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.

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.

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.

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.

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.

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.

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。

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。

Fluid characteristic of multiphase fluid in annular space between pump barrel and plunger

The pump performance parameters,such as pump pressure,plunger friction and pump valve resistance,are fundamental parameters of optimal design of pump efficiency and sucker rod pumping system (SRPS).In this paper,considering the characteristic of geometrical nonlinear and rheology property of multiphase fluid,the pump performance parameters are studied.Firstly,a dynamics model of annular fluid flow is built.In the detail,a partial differential equation of annular fluid is established and a computing model of fluid pressure gradient is built.Secondly,the simulation models of plunger friction and hydraulic resistance of pump valve are built.Finally,a novel simulation method of fluid pressure in annular space is proposed with software ANSYS.In order to check up the correction of models proposed in this paper,the comparison curves of experiment and simulation results are given.Based on above model,the whole simulation model of plunger pump is simulated with Visual Basic 6.0.The results show that the fluid friction of pump plunger and instantaneous resistance of pump valve are nonlinear.The impact factors of pump performance parameters are analyzed,and their characteristic curves are given,which can help to optimize the pump motion parameters and pump structural.

同井注采工艺技术及其矿场应用

目前高含水老油田的年产油量在中国年产油量的占比在70%以上,要保持稳产就必须要保证高含水老油田产量稳定的开发需求,为了满足这一现场需求,通过完善回注层段分层注水技术、不动管柱实施增注工艺以及同井注采采出层及回注层参数录取方法,大庆油田提出了一种结合高效井下油水分离、桥式封隔器等工艺的有杆泵同井注采技术。结果表明:同井注采技术在不打新井的情况下可有效增加油水井对应连通方向、增加注水层点和提高波及体积;同时能够将同一区块分采的2套或多套层系构建起一套立体高效开发层系,使大部分水不举升到地面而直接在地层内部循环驱替。现场试验表明,试验区平均单井产液量降低了94.5%,综合含水率下降了34.1%;地下回注注水单耗降低了83.0%;井下管柱平均工作寿命可增加到1.5 a以上。研究成果能够有效提高油井产量、降低开采成本、提高采收率,实现了超过目前“极限含水”条件下继续经济、有效的开采,对老油田长期持续稳产具有重要意义。

Alternating Current Heating Technique of Hollow Rod

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无储能光-电微网下的抽油机井群间抽混合整数非线性优化方法

多数低渗透油藏丛式井因供液不足而采用间抽采油方式,光伏、风电等绿电引入油田生产后在减少碳排放方面发挥了重要作用。为解决人工制定的错峰开井和间抽制度存在的井群运行能耗高等问题,以各抽油机的启停状态和电源频率,以及各光伏机组和高压电网的出力为决策变量,用直流母线实现抽油机组倒发电电能互馈,根据井群生产需求充分考虑源荷端约束,以系统运行成本最低为目标,建立一种无储能环节光-电微网下的错峰开井和间抽运行的混合整数非线性模型,用Gurobi对该问题求解。案例分析结果表明,所建模型求解结果与高压电网供电下井群常开以及人为制定间抽制度比较,井群耗电量分别降低35.687%和15.219%,系统运行成本分别降低35.471%和23.884%,并且相较于后者井群日产量提高21.620%。研究将光伏引入抽油机间抽系统,建立调度模型,大幅降低井群运行能耗和运行成本,凸显了模型的有效性。

抽油机井原油产量计量新方法

产量计量是油田开发生产过程中最重要的基础工作之一,准确的计量结果对于抽油机井工作状态诊断、工作制度调整以及措施方案效果评价都具有重要意义。但传统两相分离式量油和功图量油技术普遍存在投资和维护成本高、自动化程度低、适应性差等问题。为了提高量油效率和精度,利用深度学习技术,以生产大数据样本做支撑,建立电参量油模型,提出了由有功功率数据直接计算产量的新方法。电参量油模型包含特征提取模块和参数融合模块,分别由双层GRU网络和三层全连接网络组成。特征提取模块获取有功功率曲线数据中的生产参数信息,参数融合模块实现了冲程、冲次和泵径特征与有功功率数据挖掘结果的信息融合,提高了电参量油模型的准确性和泛化性。实例井验证结果表明,油井工况越好,实际产量越高,预测产量的精度越高,平均预测精度为94.08%。该研究成果为油井计量开创了新思路,为低成本智能油田建设提供了技术支撑。

抽油机井立体优化节能技术应用

随着油田进入开发后期,供排关系不合理的抽油机井数量多、举升能耗高等问题日益突出,为进一步降低抽油机井举升能耗,开展了抽油机井立体优化节能技术研究并进行现场应用。在满足抽油机井目标产液量的前提下,合理匹配设计管径、泵径、泵深、杆柱钢级、杆柱组合、冲程、冲次等参数,结合油井实际生产运行状态,实施相应节能优化措施,挖掘地面和井下节能降耗潜力。通过对3743口抽油机井实施立体优化节能技术,平均系统效率提高3.1个百分点,节电率达9.42%。现场应用结果表明,抽油机井立体优化节能技术对于实现抽油机井高效运行,进一步降低举升能耗具有重要意义。

大港南部油田有杆泵井偏磨机理探讨及综合防治

大港南部油田部分油井抽油杆和油管偏磨严重,造成抽油杆断脱、油管漏失及频繁作业,严重影响了油田的正常生产。通过对165口因杆管偏磨造成抽油杆断脱、油管漏失的井进行调查分析,结合抽油杆下行阻力理论计算,发现造成杆管偏磨的主要原因是高冲次、高含水、低沉没度导致抽油杆下行弯曲和井斜变化大。结合生产实际提出了抽油杆底部集中加重、中性点扶正、配套应用大流道泵减少抽油杆下行弯曲;底部减少加重、偏磨段连续扶正、上部延伸保护和井口旋转减少井斜偏磨;确定合理的生产参数减少杆柱共振等综合配套防治技术。现场应用表明,提出的方法可有效地改善大港南部油田偏磨现象。

利用低摩阻柱塞抽油泵提高泵效及防偏磨技术的应用

大庆油田杆管偏磨井数逐年增多,严重影响了聚合物驱采油效果和规模应用。对杆柱屈曲的原因、规律和偏磨状态以及偏磨机理进行了分析,研制并应用聚合物驱低摩阻柱塞泵解决了摩阻小、漏失量也小的难题。实施了防偏磨配套技术,研制了3种杆串在线测试仪,解决了杆管偏磨的问题,延长了杆管工作寿命,提高了泵效。

优化抽油机井系统设计技术的应用与展望

为了提高抽油机井系统效率,华北油田从2002年起,开展了"抽油机井系统优化设计方法研究与现场应用"的课题研究,利用参数敏感性分析法建立了以"产量、效率、寿命"三者统一为原则的优化设计方法,实现了从提高抽油机井系统效率(SysEff)软件向优化抽油机井系统设计软件(OPRS)系统的转化,5年来OPRS系统在华北油田实现了规模应用,已成为油田节能、提高油井管理水平的重要技术。

抽油机井泵效影响因素之主成分分析法

提高抽油机井泵效是油井管理的一项重要工作,由于影响抽油机井泵效的因素很多,不同因素之间相互影响,因此通过某一个或少数几个因素对泵效的影响进行评价时存在一定的局限性。为了科学地确定各个因素的主次关系,避免主观随意性带来的偏差,采用主成分分析法,对影响抽油机井泵效的众多因素进行分析。选取16个原始指标,应用SPSS分析软件进行计算,从中提取了7个主成分,综合分析表明:地层能量、油藏条件、原油性质、生产参数、井身轨迹、管杆泵匹配及抽油机平衡度是主要因素。

抽油机井杆、管防偏磨工具优选与应用

为了对油井杆、管偏磨进行有效的治理,对近三年应用的多种防偏磨工具按照技术评价、使用效果、性价比以及质量保证的评价方法,从结构、材质、质量等方面优选出了双向耐磨接箍、叶片扶正器、玻璃内衬管等应用效果较好的防偏磨工具。在结合偏磨机理分析和治理对策的基础上,针对高液量和低液量斜井、稠油、高含蜡斜井等井况制定了相应的综合配套措施并进行了现场推广应用,实现了短周期井的有效治理,为今后井下工具实行优胜劣汰提供了一条有效的途径。