Interpreting Epithermal Neutron Lifetime Measurements for Porosity in Complex Lithologies


C.C Purdy, J.L Olmos, D.C. Stromsworld, Mobil Exploration and Development


Mobil’s Pulsed Neutron Porosity (PNP) well logging tool has been run in two west Texas wells and compared with extensive core data and commercial well logs. The PNP determination of porosity is based on measurement of epithermal neutron lifetimes, and it can provide improvement over conventional porosity determination and analysis schemes because it gives a virtually lithology-independent porosity. This can be particularly important in unknown or changing lithologies.