Study of inter-well interference in shale gas reservoirs by a robust production data analysis method based on deconvolution

In order to overcome the defects that the analysis of multi-well typical curves of shale gas reservoirs is rarely applied to engineering,this study proposes a robust production data analysis method based on deconvolution,which is used for multi-well inter-well interference research.In this study,a multi-well conceptual trilinear seepage model for multi-stage fractured horizontal wells was established,and its Laplace solutions under two different outer boundary conditions were obtained.Then,an improved pressure deconvolution algorithm was used to normalize the scattered production data.Furthermore,the typical curve fitting was carried out using the production data and the seepage model solution.Finally,some reservoir parameters and fracturing parameters were interpreted,and the intensity of inter-well interference was compared.The effectiveness of the method was verified by analyzing the production dynamic data of six shale gas wells in Duvernay area.The results showed that the fitting effect of typical curves was greatly improved due to the mutual restriction between deconvolution calculation parameter debugging and seepage model parameter debugging.Besides,by using the morphological characteristics of the log-log typical curves and the time corresponding to the intersection point of the log-log typical curves of two models under different outer boundary conditions,the strength of the interference between wells on the same well platform was well judged.This work can provide a reference for the optimization of well spacing and hydraulic fracturing measures for shale gas wells.

Opto-mechanical-thermal integration analysis of Doppler asymmetric spatial heterodyne interferometer

In order to improve the detection accuracy of Doppler asymmetric spatial heterodyne(DASH)interferometer in harsh temperatures,an opto-mechanical-thermal integration analysis is carried out.Firstly,the correlation between the interference phase and temperature is established according to the working principle and the phase algorithm of the interferometer.Secondly,the optical mechanical thermal analysis model and thermal deformation data acquisition model are designed.The deformation data of the interference module and the imaging optical system at different temperatures are given by temperature load simulation analysis,and the phase error caused by thermal deformation is obtained by fitting.Finally,based on the wind speed error caused by thermal deformation of each component,a reasonable temperature control scheme is proposed.The results show that the interference module occupies the main cause,the temperature must be controlled within(20±0.05)℃,and the temperature control should be carried out for the temperature sensitive parts,and the wind speed error caused by the part is 3.8 m/s.The thermal drift between the magnification of the imaging optical system and the thermal drift of the relative position between the imaging optical system and the detector should occupy the secondary cause,which should be controlled within(20±2)℃,and the wind speed error caused by the part is 3.05 m/s.In summary,the wind measurement error caused by interference module,imaging optical system,and the relative position between the imaging optical system and the detector can be controlled within 6.85 m/s.The analysis and temperature control schemes presented in this paper can provide theoretical basis for DASH interferometer engineering applications.

Co-Frequency Interference Analysis and Avoidance Between NGSO Constellations: Challenges, Techniques, and Trends

In recent years,as giant satellite constellations grow rapidly worldwide,the co-existence between constellations has been widely concerned.In this paper,we overview the co-frequency interference(CFI)among the giant non-geostationary orbit(NGSO)constellations.Specifically,we first summarize the CFI scenario and evaluation index among different NGSO constellations.Based on statistics about NGSO constellation plans,we analyse the challenges in mitigation and analysis of CFI.Next,the CFI calculation methods and research progress are systematically sorted out from the aspects of interference risk analysis framework,numerical calculation and link construction.Then,the feasibility of interference mitigation technologies based on space,frequency domain isolation,power control,and interference alignment mitigation in the NGSO mega-constellation CFI scenario are further sorted out.Finally,we present promising directions for future research in CFI analysis and CFI avoidance.

Well interference evaluation considering complex fracture networks through pressure and rate transient analysis in unconventional reservoirs

Severe well interference through complex fracture networks(CFNs)can be observed among multi-well pads in low permeability reservoirs.The well interference analysis between multi-fractured horizontal wells(MFHWs)is vitally important for reservoir effective development.Well interference has been historically investigated by pressure transient analysis,while it has shown that rate transient analysis has great potential in well interference diagnosis.However,the impact of complex fracture networks(CFNs)on rate transient behavior of parent well and child well in unconventional reservoirs is still not clear.To further investigate,this paper develops an integrated approach combining pressure and rate transient analysis for well interference diagnosis considering CFNs.To perform multi-well simulation considering CFNs,non-intrusive embedded discrete fracture model approach was applied for coupling fracture with reservoir models.The impact of CFN including natural fractures and frac-hits on pressure and rate transient behavior in multi-well system was investigated.On a logelog plot,interference flow and compound linear flow are two new flow regimes caused by nearby producers.When both NFs and frac-hits are present in the reservoir,frac-hits have a greater impact on well#1 which contains frac-hits,and NFs have greater impact on well#3 which does not have frac-hits.For all well producing circumstances,it might be challenging to see divergence during pseudosteady state flow brought on by frac-hits on the logelog plot.Besides,when NFs occur,reservoir depletion becomes noticeable in comparison to frac-hits in pressure distribution.Application of this integrated approach demonstrates that it works well to characterize the well interference among different multi-fractured horizontal wells in a well pad.Better reservoir evaluation can be acquired based on the new features observed in the novel model,demonstrating the practicability of the proposed approach.The findings of this study can help for better evaluating well interference degree in multi-well systems combing PTA and RTA,which can reduce the uncertainty and improve the accuracy of the well interference analysis based on both field pressure and rate data.

基于模糊神经网络的电网消防预警算法

针对传统基于阈值判别方法的电网火灾预警系统预测精度低、抗干扰能力弱的问题,提出了一种基于模糊神经网络的电网消防预警算法。该算法利用神经网络学习大规模电网数据,使用模糊逻辑推理算法来提升预测结果的推理能力,并通过结合神经网络对大规模数据的学习能力和模糊逻辑算法的推理能力来分析电网线路参数,从而提升电网消防预警系统的精度和抗干扰能力。实验与仿真结果表明,所提出方法能显著提升电网火灾的预警精度,且使用模糊逻辑推理可以得到更符合实际情况的电网火灾预警结果。

深厚覆盖层上土石坝防渗墙损伤开裂精细化分析及防渗功能评价

混凝土防渗墙是覆盖层上土石坝坝基的关键防渗结构,由于防渗墙与覆盖层的刚度和尺度差异巨大,通常的数值分析方法难以保证精度,且现有基于强度的安全评价方法,无法适应防渗墙作为防渗结构而非承载结构的功能评价要求。本文提出了比例边界元-有限元耦合跨尺度离散、塑性损伤模型和内聚力模型分离描述压损伤和受拉开裂、破损后防渗功能目标评价的精细化分析方法,实现了深厚覆盖层上土石坝防渗墙的性态演化评价。研究结果表明:超深覆盖层上悬挂式防渗墙在两岸底部因近似垂直于岸坡的高压应力发生压损伤,类“外伸梁”的面内弯曲变形使靠近防渗墙两岸的顶部和底部区域产生坝轴向高拉应力导致槽段间出现竖向裂缝;在防渗墙两岸的上游侧局部设置辅助防渗措施,可有效降低防渗墙破损后的渗流量。本文方法揭示了混凝土防渗墙的损伤开裂模式,定位了防渗墙薄弱区域,评价了防渗墙损伤开裂对防渗功能的影响,量化防渗措施效果,实现了防渗墙从传统承载能力评价到功能性态评价的跨越,可为深厚覆盖层上土石坝防渗墙的安全评价和设计优化提供理论和技术支持。

过盈配合工况下收缩管吸能特性分析及结构参数优化

轨道车辆收缩管在轴向冲击载荷及过盈配合下的吸能特性是吸能结构研究中的重要课题,其吸能过程依靠收缩管与锥形衬套之间的摩擦做工及收缩管的塑性变形实现,过盈配合通过影响收缩管与衬套间的接触力提高收缩管的能量耗散。为提高收缩管的吸能特性,研究过盈配合对吸能能力的影响,采用试验与有限元模型相结合的方法,基于多目标优化算法获取包括过盈量在内的收缩管最优结构参数。进行空心轴与轴套过盈静压试验,验证接触力理论公式的正确性;利用台车冲击试验研究收缩管碰撞过程中的吸能特性,构建有限元模型进行验证;推导过盈配合条件下收缩管接触表面压力的理论模型;使用全因子和Hammersley设计方法对过盈配合工况下收缩管结构参数进行研究,包括厚度(T)、过盈量(I_(ntf))、锥角长边(α_(x))和收缩比(R_(atio))。基于此,利用移动最小二乘法(MLSM)构建峰值力(PCF)、比吸能(SEA)和平均力(MCF)的近似模型。主效应分析表明,收缩比对PCF、SEA和MCF的影响最为显著。以获取最小PCF、最大SEA以及MCF最接近设计要求650 kN为优化目标,进行全局响应面(GRSM)优化,获得最优结构配置,与初始设计相比,SEA提高28.54%,PCF降低12.37%。代理模型最优解得出的MCF与有限元模型误差为2.01%,证明构建的代理模型具有较高的精度,可用于优化计算。优化后的结构有效提高了收缩管的吸能能力,降低了碰撞的初始峰值力。

数控压机伺服控制系统复合控制器I-ABC与PID优化

为了提高数控压机伺服控制系统的控制精度,针对伺服控制系统运行控制过程构建数学模型,在人工蜂群算法基础上融入了云分析模型,之后采用改进人工蜂群算法(Improved Artificial Bee Colony,I-ABC)调节比例-积分-微分(Proportional Integral Differential,PID)参数,建立了一种复合控制方法。研究结果表明:以I-ABC进行PID控制时,可以使幅度差降低到0.4%,相位差基本在-0.54°之内,系统加载精度也获得了明显提升,表现出了更优的跟踪性能。以I-ABC进行PID控制时,能够对多余力起到明显抑制作用,响应速度也获得明显提升,可以有效满足系统的准确控制要求。在系统内加入干扰信号,引入I-ABC实施PID调节可以减小系统超调量,还可以获得更短调节时间,使系统获得更强抗干扰性能。

广域网环境中舰船通信网络信息安全传输方法

为满足舰船在广域网环境的安全通信需求,提出广域网环境中舰船通信网络信息安全传输方法。基于云计算技术构建具备信息调度的舰船通信网络信息安全传输模型,并针对舰船通信广域网环境存在的来自不同方向的通信干扰源、信号衰减和噪声干扰,结合噪声消除算法进行舰船通信网络信息传输抗干扰设计,降低外界干扰影响;针对舰船通信广域网环境中实时信息在传输过程中面临的攻击、窃听、截取等多种安全威胁,采用双混沌互反馈加密方法完成舰船通信网络传输信息加密,保障信息在广域网环境下安全传输。实验结果表明,该方法可显著提升舰船通信速率,在不同干扰类型下均表现出良好的抗干扰性能;加密后信息可成功掩盖原始数据分布特征,保障传输信息安全性。

快速射电暴观测数据干扰缓解方法研究

从海量的天文观测数据中快速搜寻罕见的快速射电暴(Fast Radio Burst,FRB)事件,干扰缓解是其中一项关键而具有挑战的工作.射频干扰(Radio Frequency Interference,RFI)会淹没真实的天文事件,还会导致搜寻管线输出大量的假阳性候选体.由于干扰来源及其种类的复杂性,目前并没有一种通用的方法可以解决这个问题.为了降低干扰对FRB观测搜寻的影响,分析和研究了南山26m射电望远镜L波段观测数据中的干扰情况,针对主要的窄带干扰和宽带干扰建立了3层次的干扰缓解处理流程,从而有效缓解了观测数据的干扰污染情况.将该流程嵌入到FRB色散动态谱搜寻(Dispersed Dynamic Spectra Search,DDSS)管线中,实验结果表明,搜寻管线的检测率和检测精度得到了进一步的提高.该方法为FRB观测数据干扰缓解处理提供了有价值的参考.

基于5G电子通信的无人机导航网络信号抗干扰技术

为提升无人机在自主飞行过程中传输导航网络信号时的抗干扰能力,研究基于5G电子通信技术的无人机导航网络信号抗干扰技术。构建无人机通信结构,结合5G电子通信技术与电力线通信技术创建无人机导航网络信号模型;通过频谱感知方法中的能量检测算法建立无人机干扰信号检测模型,利用自适应滤波算法抑制干扰信号以及噪声干扰,实现无人机导航网络信号干扰抑制。实验结果表明,该方法具备不同干扰模式下的信号抗干扰能力。

不同检测系统D-二聚体内源性干扰物最大抗干扰能力分析

目的对不同检测系统的D-二聚体检测时可接受的最大干扰物浓度进行分析、比较。方法随机收集50份患者样本,利用SYSMEX干扰物检测试剂盒4种干扰物胆红素F、胆红素C、溶血血红蛋白、乳糜分别与患者血浆按一定比例稀释,稀释后血浆所含干扰物质浓度与两种检测系统试剂说明书中抗干扰物最大浓度接近,分别在两种检测系统上机检测。结果当干扰物胆红素F浓度达到D-dimer HS及AcuSTAR D-dimer两种检测系统抗干扰Max浓度时,相对偏差<10%的结果占比分别为26%、46%;当干扰物胆红素C浓度达到D-dimer HS及AcuSTAR D-dimer两种检测系统抗干扰Max浓度时,相对偏差<10%的结果占比分别为18%、86%;当干扰物溶血血红蛋白浓度达到D-dimer HS及AcuSTAR D-dimer两种检测系统抗干扰Max浓度时,相对偏差<10%的结果占比分别为44%、88%;当干扰物乳糜浓度达到D-dimer HS及AcuSTAR D-dimer两种检测系统抗干扰Max浓度时,相对偏差<10%的结果占比分别为30%、58%。结论在检测D-二聚体时化学发光法抵抗高浓度内源性干扰物质能力优于免疫比浊法。

基于均匀圆阵的压制式相干干扰DOA估计算法

针对导航抗干扰中一般干扰信号波达方向(direction-of-arrival, DOA)算法无法在均匀圆阵上有效地估计含有相干干扰的信号来向问题,提出了一种基于虚拟线阵的协方差矩阵重构的MUSIC算法。该算法通过对均匀圆阵进行模式空间变换,形成虚拟线阵,将模式空间变换后的数据协方差矩阵的所有行进行Toeplitz重构,并将所有Toeplitz矩阵构造成一个新的等效的满秩数据协方差矩阵,以此来达到解相干的目的。结合在虚拟线阵上的MUSIC算法,并通过多谱峰搜索算法直接得到空间谱的谱峰位置,从而完成对干扰来向的DOA估计。经仿真验证,该算法在存在相干信号且信号角度相隔30°左右的条件下,依旧能够对信号的波达方向进行有效估计。

基于遗传模糊PID算法的倒立摆稳摆抑噪抗扰实验与分析

倒立摆稳摆控制原理应用的实际工程需求牵引,使倒立摆成为检验各类控制算法的理想替代实验研究平台。因此,将倒立摆摆杆的姿态稳定控制和抑噪抗扰作为研究内容,以理论分析、编程实现、仿真实验和实物实验验证作为研究手段,聚焦控制器设计的优化。首先,引入模糊控制对PID参数调节进行优化,改固定参数调节为在线参数调节,旨在提高系统的鲁棒性与抗扰性;然后,运用遗传算法的量化因子和比例因子完成调节参数的在线寻优,通过设计适应度函数和选择算子,经过选择、交叉、变异不断演化迭代,最终获取最佳适应度个体、找到最优解,通过仿真验证遗传模糊PID算法突出的抑噪抗扰优势;最后,基于该控制策略进行倒立摆实物实验,验证了其指令跟踪有效性的结论。该研究表明:遗传模糊PID算法具有良好的指令跟踪和抑噪抗扰性能,具有一定的工程应用价值。

基于空域自适应单脉冲的抗干扰雷达多目标参数估计算法

基于空时级联单脉冲的多目标参数高效估计算法(M-STCMP)是一种高效的雷达多目标参数估计算法,但在干扰环境下其参数估计性能将严重下降。文中提出了基于空域自适应单脉冲的抗干扰多目标参数估计(AM-STCMP)算法。首先,将空域自适应单脉冲技术引入M-STCMP算法,自适应形成和差波束抑制干扰信号,提高各目标的信干噪比,并迭代修正自适应和差波束的鉴角曲线;其次,采用空时级联单脉冲技术估计各目标的距离-速度两维参数;最后,采用Relax算法高精度迭代估计各目标的角度-速度-距离三维参数。理论分析和仿真结果验证了AM-STCMP算法的有效性,其参数估计性能接近无干扰情形。

一种基于变参考电平的零点凹口双重可控方向图综合改进方法

为了解决基于变参考电平的自适应波束形成方法无法同时控制方向图零点和凹口的问题,研究了基于最大信噪比准则的任意阵列方向图综合方法,重点对主瓣宽度固定条件下能够实现最低等副瓣电平的方向图综合方法进行了理论分析,并对前人提出的可变参考电平参量进行了重新定义,新定义的变参考电平能够在波束主瓣宽度固定的前提下,同时产生等副瓣电平、可控凹口宽度和深度和可控零点深度的抗干扰波束,并通过计算机仿真验证了算法的有效性.该方法对于提升相控阵雷达对抗杂波和干扰性能具有较高的应用价值.

基于强化学习的多雷达抗干扰算法研究

针对多雷达系统在受到环境的扫频干扰下无法工作的问题,研究了基于深度强化学习的多雷达共存抗干扰算法。文中将环境划分为多个子频段,对干扰占用频段过程进行建模,用马尔可夫模型对多雷达系统进行建模;对双深度Q网络(Double DQN)强化学习算法进行改进,与门控单元循环神经网络相结合,使之能处理依赖于长时间序列的干扰问题;提出了基于门控循环记忆的深度确定性策略强化学习算法,针对Double DQN强化学习中的网络臃肿和行动集合较大的问题进行了改进,采用直接输出行动策略,有效降低了网络复杂度。实验仿真结果表明,在多雷达存在的情况,该算法通过避开存在干扰的频点,不仅能够有效降低来自外界的干扰,还能减少己方雷达相互之间的干扰。

水下抗分散水泥土正交试验及配比优化方法研究

水流经过桩基时会形成漩涡侵蚀床面,影响桩基及上部结构的稳定性,冲刷治理是工程界关注的热点问题。为促进固化土技术在桩基冲刷修复中的应用,设计开展了抗分散水泥固化土系列正交试验。针对高岭土和淤泥土,选用PAM、EVA、黄原胶、HPMC四种抗分散剂,采用平均效果分析和极差分析,研究了抗分散剂种类、抗分散剂掺量、含水量和水泥掺量对流动度、浊度、7 d和28 d无侧限抗压强度的影响。结果表明:对于高岭土,抗分散剂掺量从0.25‰增大到1‰,水泥土流动度减小20%,浊度减小25%,抗分散剂掺量对流动性和抗分散性的影响显著。对于淤泥土,对抗分散性影响显著的仍是抗分散剂掺量,而对流动性的影响显著的则是含水量,含水量从1.4倍液限增大到2.0倍液限,水泥土流动度增大45%。基于综合平衡法、矩阵分析法和多元线性回归模型,提出了一种抗分散水泥土配比设计方法,研究得到了高岭土和淤泥土抗分散水泥固化土的推荐配比,其在泥沙起动实验中的抗冲刷特性明显优于原始土样。

一种100 MHz~4 GHz宽带抗干扰射频接收机的设计

为满足导航、通信、相控阵雷达以及电子对抗等领域对高性能接收终端的需求,提高系统的抗干扰、通用化和小型化性能,设计了一款工作频率在100 MHz~4 GHz的宽带抗干扰接收机芯片。接收机结构采用直接下变频形式,包括单转差巴伦、无源混频器和移相器等,能够有效抑制频带内的干扰信号,在强干扰信号下整个接收机通道不阻塞,能检测出极小的有用信号,同时保证与没有干扰状态相比性能不恶化。针对零中频(zero-Intermediate Frequency,zero-IF)接收机容易产生本振泄露、自混频等现象,设计了直流失调校准、本振相位调整等功能,可实现直流偏置点5 mV的补偿。射频输入100 MHz~4 GHz变化时,混频器转换增益≥31.2 dB。

非线性均衡约束下的光纤数据抗干扰通信方法

为了更加精准地解决非线性扰动变量对光纤通信造成的影响,消除扰动噪声对通信速率及通信质量的负面影响,结合扰动参量的非线性特征,对其约束均衡参量进行逐级优化,通过对其常规状态下光纤数据通信扰动模型的建立与抗扰条件分析、扰动信号的非线性分布范围确定与非线性均衡约束下扰动信号优化,实现扰动参量的彻底消除,同时提升原有光纤数据传输能力.通过创建的仿真数据对比证明提出方法的抗扰效果真实有效,其优化效果能够满足现阶段全场景应用需要,切实解决光纤数据通信扰动问题.