An enhanced accuracy method to determine oil saturation by carbon/oxygen logging in tight reservoirs

The low porosity and permeability characteristics of tight oil reservoirs have brought challenges to monitoring oil saturation recently. Although carbon/oxygen logging is effective for oil saturation evaluation, the statistical fluctuations of the measured energy spectrum in tight reservoirs make it impossible to distinguish the different signals between oil and water. Thus, Noise Adjusted Singular Value Decomposition (NASVD) is applied to denoise the raw energy spectrum and evaluate the oil saturation quantitatively. The energy spectrum matrix, which is composed of the energy spectrum of the measurement point and its adjacent depth points, is decomposed and reconstructed to remove non-informative signals and improve the signal-to-noise ratio (SNR) of the raw energy spectrum. The parameter K evaluates the smoothness of the logging curves, reflecting the influence of the number of energy spectra and singular values on NASVD. Meanwhile, the NASVD, Savitzky-Golay (S-G) filtering and depth averaging methods are compared for calculating the accuracy of C/O, Si/Ca and oil saturation with the Monte Carlo method, indicating that NASVD is better than the other two methods for eliminating the statistical fluctuations of the raw energy spectrum. A simulation example indicates that NASVD can control the calculation errors of tight reservoir oil saturation to within 15%, which significantly improves the accuracy of the estimated oil saturation. An oil field example shows that the oil saturation interpretation result for tight reservoirs is in good agreement with the oil saturation from open hole log analysis, signifying that the NASVD energy spectrum denoising method can provide a quantitative estimate of oil saturation in tight oil reservoirs.

Assessment of shutdown dose rates in the ITER Collective Thomson Scattering system and in equatorial port plug 12

The ITER Collective Thomson Scattering (CTS) system will be the main diagnostic responsible for measuring the velocity distribution function of fusion-born alpha particles in the plasma. As the CTS diagnostic is integrated in the equatorial port plug 12 (drawer 3), with direct apertures to the port interspace where maintenance hands-on operation will be carried out, it is essential to assess the shutdown dose rates (SDDR) in these maintenance areas. In this work, the D1S-UNED3.1.4 Monte-Carlo transport code, based on the implementation of the direct-one-step methodology in MCNP5 v1.60, was used to estimate the dose rate level 12 days (106 s) after shutdown in the port interspace. The results show that the CTS system does not contribute significantly to the SDDR in the area where hands-on maintenance is foreseen with contribution to dose rates less than 1 µSv/h. This is consistent with previous estimates, although with the most recent model of the CTS design there is a slight increase of the SDDR values. This deviation can be attributed to design changes and improved shielding modelling and/or most importantly, to statistical fluctuations of the D1S simulations. From a neutronics point of view, the increase in the SDDR falls within the range of the statistical fluctuations, and the design is still compliant with the radiation safety ALARA principle aiming at minimizing radiation doses, and there is no requirement for further design optimizations.

Cosmic-ray-related Signals from Detectors in Space: The Spitzer/IRAC Si:As IBC Devices

We evaluate the hit rate of cosmic rays and their daughter particles on the Si:As IBC detectors in the IRAC instrument on the Spitzer Space Telescope. The hit rate follows the ambient proton flux closely, but the hits occur at more than twice the rate expected just from this flux. Toward large amplitudes, the size distribution of hits by single-charge particles (muons) follows the Landau Distribution. The amplitudes of the hits are distributed to well below the energy loss of a traditional “average minimum-ionizing proton” as a result of statistical fluctuations in the ionization loss within the detectors. Nonetheless, hits with amplitudes less than a few hundred electrons are rare; this places nearly all hits in an amplitude range that is readily identified given the read noises of modern solid-state detectors. The spread of individual hits over multiple pixels is dominated by geometric effects, i.e., the range of incident angles, but shows a modest excess probably due to: (1) showering and scattering of particles; (2) the energy imparted on the ionization products by the energetic protons; and (3) interpixel capacitance. Although this study is focused on a specific detector type, it should have general application to operation of modern solid-state detectors in space.

Identifying and Addressing the Underlying Core Problems in Healthcare Environments: An Illustration Using an Emergency Department Game

The emergency department (ED) crowding is a critical healthcare issue worldwide that leads to long waits and poorer healthcare outcomes. Goldratt’s theory of constraints (TOC) has been used effectively to improve such problematic environments for more than three decades. While most TOC solutions are simple, with many viewing them as purely common sense, they represent paradigm shifts in how to manage complex, uncertain, and silo environments. Goldratt used a simple dice game with a straight flow (I-shape) to illustrate the impact of dependent resources and statistical fluctuations in managing resources. Additionally, games help to overcome resistance to change and gain ownership by having participants develop their solutions. This new cooperative game illustrates an ED environment where patients may follow different care pathways according to their clinical needs, timeliness of care is measured in minutes, the demand is highly uncertain, and treatment must frequently start almost immediately. A Monte Carlo simulation validated the TOC solution to this ED game, achieving results similar to the real TOC’s implementations. Moreover, this article provides a thorough process to Socratically introduce TOC to healthcare professionals and others to recognize that the EDs’ (like other healthcare systems’) core problem is the traditional approach to managing them.

Parameters optimization based on neural network of practical wavelength division multiplexed decoy-state quantum key distribution

The integration of quantum key distribution (QKD) devices with the existing optical fiber networks is of great significance in reducing the deployment costs and saving fiber resources. Wavelength division multiplexing (WDM) is expected to be a desirable approach to fulfill this ultimate task. In this paper, we analyze the dominant noises in WDM-based QKD system and optimize the key parameters based on a modified model with 200 GHz channel spacing. Then, an appropriate decoy-state method is adopted to estimate the system performance considering statistical fluctuations. Finally, a three-layer artificial neural network is used to train and predict the optimal mean photon numbers within different situations. Our work provides a useful method for the parameters optimization of WDM-QKD system and accelerates the practical development of QKD that coexists with the current backbone fiber infrastructure.

Rotated twisted-mass: a convenient regularization scheme for isospin breaking QCD and QED lattice calculations

We propose a scheme of lattice twisted-mass fermion regularization which is particularly convenient for application to isospin breaking (IB) QCD and QED calculations, based in particular on the so called RM123 approach, in which the IB terms of the action are treated as a perturbation. The main, practical advantage of this scheme is that it allows the calculation of IB effects on some mesonic observables, like e.g. the $$\pi ^+ - \pi ^0$$ π + - π 0 mass splitting, using lattice correlation functions in which the quark and antiquark fields in the meson are regularized with opposite values of the Wilson parameter r. These correlation functions are found to be affected by much smaller statistical fluctuations, with respect to the analogous functions in which quark and antiquark fields are regularized with the same value of r. Two numerical application of this scheme, that we call rotated twisted-mass, within pure QCD and QCD + QED respectively, are also provided for illustration.

A Simplified Algorithm for Count Rate Processing in Radiation Monitors That Address Statistical Fluctuations and Spurious Counts

While processing the signals from radiation detectors, for finding the true mean-count-rate, algorithms with hybrid pulse collection methodology have been proposed and used over the years. An algorithm based on this technique with a new methodology of adoption and implementation including spurious rejection is proposed here. It enables a specified and controllable error when the mean-count-rate remains within certain predefined limits from its true value. Effort is made to optimize the response time of prediction at low count rates preserving the optimum possible relative-standard-deviation (RSD). Chi-squared test is utilized for verifying the counting system to check if the observed fluctuations are consistent with the expected statistical fluctuations. A C-program code has been developed to test the algorithm. An observed set of detector outputs are given as input to the program and the corresponding Output is analyzed. A comparative study between the proposed method and floating-mean method is presented for the same set of observations. A typical short-lived high voltage (HV) induced spurious noise pattern is fed as input to the program verifying limited-spurious rejection capability of the algorithm. An embedded C program was written for microcontroller implementation of the algorithm. Case-study of a neutron roentgen equivalent man (REM) counter is presented for evaluating response time for various ranges of operation with calculation of RSD at these ranges. This general-purpose algorithm can enhance the read-out accuracy of radiation monitors used for radiation safety applications.

A new approach to probe non-standard interactions in atmospheric neutrino experiments

We propose a new approach to explore the neutral-current non-standard neutrino interactions (NSI) in atmospheric neutrino experiments using oscillation dips and valleys in reconstructed muon observables, at a detector like ICAL that can identify the muon charge. We focus on the flavor-changing NSI parameter εμτ, which has the maximum impact on the muon survival probability in these experiments. We show that non-zero εμτ shifts the oscillation dip locations in L/E distributions of the up/down event ratios of reconstructed μ− and μ+ in opposite directions. We introduce a new variable ∆d representing the difference of dip locations in μ− and μ+, which is sensitive to the magnitude as well as the sign of εμτ, and is independent of the value of $$ \Delta {m}_{32}^2 $$ Δ m 32 2 . We further note that the oscillation valley in the (E, cos θ) plane of the reconstructed muon observables bends in the presence of NSI, its curvature having opposite signs for μ− and μ+. We demonstrate the identification of NSI with this curvature, which is feasible for detectors like ICAL having excellent muon energy and direction resolutions. We illustrate how the measurement of contrast in the curvatures of valleys in μ− and μ+ can be used to estimate εμτ. Using these proposed oscillation dip and valley measurements, the achievable precision on |εμτ| at 90% C.L. is about 2% with 500 kt·yr exposure. The effects of statistical fluctuations, systematic errors, and uncertainties in oscillation parameters have been incorporated using multiple sets of simulated data. Our method would provide a direct and robust measurement of εμτ in the multi-GeV energy range.

Consistency of cosmic shear analyses in harmonic and real space

Recent cosmic shear studies have reported discrepancies of up to 1σ on the parameter ${S_{8}=\sigma _{8}\sqrt{{\Omega _{\rm m}}/0.3}}$ between the analysis of shear power spectra and two-point correlation functions, derived from the same shear catalogs. It is not a priori clear whether the measured discrepancies are consistent with statistical fluctuations. In this paper, we investigate this issue in the context of the forthcoming analyses from the third year data of the Dark Energy Survey (DES-Y3). We analyze DES-Y3 mock catalogs from Gaussian simulations with a fast and accurate importance sampling pipeline. We show that the methodology for determining matching scale cuts in harmonic and real space is the key factor that contributes to the scatter between constraints derived from the two statistics. We compare the published scales cuts of the KiDS, Subaru-HSC and DES surveys, and find that the correlation coefficients of posterior means range from over 80% for our proposed cuts, down to 10% for cuts used in the literature. We then study the interaction between scale cuts and systematic uncertainties arising from multiple sources: non-linear power spectrum, baryonic feedback, intrinsic alignments, uncertainties in the point-spread function, and redshift distributions. We find that, given DES-Y3 characteristics and proposed cuts, these uncertainties affect the two statistics similarly; the differential biases are below a third of the statistical uncertainty, with the largest biases arising from intrinsic alignment and baryonic feedback. While this work is aimed at DES-Y3, the tools developed can be applied to Stage-IV surveys where statistical errors will be much smaller.