Hierarchy and subsurface correlation of muddy baffles in lacustrine delta fronts： a case study in the X Oilfield, Subei Basin, China

Muddy baffles are one of the major geological factors controlling the underground fluid flow as well as the remaining oil distribution. This study used detailed drilling data from the E1f1 reservoir in the X Oilfield, Subei Basin, China, to investigate the hierarchical muddy baffles developed on lacustrine delta fronts and their precise cross-well correlation.According to the theories on allogenic and autogenic cycles as well as the genesis and scales of muddy baffles, five orders of muddy baffles were classified, which provided various degrees of difficulty when attempting interwell correlation. Under the guidance of a reliable stratigraphic model, the precise cross-well correlation of muddy baffles could be achieved and the key point of establishment of this stratigraphic model was to calculate foreset angles of hierarchical muddy baffles during deposition. During calculation, the relationships between sediment flow direction, higher-order strata dipping direction,well types and well trajectory direction should all be taken into consideration and some other angles（referred to here as θ1,θ2 and θ3） should also be measured. Such new methods of cross-well correlation for hierarchical muddy baffles could greatly reduce the uncertainties and multiple solutions, which in turn would be significant for efficient development and oil recovery enhancement in the reservoirs.

High-Resolution Sequence Stratigraphy of Shallow Lacustrine Delta Front: The Second Member of Sangonghe Formation, Central Junggar Basin

Shallow lacustrine delta front （SLDF） comprises mainly sheetlike subaqueous distributary channels （SDC） formed in shallow, gentle, and tectonically steady slope （Cai and Zhu, 2011）. SDC proves an important hydrocarbon reservoir type in the Daqing oilfield, Changqing oilfield, and the newly discovered Moxizhuang oilfield in Central Junggar Basin. However, SDC tends to prograde quickly and move laterally frequently,

The influence of water level changes on sand bodies at river-dominated delta fronts:The Gubei Sag,Bohai Bay Basin

Changes in water level are one of the important factors controlling the constructive characteristics of deltas.The paper studies the influence of water level changes on sand bodies in the third member of the Shahejie Formation(Es3)on the gentle southern slope of the Gubei Sag,Bohai Bay Basin and draw some conclusions that,for complex sand bodies,with the increase in water level the distributary channels bifurcate frequently,from a simple branching shape to a network shape along with the increase in the development of crevasse splays,mouth bars and sheet sands.For single sand bodies,with an increase in water level in the slope zone of the lake basin close to the source area,the superimposition style transitioned from vertical cutting-stacking and lateral isolation to vertical stitching,isolation and lateral stitching.However,in the central zone of the lake basin far from the source area,the superimposition style transitioned from vertical stitching and lateral stitching to vertical isolation and lateral isolation.When water level stays stable,the greater the distance from the source area the greater the disaggregation ratio of a single sand body.At the same distance from the source area,higher water level tends to result in greater disaggregation ratio of a single sand body.

Cretaceous Sandbody Characters at Shallow-Water Lake Delta Front and the Sedimentary Dynamic Process Analysis in Songliao Basin,China

Based on the abundant information from drilling, cores, and logging, the influence of topography, size of rivers and lakes, climate changes and the lake level＇s fluctuation on the sandbodies at shallow-water delta front are systematically summarized and the sedimentary dynamic processes are analyzed. The interwell communication among the sandbodies and their planar distribution revealed from the hydrodynamic features of the development wells are integrated during the analysis. The fundamental requirements for the development of the shallow-water delta included flat topography and uniform subsiding rate. The delta plain was connected smoothly with the wide delta front and predelta, without the three-fold structure of topset, foreset, and bottomset as defined in the Gilbert Delta Model. Because of the weak fluvial effect and the lake energy is strong, the small and scattered shallow-water delta is destroyed by the scouring-backwashing, coastal current, and lake wave, resulting in the coastal sheet deposition. As the fluvial effect became stronger and the lake energy became weaker, the shape of the shallow-water deltas transferred from sheets to lumps and then branches.

Sandbody architecture of the bar finger within shoal water delta front:Insights from the Lower Member of Minghuazhen Formation,Neogene,Bohai BZ25 Oilfield,Bohai Bay Basin,East China

Core, well logging and seismic data were used to investigate sandbody architectural characteristics within Lower Member of Minghuazhen Formation in Neogene, Bohai BZ25 Oilfield, and to analyze the sedimentary microfacies, distribution and internal architecture characteristics of the bar finger within shoal water delta front. The branched sand body within shoal water delta front is the bar finger, consisting of the mouth bar, distributary channel over bar, and levee. The distributary channel cuts through the mouth bar, and the thin levee covers the mouth bar which is located at both sides of distributary channel. The bar finger is commonly sinuous and its sinuosity increases basinward. The distributary channel changes from deeply incising the mouth bar to shallowly incising top of the mouth bar.The aspect ratio ranges from 25 to 50 and there is a double logarithmic linear positive relationship between the width and thickness for the bar finger, which is controlled by base-level changing in study area. For the bar finger, injection and production in the same distributary channel should be avoided during water flooding development. In addition, middle–upper distributary channel and undrilled mouth bar are focus of tapping remaining oil.

Analysis on Preferred Flowing Path in Shallow Water Delta Front Based on Reservoir Architecture

1 Introduction The shallow water delta reservoir in South Wen 79Block is in the stage of high water-cut stages,and is still on the rise.The degree of recovery is low,preferredflowing path is developed and surplus oil is generally distributed with local enrichment(Zhang,2009).The potential of surplus oil is considerable,while the difficulty is also great.And the basis of effective tapping for

The influence of bioturbation on sandy reservoirs: the delta front sand of the lower Zhujiang Formation, Baiyun Depression, Zhujiang River Mouth Basin

Ichnofossils are well developed in clastic rock reservoirs in marine and transitional facies, which can considerably change the physical properties of the reservoir. However, this influence is not well understood, raising an important problem in the effective development of petroleum reservoirs. This paper analyzes continental shelf margin delta reservoirs through core observation, cast thin section observation and reservoir physical property test. Some important scientific insights are obtained:(1) The presence of Cruziana ichnofacies, including Asterosoma, Ophiomorpha, Planolites, Skolithos, Thalassinoides, and other ichnofossils can be used to identify in subaqueous distributary channels, subaqueous levee, frontal sheet sand, abandoned river channels, crevasse channels, main channels and channel mouth bars. Considerable differences in the types of ichnofossils and the degree of bioturbation can be observed in the different petrofacies.(2) Ichnofossils and bioturbation play a complex role in controlling reservoir properties. The reservoir physical properties have the characteristics of a decrease–increase–decrease curve with increasing bioturbation degree. This complex change is controlled by the sediment mixing and packing of bioturbation and the diagenetic environment controlled by the ichnofossils.(3) Sea-level cycle changes affect the modification of the reservoir through sediment packing. Bioturbation weakens the reservoir's physical property when sea level slowly rises and improves the reservoir's physical property when base level slowly falls.

Research of Extent of Well Control of Explored Reserves of Lithologic Deposit in Delta Front Area

Recently the explored reserves submitted in the oil field mainly situate at the end of deposit in delta front area. During the exploitation and production, problems mainly show on lithologic deposit, for example, reserves are low and difficulty of producing is huge. Based on results of sand body dissection of dense well network of developed oil deposit, and combined with explored reserves, this article researches a relation between extent of well control and reserves precision of explored reserves of lithologic deposit in delta front area by well diluted method. This article has significant influence on objectively understanding our unexploited

Delta EEG Activity in Left Orbitofrontal Cortex in Rats Related to Food Reward and Craving

The orbitofrontal cortex （OFC） is particularly important for the neural representation of reward value. Previous studies indicated that electroencephalogram （EEG） activity in the OFC was involved in drug administration and withdrawal. The present study investigated EEG activity in the OFC in rats during the development of food reward and craving. Two environments were used separately for control and food-related EEG recordings. In the food-related environment rats were first trained to eat chocolate peanuts; then they either had no access to this food, but could see and smell it （craving trials）, or had free access to this food （reward trials）. The EEG in the left OFC was recorded during these trials. We showed that, in the food-related environment the EEG activity peaking in the delta band （2-4 Hz） was significantly correlated with the stimulus, increasing during food reward and decreasing during food craving when compared with that in the control environment. Our data suggests that EEG activity in the OFC can be altered by food reward; moreover, delta rhythm in this region could be used as an index monitoring changed signal underlying this reward.

基于多模型和改进WOA算法的Delta机器人柔性夹持器抓取方法研究

[目的]解决Delta机器人柔性夹持器抓取方法存在的控制精度和适应性较差等问题。[方法]以Delta机器人柔性夹持器为研究对象,提出一种多模型和改进鲸鱼算法相结合的Delta机器人柔性夹持器抓取方法。建立稳定抓取优化模型,在抓持对象表面寻求最佳接触位置。建立无损抓取优化模型,在确保稳定抓起物体的前提下使接触力尽可能地小。结合粒子群算法和鲸鱼算法求解模型。通过试验验证了所提抓取方法的优越性。[结果]所提方法不仅具有良好的控制精度,还能够适应不同形状和大小的物体,具有较高的灵活性和适应性,抓取成功率>96%,抓取损伤率为0。[结论]所提方法有效提高了Delta机器人柔性夹持器抓取方法的性能,适用于果蔬和易碎物品的分拣工作。

Delta大通道内镜辅助下后路椎管减压椎间植骨融合术治疗退变性腰椎疾病的临床疗效

目的:探讨Delta大通道内镜辅助下后路椎管减压椎间植骨融合术治疗退变性腰椎疾病的效果。方法:回顾性分析2021年9月~2022年9月我院收治的80例退变性腰椎疾病患者的病历资料,根据患者治疗方式分为观察组(38例,男17例,女21例,年龄61.0±4.9岁)和对照组(42例,男20例,女22例,年龄60.5±5.4岁),观察组患者采取Delta大通道内镜下Endo-PLIF治疗,对照组采取开放后路腰椎椎间融合术治疗,记录两组患者术中出血量、术后引流量、手术时间、手术切口长度、住院时间,比较患者并发症发生情况。于术前、术后1周、1个月、3个月、6个月使用视觉模拟量表(visual analogue scale,VAS)评分评估患者腰痛情况,并采用Oswestry功能障碍指数(Oswestry disability index,ODI)评估患者腰椎功能;使用改良Macnab标准对患者进行疗效评估。根据患者术后1年随访时的腰椎影像学复查结果,使用Bridwell椎间融合标准对患者手术节段融合情况进行评估。结果:观察组患者的术中出血量及术后引流量分别低于对照组(88.46±10.98mL vs 112.99±12.01mL、159.73±18.42mL vs 201.36±23.06mL,P<0.05),手术切口及住院时间分别短于对照组(1.54±0.36cm vs 5.43±1.01cm、6.79±1.22d vs 8.03±1.43d,P<0.05),手术时间长于对照组(162.33±19.57min vs 126.87±23.15min,P<0.05)。80例患者术后均获随访,随访时间15~40个月(19.0±6.3个月)。观察组患者术后1周、术后1个月的VAS评分分别为2.46±0.51分、1.21±0.38分,ODI分别为(17.84±4.15)%、(10.69±1.88)%,均低于对照组[VAS评分分别为3.68±0.62分、2.01±0.41分,ODI分别为(21.33±3.48)%、(12.33±2.17)%,均P<0.05],两组患者术后3个月、术后6个月的VAS评分比较无统计学差异(P>0.05)。观察组治疗优良率为92.11%,与对照组的85.71%比较无统计学意义(P=0.487)。两组患者融合分级比较,差异无统计学意义(Z=0.487,P=0.624)。观察组术后并发症发生率为5.26%,与对照组的9.52%比较无统计学差异(P=0.678)。结论:Delta大通道内镜辅助下后路椎管减压椎间植骨融合术治疗退变性腰椎疾病效果良好,可以减少术中出血量,缩短手术切口和住院时间,更快改善患者术后短期内疼痛、腰椎功能,安全性较好。

单边双通道内镜与Delta大通道内镜技术治疗L5/S1椎间盘突出并椎管狭窄的临床疗效分析

目的 探讨Delta大通道内镜技术与单边双通道内镜技术(unilateral biportal endoscopy, UBE)治疗L5/S1单节段椎间盘突出并椎管狭窄的疗效。方法 回顾性分析2018年1月至2022年8月手术治疗的60例L5/S1单节段腰椎间盘突出并椎管狭窄患者的临床资料,其中32例采用Delta大通道内镜技术行经皮椎板间入路内镜下椎间盘切除术(Delta内镜组),28例采用UBE内镜技术行椎管减压髓核摘除术(UBE组)。比较两组围手术期指标、腰腿痛VAS评分、 ODI及并发症情况,末次随访时按Macnab标准评价疗效。结果 两组患者均顺利完成手术。Delta内镜组术中出血量少于UBE组,手术时间、住院时间短于UBE组(P<0.001)。两组患者术后腰腿痛VAS评分及ODI均较术前明显降低,且Delta内镜组术后3 d腰痛VAS评分及术后1月腿痛VAS评分均低于UBE组(P<0.05)。术后随访6个月,末次随访按Macnab标准评价疗效:Delta内镜组优30例,可2例,优良率为93.75%;UBE组优27例,可1例,优良率为96.43%;组间比较差异无统计学意义(P>0.05)。Delta内镜组硬膜撕裂1例,因撕裂处较小仅严密缝合手术切口;UBE组出现腿部疼痛加重1例。结论 Delta大通道内镜技术与UBE治疗L5/S1单节段椎间盘突出并椎管狭窄均可获得良好的近期效果,但Delta内镜手术术中出血少,软组织损伤小,操作时间短,术后短期疼痛缓解明显,患者恢复快,而UBE适应证范围相对广泛。

Delta并联机器人运动学性能分析与结构参数优化

Delta并联机器人具有速度快、结构简单、承载力强等优点,在钵苗移栽、产品分拣与包装中应用广泛。针对目前Delta并联机器人各结构参数对运动学性能的影响及系统性结构参数优化设计缺乏完整理论体系的问题,本文分析可达工作空间雅可比矩阵条件数分布规律、结构参数约束关系、运动学性能随结构参数的变化规律及相关性,获得条件数分布特性和失真约束条件,在此基础上得出动静平台半径差和主动臂长度增加和从动杆长度减小能够使得机构性能较优。给定设计工作空间,对原结构进行参数优化设计,通过建立包络惩罚函数,采用多元非线性拟合与线性加权组合法得到运动学性能评价函数,结合条件数分布特性和失真约束条件建立优化模型,利用遗传算法进行优化。相较于优化前,优化后可达工作空间体积减小14.26%,设计工作空间的全局条件数均值和全局条件数标准差分别减小31.20%和11.78%,且设计工作空间各截面条件数分布规律验证了条件数分布特性的可靠性。

Delta型FDM打印设备结构参数设定及运动学研究

FDM打印设备的扫描路径、打印速度、温度、层厚等问题是影响制件外形精度和成型效率的工艺参数的重要因素。Delta型结构作为最常用的FDM设备结构型式之一,其末端打印头的运动由多杆共同作用,运动分析较繁琐,为设备的参数设定增添了很大的难度,存在参数设定和运动分析难的问题。从Delta型的结构分析出发,重点研究了各结构尺寸之间的关联,总结了参数设定和计算的依据。考虑到Delta结构的打印头与3个滑车之间坐标的对应关系并不能通过简单推算得出,需要大量的三角函数运算,建立了Delta型结构的正、逆解运动学模型,结合几何的方式详细推导了运动学反解和正解的解法,分析和求解的结果为设定Delta型设备参数和确定控制程序算法提供了理论依据。经过分析与计算,基于并联机构内核的Delta结构采用正运动求解更便于规避正解集合中的不合理结果。

Seismism and Fluxoturbidite in Front of Delta

Seism is one of the main triggering mechanisms of forming fluxoturbidite in front of delta. The forming process of fluxoturbidite in front of delta under seismism was experimentally simulated in lab. The results show that there are two kinds of slumping and three kinds of fluxoturbidites in front of delta under seismism. The liquefied fluxo- turbidite and secondary overlapped turbidite move by their own gravity, and develop mainly on the base of foreslope and the frontal bed slope. They have a small sedimentary scale and can’t move too far. On the contrary, the faulted fluxoturbidites have a larger scale and can move a long distance. The collision- power from hinder overlapped sand body is also the motivity of the faulted fluxoturbidite’s migration besides its own gravity. They mostly develop in the deep sag in front of delta, and are the favorable room to accumulate petroleum. Finally, according to the demonstration and inversion of similarity, at least 7.35 M of earthquake had happened in middle- Shasan period of Paleogene, which induced the slumping of delta front. So the tectonic action of northern steep slope is the main reason to induce earth- quake.

基于Delta分位数映射法的青藏高原中东部IMERG卫星降水误差订正

可靠的降水资料对理解青藏高原水量平衡和水循环过程尤为重要。IMERG(Integrated MultisatellitE Retrievals for Global Precipitation Measurement)是新一代卫星降水产品,具有更广的覆盖范围与更高的时空分辨率,但在高原复杂地形条件下仍然存在较大的不确定性。鉴于此,本研究应用Delta分位数映射法(Quantile Delta Mapping,QDM),对IMERG日降水数据进行偏差订正,使用2001-2010年的中国区域地面气象要素数据集(China Meteorological Forcing Dataset,CMFD)降水数据和IMERG日降水产品分季节建立传递函数,对2011-2014年的IMERG逐日降水进行订正。研究结果表明:(1)Delta分位数映射法能够有效订正IMERG的降水频率、数值和空间分布,对极端降水和负偏差较大区域的订正效果更为明显。订正后的IMERG降水概率分布更加接近观测概率分布,降水偏差也更符合正态分布,改进了对全年和季节降水空间分布的刻画,提高了月降水的精度。(2)订正后日降水量均方根误差由1.49 mm·d^(-1)降低到1.26 mm·d^(-1),精度提高了15.44%;订正后的日降水在不同降水量级的临界成功指数CSI、命中率POD、误报率FAR、准确率Precision和F评分Fscore均有提高,降低了微量和暴量降水的空报率。(3)对极端降水的订正效果显著,降水强度SDII以及极强降水量R95p和R99p的均值更接近观测值;有效提高了对极端降水空间分布的表征,极端降水偏差从30%以上降低到5%以内;SDII、R95p和R99p的均方根误差从1.59 mm·d^(-1)、6.54 mm·d^(-1)、14.89 mm·d^(-1)降为0.65 mm·d^(-1)、3.01 mm·d^(-1)、8.99 mm·d^(-1),精度分别提高了59.12%、53.98%和39.62%。本研究验证了Delta分位数映射法在青藏高原的适用性,有利于为青藏高原气象和水文研究获取更精确的降水数据。

一种具有1~128倍可变增益放大器的低功耗Sigma⁃Delta ADC

为满足传感器应用的低功耗需求,设计并实现了一种低功耗Sigma⁃Delta模数转换器(ADC)芯片。该ADC采用一阶全差分开关电容Sigma⁃Delta调制器,且集成了可编程增益放大器(PGA)和Bandgap;使用1.5 bit量化结构,相较于1 bit量化结构减小了3 dB的量化误差;使用优化的反馈电路,减小了电容失配引入的误差;PGA采用轨到轨的运放电路拓扑,增大了整个芯片的电压适应范围。基于180 nm CMOS工艺对该ADC进行了设计和流片。测试结果表明:该Sigma⁃Delta ADC在采样频率512 kHz、过采样率(OSR)为256时,峰值信噪谐波失真比(SNDR)和有效位数(ENOB)分别为75.29 dB和12.21 bit,芯片功耗仅为0.92 mW。芯片能在2.3~5.5 V宽电源电压范围内正常工作,可实现最大128 V/V的增益。适用于小型传感器的信号测量应用,可以满足小型传感器低功耗、高精度的需求。

FACTORIAL ANALYSIS OF ANNUAL EROSION-ACCRETION CYCLES OF TIDAL FLATS IN THE FRONT AREA OF THE SOUTHERN CHANGJIANG RIVER DELTA

Based on surveyed data from seven coastal sections and the collected data of wind, sea level, tide, nearshore suspended sediment concentration and river flux from adjacent stations, this paper deals with regressive correlation between monthly average flat elevation and monthly average figures of the influential factors. All sections except one which is located within the river mouth showed negative correlation between flat elevation and sea level and between flat elevation and tidal range, with correlation coefficients being 0.53- 0.91(-0.77 on the average) in the former condition and 0.56- 0.97 (-0.80 on the average) under the latter. Each of the sections with available suspended sediment concentration (SSC) data shows a positive correlation between flat elevation and SSC, with correlative coefficients being 0.35-0.97 (0.66 on the average). Only two sections (one in the Changjiang River Estuary and the other in the Hangzhou Bay) which are similar to beaches in sediment grain size and slope gradient showed a negative correlation between flat elevation and onshore wind frequency and between flat elevation and average wind velocity, with correlative coefficients being respectively -0.57 and -0.69 (-0.63 on the average) in the former situation and -0.61 and -0.75 (-0.68 on the average) in the latter. Other sections did not show uniform relationship between flat elevation and wind conditions. Due to local marine factors the nearshore SSC in the studied area is negatively correlated with the Changjiang River sediment flux (r=-0.78), which results in false negative correlation between flat elevation and river sediment flux. The paper also gives sediment dynamic and morphodynamic explanation for the above correlations. Sea level rise results in the spread of breaker zone from subtidal area to intertidal area and then increases the intertidal water energy. The larger the tidal range, the stronger the tide currents and the easier for the flat to be eroded. The higher the SSC of flood water, the easier for the sediment to deposit down. Because of correlations among the influential factors, it is difficult to give the prime one which dominates the erosion and accretion processes in tidal flats.

首次从湖南猪源大肠杆菌中检出mcr-1阳性IncI2(Delta)质粒

近年来,由于抗生素耐药基因的广泛传播及多重耐药细菌的出现,导致抗生素的使用面临严峻挑战,致使毒性较强的多黏菌素又重新引起业界的重视,为此对多黏菌素耐药情况的研究也变得十分重要。为了调查畜牧场中多黏菌素耐药基因mcr-1的流行情况,本研究选择我国湖南省某猪场240份肠肛拭子样品,培养分离鉴定出含有mcr-1耐药基因的大肠杆菌菌株,选取多黏菌素等10种抗菌药物对分离的菌株进行耐药性试验,对所有含mcr-1耐药基因的大肠杆菌阳性株进行全基因组测序(whole-genome sequencing,WGS),采用多位点序列分型(multi-locus sequence typing,MLST)技术进行大肠杆菌的遗传多样性分析。研究结果表明,在分离出的172株大肠杆菌中,来自不同个体的9株携带mcr-1基因的大肠杆菌均表现出多重耐药现象;MLST分析共鉴定出ST10、ST196、ST46和ST5229共4种分型和4种血清型(O83:H5,O16:H7,O16:H51,O9:H4)。生物信息学分析显示,所有阳性菌株均未发现与mcr-1基因传播有关的典型可移动遗传元件ISApl1,但均检出可能会导致mcr-1传播的IV型分泌系统基因。质粒接合转移试验与单倍型的MLST多态性结果表明,mcr-1基因主要以质粒介导的水平传播为主。本研究是国际上首次在猪源细菌中检出常见于人医临床细菌的携带有mcr-1抗性基因的IncI2(Delta)质粒。

Delta超声组学对早期乳腺癌新辅助治疗疗效的预测价值

目的探讨Delta超声组学对乳腺癌新辅助治疗(NAT)后疗效的预测价值。方法将140例乳腺癌新辅助治疗患者按照软件中的随机种子数以7∶3比例分成训练集(98例)及验证集(42例)。基于肿瘤NAT治疗前、NAT治疗2个疗程后最大径相对退缩值构建传统影像模型;基于治疗前与2个疗程后的超声图像提取和筛选相应影像组学特征并计算其Delta,构建Delta超声组学模型并计算其影像组学得分(Radscore);基于有意义的临床病理指标结合Radscore构建综合模型,采用受试者操作特征曲线(ROC)评估模型预测乳腺癌NAT后病理完全缓解(pCR)的效能,比较它们的曲线下面积(AUC)、准确度、灵敏度、特异度。使用临床校正曲线与临床决策曲线对模型进行评估与对比。结果综合模型预测pCR的效能最佳,其AUC值在训练集与验证集分别达0.92、0.85;其次为Delta超声组学模型,AUC分别为0.80、0.82;传统影像模型效能最低,AUC分别为0.67、0.72。临床校准曲线显示综合模型预测值与实际值一致性较高,临床决策曲线显示综合模型优于其他两种模型。结论Delta超声组学是早期预测乳腺癌NAT疗效的标记物。基于Delta超声组学结合临床病理指标构建的综合模型可作为早期准确预测NAT疗效的评估手段。