Hasil untuk "Oils, fats, and waxes"

Chao NI, Anping HU, Tianjie JIN et al.

Focusing on the geochronological issues related to the matching relationship between the strike-slip fault activity and the stages of hydrocarbon generation, reservoir formation, and hydrocarbon accumulation, this study aims to quantitatively constrain the tectonic–burial history, hydrocarbon generation history, reservoir porosity evolution history, and hydrocarbon accumulation history by determining the isotopic ages and temperatures of multiphase calcites (particularly the calcites which contain hydrocarbon-bearing fluid inclusions) and quartzs filling the fractures in the Ordovician strata within the non-foreland area of Tarim Basin. Three major findings have been obtained. (1) According to the tectonic–burial history restored under the constraint of the isotopic ages and temperatures, the non-foreland area of the Tarim Basin experienced a continuous burial process during the Cambrian–Ordovician period, with only a minor uplift at the end of the Silurian. Overall, the area was characterized by continuous hydrocarbon generation and a gradual increase in vitrinite reflectance (Ro). (2) While mechanical compaction and pressure-solution during burial progressively reduced the matrix porosity, the strike-slip fault activity during the Middle Caledonian II and III episodes induced physical fragmentation, which created extensive interbreccia pores, fault cavities, and structural fractures as seepage pathways for surface runoff, and, in conjunction with interlayer karstification, led to the development of widespread dissolution vugs. The formation of fracture-vug system in the Ordovician limestone provided effective storage space for hydrocarbons generated during the Late Caledonian and subsequent periods. (3) The Ordovician fault–karst limestone reservoirs underwent four stages of hydrocarbon accumulation: low–medium maturity liquid hydrocarbons during the Middle–Late Caledonian, medium–high maturity liquid hydrocarbons during the Middle–Late Hercynian, high maturity liquid hydrocarbons during the Indosinian, and high–over maturity gas during the Middle Yanshanian. Variations in hydrocarbon accumulation among different strike-slip faults or different segments of the same fault are controlled by differences in source rock maturity across structural units, as well as by the timing of fault activity and fault-related connectivity to hydrocarbon sources. This research also establishes a geochronological framework for investigating strike-slip fault- controlled reservoir formation and hydrocarbon accumulation, facilitating a more accurate determination of the reservoir formation and hydrocarbon accumulation stages, and providing critical insights for evaluating hydrocarbon enrichment zones in fault-controlled reservoirs.

LI Mingfei, HUANG Jingfu, JIA Hai et al.

In order to increase the effective penetration depth of perforation and establish efficient oil and gas channels, it is often required that the perforation channels should be parallel to the reservoir direction during perforation construction. However, geological structures such as folds and faults often cause the reservoir to be inclined, which results in the channels intersecting the casing at an angle rather than perpendicularly, that is, the casing is perforated at an inclined angle. Inclined perforation breaks through the limitation in existing perforation technology that requires the perforation direction to be perpendicular to the casing. However, after perforation, the perforation holes alter the casing structure. When the casing is subjected to external forces, stress concentration occurs around the holes, reducing the casing's strength. As a result, perforated casings are more prone to damage compared to regular casings. Since there is relatively limited research on the residual strength of casing perforated at inclined angles. In this paper, a three-dimensional finite element model is established to analyze the residual strength of inclined perforated casing. The analysis results show that when the perforation parameters such as hole diameter, hole density, and phase angle are constant, as the perforation inclination angle increases (from 0 to 30°), the remaining external squeeze strength of the casing gradually decreases, and the reduction in the remaining strength of the perforation casing does not exceed 13.00%. When the inclination angle is set to 30° and the phase angle varies from 30° to 180°, the change in the remaining strength of the perforation casing does not exceed 10.20%. When the phase angle is 90°, the remaining strength of the perforation casing is relatively optimal. When the inclination angle is set to 30° and the hole diameter increases from 10 mm to 18 mm, the reduction in the remaining strength of the perforation casing can reach 17.45%. The study can provide theoretical support for the analysis of the remaining strength of inclined perforation casings and practical application in perforation construction.

I. Chittumuri, N. Alshehab, R. J. Voss et al.

This paper presents a risk analysis of flowlines in the oil and gas sector using Geographic Information Systems (GIS) and machine learning (ML). Flowlines, vital conduits transporting oil, gas, and water from wellheads to surface facilities, often face under-assessment compared to transmission pipelines. This study addresses this gap using advanced tools to predict and mitigate failures, improving environmental safety and reducing human exposure. Extensive datasets from the Colorado Energy and Carbon Management Commission (ECMC) were processed through spatial matching, feature engineering, and geometric extraction to build robust predictive models. Various ML algorithms, including logistic regression, support vector machines, gradient boosting decision trees, and K-Means clustering, were used to assess and classify risks, with ensemble classifiers showing superior accuracy, especially when paired with Principal Component Analysis (PCA) for dimensionality reduction. Finally, a thorough data analysis highlighted spatial and operational factors influencing risks, identifying high-risk zones for focused monitoring. Overall, the study demonstrates the transformative potential of integrating GIS and ML in flowline risk management, proposing a data-driven approach that emphasizes the need for accurate data and refined models to improve safety in petroleum extraction.

Yao-Bei Liu, Jing-Wei Lian

Heavy Majorana neutrinos ($N$) are predicted in many models of physics beyond the Standard Model. In this work, we explore the production and detection prospects of TeV-scale heavy neutrinos ($m_N \gtrsim 1$ TeV) at a future 3 TeV Compact Linear Collider (CLIC). We focus on two distinct decay topologies: (i) $N \to \ell^{\pm} W^{\mp}$ with hadronic $W$ boson decay, leading to a final state with one charged lepton and a hadronic fat-jet $J_W$; and (ii) $N \to νh$ with subsequent Higgs decay $h \to b\bar{b}$, yielding a Higgs-tagged fat-jet $J_h$ and $\slashed{E}_T$. Based on comprehensive detector-level simulations and background analysis, we present both $2σ$ exclusion limits and $5σ$ discovery reaches in the $m_N$-$|V_{\ell N}|^2$ plane. We further extract 95\% confidence level upper limits on the mixing parameter $|V_{\ell N}|^2$, and perform a detailed comparison with existing constraints from direct searches at future colliders and indirect global fits. Our findings demonstrate that a 3 TeV CLIC can improve the sensitivity to $|V_{\ell N}|^2$ by about two orders of magnitude compared to the projected reaches of future hadron colliders, while remaining competitive with other CLIC search channels.

曹冲1,2，袁国军1,2，宋锋华3CAO Chong1,2, YUAN Guojun1,2, SONG Fenghua3

旨在为保障国内油料安全提供参考依据,基于中国植物油料进口实际情况，构建改进的贸易引力模型，以2013—2022年中国植物油料进口贸易的26个国家为研究对象，实证考察中国植物油料进口流量的影响因素及潜力。结果表明：经济规模、地理距离、相似需求、边界相邻对中国植物油料进口起到促进作用，而人口规模、要素禀赋、开放程度、汇率水平、区域组织则对中国植物油料进口产生一定的阻碍作用；中国从巴西进口的植物油料属于“过度进口”，从蒙古国、美国、俄罗斯、巴基斯坦等22个国家进口的植物油料属于“进口饱和”，而从墨西哥、乌克兰、布基纳法索进口的植物油料属于“进口不足”。因此，需要提高国内植物油料生产效率和能力、鼓励国内企业积极参与植物油料进口市场、重视中国与植物油料贸易伙伴国的国别异质性、努力推动新兴市场战略等则有利于实现优势互补，进而保障国内植物油料安全。To provide a reference basis for ensuring the safety of domestic plant oilseed, an improved trade gravity model was constructed based on the actual situation of China′s plant oilseed import, and 26 countries of China′s plant oilseed import trade from 2013 to 2022 were used to investigate the influence factors and potential of China′s plant oilseed import flow. The results showed that economic scale, geographical distance, similar demand and adjacent borders played a promoting role in China′s plant oilseed import, while population size, factor endowment, openness degree, exchange rate level and regional organization had some hindering effect. Plant oilseed imported from Brazil was "excessive import", plant oilseed imported from 22 countries, including Mongolia, the United States, Russia and Pakistan, was "import saturation", while plant oilseed imported from Mexico, Ukraine and Burkina Faso was "insufficient import". Therefore, it is necessary to improve the efficiency and capacity of plant oilseed production of China, encourage domestic enterprises to actively participate in the plant oilseed import market, attach importance to the national heterogeneity between China and plant oilseed trading partners, and promote the promotion of emerging market strategy, which are conducive to realize complementary advantages and ensure the safety of domestic plant oilseed.

田瑞1，2，王风艳1,2，孙尚德1，王翔宇2，酉琳娜2，江鑫2，魏安池1，陈焱2 TIAN Rui1,2, WANG Fengyan1,2, SUN Shangde1, WANG Xiangyu2, YOU Linna2, JIANG Xin2, WEI Anchi1, CHEN Yan 2

旨在为植物油煎炸品质的综合评价提供参考，对市场上常见的6种植物油（大豆油、菜籽油、棕榈油、玉米油、葵花籽油和棉籽油）进行煎炸实验，考察煎炸过程中植物油的总极性组分(TPC)含量、酸值（AV）、过氧化值（POV）、p-茴香胺值（p-AV）、脂肪酸和碘值等常规理化指标，（E,E）-2,4-癸二烯醛含量，黏度和色泽以及维生素E（VE）和植物甾醇含量的变化，分析各指标的两两相关性，并对11项检测指标进行主成分分析（PCA）。结果表明：6种植物油煎炸过程中11项指标的变化存在一定差异，随着煎炸时间的延长，煎炸油的TPC含量、AV、POV、p-AV、红值和黏度不断增加，C18∶ 2与C16∶ 0比值、碘值、VE和植物甾醇含量不断降低，（E,E）-2,4-癸二烯醛含量先增加后降低；不同指标之间存在一定的相关性，其中TPC、AV和黏度两两之间呈极显著正相关，C18∶ 2与C16∶ 0比值、碘值与VE含量两两间存在极显著的正相关性,（E,E）-2,4-癸二烯醛含量与p-AV呈极显著正相关;PCA得到的3个主成分的累积贡献率为86.225%，通过计算3个主成分的加权得分建立了煎炸油的综合评价模型，并通过计算得出6种植物油中棕榈油的煎炸稳定性最好。综上，所建立的煎炸油综合评价模型可以对6种植物油煎炸品质进行评价，棕榈油的煎炸品质最好。Aiming to provide a reference for the comprehensive evaluation of the frying quality of vegetable oils, frying experiments were carried out on six common vegetable oils available in the market (soybean oil, rapeseed oil, palm oil, corn oil, sunflower seed oil, and cottonseed oil) to investigate the total polar component (TPC) content, acid value (AV), peroxide value (POV), p-anisidine value (p-AV), fatty acid and iodine value conventional physicochemical indexes, the content of (E,E)-2,4-decadienal, viscosity and colour, and the contents of vitamin E (VE) and phytosterols of vegetable oils during the frying process were detected to analyse the two-by-two correlation of the indexes, and the 11 tested indexes were subjected to the principal component analysis (PCA).The results showed that there were some differences in the changes of 11 indexes during the frying process of six vegetable oils. With the prolongation of frying time, the TPC content, AV, POV, p-AV, red value and viscosity of the frying oils increased, the ratio of C18∶ 2 to C16∶ 0, iodine value and contents of VE and phytosterol decreased, and the content of (E,E)-2,4-decadienal first increased and then decreased. There were some correlations between them, including highly significant positive correlations between TPC, AV and viscosity, and highly significant positive correlations between the ratio of C18∶ 2 to C16∶ 0, iodine value and the content of VE. There were highly significant positive correlation between the (E,E)-2,4-decadienal content and p-AV. The cumulative contribution rate of the three principal components obtained was 86.225%, and a comprehensive evaluation model of frying oils was established by calculating the weighted scores of the three principal components. The frying stability of palm oil was the best among the six vegetable oils. In conclusion, the frying quality can be evaluated by the established comprehensive evaluation model of frying oil, and the frying quality of palm oil is the best.

LI Xiang, WANG Jun, SONG Caiyu et al.

<b>[Objective]</b> Compared with conventional gas fuel, hydrogen is more susceptible to explosion. Meanwhile, the existence of obstacles notably stimulates hydrogen combustion and accelerates flame propagation, causing more serious consequences of accidents. To reduce destructive damage caused by hydrogen combustion under obstacle conditions, it is particularly important to reveal the influences of different obstacle conditions on the characteristics of flame propagation of hydrogen. <b>[Methods]</b> Based on large eddy simulation, the hydrogen/air combustion and explosion processes under different obstacle shapes and blockage rate conditions were numerically simulated.Focus was given to the research on different flame propagation velocities caused by different obstacle shapes and the sensitivity to blockage rate changes. <b>[Results]</b> Under low blockage rate, grid-type obstacles had a stronger destructive effect on the regular flow field at the flame front than single-side obstacles, and as the number of voids in grid-type obstacles increased, their destructive effect on the flow field motion further intensified, making it difficult for the flame front to recover to a regular state. When the blockage rate went up, the difference of the shapes of obstacles became insignificant in causing damage to the regular flow field, and the flame front was continuously distorted under all obstacle conditions. As the blockage rate continued to increase, single-side obstacles brought higher peak flame propagation velocity than grid-type obstacles. At the same blockage rate, the mechanism of flame acceleration by grid-type obstacles can be changed by adjusting the single void area to enhance the acceleration effect. <b>[Conclusion]</b> The shape and blockage rate of obstacles are the key factors influencing the state of flame front behind obstacles.The single-side obstacle is more sensitive to the blockage rate,while the grid-type obstacle has higher acceleration potential.The research results provide basic reference data for the prevention and control of hydrogen fire accidents and serve as a reference for the design of hydrogen power systems.

Constantin Slioussarenko, Pierre-Yves Baudin, Marc Lapert et al.

Over the past decade, Magnetic Resonance Fingerprinting (MRF) has emerged as an efficient paradigm for the rapid and simultaneous quantification of multiple MRI parameters, including fat fraction (FF), water T1 ($T1_{H2O}$), water T2 ($T2_{H2O}$), and fat T1 ($T1_{fat}$). These parameters serve as promising imaging biomarkers in various anatomical targets such as the heart, liver, and skeletal muscles. However, measuring these parameters in the upper body poses challenges due to physiological motion, particularly respiratory motion. In this work, we propose a novel approach, motion-corrected (MoCo) MRF T1-FF, which estimates the motion field using an optimized preliminary motion scan and uses it to correct the MRF acquisition data before dictionary search for reconstructing motion-corrected FF and $T1_{H2O}$ parametric maps of the upper-body region. We validated this framework using an $\textit{in vivo}$ dataset comprising ten healthy volunteers and a 10-year-old boy with Duchenne muscular dystrophy. At the ROI level, in regions minimally affected by motion, no significant bias was observed between the uncorrected and MoCo reconstructions for FF (mean difference of -0.7%) and $T1_{H2O}$ (-4.9 ms) values. Moreover, MoCo MRF T1-FF significantly reduced the standard deviations of distributions assessed in these regions, indicating improved precision. Notably, in regions heavily affected by motion, such as respiratory muscles, liver, and kidneys, the MRF parametric maps exhibited a marked reduction in motion blurring and streaking artifacts after motion correction. Furthermore, the diaphragm was consistently discernible on parametric maps after motion correction. This approach lays the groundwork for the joint 3D quantification of FF and $T1_{H2O}$ in regions that are rarely studied, such as the respiratory muscles, particularly the intercostal muscles and diaphragm.

Mahdi Goldani, Soraya Asadi Tirvan

The Gulf Cooperation Council countries -- Oman, Bahrain, Kuwait, UAE, Qatar, and Saudi Arabia -- holds strategic significance due to its large oil reserves. However, these nations face considerable challenges in shifting from oil-dependent economies to more diversified, knowledge-based systems. This study examines the progress of Gulf Cooperation Council (GCC) countries in achieving economic diversification and social development, focusing on the Social Progress Index (SPI), which provides a broader measure of societal well-being beyond just economic growth. Using data from the World Bank, covering 2010 to 2023, the study employs the XGBoost machine learning model to forecast SPI values for the period of 2024 to 2026. Key components of the methodology include data preprocessing, feature selection, and the simulation of independent variables through ARIMA modeling. The results highlight significant improvements in education, healthcare, and women's rights, contributing to enhanced SPI performance across the GCC countries. However, notable challenges persist in areas like personal rights and inclusivity. The study further indicates that despite economic setbacks caused by global disruptions, including the COVID-19 pandemic and oil price volatility, GCC nations are expected to see steady improvements in their SPI scores through 2027. These findings underscore the critical importance of economic diversification, investment in human capital, and ongoing social reforms to reduce dependence on hydrocarbons and build knowledge-driven economies. This research offers valuable insights for policymakers aiming to strengthen both social and economic resilience in the region while advancing long-term sustainable development goals.

Ahmed Farid Ibrahim, Sulaiman A. Alarifi, Salaheldin Elkatatny

Abstract This study proposes the use of different machine learning techniques to predict the estimated ultimate recovery (EUR) as a function of the hydraulic fracturing design. A set of data includes 200 well production data, and completion designs were collected from oil production wells in the Niobrara shale formation. The completion design parameters include the lateral length, the number of stages, the total injected proppant and slurry volumes, and the maximum treating pressure measured during the fracturing operations. The data set was randomly split into training and testing with a ratio of 75:25. Different machine learning methods were to predict EUR from the completion design including linear regression, random forest (RF), and decision tree (DT) in addition to gradient boosting regression (GBR). EUR prediction from the completion data showed a low accuracy. As result, an intermediate step of estimating the well IP30 (the initial well production rate for the first month) from the completion data was carried out; then, the IP30 and the completion design were used as input parameters to predict the EUR. The linear regression showed some linear relationship between the output and the inputs, where the EUR can be predicted with a linear relationship with an R-value of 0.84. In addition, a linear correlation was developed based on the linear regression model. Moreover, the other ML tools including RF, DT, and GBR presented high accuracy of EUR prediction with correlation coefficient (R) values between actual and predicted EUR from the ML model higher than 0.9. This study provides ML application with an empirical correlation to predict the EUR from the completion design parameters at an early time without the need for complex numerical simulation analysis. Unlike the available empirical DCA models that require several months of production to build a sound prediction of EUR, the main advantage of the developed models in this study is that it requires only an initial flow rate along with the completion design to predict EUR with high certainty.

张晓晓，孙聪，杨瑞楠，张林尚，康宝，陈雁然，梁慧敏，梁少华ZHANG Xiaoxiao, SUN Cong, YANG Ruinan, ZHANG Linshang, KANG Bao, CHEN Yanran, LIANG Huimin, LIANG Shaohua

旨在为可可脂生产提供新的基料油，同时为高油酸花生油的高值化利用提供研究基础，以高油酸花生油和棕榈酸乙酯为原料，脂肪酶NS40086为催化剂，在无溶剂体系下酶法合成1,3-二棕榈酸-2-油酸甘油三酯（POP）。采用单因素实验研究反应条件对POP含量、酰基位移、sn-2位油酸相对含量的影响，并采用响应面法进行优化。结果表明：高油酸花生油酶促酯交换制备POP的最佳反应条件为反应时间3 h、底物（棕榈酸乙酯与高油酸花生油）物质的量比11∶ 1、酶添加量（以底物总质量计）3%、反应温度50 ℃，在此条件下POP含量为86.48%，酰基位移为3.25%，sn-2位油酸相对含量为72.88%。In order to provide new base oil for the production of cocoa butter and research basis for the high-value utilization of high-oleic peanut oil, with high-oleic peanut oil and ethyl palmitate as raw materials, NS40086 lipase as catalyst, 1,3-dipalmitoyl-2-oleoylglycerol (POP) was synthesized by enzymatic transesterification in a solvent-free system. The effects of reaction conditions on the POP content, acyl migration and the relative content of sn-2 oleic acid were studied by single factor experiment, and response surface methodology was used to determine the optimal reaction conditions. The results showed that the optimal reaction conditions were obtained as follows: reaction time 3 h, molar ratio of ethyl palmitate to high-oleic peanut oil 11∶ 1, dosage of enzyme 3% (based on total substrates mass), reaction temperature 50 ℃. Under these conditions, the POP content, acyl migration and the relative content of sn-2 oleic acid were 86.48%, 3.25% and 72.88%, respectively.

XUE Gang, XIONG Wei, ZHANG Peixian

There are two types of shale gas reservoirs in the Wufeng-Longmaxi shale formation of southeast margin of Sichuan Basin: normal pressure shale gas reservoir in Wulong residual syncline and abnormal over-pressure shale gas reservoir in Fuling anticline. This study takes an integrated geology-engineering approach to analyze the genesis and formation mechanisms of normal pressure shale gas reservoirs in the Wulong area. The analysis is based on shale burial history curves, drilling data, horizontal well fracturing parameters, and the geological characteristics specific to normal pressure shale gas reservoirs. Combined with the actual production effects of two horizontal shale gas wells, the fracturing process parameters of normal pressure shale gas reservoirs are optimised. Then three main points have been obtained in this study: ①The normal pressure shale gas reservoir of the Wufeng-Longmaxi Formation in Wulong area is formed during the structural destruction adjustment of the Yanshanian and Himalayan tectonic periods. ②The shale gas escaping caused by tectonic elevation is the main reason for the formation of normal pressure shale gas. ③Compared with the Marcellus normal pressure shale gas reservoir, Wulong normal pressure shale gas reservoir has the similar geological characteristics, but the development effect varies greatly. The fracturing scale simulation shows that it is necessary to further optimise the horizontal well segmented fracturing parameters, increase the output of single wells, and reduce development costs. Only in this way can effective development be realised.

曹芷郡1，2，3，陈佳鹏1，任健1，2，3，宋春丽1，2，3，刘军3 CAO Zhijun1,2,3, CHEN Jiapeng1, REN Jian1,2,3, SONG Chunli1,2,3, LIU Jun3

为改善大豆分离蛋白膜的性能，利用碱性蛋白酶制备玉米醇溶蛋白酶解产物（ZH），通过转谷氨酰胺酶（TGase）催化大豆分离蛋白（SPI）与ZH发生交联反应，对反应条件进行了优化；通过控制反应时间得到4种修饰产物（分别为0 h-SPI/ZH、0.5 h-SPI/ZH、1 h-SPI/ZH、1.5 h-SPI/ZH），并对修饰产物制备的膜性能进行研究。结果表明：最佳的TGase催化SPI与ZH交联反应条件为SPI与ZH质量比3.5∶ 1、底物质量浓度40 mg/mL、pH 7.5、酶添加量10 U/g（以蛋白质质量计）、反应温度45 ℃、反应时间1.5 h；随着反应时间的延长，4种修饰产物制备的复合膜抗拉强度和不透明度增加，含水量、断裂伸长率和水蒸气透过率降低；与SPI膜相比，1.5 h-SPI/ZH制备的复合膜的抗拉强度增加了5.5%，含水量与水蒸气透过率分别下降了25.6%和32.2%，不透明度增加了114.2%。综上，采用TGase催化SPI与ZH发生交联，所制的复合膜综合品质较好，为SPI复合膜的开发提供了技术支持。 In order to improve the properties of soybean protein isolates film, the enzymatic hydrolysates of zein (ZH) was prepared by alkaline protease. The cross-linking reaction between soybean protein isolates (SPI) and ZH was catalyzed by transglutaminase (TGase), and the reaction conditions were optimized. Four modified products(0 h-SPI/ZH, 0.5 h-SPI/ZH, 1 h-SPI/ZH, and 1.5 h-SPI/ZH) were obtained by controlling the reaction time, and the properties of the film produced by the modified products were investigated. The results showed that the optimal reaction conditions were as follows: mass ratio of SPI to ZH 3.5∶ 1, substrate mass concentration 40 mg/mL, pH 7.5, TGase addition 10 U/g(based on the mass of protein), reaction time 1.5 h and reaction temperature 45 ℃. With the prolonging of reaction time, the tensile strength and opacity of the composite film prepared by the four modified products increased, while the water content, elongation at break and water vapor transmission rate decreased. Compared with SPI film, the tensile strength of the composite film prepared by 1.5 h-SPI/ZH increased by 5.5%, the water content and water vapor transmission rate decreased by 25.6% and 322%, respectively, and the opacity increased by 114.2%. In conclusion, the overall quality of the composite film prepared by TGase catalyzed cross-linking of ZH and SPI is good, providing technical support for the development of SPI composite film.

Adèle LC Mackowiak, Christopher W Roy, Mariana BL Falcão et al.

Purpose To achieve whole-liver motion-corrected fat fraction (FF) and R2* quantification with a 3-minute free-breathing (FB) 3D radial isotropic acquisition, for increased organ coverage, ease-of-use, and patient comfort. Methods A FB 3D radial multiecho gradient-echo liver acquisition with integrated Pilot Tone (PT) navigation and NTE=8 echoes was reconstructed with a motion-correction algorithm based on focused navigation and guided by PT signals (PT-fNAV), with and without a denoising step. Fat fraction (FF) and R2* quantification using a graph cut algorithm was performed on the motion-corrected whole-liver multiecho volumes. Volunteer experiments (n=10) at 1.5T included reference 3D and 2D Cartesian breath-hold (BH) acquisitions. Image sharpness was assessed to evaluate the quality of motion correction with PT-fNAV, compared to a motion-resolved reconstruction. Fat-water images and parametric maps were compared to BH reference acquisitions following Cartesian trajectories, and to a routinely used clinical software (MRQuantiF). Results The image sharpness provided by PT-fNAV (with and without denoising) was similar in end-expiratory motion-resolved reconstructions. The 3D radial FB FF maps compared well with reference BH 3D Cartesian maps (bias +0.7%, limits of agreement (LOA) [-2.5; 4.0]%) and with 2D quantification with MRQuantiF (-0.2%, LOA [-1.1; 0.6]%). While expected visual deviations between proposed FB and reference BH R2* maps were observed, no significant differences were found in quantitative analyses. Conclusion A 3D radial technique with retrospective motion correction by PT-fNAV enabled FF and R2* quantification of the whole-liver at 1.5T. The FB whole-liver acquisition at isotropic spatial resolution compared in accuracy with BH techniques, enabling 3D assessment of steatosis in individuals with limited respiratory capabilities.

Xiangdong Guo, Min Lv, Hongjun Cui et al.

Abstract Based on static geology and dynamic production of typical wells in Yan'an gas field, a convenient method of the wells controlled reserves was established combining with material balance method (MB). The method was applied to 88 wells in Yan'an tight gas field. The results show that: ①Controlled by pore structure, wells are divided into three types based on the morphology of the capillary pressure curve and the analysis of the parameter characteristics, and their productivity is evaluated, respectively. ②The flow material balance method (FMB) ignores the change of natural gas compressibility, viscosity and Z in the calculation. After the theoretical calculation of 30 gas samples, the slope of the curve of the relationship between bottom hole pressure and cumulative production and the slope of the curve of the relationship between average formation pressure and cumulative production are not equal. ③Compared with the results of the MB, the result of the FMB is smaller, and the maximum error is 34.66%. The consequence of the modified FMB is more accurate, and the average error is 2.45%, which has good applicability. The established method is simple, only requiring production data with high precision, providing a new method to evaluate well-controlled reserves of tight gas sandstone. This method with significant application value can also offer reference values for other evaluating methods of well-controlled reserves.

Junfeng ZHANG, Xingyou XU, Jing BAI et al.

Distribution characteristics, organic matter development characteristics, gas-bearing characteristics, reservoir characteristics, and preservation conditions of the Shahezi Formation shale of Lower Cretaceous in the Lishu fault depression, Songliao Basin, NE China, are analyzed using organic geochemical, whole rock, and SEM analysis data, and CO2 and N2 adsorption and high-pressure mercury injection experiment data in combination with the tectonic and sedimentation evolution of the region to reveal the geological conditions for enrichment and resource potential of continental shale gas. The organic-rich shale in the Lower Cretaceous of the Lishu fault depression is mainly developed in the lower submember of the second member of the Shahezi Formation (K1sh21 Fm.) and is thick and stable in distribution. The shale has high TOC, mainly types II1 and II2 organic matter, and is in the mature to the over-mature stage. The volcanic activity, salinization, and reduction of the water environment are conducive to the formation of the organic-rich shale. The shale reservoirs have mainly clay mineral intergranular pores, organic matter pores, carbonate mineral dissolution pores, and foliated microfractures as storage space. The pores are in the mesopore range of 10–50 nm, and the microfractures are mostly 5–10 μm wide. Massive argillaceous rocks of lowland and highstand domains are deposited above and below the gas-bearing shale separately in the lower submember of the K1sh21 Fm., act as the natural roof and floor in the process of shale gas accumulation and preservation, and control the shale gas enrichment. Based on the above understandings, the first shale gas exploration well in Shahezi Formation was drilled in the Lishu fault depression of Songliao Basin. After fracturing, the well tested a daily gas production of 7.6×104 m3 marking a breakthrough in continental shale gas exploration in the Shahezi Formation (K1sh Fm.) of the Lishu fault depression in Songliao Basin. The exploration practice has reference significance for the exploration of continental shale gas in the Lower Cretaceous of Songliao Basin and its periphery.

Zhouhua WANG, Tao WANG, Hui LIU et al.

Based on the oil, gas and water distribution characteristics of Khasib reservoir in Halfaya oilfield, Iraq, a core displacement experiment is designed to evaluate the influence of different displacement methods and displacement parameters on oil displacement efficiency. The research shows that, in the displacement method with water injected from the edge of the reservoir, early depletion production is conducive to the elastic expansion of the gas cap, forming the three-dimensional displacement of “upper pressure and lower pushing”, and the oil displacement effect is good. When gas injection at the top and water injection at the edge are used for synergistic displacement, the injection timing has different influences on the oil displacement effects of high and low parts. Considering the overall oil displacement efficiency, the injection pressure should be greater than the bubble point pressure of crude oil. Two displacement methods are recommended with the reasonable injection time at 20–25 MPa. The injection speed has the same influence on different injection media. Appropriately reducing the injection speed is conducive to the stability of the displacement front, delaying the breakthrough of injection media and improving the oil displacement effect. The reasonable injection rate of water flooding is 0.075 mL/min, the reasonable injection rates of water and gas are 0.15 mL/min and 0.10 mL/min, respectively in gas-water synergistic displacement. Gas-water synergistic displacement is conducive to the production of crude oil at high position, and has crude oil recovery 5.0%–14.8% higher than water flooding from the edge, so it is recommended as the development mode of Khasib reservoir at the middle and late stages.

Samar Allouch, Vuk Milisic

Several results in previous works, strongly depend on the exponential tail of the linkages' distribution in our adhesive models. The purpose of this paper is to weaken this hypothesis and to allow more fat tails for large ages. From the biological point of view this means that we allow adhesions to be stronger, because linkages break less often. Moreover, in our previous articles, the asymptotic expansion of adhesion site's position and the corresponding error estimates also used some fast decay properties of the kernel, we show, when the kernel is a given function of age but constant in time, how to overcome this problem and construct asymptotic expansions in a systematic way at any order with respect to a small parameter $ε$ representing the linkages' turnover.

WEI Jiaxin, ZHANG Yan, SHANG Jiaohui et al.

In order to clarify the main principal factors that affect the initial productivity during the development of shale oil reservoirs, a comprehensive data analysis method involved both the hierarchical cluster analysis and the principal component analysis in data statistics is presented; and then the deta of the static formation parameters, fracturing operation parameters and the oil productivity of 51 wells in Block Li-151 are analyzed quantitatively. At first, the wells in the block are divided automatically into two types, Type A and Type B, by the hierarchical cluster analysis method. Then, a principal component analysis method is used to analyze the principal productivity factors for different types of wells. Analysis results show that, when the well shut-in time is less than 125 days, the oil production decline rate can be reduced effectively by the well shut-in measures; however, when it is greater than 125 days, the effect of well shut-in measures on oil production decline rate becomes negative. The production decline rate of Type A wells is highly negative with the amount of injected fracturing water; the main principal factors for the production decline rate of Type B wells are the moving liquid level and the porosity of shale matrix. The principal factors for the production rate of Type B wells are the number of fracturing sections. All in all, for the production optimization of shale oil development in Block Li-151, the differences of principal production factors between Type A wells and Type B wells should be considered and the different analysis results of the principal factors that affect the initial shale oil productivity under different well types should be fully utilized. Some guidance can be provided specifically for the formulation of a reasonable shale oil efficient development plan.

Hao-Lin Shao, Ying-Hui Shao, Yan-Hong Yang

This paper investigates the cointegration between possible determinants of crude oil futures prices during the COVID-19 pandemic period. We perform comparative analysis of WTI and newly-launched Shanghai crude oil futures (SC) via the Autoregressive Distributed Lag (ARDL) model and Quantile Autoregressive Distributed Lag (QARDL) model. The empirical results confirm that economic policy uncertainty, stock markets, interest rates and coronavirus panic are important drivers of WTI futures prices. Our findings also suggest that the US and China's stock markets play vital roles in movements of SC futures prices. Meanwhile, CSI300 stock index has a significant positive short-run impact on SC futures prices while S\&P500 prices possess a positive nexus with SC futures prices both in long-run and short-run. Overall, these empirical evidences provide practical implications for investors and policymakers.