Unconventional neutron sources for oil well logging

• AmBe sources are widely used for well logging purposes.
• Governmental bodies would prefer to minimize AmBe use.
• Other neutron sources are available, both radiological and electronic.
• Tritium–tritium spectrum neutrons have similar logging tool response to AmBe.
• A tritium–tritium neutron generator may be a viable AmBe replacement.

Americium–Beryllium (AmBe) radiological neutron sources have been widely used in the petroleum industry for well logging purposes. There is strong desire on the part of various governmental and regulatory bodies to find alternate sources due to the high activity and small size of AmBe sources. Other neutron sources are available, both radiological (252Cf) and electronic accelerator driven (D–D and D–T). All of these, however, have substantially different neutron energy spectra from AmBe and thus cause significantly different responses in well logging tools. We report on simulations performed using unconventional sources and techniques to attempt to better replicate the porosity and carbon/oxygen ratio responses a well logging tool would see from AmBe neutrons. The AmBe response of these two types of tools is compared to the response from 252Cf, D–D, D–T, filtered D–T, and T–T sources.