UHT-PNN – 1500.0000 ULTRA HIGH TEMPERATURE PULSED NEUTRON NEUTRON TOOL

1500.0000 pulsed neutron tool is the latest innovation from Pnnplus GmbH. laboratory. The new design allows measure-ments in ultra-high-temperature boreholes, without losing the familiar characteristics of previous Pnnplus pulsed neutron tool designs. For shorter time interval, logging in ambient temperatures above 200°C is operable. The special tool de-sign allows not only logging at ambient temperatures about 200°C [392°F], but it also increases the lifetime of the neutron generator.

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

UHT-PNN Application 

• Determination of water saturation behind casing
• Porosity evaluation
• Estimation of remaining hydrocarbon reserves
• Identification of oil–water, gas–water, and gas–oil contacts
• Monitoring of reservoir dynamics and fluid movement
• Evaluation of low-salinity formations
• Applications in geothermal energy projects

PNN technology is particularly effective in complex reservoir conditions where conventional thermal decay tools face limitations, especially in low-salinity and low-porosity environments.

UHT-PNN Operation

The formation is bombarded with pulses of high-energy neutrons (14 MeV) generated by the tool. These neutrons interact with the surrounding atoms, and during the time interval between successive pulses, the population of thermal neutrons reaching the detectors is measured.

The tool uses two neutron detectors, each with 60 time channels, to sample the thermal neutron population over time. The neutron counts recorded in each channel are used to compute the decay rate, which is equivalent to measuring how quickly thermal neutrons are absorbed by the formation.

The greater the ability of the formation fluids and minerals to capture thermal neutrons, the higher the resulting Sigma value.

UHT-PNN TOOL SPECIFICATIONS: