DOC PREVIEW
TAMU GEOL 404 - Logging
Type Lecture Note
Pages 3

This preview shows page 1 out of 3 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 3 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 3 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Geol 404 1st EditionLecture 8Outline of Last Lecture II. GeophysicsIII. DHI Gas EffectIV. Drilling Rig SystemsV. LoggingVI. Borehole EnvironmentVII. Salinity and TemperatureOutline of Current Lecture VIII. LoggingIX. Nuclear LoggingX. Gamma Ray and NeutronsXI. Natural Gamma RayXII. Neutron LoggingXIII. Natural RadioactivityXIV.Sonic LogsXV. Bedding and FractureXVI. Borehole BreakoutsCurrent LectureVIII. Logginga. Electrical devices such as resistivity logs or spontaneous potential logs measure the fluid content and saturation, rock matrix, porosity, and density. Note that most logs only log a few traits and not all the reservoir information. b. Density=Porosity(SaturationWat*DensityWat+SaturationHydrocarbon*DensityHydrodarcon)+(1-Porosity)*PorosityMc. Resistance= V/Id. Impedance(Z)=V/I=V*e^io/Ime. Conductivity(stress)=i*w*e*eif. Dielectric Constant€=E-i*(stress/w*E)IX. Nuclear Loggingi. Measures formation and fluid propertiesii. Magnetic Resonance Logging1. Proton precession or wobbling under pulsed magnetic field2. The proton precession decay rate relates to it’s mobility3. Data on movable fluids, permeability and sandstoneThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.4.X. Gamma Ray and Neutroni. Measure high penetration potentialsii. Normally calibrated for an 8 inch hole, 10lb mud with 3 5/8 tooliii. Radioactivity Scale1. Sandstone<Dolomite<Anhydrite<Limestone<HaliteXI. Natural Gamma Rayi. To distinguish sands from shale’sb. Gamma Ray Absorption/Density Loggingi. Scattering of emitted gamma rays by electrons for density readingsii. Compton Scattering- Dependent on electron density1. Interaction occurs with medium gamma ray2. Low electron density=low bulk density=badiii. Photoelectric Effect1. Dependent on low energy gamma ray and average atomic numberof material2. Involves absorption of low energy gamma ray, lithology dependentXII. Neutron Loggingi. Scattering of emitted neutrons by hydrogens in formation for porosityii. The neutrons lose energy from collisionsiii. The more hydrogen in the formation, the fewer counts at the detectors.iv. Fewer counts=Higher porosity=Goodv. Overlapping Lines – Oil or Watervi. Lines Separated (box) - GasXIII. Natural Radioactivityi. It’s the spontaneous decay of one isotope into anotherii. Alpha, Beta particlesiii. Gamma Rays –Emission of electromagnetic waves 10^20Hz1. High energy, short wavelength, with high penetrationXIV.Sonic Logsi. Waves depend on rock type, saturation, compaction, pressure, porosityii. P Wave – Compressional Waveiii. S Wave – Shear Waveiv. Pseudo Rayleigh Wavev. Stoneley Wavesvi. Surface Wavesvii. Measure the compressibility and flexibility of the formation.viii. Higher compressibility = slower waves travel = more porous or more gasXV. Bedding and Fracturea. Bedding – Horizontal lines b. Conductive – Cracks in rocksc. Resistive – Sealed rock (clay)XVI. Borehole Breakoutsa. Stress in the borehole greater than it’s strength causes failure and then breakoutb. Shear failure occurs at the borehole in the minimum horizontal stress directionc. Shear failure creates triangular fracture bound areas of rock with fail, and enlargeand oversize the boreholed. Collapse will occur if the zone and failure is too


View Full Document
Download Logging
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Logging and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Logging 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?