Adaptability analysis and optimization of log suite for uncased wellbores of shale gas reservoirs:A case study of Sichuan Basin,China

Significant progress has been made in the exploration and development of unconventional gas resources in China since the beginning of the 21st century.With a rapid increase in yield,the exploration and development of shale gas have been upgraded to a level of national strategy.Logging is one of the core technologies in gas exploration and development.However,logging technologies face the challenges of complex geological conditions and well casing environment,high temperature,high pressure,and strong heterogeneity.Despite the rich experience accumulated,unified understanding and implementation specifications are yet to be established for shale gas well logging.Given the analysis and comparison of the effectiveness and adaptability of logging technologies at different stages of shale gas exploration and development for the Sichuan Basin,this study optimizes the log suite to meet the demand for highefficiency exploration and development of shale gas.According to the adaptability analysis of shale gas log suite,the mandatory logging items of exploratory wells should include caliper log(CAL),natural gamma ray spectrometry(NGS)log,spontaneous potential(SP)log,directional survey,borehole compensated sonic log,litho-density log(LDL),compensated neutron log(CNL),dual laterologmicrospherically focused log/dual induction-laterolog log/array induction log,temperature log,elemental capture spectroscopy(ECS)log,formation microimager(FMI)log,and array sonic log.The log suite of appraisal wells is almost the same as that for exploratory wells,excluding the ECS log and microresistivity scanning imaging.Meanwhile,for the logging of horizontal/highly-deviated holes,the log suite of vertical wells should be referred to according to specific well conditions.

不同单节理产状岩石力学性质数值模拟与强度预测模型

节理岩石力学性质对于各类岩体工程长期稳定具有重要意义,而岩石的力学性质受节理产状影响极大,甚至起决定作用。为研究节理产状对岩石强度和破坏模式的影响机制,基于节理产状参数准确预测岩石的单轴抗压强度,采用PFC软件建立了不同单节理产状的岩石数值模型,开展了一系列单轴压缩数值模拟试验,得到了节理尺寸和倾角对岩石力学特性的影响规律:随着节理尺寸增大,岩石破坏模式逐渐由沿一定角度的剪切破坏变为节理端部裂纹扩展破坏,单轴抗压强度逐渐减小;随节理倾角增大,当节理倾角小于内摩擦角时,岩石的单轴抗压强度逐渐减小,破坏模式主要是节理端部翼裂纹扩展破坏;当节理倾角超过内摩擦角继续增大时,岩石的单轴抗压强度则逐渐增大,破坏模式主要是沿一定角度穿切岩石或次生裂纹扩展的剪切破坏。在此基础上,结合损伤力学和断裂力学理论提出了单节理岩石单轴抗压强度预测模型,充分考虑了由单节理产状差异导致的不同破坏模式对岩石强度的影响,模型参数易于获取。经算例验证,模型具有较高精度,能够满足工程现场需求。

Steam reforming of acetic acid over Ni/biochar of low metal-loading:Involvement of biochar in tailoring reaction intermediates renders superior catalytic performance

Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming,which could influence the formation of reaction intermediates and modify catalytic behaviors.Herein,the Ni/biochar as well as two comparative catalysts,Ni/Al_(2)O_(3) and Ni/SiO_(2),with low nickel loading(2%(mass))was conducted to probe involvement of the varied carriers in the steam reforming.The results indicated that the Ni/biochar performed excellent catalytic activity than Ni/SiO_(2) and Ni/Al_(2)O_(3),as the biochar carrier facilitated quick conversion of the -OH from dissociation of steam to gasify the oxygen-rich carbonaceous intermediates like C=O and C-O-C,resulting in low coverage while high exposure of nickel species for maintaining the superior catalytic performance.In converse,strong adsorption of aliphatic intermediates over Ni/Al_(2)O_(3) and Ni/SiO_(2) induced serious coking with polymeric coke as the main type(21.5%and 32.1%,respectively),which was significantly higher than that over Ni/biochar(3.9%).The coke over Ni/biochar was mainly aromatic or catalytic type with nanotube morphology and high crystallinity.The high resistivity of Ni/biochar towards coking was due to the balance between formation of coke and gasification of coke and partially biochar with steam,which created developed mesopores in spent Ni/biochar while the coke blocked pores in Ni/Al_(2)O_(3) and Ni/SiO_(2) catalysts.

Thermal pretreatment of willow branches impacts yield and pore development of activated carbon in subsequent activation with ZnCl_(2) via modifying cellulose structure

Development of pore structures of activated carbon(AC)from activation of biomass with ZnCl_(2) relies on content and structure of cellulose/hemicellulose in the feedstock.Thermal pretreatment of biomass could induce dehydration and/or aromatization to change the structure of cellulose/hemicellulose.This might interfere with evolution of structures of AC,which was investigated herein via thermal pretreatment of willow branch(WB)from 200 to 360℃and the subsequent activation with ZnCl_(2) at 550℃.The results showed that thermal pretreatment at 360℃(WB-360)could lead to substantial pyrolysis to form biochar,with a yield of 31.9%,accompanying with nearly complete destruction of cellulose crystals and remarkably enhanced aromatic degree.However,cellulose residual in WB-360 could still be activated to form AC-360 with specific surface area of 1837.9 m~2·g^(-1),which was lower than that in AC from activation of untreated WB(AC-blank,2077.8 m~2·g^(-1)).Nonetheless,the AC-200 from activation of WB-200 had more developed pores(2113.9 m~2·g^(-1))and superior capability for adsorption of phenol,due to increased permeability of ZnCl_(2) to the largely intact cellulose structure in WB-200.The thermal pretreatment did increase diameters of micropores of AC but reduced the overall yield of AC(26.8%for AC-blank versus 18.0%for AC-360),resulting from accelerated cracking but reduced intensity of condensation.In-situ infrared characterization of the activation showed that ZnCl_(2) mainly catalyzed dehydration,dehydrogenation,condensation,and aromatization but not cracking,suppressing the formation of derivatives of cellulose and lignin in bio-oil.The thermal pretreatment formed phenolic-OH and C=O with higher chemical innerness,which changed the reaction network in activation,shifting morphology of fibrous structures in AC-blank to“melting surface”in AC-200 or AC-280.

Distribution of modified Circumpolar Deep Water and its threat in Vincennes Bay,East Antarctica

The Antarctic Bottom Water formation site Vincennes Bay,East Antarctica is experiencing a substantial intrusion of modified Circumpolar Deep Water(mCDW),which may inhibit the formation of Dense Shelf Water(DSW)and drive basal melting of the ice shelves.Based on hydrographic data obtained from March to November in 2012,we evaluated the spatial spread of mCDW over the continental shelf region of Vincennes Bay and the associated temporal evolution of water properties,as well as the sea ice formation effect on water column in the coastal polynya.Results show that two branches of mCDW occupied the deep layers of the continental shelf,distinguished by the potential density(smaller than 27.8 kg/m^(3) or not)when potential temperatureθ=0.5°C in theθ-salinity space.The warmer and less dense branch observed on the east plateau,accessed the eastern ice shelves in the coastal polynya to drive basal melting of ice shelves.In contrast,the other colder and denser branch in the mid-depression reached the western Underwood Ice Shelf.DSW formation was detectable in the coastal polynya during September-November,proving the occurrence of deep convection.Surface heat loss and brine rejection during the intensive sea ice formation contributed to the destratification of the water column in the coastal polynya.It was estimated that at least 1.11±0.79 TW heat carried by mCDW into the inner part of the polynya.

Ship recognition based on HRRP via multi-scale sparse preserving method

In order to extract the richer feature information of ship targets from sea clutter, and address the high dimensional data problem, a method termed as multi-scale fusion kernel sparse preserving projection(MSFKSPP) based on the maximum margin criterion(MMC) is proposed for recognizing the class of ship targets utilizing the high-resolution range profile(HRRP). Multi-scale fusion is introduced to capture the local and detailed information in small-scale features, and the global and contour information in large-scale features, offering help to extract the edge information from sea clutter and further improving the target recognition accuracy. The proposed method can maximally preserve the multi-scale fusion sparse of data and maximize the class separability in the reduced dimensionality by reproducing kernel Hilbert space. Experimental results on the measured radar data show that the proposed method can effectively extract the features of ship target from sea clutter, further reduce the feature dimensionality, and improve target recognition performance.

液体火箭发动机翻转对接工装的设计

液体火箭发动机与运载火箭箭体结构对接方式为空中吊装对接,工序多,难度大,耗时长,对接前后工装拆装不便,对接过程中需要吊车吊装保证安全。为解决对接的可靠性、便捷性、安全性问题,应用翻转对接工装,可以提高对接装配质量,缩短对接时间,优化对接工序,减小对接风险,操作更为简单。由此,设计了液体火箭发动机翻转对接工装。介绍了翻转对接工装的设计方案和结构,进行了位移和应力分析。

BArcherFuzzer:An Android System Services Fuzzier via Transaction Dependencies of BpBinder

By the analysis of vulnerabilities of Android native system services,we find that some vulnerabilities are caused by inconsistent data transmission and inconsistent data processing logic between client and server.The existing research cannot find the above two types of vulnerabilities and the test cases of them face the problem of low coverage.In this paper,we propose an extraction method of test cases based on the native system services of the client and design a case construction method that supports multi-parameter mutation based on genetic algorithm and priority strategy.Based on the above method,we implement a detection tool-BArcherFuzzer to detect vulnerabilities of Android native system services.The experiment results show that BArcherFuzzer found four vulnerabilities of hundreds of exception messages,all of them were confirmed by Google and one was assigned a Common Vulnerabilities and Exposures(CVE)number(CVE-2020-0363).

浆细胞性乳腺炎与乳腺导管内癌的超声及MRI影像特点观察

目的 分析浆细胞性乳腺炎与乳腺导管内癌的超声及MRI影像特点。方法 选取2018年12月至2020年12月在本院进行乳腺检查的患者50例作为研究对像,所有患者均接受超声和MRI检查,之后经病理学证实为乳腺导管内癌、浆细胞性乳腺炎患者,观察超声和MRI检查的影像学特点,并探讨联合应用超声和MRI检查的诊断准确率。结果 经病理证实50例患者中浆细胞性乳腺炎20例,乳腺导管内癌30例。与病理结果相比较,超声诊断结果的准确率为58.00%,敏感度55.00%,特异度60.00%;与病理结果相比较,超声联合MRI诊断结果的准确率为90.00%,敏感度85.00%,特异度93.33%。结论 超声和MRI两种检测方法各有优点,对于超声诊断困难的乳腺病患者,可联合MRI进行检测,提高乳腺疾病诊断的准确率,为临床医师治疗方案的制定提供参考依据,现报道如下。

融合注意力机制与全局特征网络的行人重识别算法研究

行人重识别是近年来计算机视觉领域的研究热点,已被广泛应用在智能视频监控、安保系统等多个领域。但在实际应用场景中,图像数据会受到摄像机差异、物体遮挡、行人姿态视角改变等因素的影响,因此,克服以上问题成为了当前行人重识别研究所关注的重点问题。对于行人重识别方法在面对遮挡和复杂背景应用场景下的干扰信息影响精度的问题,提出了引入空间注意力机制,对拓扑关系遮挡行人重识别算法的全局特征提取网络进行改进,将基于空间注意力的特征提取网络与拓扑关系遮挡行人重识别算法中的作为Backbone网络的RestNet50进行优化改进。在公开的Occluded-Duke数据集和Market-1501数据集上进行测试,实验结果显示改进算法的评价指标有明显提升。

A new NMR-data-based method for predicting petrophysical properties of tight sandstone reservoirs

Evaluating the permeability and irreducible water saturation of tight sandstone reservoirs is challenging.This study uses distribution functions to fit measured NMR T_(2)distributions of tight sandstone reservoirs and extract parameters for characterizing pore size distribution.These parameters are then used to establish prediction models for permeability and irreducible water saturation of reservoirs.Results of comparing the fit of the T_(2)distributions by the Gauss and Weibull distribution functions show that the fitting accuracy with the Weibull distribution function is higher.The physical meaning of the statistical parameters of the Weibull distribution function is defined to establish nonlinear prediction models of permeability and irreducible water saturation using the radial basis function(RBF)method.Correlation coefficients between the predicted values by the established models and the measured values of the tight sandstone core samples are 0.944 for permeability and 0.851 for irreducible water saturation,which highlight the effectiveness of the prediction models.

前侧入路的两种不同显露方式治疗肱骨近端骨折

目的 探讨肩关节前侧入路的两种不同显露方式治疗肱骨近端骨折的疗效差异。方法 回顾性分析2018年4月至2020年3月在孝感市第一人民医院治疗的47例肱骨近端骨折的病例资料。采用肩关节前侧入路,一种手术方式经胸大肌三角肌间隙进入26例(胸三角肌间隙组),平均年龄(62.5±2.2)岁,根据Neer分型,二部分4例,三部分9例,四部分13例;另一种于三角肌前缘外0.5~1.0 cm,经三角肌间隙进入21例(三角肌间隙组),平均年龄(61.3±2.2)岁,根据Neer分型,二部分4例,三部分7例,四部分10例。比较两种不同显露方式治疗的手术时间、术中出血量、骨折愈合时间、肩关节功能评分、疼痛评分及术后并发症发生情况。结果 47例患者均获随访,随访时间10~25个月,平均(15.6±4.7)个月,末次随访时骨折均一期愈合。胸三角肌间隙组与三角肌间隙组的手术时间、术中出血量、骨折愈合时间比较,差异无统计学意义(P>0.05)。末次随访Constant-Murley评分,胸三角肌间隙组为(81.2±1.5)分,三角肌间隙组为(79.4±2.1)分,两组比较差异有统计学意义(P<0.05),胸三角肌间隙组肩关节功能优于三角肌间隙组。末次随访VAS评分,胸三角肌间隙组与三角肌间隙比较,差异无统计学意义(P>0.05)。胸三角肌间隙组术后发生并发症1例,三角肌间隙组发生并发症7例,两组比较差异有统计学意义(P<0.05),三角肌间隙组有更高术后并发症发生,影响手术疗效。胸三角肌间隙组显露满意,不损伤三角肌,三角肌间隙组在需要较好显露肩胛盂时有一定困难,牵拉过程中可能造成三角肌前部断裂,影响肩关节前屈上举功能。结论 胸三角肌间隙显露方式较劈三角肌显露方式暴露更充分,对三角肌的损伤更小,肩关节功能恢复更满意。

火箭质量、质心测量设备的校准

质心是运载火箭控制的主要技术参数,会影响飞行的成败,由此,需要对火箭质量、质心测量设备的数据准确性和精度进行评估。为验证某型火箭质量、质心测量设备的测量精度是否能满足要求,对比有限元分析结果和测量数据,进行火箭质量、质心测量设备的校准试验。介绍了试验过程,并对试验结果进行了分析。

Quantitative evaluation of fracture porosity from dual laterlog based on deep learning method

Fracture porosity is one of the key parameters for characterizing fractured reservoirs.However,fracture porosity calculation is difficult with conventional logging data due to severe anisotropy of the reservoirs.To deal with the problem,the equivalent macroscopic anisotropic formation model based on dual laterolog(DLL)data is adopted to cyclically assign such parameters as bedrock resistivity(RB),fluid resistivity in fractures(RFL),fracture dip angle(FDA)and fracture thickness as well as fracture spacing,and to produce massive data for formation modeling.A large number of training data obtained through three dimensional finite element forward modeling and the functional relationship between DLL responses and fracture parameters that are trained and summarized by deep neural network,are combined to establish a new fast forward model for calculating DLL responses in fractured formations.A new fracture porosity inversion model for fractured reservoirs based on gradient optimization inversion algorithm combined with multi-initial inversion strategy is then proposed.While running the model,formation is divided into eight intervals according to bedrock resistivity and fracture dip angle from 0°to 90°is divided every 0.5°to improve the operation speed and efficiency.The results of numerical verification show that when bedrock resistivity is greater than 1000Ωm,the mean absolute error(MAE)of fracture porosity inversion is 0.001658%for horizontal fractures,0.00413%for intermediate fractures and 0.0027%for quasi-vertical fractures.When bedrock resistivity is between 100Ωm and 1000Ωm,MAE of fracture porosity inversion is 0.003%for horizontal fractures,0.0034%for intermediate fractures and 0.00348%for quasi-vertical fractures.Fracture parameters determined by the fracture porosity inversion model with actual data are in good agreement with the results of micro resistivity imaging logging.

Non-resistivity-based saturation evaluation methods in shale gas reservoirs

Free gas saturation is a key parameter for calculating shale gas reserves.The complex conductivity mechanism of shale reservoirs restricts the application of Archie's formula and its extended form for the evaluation of free gas saturation.Instead,a number of non-resistivity-based saturation evaluation methods suitable for shale gas reservoirs have been established,including core calibration(TOC method,clay content method),gas porosity cutoff,excavation effect and four-pore modeling.These methods,together with adsorbed phase porosity correction,are used to calculate the free gas saturation.These methods are applied to shale reservoirs of the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation in the Sichuan Basin,southwestern China to test their applicability and accuracy.The results,when compared with measured data from core samples,show that the TOC-based core calibration is more accurate in evaluating free gas saturation in the entire shale gas interval,which is of great significance to the calculation of shale gas reserves.

Unveiling shared genetic pathways in cardiovascular diseases:towards personalized therapies and holistic treatment approaches

Cardiovascular diseases(CVDs),encompassing diverse pathologies such as atherosclerosis,hypertension,cardiomyopathy,arrhythmia,and valvular diseases,represent a significant public health challenge,severely undermining human health[1].According to the World Health Organization,CVDs claimed approximately 17.9 million deaths in 2019,representing 32%of all global deaths[2,3].The risk of CVDs morbidity and mortality increases with age,with the majority of CVDs and deaths occurring in elderly aged 75 years and older[4,5].In developed nations,CVDs are the principal cause of mortality,while in developing countries,they are a leading cause of death as well.

金属铀电子束熔炼实验及数值模拟研究

采用有限元方法对金属铀电子束熔炼过程进行数值模拟,研究了熔炼过程温度场分布。结果表明,单电子束枪熔炼时,熔池中的等温线近似呈半椭圆形,随着电子束功率增加,熔池温度增大,坩埚中被熔化的金属增多。采用双电子束枪熔炼时,可以获得更均匀的温度场,且当电子束功率大于25 kW时,可获得较大的熔池深度和宽度。根据数值模拟结果开展贫化铀电子束熔炼试验,获得的贫化铀铸锭中夹杂物主要集中在铸锭边缘,夹杂物含量明显降低。

基于稀疏采样阵列优化的APG-MUSIC算法

针对稀疏阵列下2维波达方向(DOA)估计问题,该文提出一种基于稀疏采样阵列优化的加速逼近梯度(APG)算法与多重信号分类(MUSIC)算法相结合的2D-DOA估计方法。首先,建立稀疏阵列下的2D-DOA估计信号模型,并证明其具备低秩特征,满足零空间性质(NSP)。其次,为提高稀疏阵列下矩阵填充方法重构接收信号矩阵性能和以此为基础的2D-DOA估计精度,提出基于遗传算法(GA)的稀疏采样阵列优化方法。最后,将APG和MUSIC算法相结合,在重构完整平面阵列接收信号矩阵的基础上完成2维波达方向估计。计算机仿真结果表明,该方法在保证2维波达方向估计精度前提下,大幅提高阵元利用率,有效降低空间谱平均旁瓣,与常规2D-DOA估计方法相比具有优势。

复杂地质条件下巨型水电站岩锚梁开挖施工技术

岩锚梁的开挖施工是水电站地下厂房开挖施工中质量要求最高、工艺要求最严格、技术难度最大的关键部位,岩锚梁开挖的成型质量直接影响到后期岩锚梁的运行安全,是岩锚梁成败与否的第一关键要素。复杂地质条件下岩锚梁开挖难度更大,对技术要求更高。以白鹤滩水电站左岸地下厂房岩锚梁开挖为例,阐述了复杂地质条件下巨型水电站岩锚梁开挖施工技术。

细胞焦亡的研究进展

细胞焦亡(pyroptosis)是促炎形式的程序性细胞死亡,并且依赖于半胱氨酸天冬氨酸特异性蛋白酶(caspases)活性。由caspases通过切割gasermin D(GSDMD)的氨基端和羧基端的连接体调控,后者移位到膜上并穿孔,诱导水分渗透,细胞肿胀并释放炎性因子,继而发生细胞焦亡。细胞焦亡的形态学特征、发生及调控机制等均不同于凋亡、坏死等其他细胞死亡方式,其是机体一种重要的天然免疫反应,在抗击感染以及疾病中均有重要作用。通过对细胞焦亡的更深入研究,可以认知其在相关疾病中的作用,为临床提供新的治疗思路。