Analysis of coAnalysis of co--located located pressure and particle velocity pressure and particle velocity

measurements measurements

Alejandro D. Alcudia and Alejandro D. Alcudia and Robert R. StewartRobert R. Stewart

November 29November 29thth, 2007, 2007

OutlineOutline

ApplicationsApplications

ModellingModelling of sourceof source--generated airwavegenerated airwave

Microphones at Pikes Peak oil fieldMicrophones at Pikes Peak oil field

Vibration monitoring at Vibration monitoring at NantonNanton, Alberta, Alberta

ConclusionsConclusions

Lawton, D., 2004

Sound pressure level (dB)Sound pressure level (dB)

10102020

0000

3030404050506060707080809090

100100110110120120130130140140

Threshold of human hearing

Threshold of pain

⎟⎠⎞

⎜⎝⎛⋅=

20uPaΔPlog20dB 10

ΔPatm1Ptotal =−

Acoustic source Acoustic source modellingmodelling

Sallas et al. 1989; Norton and Karczub, 2003

Piston

Circular pistonvibrating in an infinite baffle

of radius r

Vibrator’s baseplatebehaves as a

big loudspeaker

Pistonaxis

Sound pressure simulationSound pressure simulation

Experiment at Pikes Peak oil fieldExperiment at Pikes Peak oil field

Dey et al., 2000; Hoffe et al., 2000

Pikes Peak 3Pikes Peak 3--C 2C 2--D field layoutD field layout

Hoffe et al., 2000

Shot gather Shot gather –– Microphone Microphone vsvs VerticalVertical

Linear sweep 8-25 HzNon-linear sweep 25 –150 Hz16 s length4 s listening

Microphone 100 m offset

Correlated microphone 100 m offset

Correlated microphone 460 m offset

Vertical geophone460 m offset

Horizontal geophone 460 m offset

Vibration monitoring at Vibration monitoring at NantonNanton, Alberta, Alberta

Protecting water springsDynamite and vibroseis sourcesPeak particle velocity (PPV) and peak over-pressure (PSPL)

StandStand--off distance (m)off distance (m)

100 m90 m64 mWater well 50 m90 m64 mArea of public congregation50 m90 m64 mResidence50 m90 m64 mStructure with concrete base15 m45 m32 mPipeline15 m45 m32 mOil or gas well100 m90 m64 mDam

Vibroseis2 kg < dynamite < 4kgdynamite < 2 kg

Stand-off distanceFacility

Canada Oil and Gas Geophysical Operations Regulations (SOR/96-117)

Dynamite 5m offset

PPV = 113 mm/s

PPV = 145 mm/s

PPV = 40.1 mm/s

Vibroseis 5m offset

PPV = 12.7 mm/s

PPV = 10 mm/s

PPV = 18.8 mm/s

0

1

1

1

1

0

0

0

0.5

0.5

0.5

0.5

ConclusionsConclusionsAirblast frequencies are affected by the sound radiation pattern

Airwave coupling is broadband. Stronger at low frequencies.

Lobes of radiated sound might impact the frequency content of the coupled airwave.

Measure three components for true PPV

AcknowledgementsAcknowledgementsAOSTRA and Husky Energy Inc.

Nanna Eliuk of Compton Petroleum Corporation

Rick Espersen

Greg Nieuwenhuis of WorleyParsons Komex

CREWES sponsors and staff for their support

Dr. Gary Margrave for Gabor transform code and Dr. Robert Ferguson for discussions.