What does a density log measure?

What does a density log measure?

electron density
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.

What is DRHO 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.

Why double detector is used in density log?

To overcome the problems of mudcake and hole irregularities, the new compensated formation density logging device employs two detectors spaced at different intervals from the source. The detector at the shorter spacing is particularly sensitive to the density of material immediately adjacent to the face of the pad.

What is the working principle of litho density log?

The litho-density log is a new form of the formation density log with added features. It is typified by Schlumberger’s Litho-Density Tool (LDT). These tools have a caesium-137 source emitting gamma rays at 0.662 MeV, a short-spaced and a long-spaced detector in the same way as the basic formation density tool.

What is density of shale?

Average densities and corresponding average depths are as follows: sandstone, 2.42 g/cm” (I I20 ft); siltstone, 2.46 g/cm” (1537 ft); shale, 2.43 g/cm” (136.5 ft); limestone, 2.63 g/cm:’ (4156 ft): and dolomite, 2.64 g/cm” (3380 ft). In general it is seen that there is a distinct contrast.

What is density log and its purpose?

Density Log: Density logging is a well logging tool that can provide a continuous record of a formation’s bulk density along the length of a borehole. In geology, bulk density is a function of the density of the minerals forming a rock (i.e. matrix) and the fluid enclosed in the pore spaces.

What type of log Do we use for lithology identification?

Neutron and density logs combined. Neutron and density logs each react to both lithology and porosity, so by analyzing the two logs together, one can begin to distinguish lithology from porosity.

What is density porosity?

Porosity from porosity log is never a measurement, it is a calculation, from what we think might represent the porosity of the rock. In density logs, which measure electron density and transform it into bulk density, porosity is calculated by assuming the matrix density and fluid density.

How do you read bulk density?

Bulk density is usually expressed in megagrams per cubic metre (Mg/m3) but the numerically equivalent units of g/cm3 and t/m3 are also used (1 Mg/m3 = 1 g/cm3 = 1 t/m3) (Cresswell and Hamilton, 2002).

Is clay more dense than sand?

Sandy soils have relatively high bulk density since total pore space in sands is less than that of silt or clay soils.

What is density of stone?

density of stone, crushed is equal to 1 602 kg/m³.

What is the purpose of the formation density log?

The formation density log measures the bulk density of the formation. Its main use is to derive a value. for the total porosity of the formation. It s also useful in the detection of gas-bearing formations and in. the recognition of evaporites.

Is there a universal correction for density logging?

This correction is presented as a curve with the density log. Above an inch or so of standoff, the compensation fails. There is no universal correction threshold, but corrections greater than 0.05 to 0.1 g/cm 3 are suspicious.

How does the density log measure electron density?

The density log measures the electron density of a formation. The logging device is a contact tool that emits gamma rays from a source.

What does the litho density logging tool look like?

The litho density logging tool and the log display look very similar to the older version, except for the addition of one new log curve, the photo electric effect (PE or PEF). The energy of the returning gamma rays is a function of the PEF of the rock, which is indicative of mineralogy.

What does a density log measure? electron density 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. What is DRHO log? The density correction (DRHO) curve…