Pulsed-Neutron Decay PND Spectrum Tool
Provides comprehensive through-casing saturation measurements
- Determining water saturation in high-salinity formations
- Determining oil saturation in formations with low or unknown water salinity
- Evaluating producing zones for primary and secondary recovery
- Locating bypassed pay zones
- Identifying formation fluid contacts (gas, oil, and water)
- Detecting gravel-pack problems
- Determining production profile
- Identifying sources of water production
Features and Benefits
- Emits high-energy neutrons at 14.3 MeV. Two spectroscopic detectors measure the resulting gamma radiation, which can be used to determine reservoir properties and fluid saturation.
- Records inelastic measurements during the burst from a short, fixed-rate pulse of 1,428 Hz.
- Records capture data after the burst using a long, variable pulse and variable windows that change with Tau or the formation-decay rate.
- Uses the measured formation capture cross section (∑) to determine water saturation in high-salinity formations.
- Offers operational flexibility with standard and high-temperature versions of the tool.
The PND spectrum tool is a slimhole pulsed neutron spectroscopy tool that combines conventional pulsed neutron capture, neutron porosity, and inelastic density measurements in one device. When operating in inelastic mode, the tool obtains carbon/oxygen and inelastic density measurements that, combined with capture sigma and neutron porosity, address a broad range of formation-evaluation and reservoir monitoring applications.
The PND spectrum tool can determine the source of unwanted water production in a flowing well, which informs decisions on isolating pay zones from the water-producing portion of the completion interval. The cased-hole density-porosity measurement differentiates between low-porosity formations and gas-filled-porosity formations, identifies pressure-depleted zones, and locates gas/oil contacts in shale reservoirs.