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What does the sonic log measure?
A) Measure travel time of an elastic wave through the formation.
B) Measure natural waves in the formation
C) Measure frequency of collison of the waves
D) Measure the amplitude of a wave through the formation |
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Definition
| A) Measure travel time of an elastic wave through the formation. |
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What is the main use of a sonic log?
A) To find permeability
B) To find the density of the formation
C) To find Elvis
D) To provide information to support and calibrate seismic data and to derive the porosity of a formation |
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Definition
| D) To provide information to support and calibrate seismic data and to derive the porosity of a formation |
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| Does the sonic tool work at a higher or lower frequency than seismic waves? |
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Definition
| The sonic tool works at a higher frequency than seismic waves. |
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| What is the first type of wave that will arrive the receiver? |
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Definition
| The first wave to arrive is the compressional (P-wave). |
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| What type of wave will arrive after the P-wave? |
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Definition
| The next wave, usually, to arrive is the transverse or shear wave. |
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| Can shear wave propagate in fluids? |
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Definition
| The shear wave cannot propagate in fluids, as fluids do not behave elastically under shear deformation. |
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Definition
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| How can we find the velocity of the wave? |
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Definition
| Measure the distance from transmitter to receiver. dt=1/Vp |
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| How is sonic log data presented? |
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Definition
| The data is presented as a slowness or the travel time per foot traveled through the formation, which is called delta t, and is usually measured in microseconds per ft. |
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| What does the velocity of the p-wave depend on? |
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Definition
| Depends upon the elastic properties of the rock (matrix plus fluid), so the measured slowness varies depending upon the composition and microstructure of the matrix, the type and distribution of the pore fluid and the porosity of the rock. |
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