which is commonly referred to as a 'kick', is detected during active drilling of the borehole. In a preferred embodiment of the invention a determination of mud pump noise round trip transit time T by evaluating a function T=(n-.PHI./2.pi.)f where .PHI. is the phase between standpipe and annulus signals and f is the frequency of a drill fluid oscillation caused by a mud pump and n is an integer which is incremented or decremented until the rate of change of T with respect to frequency is zero. An alarm signal is generated when the rate of change of T with respect to time exceeds a predetermined threshold. In another embodiment of the invention a determination of the Doppler frequency shift of a mud pump signal expressed as a ratio signal, .DELTA.f/f.sub.0 where .DELTA.f is the change in frequency measured at the annulus from the frequency f.sub.0 of the mud pump signal measured at the standpipe. The ratio is compared with a threshold signal to determine whether or not gas influx has entered the annulus.