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![Example of wireline logging from [1].](publication/319672744/figure/fig1/AS:538381365268480@1505371528326/Example-of-wireline-logging-from-1.png)
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![Figure 1. Example of wireline logging from [1].](publication/319672744/figure/fig1/AS:538381365268480@1505371528326/Example-of-wireline-logging-from-1_Q320.jpg)
Oil↓eld service companies help identify and assess reserves and future production for oil and gas reservoirs, by providing petrophysical information on rock formations. Some parameters of interest are the fraction of pore space in the rock, the quantity of oil or gas contained in the pores, the lithology or composition of the rock matrix, and the e...
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... the depth of investigation of nuclear measurements is limited, the instrument may measure characteristics of the invading fluid instead of the one that was originally in the rock. Figure 1 presents a typical wireline land acquisition configuration. At the surface, there are the rig and the truck that powers the wireline tool and records the measurements. ...
Context 2
... allows optimization of detector and radiation source positions, and selection of the best materials to maximize the signal-to-noise ratio. Figure 10 visualizes simplified modeling performed to optimize signal for a gamma-gamma density mea- surement. The goal is to reduce the number of particles reaching the detector directly through the tool without scattering in the formation. ...
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p>Efforts are made to find the remaining hydrocarbons in the reservoir, requiring several methods to calculate the parameters of reservoir rock characteristics. For this reason, logging and core data are required. The purpose of this research is to estimate the Remaining Hydrocarbon Saturation that can be obtained from log data and core data. With...
Hydrocarbon gas chromatographic investigation is regarded as the initial indicator of a reservoir's fluid properties. This study shows the assessment of fluid types of A/R “A, E, and F” members by using gas chromatographic analysis. The analysis entails examining the gas composition found in the drilling mud. The interpretation of the lighter gas c...
The quality of the reservoirs in terms of porosity, permeability decreases down the depth. Therefore, it can be concluded that the hydrocarbon potential and productivity of the reservoir sands can be classified in decreasing order of arrangement as A, B and C. The reservoir A in well Bonn 007, 009, 013, 015, 017 and 019 is the best in terms of hydr...
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... Nowadays, there is a high demand for experiments focusing on the measurement of prompt gamma produced during neutron interactions (Bernstein et al., 2015(Bernstein et al., , 2019Kolos et al., 2022;Lawrence and Peplowski, 2021;Romano et al., 2018). This radiation negatively affects, for example, the long-term operation of power reactors (Harutyunyan et al., 2017), but it also has a relatively wide range of applications such as space exploration (Kolos et al., 2022;Parsons, 2020), geological exploration (Mauborgne et al., 2017), or hazardous material detection (Bishnoi et al., 2013;Nunes et al., 2002). However, despite its importance, the description of the production of the prompt gamma radiation in current nuclear data libraries is significantly inaccurate (Mauborgne et al., 2020). ...
Prompt gamma radiation is an important part of radiation fields with neutrons. Its good description is vital for precise predictions in void swelling issues because it is a contributor in gamma heating effect. The energy of prompt gamma rays is unique for each nuclide, thus can be used as its signature. Prompt gamma activation analysis is a technique using these gammas in nuclide identification. Despite the prompt gamma importance, current nuclear data libraries describe its origins very inaccurately. Measurement of gamma leakage spectrum of manganese bath with 252Cf neutron source was performed using well-defined HPGe detector with high-density polyethylene shielding and stilbene scintillator. Stilbene measured gamma/neutron spectrum was separated by a Pulse Shape Discrimination method. MCNP6.2 simulation of the experiment was performed with ENDF/B-VIII.0 and JEFF-3.3 libraries for neutrons (and gamma production from neutron interactions) and MCPLIB04 library for photons. Analysis of results revealed that ENDF/B-VIII.0 and JEFF-3.3 description of prompt gamma radiation production is significantly discrepant. INDEN updated data for gamma production on 55Mn was tested as well and show significant improvement compared to original ENDF/B-VIII.0 data. Nevertheless, significant discrepancies up to 50% were still observed. An alternative approach using prompt gamma production tables provided by IAEA was tested as well. Its results are basically in agreement with the calculation using INDEN updated 55Mn data.
... Prompt gamma radiation, coming from neutron interactions, both radiative capture and inelastic scattering, is an important part in neutron/gamma mixed fields. Its proper knowledge is important in many areas, not only for reactors operation (reactor and reactor-internal dosimetry, radiation protection (1) ), but in subsurface isotopic identification in soils (2) and space (3) as well. ...
The inelastic neutron scattering is often followed by the emission of gamma photon. As the prompt gammas have a discrete level character they can be used for the identification of nuclides. Because of this fact, a good knowledge of photon production from inelastic scattering is important. Described research deals with the measurement of gamma originated from inelastic scattering of neutrons on 16O. The 241Am–Be was used as a neutron source because of its high average neutron energy. The oxygen in form of heavy water was used for maximization of neutron flux on oxygen and minimization of background gammas’ production, namely 2223 keV gammas accompanying capture on hydrogen 1H. The gamma spectrum was measured by HPGe and the stilbene detector. The HPGe measured quantities are comparted with calculation and discrepancies between measured and calculated gamma fluxes are reported. Stilbene measurement shows indistinguishability of gamma peaks above 6 MeV.
... Full wrapping of the 2" size cylindrical scintillator EJ-299-33A with EJ-426 thin foils proved to be possible in order to obtain enhanced triple discrimination, but this approach is very challenging in practice, owing to the foils fragility [8]. Another critical issue for commercial thermal neutron detectors is their low heat resistance, which prevents their use in environments where the temperature is higher than in normal conditions, as for example in applications related to oil well logging [9]. The possibility to produce flexible, thermally resistant and easy to handle detectors has been herein explored, by synthesizing 6 LiF crystals by co-precipitation method [10] and mixing them with ZnS:Ag commercial powder. ...
The production of flexible and robust thermal neutron detectors with improved properties as compared to the commercial ZnS:Ag based phosphors is here pursued, exploiting a siloxane binder, whose intrinsic properties as related to the chemical features of the functional groups and to the optical properties are investigated and tailored in correlation with the final performances of the detectors. Two different siloxanes either with pendant phenyl groups or with aliphatic groups have been used, the former being intrinsically fluorescent and with higher polarizability than the latter. Moreover, 6LiF crystals have been synthesized by co-precipitation method and the solvent/co-solvent ratio has been changed in order to tune the crystal size. Then, the size effect on the detector efficiency to thermal neutrons has been investigated as related to the energy loss of thermal neutron reaction products inside the crystal and the dispersion homogeneity of the crystals into the composite. To complete the characterization of the produced flexible detectors, the response to {\gamma}-rays has been measured and compared to a commercial detector. The careful choice of both the base resin and the 6LiF crystals size allows to produce flexible detector for thermal neutrons with performances comparable to the commercial standard and with higher mechanical robustness and stability.
Prompt gamma radiation from neutron interactions is an important issue as it affects the operation of nuclear facilities (radiation protection or gamma heating issues) or has various uses (non-destructive identification of elements). Despite of importance, its production is inaccurately described in present nuclear data libraries. Therefore, a set of experiments have been carried out focusing on this radiation - prompt gamma from neutron inelastic scattering on oxygen and prompt gamma from radiative capture on manganese, both present the form of an aqueous solution. The gammas were induced by the Am-Be neutron source (for oxygen) and 252Cf spontaneous fission neutron source (for manganese). In the case of oxygen, the present libraries can be used, but all the libraries tested overestimated the experiment by 20–30%, considering the experimental uncertainty of 6-9%. INDEN-4.0 library is giving the best results. In the case of manganese, none of the libraries tested give acceptable results. The INDEN updated data for gamma production on manganese give usable results, but there is still a discrepancy from -36% to 55% with uncertainties from 6-15%.
In the oil field, exploration of the subsurface through well logging provides measurements of the characteristics of rock formations and fluids to help identify and evaluate potential reservoirs. Downhole nuclear measurements focus on formation properties such as natural radioactivity, formation density, and hydrogen content, as well as the identification of the elemental and mineralogical composition of the rock through spectroscopy. Accurate nuclear modeling is a fundamental part of nuclear well logging tool development, from concept through design to response characterization. Underlying the accuracy of nuclear modeling is a good knowledge of nuclear cross sections of the elements in the tool, borehole, and subsurface formations. The recent focus on replacing tools based on radio-isotopic sources with those based on D-T neutron generators opens many opportunities for new measurements but highlights the deficiencies of current cross sections. For example, in neutron-induced inelastic and capture gamma ray spectroscopy, major obstacles come from a lack of or inaccuracies in the cross sections of essential materials.
A logging sonde was designed for neutron-induced gamma-ray spectroscopy in a geophysics project by re-evaluating the previous design method and modifying it for an improvement. This study further considered radiation interaction with materials and detector responses. The detector responses were calculated with pulse height (f8) tallies with a Monte Carlo transport simulation code and they were compared with the flux (f4) tally results which were mainly used for the previous sonde design. Analyses were focused on gamma rays produced from neutron capture reactions with silicon, sodium, and potassium and neutron inelastic scattering reactions with oxygen in Korean geostandard formations. Simulated responses from sodium iodine (NaI), bismuth germanate (BGO), gadolinium oxyorthosilicate (GSO), and lanthanum bromide (LaBr3) detectors were studied to compare the anticipated performances of the logging sonde depending on detector materials. We attempted to determine optimal detector locations from the simulated energy spectra, in which one can observe differences in capture and inelastic scattering gamma-ray peaks depending on the given formation configurations in a clearer manner. A comprehensive evaluation on the physical properties of detectors and the simulation result tentatively concluded that GSO detectors placed at 30, 70, and 90 cm positions can efficiently collect the data of interest from the Korean geostandard formations.
The detection of thermal neutrons is increasingly important for several fields of interest, so new versatile, manageable and adaptable detectors are needed for applications in different environments and situations. To date, scintillators for thermal neutrons available on the market are fragile and with low adaptability. In this work, flexible and robust thermal neutron scintillators with improved properties as compared to commercial ZnS:Ag based phosphors are produced. The scintillators are produced by mixing ZnS:Ag powder and ⁶ LiF nano-crystals in polysiloxane binders. ⁶ LiF nano-crystals are synthesized by co-precipitation method, and the detection efficiency is optimized by tuning the crystal size through different solvent/co-solvent ratios. Then, the detection yield to thermal neutrons is investigated as related both to the crystal size and to the binder. Two different siloxanes, either with pendant phenyl groups or with aliphatic groups are used, the former being intrinsically fluorescent and with higher polarizability than the latter. The response to γ-rays is also evaluated. Lastly, the right combination of base resin and ⁶ LiF crystals size allows to produce flexible scintillators for thermal neutrons with performances comparable to the commercial standard and with higher mechanical robustness and stability.
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.
