Method of and apparatus for detecting an influx into a well while drilling

Patent · Tue Jan 04 04:00:00 EST 1994

OSTI ID:6929194

Codazzi, D

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 [minus] [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. 20 figs.

• Assignee: Anadrill, Inc., Sugar Land, TX (United States)
• Patent Number(s): US 5275040; A
• Application Number: PPN: US 7-714103
• OSTI ID: 6929194
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
422000* -- Engineering-- Mining & Underground Engineering-- (1980-)
ALARM SYSTEMS
ANNULAR SPACE
CONFIGURATION
CONTROL
DRILLING
DRILLING FLUIDS
FLUIDS
FREQUENCY DEPENDENCE
GASES
MEASURING INSTRUMENTS
MONITORING
PROCESS CONTROL
SPACE
WELL DRILLING