DRHO
Schlumbergerlbm/gal[US]Density Correction
The correction the density tool applies for mudcake and borehole rugosity, and the primary quality flag for bulk density. A small DRHO means trustworthy RHOB; a large DRHO means the density — and any porosity derived from it — is suspect.
- Property
- Bulk Density Correction
- Correction
- Quantity
- mass per volume
- lbm/gal[US] · 0.01 grain/ft³ · µg/cm³ · grain/gal[US] · lbm/gal[UK] · 0.001 lbm/gal[UK] · 0.001 lbm/bbl · kg/dm³ · g/gal[UK] · g/m³ · mg/dm³ · t/m³ · mg/gal[US] · g/L · lbm/in³ · mg/m³ · 10 Mg/m³ · mg/L · lbm/ft³ · kg/L · lbm/bbl · 0.001 lbm/gal[US] · Mg/m³ · 0.1 lbm/bbl · g/cm³ · g/gal[US] · grain/ft³ · g/dm³ · kg/m³
- Typical range
- ~0–0.2 g/cm³
- g/cm³ of applied correction; small is good
Logging tool
No logging tool is associated with this curve.
Service company
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View Schlumberger mnemonics →What is the DRHO curve?
How it's measured
Output of the density tool's spine-and-ribs algorithm from the two-detector count ratio — the amount added to raw density to compensate for mudcake between the pad and the formation.
How it's used
Quality control for RHOB and density porosity. A common rule flags intervals where |DRHO| exceeds about 0.10–0.15 g/cm³ as density (and derived porosity) to be distrusted.
Common gotchas
It is a QC curve, not a formation property — do not interpret it geologically. Large positive DRHO usually tracks washouts on the caliper, and its sign convention varies by vendor.
In LAS files
Recorded as DRHO (or DCOR, HDRA) in g/cm³. It should always be read alongside RHOB and the caliper.
Also seen with DRHO in real logs
Curves that appear alongside DRHO in the same wells across the public corpus.