Scale and Associated Factors of Using Pyrethroid-Impregnated Mosquito Nets as Fishing Tools on Nokoué Lake within Sô-Ava Municipality in Benin, 2020

Background: In lacustrine communities, whether in Benin or elsewhere, populations use impregnated mosquito nets (IMNs) as fishing nets. This depletes the lake of its fishery resources, which in turn are contaminated by the pyrethroids impregnated in the nets. This study aims to determine the scale and factors associated with the use of pyrethroid-impregnated mosquito nets as fishing tools in the municipality of Sô-Ava in Benin. Methods: This is a cross-sectional and analytical study with two components. First, a quantitative component was made up of 280 volunteers who were interviewed in the seven districts of the city. Data collection was done in two phases: the first from September to October 2020, and the second in August 2022. Data were analyzed with Stata and logistic regression was used. Another qualitative component was made up of forty participants chosen by reasoned choice, of which 32 were split into four focus groups of eight members each, and the rest participated in semi-structured interviews. Triangulation of the different sources was used to analyze the data. Results: Around 67% of the population reported using impregnated mosquito nets as fishing tools and 33% exclusively for malaria. Seasonal fishermen (ORa = 2.03, CI = 1.35 - 4.97, P = 0.004) and years of professional experience (ORa = 1.53, CI = 1.00 - 2.05, P = 0.021) increase the risk of using these nets as fishing tools. The use of insecticide-treated mosquito nets against mosquitoes causes skin scratching and impairs breathing because of the impregnation products, as reported by respondents. Conclusion: A high prevalence of inappropriate use of impregnated mosquito nets in fishing practices is highlighted in this study. Interviews in the field revealed that nets are diverted for fishing purposes to increase the volume of catches. Consequently, it will be appropriate to assess the pyrethroid content in water and fishery products.

Integrated design and control technology of liner completion and drilling for horizontal wells

Aiming at the problems of large load of rotation drive system,low efficiency of torque transmission and high cost for operation and maintenance of liner steering drilling system for the horizontal well,a new method of liner differential rotary drilling with double tubular strings in the horizontal well is proposed.The technical principle of this method is revealed,supporting tools such as the differential rotation transducer,composite rotary steering system and the hanger are designed,and technological process is optimized.A tool face control technique of steering drilling assembly is proposed and the calculation model of extension limit of liner differential rotary drilling with double tubular strings in horizontal well is established.These results show that the liner differential rotary drilling with double tubular strings is equipped with measurement while drilling(MWD)and positive displacement motor(PDM),and directional drilling of horizontal well is realized by adjusting rotary speed of drill pipe to control the tool face of PDM.Based on the engineering case of deep coalbed methane horizontal well in the eastern margin of Ordos Basin,the extension limit of horizontal drilling with double tubular strings is calculated.Compared with the conventional liner drilling method,the liner differential rotary drilling with double tubular strings increases the extension limit value of horizontal well significantly.The research findings provide useful reference for the integrated design and control of liner completion and drilling of horizontal wells.

Simulation logging experiment and interpretation model of array production logging measurements in a horizontal well

The distributions of local velocity and local phase holdup along the radial direction of pipes are complicated because of gravity differentiation,and the distribution of fluid velocity fi eld changes along the gravity direction in horizontal wells.Therefore,measuring the mixture flow and water holdup is difficult,resulting in poor interpretation accuracy of the production logging output profile.In this paper,oil–water two-phase flow dynamic simulation logging experiments in horizontal oil–water two-phase fl ow simulation wells were conducted using the Multiple Array Production Suite,which comprises a capacitance array tool(CAT)and a spinner array tool(SAT),and then the response characteristics of SAT and CAT in diff erent fl ow rates and water cut production conditions were studied.According to the response characteristics of CAT in diff erent water holdup ranges,interpolation imaging along the wellbore section determines the water holdup distribution,and then,the oil–water two-phase velocity fi eld in the fl ow section was reconstructed on the basis of the fl ow section water holdup distribution and the logging value of SAT and combined with the rheological equation of viscous fl uid,and the calculation method of the oil–water partial phase fl ow rate in the fl ow section was proposed.This new approach was applied in the experiment data calculations,and the results are basically consistent with the experimental data.The total fl ow rate and water holdup from the calculation are in agreement with the set values in the experiment,suggesting that the method has high accuracy.

Application of Combined Production Logging Technology in Horizontal Wells

随着海上油气田开发的不断深化,水平井技术已在增储上产中起到了巨大作用,但也面临着出水及含水不断升高的问题。进行水平段储层生产测井,确定井下层内生产情况及储层动用情况,是后期控水稳产、措施挖潜的关键。水平井因井眼轨迹与储层平行、流体重力分异明显、上/下坡流共存等因素,常规居中测量中心流速的测井技术已不适用;同时,水平井为单层开采,剩余油饱和度分布无标准水层刻度,为生产层剩余油分布监测提出了挑战。提出了阵列式多相流测井仪组合(MAPS)和剩余油饱和度测井技术(RPM)的组合测井方式,通过水平段截面速度剖面、流体性质分布以及剩余油饱和度分布三者间的相互验证、综合解释的解决方案,取得了良好效果。

The virtual lover： variable and easily guided 3D fish animations as an innovative tool inmate-choice experiments with sailfin mollies-I,Design and implementation

Animal behavior researchers often face problems regarding standardization and reproducibility oftheir experiments. This has led to the partial substitution of live animals with artificial virtual stim-uli. In addition to standardization and reproducibility, virtual stimuli open new options for re-searchers since they are easily changeable in morphology and appearance, and their behavior canbe defined. In this article, a novel toolchain to conduct behavior experiments with fish is presentedby a case study in sailfin mollies Poecilia latipinna. As the toolchain holds many different and novelfeatures, it offers new possibilities for studies in behavioral animal research and promotes thestandardization of experiments. The presented method includes options to design, animate, andpresent virtual stimuli to live fish. The designing tool offers an easy and user-friendly way to definesize, coloration, and morphology of stimuli and moreover it is able to configure virtual stimuli ran-domly without any user influence. Furthermore, the toolchain brings a novel method to animatestimuli in a semiautomatic way with the help of a game controller. These created swimming pathscan be applied to different stimuli in real time. A presentation tool combines models and swim-ming paths regarding formerly defined playlists, and presents the stimuli onto 2 screens.Experiments with live sailfin mollies validated the usage of the created virtual 3D fish models inmate-choice experiments.

水平井涡轮振荡冲砂工具设计与仿真

目前水平井常用于高渗透疏松砂岩油气藏的开发,在开发过程中经常面临出砂问题,即当油层出砂之后,砂粒会紧跟原油流进井筒中,随后逐渐沉积在水平段的较低位置处而产生砂床。砂床的存在会影响石油的开采,堵塞出油通道,增加流动阻力,甚至会损坏井下设备,造成井下砂卡事故。针对我国目前常规水平井冲砂效率低、效果差且易发生堵塞等问题,文中设计了一种水平井涡轮振荡冲砂工具,确定了冲砂工具的总体方案,对振荡与冲砂参数进行了计算,并对冲洗头进行了冲砂效果仿真。研究表明,该工具通过振荡、旋转方式破砂,使得砂粒不易在井筒沉积形成砂床,在不影响冲砂效率的前提下冲砂工具不易卡涩,且该冲洗头喷嘴的布置方式可使冲洗效果更为显著。

水平井尾管完井与钻井一体化设计控制技术

针对水平井尾管导向钻井技术存在的钻机旋转系统负载大、地面扭矩传动效率低、使用与维护成本高等问题,提出了水平井双管柱尾管差速旋转钻进新方法,揭示了相应的技术原理,设计了双管柱差速旋转传动、复合旋转导向及悬挂器等井下专用工具,优化了相关工艺流程;提出了导向钻具组合工具面控制方法,建立了水平井双管柱尾管差速旋转钻进延伸极限计算模型。结果表明:水平井双管柱尾管差速旋转钻进技术配备常规随钻测量仪器和螺杆钻具,通过调节钻柱转速可以控制导向钻具组合的工具面,实现了水平井双管柱尾管差速旋转导向钻进;基于鄂尔多斯盆地东缘深部煤层气水平井工程案例计算水平井双管柱钻进延伸极限,与常规尾管钻井方式相比,采用双管柱尾管差速旋转钻进方式显著增大了水平井延伸极限,为水平井尾管完井与钻井一体化设计控制提供了参考。

仪器偏心对纵横波衰减影响的正演实验

近年来,水平井得到了越来越广泛的应用,在页岩气等非常规油气藏以及海上油气藏的勘探开发中发挥了至关重要的作用。但水平井测井在影响因素校正、资料处理和解释等方面尚存在诸多问题。针对仪器偏心对水平井声波测井响应影响的问题,开展了相关的物理模拟实验研究和数值模拟分析。提取了不同偏心率条件下的模式波的能量参数,分析了模式波能量随仪器偏心率的变化关系。结果表明,当仪器处于偏心状态时,模式波的能量均与仪器偏心率呈现类似负指数关系;仪器偏心率与模式波的能量衰减系数呈现S形曲线变化关系。研究结果有助于厘清仪器偏心对水平井声波测井响应的影响规律并为进一步开展仪器偏心对阵列声波测井响应影响校正方案研究提供指导。

基于高频水平机械扫描式声呐图像的海水网箱养殖卵形鲳鲹数量估算方法

为准确估算海水养殖网箱中的卵形鲳鲹(Trachinotus ovatus)数量,基于高频水平机械扫描式声呐和深度学习技术,提出了一种海水网箱鱼群数量的估算方法。该方法使用微分水层并逐层聚类的方式以实现计数,主要包括鱼群识别计数、鱼群聚类和鱼群数量拟合3部分。首先,使用高频水平机械扫描式声呐对海水网箱进行螺旋式的检测,获取鱼群图像信息并标注图像以构建改进的CS-YOLOv8s的训练数据集,然后训练CS-YOLOv8s模型以识别图像中的鱼类位置信息;其次,以40 cm水深间距划分网箱作为水层,对每个水层的识别坐标数据使用DBSCAN方法进行聚类处理,生成每个水层的鱼群数量数据;最后,将每个水层的数量数据与网箱中已知的鱼群数量进行拟合,构建鱼群数量拟合模型。结果表明,在海水网箱定量实验中,该方法对卵形鲳鲹数量的估算精度达到87.14%,能够较好地实现卵形鲳鲹的数量估算。

水平井泵送桥塞工具串可通过性研究

水平井泵送桥塞射孔联作工艺在页岩气、页岩油、致密油等非常规油气储层开发中得到了广泛的应用。该工艺通过水力泵送的方式,把携带有可钻桥塞和多级射孔枪连结成的工具串送到指定位置。由于井眼轨迹、井筒环境复杂,泵送遇阻、遇卡事故时有发生。本文根据水平井泵送桥塞在套管中的空间结构特点和工具串构型对工具串进行针对性简化,明确在一定狗腿度下工具串在弯曲井段中与井筒的几何关系,提出泵送桥塞工具串与管壁接触点确定方法,并分析其在弯曲井段受力弯曲特性,建立可通过性判别准则。根据实际案例,进行包括井眼轨迹、最大狗腿度与管壁内径的影响因素分析,给出泵送工具串配置参数优化方案,以减少井下事故的发生。

H24-16柔性多分支侧钻水平井钻井实践与认识

江苏油田H24-16井存在砂体能量弱、储层薄、渗透率低及注水不见效等问题。柔性多分支侧钻水平井技术将开窗、造斜、钻进所有进尺全部集中在目标储层,可以实现分支长度与储层接触面积最大化。为挖掘该井薄差层剩余油,研制了柔性钻具、叠加式斜向器及专用打捞矛,设计了分支井眼轨道,辅以井眼轨迹控制,完成了H24-16井的柔性多分支侧钻水平井钻进。首次成功实现了江苏油田在同一油层钻出2个分支水平井眼,为高效侧钻挖潜剩余油积累了宝贵经验,具有较大的推广应用价值。

超短半径水平井柔性动力钻具研制

为改善浅部煤层气开采中,超短半径水平井钻进深度不足等现状,结合超短半径水平井施工工艺,本文设计并研制了超短半径井下柔性动力钻具。该钻具采用多级涡轮叶片将钻井液冲能转化为扭矩驱动钻头旋转,并串联数节柔性单元形成弯曲半径5 m的超短半径柔性动力钻具。通过对钻具开展室内机械性能测试,揭示了超短半径柔性钻具排量-转速-扭矩耦合关系,结果表明超短半径柔性动力钻具输出扭矩可达1500 N·m,满足超短半径侧钻水平井现场施工技术要求。柔性钻杆+柔性钻具组合方式可有效提高超短半径水平井侧钻深度和钻进效率,为提高浅部煤层气的采收率提供了新的技术手段。

航空涡轮盘拉削刀具健康监测系统设计

针对航空涡轮盘拉削刀具生产周期长、造价昂贵、监测困难以及易出现损伤等问题,设计并构建了拉削刀具健康监测系统。根据拉床行业的特点、痛点及实际需求等,提出了系统的总体框架。基于加速度传感器及振动监控器,设计了拉床在线、在位的振动信号采集系统,实现了拉削过程中刀具振动信号的连续、实时采集。基于C++语言与Qt开发平台,开发了刀具健康监测系统,实现了对振动信号的实时分析处理及刀具健康监测。

水平冻结中导向板钻具组合造斜能力的影响因素研究

目前水平冻结孔定向钻进中,导向板钻具组合的使用存在造斜理论不明的问题。基于材料力学理论,以钻头转角形变量为造斜评价指标,结合冻结法特点建立钻具造斜力学模型,并讨论参数的影响,同时结合实测数据验证该模型的可行性。结果表明:(1)导向板钻具组合钻头转角与岩土层物理力学参数、钻具抗弯刚度、导向板钻头的结构参数(如导向角,钻具长度,导向板斜面面积)、钻具面向角相关;(2)全角变化率在钻具面向角接近0°时最小,接近䥺SymbolqB@180°时最大,其余钻头转角变化均在此范围内,并随着导向角的增大而增大;(3)随着岩土层强度提高,相同导向角对应的全角变化率更大,导向板钻具组合的造斜能力更强。

智能贴片示踪剂装载工具的研制及应用

常规水平井分段压裂监测过程中,使用液体示踪剂存在监测周期短、扩散作用较大、影响测试精度等问题,而智能贴片示踪剂是一种固体示踪剂,具有缓释性能,能够满足水平井长期监测(监测周期大于1年)的需求,但国内尚无配套的工具短节用于智能贴片示踪剂使用。由此设计了一种智能贴片示踪剂装载工具,该工具主要由锚卡、护罩及连接短节组成,配套生产管柱使用,能实现长期监测的目的。文章介绍了智能贴片示踪剂、装载工具设计及制造,并结合国内首次应用的案例,阐述了装载工具进行产能剖面监测的安装过程及工艺流程。现场应用表明,装载工具具有良好的稳定性能,可满足智能贴片示踪剂监测需求,填补了国内在该项技术上的空白。

螺杆钻具三卡瓦偏心打捞筒的研制及应用

钻井过程中螺杆钻具断落事故时有发生,对于螺杆钻具外筒壳体脱扣、转子断裂抽芯等事故形成的轻质“落鱼”,使用常规卡瓦打捞筒作业时的适用性不足、打捞成功率低。基于此,设计了螺杆钻具三卡瓦偏心打捞筒,通过打捞筒的锥形导向面驱动上卡瓦、中卡瓦和下卡瓦共轭环空收缩卡紧,实现对该类“落鱼”的有效打捞。三卡瓦的偏心排布结构设计,增加了有效夹持面积,提高了打捞筒对螺杆钻具的综合打捞力。结合打捞筒的工作原理,建立了卡瓦常规夹持力和挤压夹持力的计算公式,对比得出三卡瓦偏心打捞筒所需的卡瓦常规夹持应力可减少50.46%,捞牙咬深可减少13.92%。试制的打捞筒在施工现场进行了打捞实践,表明其结构设计合理,打捞性能可靠。

爬行器在水平井作业时的阻力分析与对策研究

通过对爬行器在井下运行过程中自身产生的牵引力、电缆拖拽阻力、仪器串摩擦阻力、流体阻力、井斜阻力等受力的综合分析,提出五种对策来克服或降低爬行器运行过程中受到的阻力。通过综合运用上述措施,保证爬行器顺利爬行、稳定工作,提高爬行速度和爬行距离,节约测井时间成本,为现场使用工艺和仪器后续改进升级提供了理论依据和支撑基础。

四轴数控机床对刀方法研究

根据多轴数控机床的运动结构特性对四轴数控机床进行分类,提出卡盘式立式四轴类、桥板式卧式四轴类两种四轴数控机床的对刀方法,为不同结构类型多轴数控机床的对刀提供有效参考。

中低熟页岩油小井距双水平井磁导向测量系统的研制与应用

在全球能源需求持续增长、油气工业向非常规油气资源转变的背景下,我国储量丰富的页岩油资源,尤其是中低成熟度页岩油的开发备受关注。文章聚焦于中低熟页岩油开发中面临的小井距双水平井钻井轨迹精准测量的挑战,创新研发了MixMeasure磁导向测量系统。该系统通过磁源发射的磁信号进行正钻井的定位与导向,能够自动优化滤波频带范围,有效剔除复杂环境下的噪声干扰,同时集成了高精度的测距与测角计算模型,实现了0.2 m测距精度和1.7°测角精度。这一技术突破了复杂环境下小井距钻井过程中的稳定测量难题,满足了井距10 m内的双水平井钻井导向需求。MixMeasure磁导向测量系统为页岩油的安全钻井提供了可靠的测量数据,提升了钻井的安全性和效率,不仅推动了中低熟页岩油的开发进程,也为油气勘探开发事业的持续发展提供了重要的技术支撑。

水平井智能控水模拟计算与应用研究

南海西部某油田底水油藏开发过程中面临含水率高、油井过早水淹、开发效果逐渐变差等问题。为降低开发井含水率,提高油井产量,结合分析现有智能控水工具技术原理,采用控水模拟软件进行了该油田某口水平井的分段设计、控水筛管参数设计等数值模拟,形成了水平井智能控水方案。现场应用表明采用该智能控水方案后,油井生产初期控水效果良好,最高含水率下降56.67%,产油率提升约13%,具有较好的控水效果和指导意义。