This stackable sonde is suitable for quantitative formation density measurements in uncasedbore-holes. It uses a gamma ray source and a set of two detectors at different spacing to detect the gamma rays scattered by the formation. 

The amount of scattered gamma rays is a function of the electron density of the formation material and hence, a function of its bulk density. This relationship is used to calibrate the density sonde and then use it to log the bulk density of the formations crossed by the borehole. 

In order to optimise performance, the sonde is designed with three main features:

  • A side-walling calliper to ensure that the detector measures only the radiation scattered by the formation
  • A detector mandrel diameter that is large enough to minimise the sonde and borehole curvature mismatch and improve sonde to formation contact to minimise the effect of the borehole fluid
  • An efficient detector shield to prevent gamma rays from travelling up, inside the sonde body.

Sidewall Density Sonde Specifications:

  • Weight: 26 kg 
  • Length/Diameter: 2.06 m/ 54 mm
  • Detector (NaI) spacing: 47 and 25 cm.
  • Source: 3.7GBq 60Co  or 137Cs 9.25 GBq
  • Density Range: 1 - 4.5 g/cc 
  • Calliper: 60 to 450 mm
  • Max.  Temperature: 80ÂșC Max.
  • Pressure: 20 MPa