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33 Cards in this Set
- Front
- Back
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Porosity
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Percent of void space that can contain fluid
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Water Saturation
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% of porosity occupied by water relative to HC's
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Lithology
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Nature of mineral content, grain size/sorting, texture, and color
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Explain why induction curve is separated @ ..
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Mud invasion in the flushed zone
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Log response show shallow measurement is higher than the deeper measurement, is the mud saltier?
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No the mud is not saltier. The shallow is higher because the mud is less salty than formation fluids, making it more resistive.
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Archie's Equation
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Sw= sqrt: (a*Rw)/(por^m*Rt)
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What does neutron porosity measure?
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Hydrogen Index
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Difference between thermal neutrons and fast neutrons
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Thermal neutrons have less energy, and they are absorbed by CL-
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Describe NP compared to DP
1) Water filled sand 2) Gas filled sand 3) 50/50 shale sand |
1) close to one another in the middle
2) high dp with low np, cross-over 3) Both the measurements would be close towards the middle at a given point with 50 sand 50 shale |
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What type of radioactive source is used in most density measurements
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Cesium
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Detected Radioactive?
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K,U,Th
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If matrix the matrix logges is limestone and the density porosity is computed using dolomite values, what will be the effect on the mismatched matrix values?
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porosity=(Pma-Pb)/(Pma-Pf) Dolomite: Porosity=(2.87-2.4)/(2.87-1) = 25%
LS: Porosity= (2.71-2.4)/(2.71-1) = 18% If one uses dolomite values instead of LS, then the porosity wil read higher than it truly is |
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How is bulk density similar to electron denstiy in most logging environments?
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Because the # of gamma rays that come back to the detector is a function of electron density. The denser the formation the harder it is for electrons to travel travel through, so less of them return to the detector. Dense formations. Dense formation=higher Pb and higher electron density, so the 2 are similar/related
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Equation that relates porosity to bulk density
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Porosity= 1-(Pb/Pparticle)
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Density:
SS LS Dolo Anhy Fresh water Salt water Oil Gas |
2.65
2.71 2.87 2.98 1 1.025 .6-.99 <.3 |
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microseconds
SS LS Dolo Steel Mud/water |
55.5
47.3 44 57 189 |
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Wylie time average and Raymer Hunt
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WT: Porosity= (delTlog-delTma)/(deltf-deltma)
RH: Por=C (deltlog-deltma)/deltlog |
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What are the 3 types of NMR relaxation? Which one doesnt affect T1 polarization
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surface, diffusion, bulk
diffusion |
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Explain T2 cutoff, and give the typical values of SS and LS
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Cutoff btwn movable and bound fluids
SS=33 LS=100 |
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Are the fractures in the logs opened or healed, explain
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Fracture on right is healed based on the white filling the fracture. This indicates a higher resistivity, and mineralization
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What subatomic particles are used for most all reservoir spectroscopy tools?
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neutrons
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What is the diff btwn inelastic and elastic GR counts?
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FIND OUT
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2 apps of capture spectroscopy tools
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clay type, kerogen
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How is mobility derived from sampling tool data?
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mobility is a function of viscosity, core diameter, and pressure
K/viscosity=(cpfx*Qrate)deltaPss |
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What is pumpout, whats it used for, why is it needed
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Purifying technique that moves filtrate out to get pure reservoir fluids for sampling
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Dielectric constants
Water oil gas |
56-80
2-2.4 1 |
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2 applications for dielectric tools
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FW calculations, determine whether heavy oil is movable
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oil and gas are converted by the conversion of
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kerogen
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Diagenesis
Catagenesis metagenesis |
Ro<.5, early burial of organic mater, M gas is given off
.5<Ro<2, thermal stress releases gas and oil 2<Ro<4, Dry gas is produced |
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How do faults trap hydrocarbons
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form by movement of permeable and impermeable layers along a fault line, the permeable reservoir rock containing HCs has its fluids migrate to the fault line, where an impermeable layer has sealed (trapped) the fluids from moving any farther
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3 types of reservoir drives
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Gas cap
combination solution |
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Equation for Temp
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(x-ST)/(MaxT-ST)= Desired depth/Driller Depth
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SP=
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Rmfeq/Rweq
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