What does a neutron porosity log measure?

What does a neutron porosity log measure?

The tool measures the size of the neutron cloud by characterizing the falloff of neutrons between the two detectors. Because neutrons penetrate considerably further than gamma rays, the design is much simpler than that of a density tool.

What is neutron density?

The neutron flux density, Ф, is the number of neutrons crossing through some arbitrary cross-sectional unit area in all directions per unit time. It is a scalar quantity, and it can be calculated as the neutron density (n) multiplied by neutron velocity (v).

What is density porosity log?

In density logs, which measure electron density and transform it into bulk density, porosity is calculated by assuming the matrix density and fluid density. Neutron log measures the ratio of count rate from the rock, which is equivalent to how much hydrogen index it has.

What is neutron density log?

The density–neutron log is a combination log that simultaneously records neutron and density porosity. In some zones, porosities recorded on the logs differ for three reasons: The matrix density used by the logging program to calculate porosity is different from the actual formation matrix density.

What does density log measure?

The density log measures electron density by detecting gamma rays that undergo Compton scattering. The intensity of scattered gamma rays is proportional to electron density. Electron density is the number of electrons in a volume of the formation. Electron density is proportional to bulk density.

What is neutron logging?

The neutron log is sensitive mainly to the amount of hydrogen atoms in a formation. Its main use is in the determination of the porosity of a formation. The tool operates by bombarding the formation with high energy neutrons.

How do you find the neutron log?

log > If you are unable to create networks or routers, this is the very first log file to check. It is located on Neutron/Network node. /var/log/neutron/openvswitch-agent. log > It is located on both Network and Compute nodes.

What is sonic log in geophysics?

1. n. [Geophysics] A type of acoustic log that displays traveltime of P-waves versus depth. Sonic logs are typically recorded by pulling a tool on a wireline up the wellbore. The tool emits a sound wave that travels from the source to the formation and back to a receiver.

What is density correction log?

The density correction (DRHO) curve (Fig. F88) is calculated from the difference between the short- and long-spaced density measurements and provides a further indication of the quality of the bulk density data. DRHO values in excess of 0.1 g/cm3 indicate unreliable density data.

How do you find the porosity of a density log?

Obtaining porosity from density–neutron logs Use gas density instead of water density. Plot the porosities on a density–neutron crossplot from a log interpretation chartbook. Use the appropriate crossplot for the log type (i.e., SNP, CNL) and mud type (fresh or salt).