logging tools (1)

8/11/2019 Logging Tools (1)

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AHMAD FAKHRI BIN AHMAD FUADMOHAMAD IQRAM HAIKAL BIN OTHMAN

MUHAMMAD THAM RYEN BIN NASIMINNAIMAH BINTI LUKMAN


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Acoustic logging tools can assist in evaluatingporosity because the compressional velocityof sound in fluid is less than the velocity in

rock .If there is pore space and fluid-filled inthe rock , the acoustic energy will takelonger time to reach the receiver . In simpleword , low velocity indicates high porosity .


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Determine porosity and lithologyDetermine Rwa

Determine formation mechanicalproperties, like poissons ratioEvaluate fractures and permeabilityEvaluate overpressure in basinCombined with density logs to produceseismic traces (synthetic seismograms)Evaluate cement bond


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Sonic logging tool measure the elastic or (sound)wave properties of the formation. It provides a formations interval transit timewhich is a measure the formations capacity totransmit seismic waves.Geologically, this capacity varies with lithologiesand rock textures, most notably decreasing withan increasing effective porosity.

This means that a sonic log can be used tocalculate the porosity of a formation if theseismic velocity of the rock matrix and porefluid are known, which is very useful forhydrocarbon exploration.


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Travels thru mud & rockVelocity depends on-Lithology

-Porosity/Pore fluid(s)

Fastest mode-mud 5,200 ft/sec-rock 18,000-25,000 ft/sec

Weakest mode-Fracture insensitive


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Mud + rock modeSlowest mode (VSt)

-3,300 5,000 ft/sec

Strongest mode

-Fracture sensitive-Permeabilitysensitive


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Enlarged borehole(energy may be so slow as tocause difficulty with the sonic log reading)formation fracturesgas in the borehole or formationimproper centralizationPoorly maintained logging sounds(especiallyearlier generations of tools, by causing pooracoustic coupling with the borehole fluid. )

can produce signal attenuation resulting incycle skipping or DT spikes to higher values


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increase in sonic log porosity in poorly-consolidated sands.not quantitative or predictable


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Today, geologist depends on sets of well logto map properties of subsurface formation .Several tools are run simultaneously as alogging string , and the combination of resultis more informative than each individualmeasurement . Besides that , geologist andengineer also comparing logs from anotherwells in a field to develop more effective andefficient hydrocarbon production plans .


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logging tools (1)

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