Designing tools for oil exploration using nuclear modeling

Abstract

Abstract. When designing nuclear tools for oil exploration, one of the first steps is typically nuclear modeling for concept evaluation and initial characterization. Having an accurate model, including the availability of accurate cross sections, is essential to reduce or avoid time consuming and costly design iterations. During tool response characterization, modeling is benchmarked with experimental data and then used to complement and to expand the database to make it more detailed and inclusive of more measurement environments which are difficult or impossible to reproduce in the laboratory.We present comparisons of our modeling results obtained using the ENDF/B-VI and ENDF/B-VII cross section data bases, focusing on the response to a few elements found in the tool, borehole and subsurface formation. For neutron-induced inelastic and capture gamma ray spectroscopy, major obstacles may be caused by missing or inaccurate cross sections for essential materials. We show examples of the benchmarking of modeling results against experimental data obtained during tool characterization and discuss observed discrepancies.

An all-digital associated particle imaging system for the 3D determination of isotopic distributions

“…The ENDF /B-VI library was used because of its better agreement with experiments compared to most current releases of ENDF 29 . The reason seems to be the attempt to transition from natural compounds to individual isotopes in later versions, which created gaps and overall poorer agreement with experimental data 30 . The results presented in Figure 14 show the capability of the system to analyze samples within a small volume and obtain their gamma signature.…”

Impact of the ENDF/B-VIII.0 library on modeling nuclear tools for oil exploration

“…We know that neutron-capture -ray line data are missing since ENDF/B-VII, which split the natural compound into individual isotopes [2] [6]. In ENDF/B-VIII.0 new and improved neutron-capture γ-ray lines for 23 Na, 27 Al, 28 Si, and 35 Cl and 37 Cl have been included [6].…”

“…With the introduction of pulsed neutron generators, new measurements have been developed such as capture and inelastic gamma ray spectroscopy, which directly measure elements in the formation including carbon. The complex measurements and the introduction of machine learning increase the need for accurate modeling [2] [3]. Major modeling uncertainties come from the cross sections.…”