Analysis of Maximum Liquid Carrying Capacity Based on Conventional Tubing Plunger Gas Lift

China’s unconventional gas fields have a large number of low-productivity and low-efficiency wells, many of whichare located in remote and environmentally harsh mountainous areas. To address the long-term stable productionof these gas wells, plunger-lift technology plays an important role. In order to fully understand and accurately graspthe drainage and gas production mechanisms of plunger-lift, a mechanical model of plunger-liquid column uplift inthe plunger-lift process was established, focusing on conventional plunger-lift systems and representative wellboreconfigurations in the Linxing region. The operating casing pressure of the plunger-lift process and the calculationmethod for the maximum daily fluid production rate based on the work regime with the highest fluid recovery ratewere determined. For the first time, the critical flow rate method was proposed as a constraint for the maximumliquid-carrying capacity of the plunger-lift, and liquid-carrying capacity charts for conventional plunger-lift withdifferent casing sizes were developed. The results showed that for 23/8 casing plunger-lift, with a well depth ofshallower than 808 m, the maximum drainage rate was 33 m3/d;for 27/8 casing plunger-lift, with a well depth ofshallower than 742 m, the maximum drainage rate was 50.15 m3/d;for 31/2 casing plunger-lift, with a well depthof shallower than 560 m, the maximum drainage rate was 75.14 m3/d. This research provides a foundation for thescientific selection of plunger-lift technology and serves as a decision-making reference for developing reasonableplunger-lift work regimes.

A Dynamic Plunger Lift Model for Shale Gas Wells

At present,the optimization of the plunger mechanism is shale gas wells is mostly based on empirical methods,which lack a relevant rationale and often are not able to deal with the quick variations experienced by the production parameters of shale gas wells in comparison to conventional gas wells.In order to mitigate this issue,in the present work,a model is proposed to loosely couple the dynamics of gas inflow into shale gas wells with the dynamics of the liquid inflow.Starting from the flow law that accounts for the four stages of movement of the plunger,a dynamic model of the plunger lift based on the real wellbore trajectory is introduced.The model is then tested against 5 example wells,and it is shown that the accuracy level is higher than 90%.The well‘switch’,optimized on the basis of simulations based on such a model,is tested through on-site experiments.It is shown that,compared with the original switch configuration,the average production of the sample well can be increased by about 15%.

Microstructure and properties of ductile iron bars for plunger pump prepared by horizontal continuous casting process

Ductile iron bars(DIBs) with a diameter of 145 mm, used for plunger pump production, were made by the horizontal continuous casting(HCC). The microstructure of the samples cut at three locations with different distances away from the surface(~20 mm from the surface, half of the radius and the center of the HCCDIBs)were investigated. The mechanical properties were measured by tensile and torsion tests. Results show that after the spheroidization of graphite, the iron matrix incorporates the nodules of Format I, Size 8 close to the surface, Format I, Size 7 at the half of the radius from the surface, and Format II, Size 6 in the centre of the bar,according to the ASTM A247 standard. The content of pearlite in the matrix changes from 55%(~20 mm from the surface) to 70%(half of the radius) and 80%(the center of the HCCDIBs). The strengths in tension are 552, 607 and 486 MPa with the elongations of 12.5%, 10.5% and 5.8% in samples cut at these three locations from the surface to the centre, respectively. The strength in torsion is equal to 558, 551 and 471 MPa at corresponding torsion angles of 418°, 384° and 144° respectively to the same distance from the bar surface. Fracture in tension is manifested via crack propagation through the interface between graphite nodules and matrix(Mode I), while in torsion the fracture is caused by the shear of graphite nodules(Mode II). It is shown that the transition between two fracture modes is also dependent on the size of graphite nodule. Typically, fracture Mode I was observed for nodules of smaller diameter(less than 22.7 μm) and fracture Mode II was seen for nodules of greater diameter(more than 24.8 μm).

Study on a Gas Plunger Lift Model for Shale Gas Wells and Its Effective Application

The problem of efficient gas lift for gas well annulus packers that rely on their own energy plungers is considered.The complex related gas-liquid problem is addressed in the frame of model where the gas inflow dynamics and liquid inflow dynamics of the considered shale gas wells are weakly coupled.On this basis,and with the aiding support of indoor simulation experimental data,a new gas plunger lift design taking into account liquid leakage is obtained.Finally,a dedicated software relying on this approach is developed and used to verify the reliability of the model by means of field examples.

考虑表面粗糙度与空化效应的组合密封润滑分析

为了研究表面粗糙度及空化效应对压裂泵柱塞密封副密封性能的影响,基于稳态Reynolds方程,建立了粗糙峰和空化效应影响下组合密封的弹流润滑数值模型.在数值模拟基础上,采用有限体积法求解稳态Reynolds方程,研究了密封副在表面粗糙度影响下的油膜厚度、油膜压力、油膜流速分布规律,以及不同的往复速度和滑环表面粗糙度对密封性能的影响.结果表明,外行程流体动压效应微弱,油膜在空气侧附近会出现空化现象;较高的往复速度有利于减小泄漏量及摩擦阻力;滑环表面粗糙度从0.8μm增加到1.8μm时,净泄漏量与外行程摩擦力分别升高了180.4%和11.17%.因此,在工作过程中应设置较高的往复速度和使用较低粗糙度的滑环以提高密封性能.

火星探测器进入过程防热层温度测量方法

火星探测器进入过程中的防热层烧蚀温度是防热结构设计和气动热环境辨识的关键参数之一。为了满足防热层温度在轨测量的需求,提出采用柱塞式结构大底分层测温探头和U形结构背罩测温探头,与电缆和多通道温度变换器共同组成温度传感器进行在轨测温的方法。设计内容包括测温探头热电偶元件选取、结构形式和安装方式,以及信号集中放大变换和自动冷端补偿等。开展全量程标定和风洞专项试验验证,证明所设计的温度传感器可以实现1300℃以下烧蚀温度变化全过程测量,测量精度达到0.28%。该温度传感器已在我国首次火星探测任务“天问一号”探测器的着陆巡视器上成功应用,可为进/再入航天器烧蚀温度在轨测量的实施提供借鉴和参考。

高含水致密凝析气藏稳产技术应用——以四川盆地安岳气田须家河组气藏为例

四川盆地安岳气田上三叠统须家河组二段气藏为低孔、低渗、有水、中含凝析油、弹性气驱、高压岩性圈闭的砂岩气藏,气藏底水能量充足。针对气井生产过程中受地层水水侵和反凝析污染影响造成稳产难度较大的情况,结合储层及气井产液特征,开展有水凝析气井稳产技术应用实践,分析并总结应用实践经验和成果,选取了应用效果较好的注气吞吐、电潜泵排水、车载压缩机气举、柱塞气举排液和自动化开关井5种稳产技术。结果表明:①针对储层反凝析液伤害,形成单井注气吞吐技术应用选井原则;②针对气藏水体赋存特征和水侵模式特征,调整气藏排水采气对策思路,采用电潜泵排水技术和车载压缩机气举技术;③针对地层压力低、举升能量不足,优化油、气、水三相流动条件下的柱塞气举排液技术;④针对低压间歇生产井采用自动化开关井技术,增加生产效率,降低人工成本。对5种主要稳产技术的应用情况进行了分析评价,认为一系列稳产技术的应用有助于安岳气田须二段气藏稳定生产,为类似高含水致密凝析气藏的稳产提供了借鉴和参考。

喷油器柱塞副动态泄漏及特性

为了研究高压共轨喷油器柱塞副的动态泄漏特性,建立了柱塞副间隙燃油流动的数学模型,通过有限差分法对数学模型进行数值计算,研究了不同轨压下柱塞副燃油的平均动态泄漏率的变化趋势,与试验值进行对比,验证该数学模型的有效性,并分析了轨压、进口燃油温度、柱塞最大升程和喷射脉宽四种因素对柱塞副动态泄漏量的影响及在不同柱塞速度下,油膜压力、厚度和温度参数的变化趋势。结果表明,在一个喷油循环内,动态泄漏率的变化曲线与控制腔油压变化曲线相似,平均动态泄漏率随着喷油器的轨压、入口燃油温度和柱塞最大升程的增加而增加,但随着喷射脉宽的增加而减小;随着柱塞速度由正速度到负速度的过程,油膜的厚度逐渐变薄,油膜的温度整体上升,油膜的压力变小。

基于键合图理论的斜盘多柱塞泵建模与仿真

为了研究9个柱塞组合而成的斜盘式轴向柱塞泵的性能特征,应用键合图理论,通过AMESim仿真平台建立模型,研究斜盘倾角和配流盘窗口前端的减振槽对柱塞泵流量脉动的影响,分析扩展模型中斜盘所受的力矩。结果表明:柱塞泵斜盘倾角越大,输出的流量越多,流量脉动幅度越大;配流盘窗口的减振槽形状和大小越合理,流量脉动越小;用AMESim仿真平台中的接收和发射元件可以扩展模型,获得斜盘所受的力矩曲线。

水压泵柱塞密封性能实验装置的设计

为解决油水分离式柱塞泵的柱塞与缸套的密封可靠性及选型设计问题,研制了模拟水压柱塞泵实际运行工况的柱塞密封性能实验装置及其加载系统,并对实验装置进行了动平衡设计。在建立实验装置加载系统的仿真模型后,通过仿真对比确定了合理的加载方式。该实验装置的加载实验和稳定性实验表明,实验装置运行稳定可靠,且容积效率在合理范围内。

Rubber plunger surface texturing for friction reduction in medical syringes

Friction is a genuine issue in the use of many medical devices involving rubbery materials such as plungers in medical syringes. This paper presents a new direction for the reduction of friction in medical syringes based on surface texturing of the rubber plunger. The specimens were prepared by casting poly(vinylsiloxane)(PVS) rubber into a pre-fabricated negative template obtained by 3D printing. Friction tests were performed on a home-made test-rig. It was clearly shown that friction resistance can be considerably manipulated when using textured plungers.

柱塞仿生表面织构设计和密封性能分析

排水采气柱塞的密封性能是柱塞气举排水采气工艺的关键。为研究不同柱塞表面织构对柱塞密封性能的影响,结合仿生学原理,选择矩形槽、圆弧槽、梯形槽、柱状坑和圆弧5种仿生表面织构,通过Computational Fluid Dynamics (CFD)流体模拟方法对柱塞举液上行过程中的气液两相流动进行模拟,对柱塞举液过程中的气液流动进行研究和分析,分析不同表面仿生织构对柱塞与油管壁间隙间流场流体流动和柱塞密封性能的影响。结果表明,柱塞上行过程中,仿生表面织构加剧了柱塞举液过程中气液两相流体相互作用,在织构区域形成局部湍流,消耗了气体的能量,阻碍了液体的漏失;相比于传统的槽状织构,凹坑状织构柱塞在合适的尺寸下的密封性能更好,模拟范围内密封性能最好的为圆弧坑织构,深6 mm,直径12 mm,周向均布8个。研究结果可为柱塞表面织构设计和柱塞举液工艺优化提供指导。

基于AMESim的工程机械用斜盘式轴向柱塞马达变速特性分析

为适应不同负载的需要,轴向柱塞马达在工作时需不断进行高、低速之间的转换,在高、低速转换过程中产生的冲击力可能会造成滑靴脱落、柱塞卡死和压盘断裂等一系列问题,因此需要对马达的变速特性进行分析。以某公司5.0×105 N挖掘机用轴向柱塞马达为例,利用AMESim软件搭建了柱塞马达的液压控制模型,通过阶跃信号模拟变速过程,研究斜盘角度变化过程中柱塞腔中的压力变化规律。从改变斜盘转换的频率和柱塞滑靴组件不同响应时间两个方面分析柱塞腔压力变化情况,并分析了不同压力下柱塞的应力应变。通过分析可知:柱塞滑靴组件最优响应时间为0.17 s,当响应时间大于0.17 s时斜盘转换频率对柱塞腔压力影响不大;高低速转换时响应时间过快是导致柱塞卡滞在缸孔内的主要原因之一。

基于AMESim的多液缸合流式压裂泵流量脉动特性研究

传统的机械式压裂泵存在冲次高、冲程短、曲轴易于失效等问题,为此,提出了一种多液缸合流式液压驱动压裂泵,并对其产生流量脉动的机理进行了研究。首先,详细阐述了多液缸合流式压裂泵的工作原理,基于液压流体力学等理论,建立了多液缸合流式压裂泵的数学模型,并进行了理论分析;其次,采用AMESim仿真软件搭建了多液缸合流式压裂泵工作仿真模型,选择了合理的仿真参数设置,进行了变负载压力下的仿真研究;最后,对液压动力传递链中的活塞-柱塞运动特性、泵腔流量特性、输出流量和压力脉动特性进行了研究,并对仿真结果进行了分析。研究结果表明:在25 MPa工况下,多液缸合流式压裂泵的输出压力和流量脉动率分别为36.8%和20.61%,冲次只有42次/min,符合实际工况;多液缸合流式压裂泵输出流量脉动的主要原因是各组液缸的频繁换向、泵送行程和吸入行程的切换,导致活塞-柱塞做减速停止运动和加速启动运动。

基于支撑力平衡的柱塞泵滑靴副油膜厚度动态求解方法

通过改进轴向柱塞泵的滑靴副与柱塞的结构设计以稳定建立滑靴油膜,这是轴向柱塞泵当前的研究热点之一。柱塞泵滑靴副油膜厚度的动态特性对分析柱塞泵滑靴副的支撑特性至关重要,为此,提出了一种基于支撑力平衡的柱塞泵滑靴副油膜厚度动态求解新方法。首先,对滑靴副的受力平衡机理进行了分析,并构建了柱塞泵运动学和动力学模型;然后,构建了柱塞泵整泵流场仿真模型,求解了包含滑靴底部支撑力、柱塞腔压力等在内的滑靴副支撑动态边界,并采用容积效率试验数据验证了整泵流场仿真的准确性;最后,建立了滑靴副油膜承载模型,分析了滑靴副油膜支撑特性,提出了基于插值计算理论的柱塞泵滑靴副油膜承载尺度动态求解方法,对1600 r/min与600 r/min两种典型工况的滑靴副油膜动态进行了计算。研究结果显示:大排量柱塞泵转速为1600 r/min时,柱塞惯性力导致高压侧油膜厚度进一步减薄,高压转低压过程中,柱塞腔内出现压力骤降,使滑靴副油膜无法形成,导致滑靴与斜盘发生刚性接触,在该区域内发生异常磨损;而在低转速工况(600 r/min)时,滑靴底面能够有效形成油膜,保证柱塞泵低速运行的可靠性。这表明基于支撑力平衡的柱塞泵滑靴副油膜厚度动态求解方法可以快速地对不同工况下的柱塞泵滑靴副油膜厚度进行求解。

挤压机板焊柱塞结构强度计算及优化设计

柱塞在挤压机工作时要承受很大的应力,设计时必须进行强度计算及校核。相比于传统锻焊式柱塞,板焊式柱塞在减轻自重的同时也更容易出现应力集中。对柱塞主结构进行受力分析,提取其主要载荷,使用弹性力学厚壁圆筒理论对柱塞结构中段进行强度计算,推导出第四强度理论下的等效应力计算公式。根据计算结果提出三个加筋方案,并使用有限元法分别对加筋后的柱塞结构进行强度计算,模拟柱塞受载后应力状态,校核强度并分析讨论最适合生产制造的设计方案。

基于颗粒阻尼的柱塞泵减振研究

柱塞泵以及相关管网振动过大的问题,是困扰油田注水泵站安全生产的难题之一,极大的管道振动常常会引起管道的疲劳破裂,从而引发流体泄漏等安全事故。研究了基于颗粒阻尼的专用减振器,并基于有限元与离散元耦合分析算法,建立了颗粒阻尼技术阻尼分析模型,然后利用有限元方法,分析了增加颗粒阻尼前后的设备减振效果,并结合现场测试数据以及空间安装位置,设计了合理的阻尼减振方案,并完成了阻尼器的现场安装与调试,研究发现,增加颗粒阻尼减振后,设备的振动烈度降低57.5%以上,进出口管线降低45%以上,确保了设备的安全运行。

Neck-spinning quality analysis and optimization of process parameters for plunger components:Simulation and experimental study

The plunger component is a key part of the plunger pump in the aircraft hydraulic system.Neck-spinning process is commonly used to fabricate plunger components,of which the quality of the spinning process significantly affects the performance of plunger pumps.One of the bottlenecks faced by the industry in the spinning process is to choose a suitable neck-spinning process so as to ensure the quality of plunger components.It is necessary to propose a reliable method to optimize the process parameters which affect the neck-spinning quality of plunger components.In this study,a calculable finite element analysis(FEA)model is established to simulate the threeroller neck-spinning process of the plunger component,which includes six typical slipper structures,two roller structures,and two spinning parameters.The FEA model is then validated by comparing the simulated spinning forces with the corresponding experimental results.The influence of the process conditions on the neck-spinning quality is investigated.And the orthogonal simulation results are analyzed by a combination of range method and fuzzy mathematical analysis method to recommend a reasonable slipper structure,roller structure and neck-spinning parameters.This study provides a promising method to improve the manufacturing quality of the typical plunger components.

基于地磁感应的柱塞到达传感器设计

柱塞到达检测是柱塞气举排水采气工艺的重要组成部分。针对传统柱塞到达传感器易受油管振动影响产生漏检而导致气举井生产效率偏低的问题,提出一种基于地磁感应的柱塞到达传感器设计方法。该柱塞到达传感器以STM32微处理器为核心,通过采集地磁传感器RM3100传送的数据,经过滑动平均滤波后采用自适应阈值算法判断柱塞运动状态,最后输出柱塞到达信号。实验室测试及实地应用表明,该柱塞到达传感器检测精度高,运行稳定,在柱塞气举排水采气工艺中具有一定的实用价值。

A capacitance servo control plunger for accurate lifetime measurement

The recoil distance Doppler shift method has been widely used in the study of nuclear structure to determine the level lifetime and absolute transition probabilities.A capacitance servo control plunger based on this method has been successfully developed by the Nuclear Structure Group of the China Institute of Atomic Energy.Three microscopes were employed to check the parallelism and can therefore guarantee a delicate measurement of the distance between the target and the stopper.This new plunger made a successful performance in the test experiment and the measured lifetime of the 2~＋→0~＋ transition in ^（78）Kr is in agreement with the previous value.