PULSE NEUTRON NEUTRON TOOL (PNN) 1400.0000 measures Sigma, the ability of material to capture thermal Neutrons, in capture units (c.u.).
PNN counts directly the thermal neutrons reaching the detectors after their interaction with the surrounding formation; then, the usual inference by common Thermal decay tools that count Gamma Rays where High-counts means high-Sigma-Values changes by the PNN tool into High-counts means Low-Sigma-Values, and it has the significance of obtaining statistical uncertainties reduction for low Sigma values. This sole measuring approach allows better differentiation in environments of low Sigma values, which is the case when fresh water, oil and/or gas are present in the pore spaces, overcoming by this way, the low salinity formation water problem which appears as a limitation factor of standard Thermal Decay Time tools; additionally, Neutron readings are less affected by Neutron activation, hence, logging of Time-driven Stop-Checks in area of interest helps reduce the statistical uncertainties of readings at any desired depth spot. All of this makes pnnPlus tool, in conjunction with our PNN processing and analysis, a competitive behind-casing formation evaluation tool for high to moderate water salinity formations and the ultimate thermal decay tool for evaluation of lower salinity and lower porosity formations.
Water saturation behind casing, porosity, remaining Hydrocarbon reserves estimation, Oil-water, gas-water and gas-oil contacts location, etc
The formation is bombarded with pulses of high-energy neutrons (14 MeV) generated by the tool. Neutrons interact
with the surrounding atoms and, during the lapse of time between high-energy neutron pulses, the thermal neutron
population that reaches the Neutron detectors is sampled by two detectors with 60 time channels each; Per Channel
Neutrons counted are used to compute the rate of decay, it is equivalent to measuring the rate at which thermal neutrons
are absorbed into the formation, the greater fluids and minerals capture thermal neutrons, the higher the value of Sigma.
Min Hole Diameter:
Recommended Borehole Fluid:
175°C (350 °F)
103 MPa (15,000 psi)
5.110 mm (201,18")
43 mm (1-11/16”)
47.6 mm (1-7/8")
31,57 kg (69,60 lb)
2.14 m/min (7 ft/min)
80 mA (generator off)
200 mA (generator on)