A Method for Forecasting Failures of Sucker Rod-pumped Wells

An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characteristics of failed sucker rod-pumped well randomness and strong outburst, with the gray GM (1,1) forecast model and the Markov forecast model combined, gray GM (1,1) forecast model is utilized to handle the primary data of an oilfield, and Markov forecast model is utilized to calculate the state transfer probability of forecast value. Then, the gray Markov forecast model considering the influence of randomness factors is formed. Field results prove that the calculation precision of this method is higher and the practicability is greater.

Using the curve moment and the PSO-SVM method to diagnose downhole conditions of a sucker rod pumping unit

Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification are two key steps. The dynamometer card is firstly divided into four parts which include different production information according to the ＂four point method＂ used in actual oilfield production, and then the moment invariants for pattern recognition are extracted. An improved support vector machine （SVM） method is used for pattern classification whose error penalty parameter C and kernel function parameter g are optimally chosen by the particle swarm optimization （PSO） algorithm. The simulation results show the method proposed in this paper has good classification results.

Fault diagnosis for down-hole conditions of sucker rod pumping systems based on the FBH-SC method

Dynamometer cards are commonly used to analyze down-hole working conditions of pumping systems in actual oil production. Nowadays, the traditional supervised learning methods heavily rely on the classification accuracy of the training samples. In order to reduce the errors of manual classification, an automatic clustering algorithm is proposed and applied to diagnose down-hole conditions of pumping systems. The spectral clustering （SC） is a new clustering algorithm, which is suitable for any data distribution. However, it is sensitive to initial cluster centers and scale parameters, and needs to predefine the cluster number. In order to overcome these shortcom- ings, we propose an automatic clustering algorithm, fast black hole-spectral clustering （FBH-SC）. The FBH algo- rithm is used to replace the K-mean method in SC, and a CritC index function is used as the target function to automatically choose the best scale parameter and clus- tering number in the clustering process. Different simulation experiments were designed to define the relationship among scale parameter, clustering number, CritC index value, and clustering accuracy. Finally, an example is given to validate the effectiveness of the proposed algorithm.

Approach to the Design Calculation of Sucker Rod Pumping Systems in Coalbed Methane Wells

The existing design of the pumping systems mainly focuses on the approximate computational formulae and procedures,which are developed based on the analytic approaches of conventional oil/gas fields.The calculation of polished rod loads usually just concerns about the static and inertial loads.And the computation of gearbox torque generally uses empirical formulae and correction factors.The above modeling procedures,if applied to the coalbed methane（CBM） wells,can not give the desired accuracy of the system design and its pertinent analysis.In this paper,based on the kinematic and dynamic analysis of the pumping system,the kinematic relation of polished rod is analyzed,and the variation of the total loads of polished rod is developed with the limits of CBM well conditions along the string.The gearbox torque calculation model is established by combining the counterbalance effect with the calculated dynamometer cards and torque factors.The application characteristics of this model are demonstrated by the example of ZH002-4 well in Qinshui basin.The interpretations of results show that the cranks of beam units should rotate in a counter clockwise direction viewed with the wellhead to the right.Compared with oil？gas fields,the dynamic and friction to polished rod load ratios are relatively high and the computation of polished rod loads should involve the static and inertial loads,as well as vibration and friction loads.And the dynamic load ratio decreases rapidly during the production.Besides,the total deformation of the string is small in CBM wells.As for balanced operation,the gearbox torque load usually has two approximately equal peaks and the magnitudes of instantaneous torque are just within 50% of unbalanced gearbox loadings.The proposed research improves efficiency of the pumping system,loads the pumping unit more uniformly,and provides the reasonable basis for selecting the units.

Adaptive fault diagnosis of sucker rod pump systems based on optimal perceptron and simulation data

A highly precise and timely diagnosis technology can help effectively monitor and adjust the sucker rod production system(SRPS)used in oil wells to ensure a safe and efficient production.The current diagnosis method is pattern recognition of a dynamometer card(DC)based on feature extraction and perceptron.The premise of this method is that the training and target data have the same distribution.However,the training data are collected from a field SRPS with different system parameters designed to adapt to production conditions,which may significantly affect the diagnostic accuracy.To address this issue,in this study,an improved model of the sucker rod string(SRS)is derived by adding faultparameter dimensions,with which DCs under 16 working conditions could be generated.Subsequently an adaptive diagnosis method is proposed by taking simulated DCs generated near the working point of the target SRPS as training data.Meanwhile,to further improve the accuracy of the proposed method,the DC features are improved by relative normalization and using additional features of the DC position to increase the distance between different types of samples.The parameters of the perceptron are optimized to promote its discriminability.Finally,the accuracy and real-time performance of the proposed adaptive diagnosis method are validated using field data.

Analytical model for thermal lensing and spherical aberration in diode side-pumped Nd:YAG laser rod having Gaussian pump profile

In this paper, according to the temperature and strain distribution obtained by considering the Gaussian pump profile and dependence of physical properties on temperature, we derive an analytical model for refractive index variations of the diode side-pumped Nd：YAG laser rod. Then we evaluate this model by numerical solution and our maximum relative errors are 5% and 10% for variations caused by thermo–optical and thermo–mechanical effects; respectively. Finally, we present an analytical model for calculating the focal length of the thermal lens and spherical aberration. This model is evaluated by experimental results.

Multiple fault diagnosis of down-hole conditions of sucker-rod pumping wells based on Freeman chain code and DCA

It is important to achieve continuous, stable and efficient pumping well operation in actual oilfield operation. Down-hole pumping well working conditions can be monitored in real-time and a reasonable production scheme can be designed when computer diagnosis is used. However, it is difficult to make a comprehensive analysis to supply efficient technical guidance for operation of the pumping well with multiple faults of down-hole conditions, which cannot be effectively dealt with by the common methods. To solve this problem, a method based on designated component analysis （DCA） is used in this paper. Freeman chain code is used to represent the down-hole dynamometer card whose important characteristics are extracted to construct a designated mode set. A control chart is used as a basis for fault detection. The upper and lower control lines on the control chart are determined from standard samples in normal working conditions. In an incompletely orthogonal mode, the designated mode set could be divided into some subsets in which the modes are completely orthogonal. The observed data is projected into each designated mode to realize fault detection according to the upper and lower control lines. The examples show that the proposed method can effectively diagnose multiple faults of down-hole conditions.

Novel sucker rod pumping system based on linear motor technology

Obtaining petroleum at the cost of electrical energy is a common problem in almost all oil fields, and it is mainly caused by low duty radio of induction motor used in beam pumping units. Traditional beam-pumping units have many intrinsic disadvantages such as low efficiency, complex transmission devices, poor flexibility, tremendous volume and weight in long stroke, etc.Therefore, a novel direct driven linear electromagnetic pumping unit (EMPU) has been developed by combining oil extraction technology with linear motor technology. The thrust of EMPU matches the changing of suspension center load to improve the system efficiency and cut down the consumption of energy. Based on previous experience, a small-scale prototype was developed and a simulation was conducted with it. Both theoretical analyses and experimental study showed that the problems exiting in beam pumping units can be solved with EMPU system, and this is a new method which can be used to solve high energy waste in oil fields.

注氮气机抽防腐防垢一体化管柱的研制与应用

针对塔河油田注氮气机抽井井筒及井下工具严重腐蚀结垢,易造成抽油泵卡泵、封隔器解封困难等井下故障的问题,在现有技术的基础上,优化改进结构、技术创新,研制了一种注氮气防腐防垢机抽一体化管柱。该管柱包括注气防垢杆式泵、防腐封隔器等关键工具,注气防垢杆式泵优化改进了柱塞和泵筒的结构,泵筒上部设计注气孔、下部设计封堵筒,柱塞下部设计密封堵头,注气时柱塞下部堵头将进油通道密封,能防止高压油液倒灌进入泵腔发生腐蚀结垢,消除柱塞下放失败的风险;防腐封隔器采用新型护肩式的胶筒组件及双“O”型圈、双向支撑密封结构、分级解封机构和分体式双向卡瓦锚定结构,提高封隔器胶筒的耐腐蚀性能、降低上提解封力和保证卡瓦锚定性能。经过理论校核和室内模拟试验均满足现场需求,现场应用表明,该管柱坐封、解封及注气均正常,转采成功率100%,满足开发需求,解决了注气腐蚀结垢卡泵和封隔器解封困难的工程难题,具有很高的推广价值。

基于机理仿真的抽油机有杆泵举升系统生产参数优化设计

基于传统经验法和预测模型法的抽油机有杆泵举升系统设计方法在实际应用中要么过于简单要么过于复杂,设计方案的可靠性还有待提升。因此,应用大数据驱动技术从海量抽油机井举升系统设计方案中探索规律,推荐以提高产量和节能降耗为目标的抽汲参数优化设计最优方案,将提升抽油机井举升系统设计方法的科学性和可操作性。文章分析了抽油机井产量主控因素,将软件仿真和现场获取的抽油机井举升系统设计样本进行聚类分析融合得到新的样本库,建立了抽油机井举升系统设计方案的深度学习模型,研究了基于匹配算法的方案相似度模型,开发了抽油机井有杆泵举升系统生产参数设计推荐系统。根据实例计算验证,该系统能够根据待设计井的地质特征和开发特征,从海量样本中匹配到与地质油藏条件相似度高且运行效果良好的举升设计方案,推荐方案的举升参数及举升效果与原有方案相比有较大的提升,证明了计算模型的实际可行性,为抽油机举升系统优化设计提供了新思路及方法。

齿轮齿条复合曲柄连杆机构的长冲程往复泵仿真及分析

曲柄连杆往复泵在石油钻采行业中应用广泛,但因为冲程短、冲次高、易损件寿命短等缺陷,限制了其进一步发展。文中针对上述缺陷提出了一种基于齿轮齿条和曲柄连杆的复合机构,将传统往复泵中的十字头结构替换为直齿圆柱齿轮,配合固定的上齿条和移动的下齿条,实现了活塞的长冲程往复运动。建立了活塞的运动方程,使用该复合机构的三缸往复泵动力学仿真模型,探究了在负载下活塞的运动特性和齿轮齿条的动力学特性,并对齿轮进行了疲劳分析。结果表明:新型往复泵活塞冲程比相同曲柄半径的传统往复泵增大了1倍,流量脉动率不会增大但脉动频率降低1倍,有效减少泵阀的开关次数,能较大地延长易损件的使用寿命;齿轮的疲劳寿命可以达到13000 h以上。研究结果证明了该复合机构的可行性,为后续产品的开发提供了理论支持。

“互联网+”螺杆泵智能直驱装置系统节能增效

基于“信息化、节能降耗、安全环保”为目的,联合研制“互联网+”螺杆泵智能直驱装置系统。该系统由螺杆泵交流永磁直驱同步电动机、螺杆泵数字化变频控制柜和抽油杆柔性防反转电磁制动器等组成。智能化程度高,运行稳定,提效增产。该装置系统在胜坨油田14口螺杆泵采油井进行替换试验,2021—2023年共节电29.4862×10^(4)kWh,节能率为19.93%,节能降耗效果好。

基于长短时记忆神经网络的抽油机井故障智能预警

准确预测抽油机井故障对油田生产具有重要意义。针对新疆油田某区块抽油机井故障情况,统计了500口油井的生产数据,明确了结垢、结蜡、杆管腐蚀、杆管疲劳、杆管偏磨5种引发抽油机井故障的主要因素;基于长短时记忆神经网络(long short-term memory networks,LSTM),构建了油井故障智能预警模型;筛选出影响油井故障的14种特征参数进行小波降噪处理,借助自适应矩估计算法对模型进行训练与测试。研究结果表明,模型预测准确率为96.81%,能够为油田提供较为准确的抽油机井故障预警信息。

基于Laplacian正则和协同训练的抽油井故障诊断方法

单一视角下部分不同类型的工况样本相似会导致故障诊断准确率不高、无标记样本未被使用等问题,为进一步提高有杆泵抽油井故障诊断准确率,有效利用无标记样本,充分利用示功图和电功率两种数据,采用Laplacian正则和协同训练算法设计了抽油井故障诊断方法。首先,将Laplacian正则引入到协同训练模型中,以提高初始分类器精度;其次,以示功图和电功率作为特征视角,利用三层小波包变换提取视角特征,使用特征数据训练出对应的初始分类器,两者之间交换未知信息并更新分类器,提高模型的精确性;最后,应用该方法对某采油厂抽油机井的6种典型工况进行识别,并与标准协同训练、有监督学习方法进行比较。结果表明:在有标记样本较少时,该方法识别准确率优于仅使用示功图的SVM、仅使用电功率的SVM、标准协同训练,分别提高了约23.4%、20.83%、3.42%,验证了该方法的有效性。

抽油杆防腐技术浅析

随着油田开发进入中后期的高含水阶段和复杂的井液腐蚀介质,导致抽油杆腐蚀疲劳断脱的情况频发。通过对抽油杆腐蚀现象及原因的扼要分析,总结论述了材料提升、井液改善、表面防护三个方面七类防腐技术,为防腐技术选择提供指导。有效的防腐技术将大幅延长抽油杆安全运行时长,减少检修或事故处理频次,从而提高采油的综合经济效益。

抽油机光杆防腐装置的设计应用策略

油田进入到高含水期后,抽油机的光杆会与液体接触遭到腐蚀,导致抽油机光杆上形成比较多的沟槽或者麻点,容易造成光杆损坏,引发油水渗漏,影响生产质量与后期清洁。本文主要对抽油机光杆的防腐机理进行分析,并探究相应的设计策略,促进抽油机光杆防腐工作的优化。

抽油杆断裂原因

某油田抽油杆频繁发生断裂现象。采用宏观观察、化学成分分析、力学性能测试、金相检验、扫描电镜及能谱分析等方法分析了抽油杆断裂的原因。结果表明:该抽油杆的断裂性质为腐蚀疲劳断裂;采用深抽工艺后,抽油杆承受较大的拉伸载荷,增大了抽油杆的平均应力,缩短了抽油杆的疲劳寿命;油井中含有硫化氢,对抽油杆外壁产生腐蚀作用,导致抽油杆外壁产生腐蚀坑,腐蚀坑底部应力集中程度较大,在交变载荷作用下,腐蚀坑底部产生微裂纹,微裂纹不断扩展,最终导致抽油杆断裂。

某煤岩气井聚乙烯内衬复合油管螺纹脱扣原因分析

某煤岩气开发区块为了避免“定向井”对有杆举升系统造成偏磨及结垢影响,采用高密度聚乙烯(HDPE)管材内衬于油管内部组成复合油管柱。该区块某井“二次”油管入井作业,第40支油管入井时,油管柱坠落井底。随即采用打捞作业、宏观测量、螺纹检查、材质分析、力学性能测试、显微组织分析、水质测试、腐蚀产物XRD分析等方法,综合同批次该油管质量抽检结果及制造工艺,对失效螺纹端进行分析。结果表明:制造时接箍与管体上扣扭矩不足,导致螺纹间产生缝隙腐蚀,在腐蚀性介质作用下螺纹连接处腐蚀严重,失去连接作用,致使承载力不足,油管柱落入井底。建议内衬复合油管制造及入井作业时,参考GB/T 17745—2011标准对工厂端及现场端上扣扭矩进行控制,同时使用专用螺纹脂保证工厂端和现场端的螺纹连接效果。

2400hp五缸钻井泵机壳有限元分析

五缸钻井泵已成为油气钻探的核心装备。为研究其强度性能和使用可靠性要求,以2400hp五缸钻井泵为例,建立其关键零部件——机壳的有限元模型,并对其受力情况进行理论分析,进而利用Simulation模块对机壳进行有限元分析,得到相应应力和变形大小,最后通过计算与实际材料性能要求进行对比分析,得出机壳结构满足设计合理性要求的结果,为机壳的设计与优化提供参考。