PETE 321 - Final concepts

Rocks that are not suitable for hydraulic fracturing tend to have lower Young's modulus and higher Poisson's ratio.

True

Stoneley waves can be used to detect presence of fractures.

True

Structural shale is the more common than dispersed and laminated shales.

False

Young's modulus of coal is more than that of hard sandstone.

False

Increase in calcite concentration leads to reduction in brittleness index.

True

Volumetric concentration of shale includes clay-bound water.

True

Young's modulus is an indicator of ductility and Poisson's Ratio is an indicator of stiffness.

False

Photoelectric absorption index (Pe) obtained using density logging tool is primarily dependent on lithology (i.e. the rock matrix), and secondarily dependent on porosity and pore fluid.

True

Cesium-137 source is a chemical source and not a pulsed source. Cesium-137 source emits gamma rays only when it is energized/activated.

False

Density logging tool has deeper depth of investigation than sonic logging tool.

True

Oil in large pore exhibits NMR response at higher T2 time compared to oil in small pores

True

NMR log can be used to determine the bound fluid vs. movable fluid volumes.

True

As compared to laminated sand-shale formations, dispersed pore-filling sand-shale formations exhibit greater reduction in porosity with the increase in volumetric fraction of shaly material.

True

Compared to heavy oil, gas exhibits NMR response at smaller T2 times.

False

Capillary bound water includes clay-bound water.

False

A rock sample can have substantial total porosity and negligible permeability.

True

The number of Compton scattering collisions is related directly to the electron density of the formation, which approximates the bulk density of the formation.

True

Wettability of the rock grains does not affect resistivity measurements.

False

Thermal neutrons are more easily captured by hydrogen as compared to chlorine.

False

As compared to water-filled 30% porosity rock, gas-filled 20% porosity rock will require more collisions of a fast neutron to reach to the thermal-neutron energy level.

True

As compared to neutron logging, density logging is more reliable for porosity estimation.

True

At a constant porosity, formation resistivity factor increases with tortuosity.

True

SP log response will show deflection from the shale baseline in a formation with negligible permeability.

False

What is the special capability of dual laterolog tool compared to older generation laterolog tools, such as LL3 and LL7?

Compared to older generation laterolog tools like LL3 and LL7, dual laterolog tool can measure LLS and LLD at similar vertical resolution

Describe the role of bucking electrodes in laterolog and microresistivity logging tools.

To force currents to flow deeper into the formation and to obtain deeper depth of investigation and higher vertical resolution

A logging tool, other than neutron and density logging tools, generally used to estimate effective porosity.

Sonic (acoustic) logging

List two uses of microresistivity logging, like MSFL. Do not confuse with micro imagers.

1. Resistivity of flushed/invaded zone 2. Used along with deep and shallow resistivity logs to estimate true resistivity

What are the three main interpretations obtained using both density and neutron logs?

1. Porosity estimation 2. Lithology determination 3. Fluid type determination

Three examples when SGR helps improve petrophysical evaluation of the subsurface?

1. Improve clay typing and lithology identification 2. Improve grain density estimation that improves porosity estimation 3. Improve shale volume estimation and the net pay thickness calculation 4. Improve resistivity interpretation and water saturation estimation

Three limitations of micro imaging, i.e. 3 scenarios when micro imaging is not suitable.

o Oil based mud o Cased hole o Abrupt, drastic change in borehole size

What are the two principal interactions of neutrons for purposes of conventional neutron logging tool for porosity estimation?

Thermal Capture Elastic scattering

What are the three main uses of density log?

1.Porosity indication 2.Lithology determination 3.Fluid type determination