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.

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.

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.

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.

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.

Dynamic simulation and efficiency analysis of beam pumping system

An improved whole model of beam pumping system was built. In the detail, for surface transmission system(STS), a new mathematical model was established considering the influence of some factors on the STS's torsional vibration, such as the time variation characteristic of equivalent stiffness of belt and equivalent rotational inertia of crank. For the sucker rod string(SRS), an improved mathematical model was built considering the influence of some parameters on the SRS's longitudinal vibration, such as the nonlinear friction of plunger, hydraulic loss of pump and clearance leakage. The dynamic response and system efficiency of whole system were analyzed. The results show that there is a jumping phenomenon in the amplitude frequency curve, and the system efficiency is sensitive to motor power, pump diameter, stroke number, ratio of gas and oil, and submergence depth. The simulation results have important significance for improving the efficiency of beam pumping system.

Alternating Current Heating Technique of Hollow Rod

ＡｌｔｅｒｎａｔｉｎｇＣｕｒｒｅｎｔＨｅａｔｉｎｇＴｅｃｈｎｉｑｕｅｏｆＨｏｌｌｏｗＲｏｄ￥ＮａＷｅｉｓｈｅｎｇａｎｄＳｈｉＴｏｎｇｈａｏ（Ｓｕｒｖｅｙ＆ＤｅｓｉｇｎＩｎｓｔｉｔｕｔｅ，ＬｉａｏｈｅＯｉｌｆｉｅｌｄ）Ｋｅｙｗｏｒｄｓ：Ｃｒｕｄｅｏｉｌ...

多指标排序优选抽油井工作参数软件研发

针对原有抽油机井工作参数软件与采油生产实际结合不够紧密、使用不方便的问题,经过技术攻关研发出多指标排序优选抽油井工作参数软件。首先确立以产液量指标为主、井下效率指标为辅、安全指标可靠的优选抽油井工作参数的设计思路,其次是建立以产液量计算为核心的系统算法。应用工程计算和经验公式相结合的方法,通过抽油泵沉没压力使供液量与排液量建立联系,将与供液量接近的排液量作为产液量,进而计算出井下效率、悬点载荷和抽油杆负载率。对所有“泵径、冲程、冲次”组合的优势产液量和优势井下效率及其对应的指标和下泵深度以列表方式输出,对所有指标与井下效率的关系以曲线方式输出,经过排序对比即可挑选出各项指标均占优势且稳定可靠的抽油井工作参数组合,实现抽油井工作参数优化设计的目标。该软件自2017年应用以来年均指导调参130井次,平均单井增产原油63.54 t,提高井下效率3.2%,取得了显著的应用效果。

抽油杆偏磨机理及防偏磨技术研究现状

在石油开采过程中,有杆泵是目前应用最广泛的人工举升方法之一。有杆采油系统在石油和天然气行业中被认为是一项成熟的技术,具有易于应用、使用成本低等优势,在世界范围内应用普遍。但在实际运行过程中,抽油杆与油管之间的偏磨问题较为严重,由此带来的经济损失较大。通过对抽油杆产生偏磨的原因进行分析,总结了五大类最新的防偏磨技术,并提出了现有技术的发展方向,以期对生产实践起到一定的指导作用。

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。

“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。

有杆抽油系统效率分析及抽汲参数优化设计

针对有杆泵往复抽汲采油方式使用广泛,但系统效率较低的实际情况,对有杆泵抽油系统进行了能量消耗分析,以机械采油系统效率最高为目标,确立了机械采油系统优化设计的目标函数和约束条件,给出了有杆泵抽油时机、杆、泵及抽汲参数的优化设计方法。该方法可应用于机抽油井的参数优化和新投产井的优化设计。胜利采油厂的应用实例表明,参数优化后油井的系统效率提高了11.6%,降低了综合成本,提高了经济效益。

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。

提高机械采油系统效率的理论研究及应用

提出了将有杆泵抽油系统输入功率划分为有效功率、地面损失功率、井下粘滞损失功率、井下滑动损失功率、溶解气膨胀功率 5部分的新观点 ,找出了各部分功率的影响因素 ,并确定了其函数关系。建立了油井在各种不同物性参数、井斜参数、设备参数、生产参数组合条件下所对应输入功率的数学计算公式 ,提出了以能耗最低或以成本最低为原则的确定机采参数的新方法。据此找出的最经济机采参数组合能大幅度提高机采系统效率 ,从而实现经济采油的目标。

斜直井有杆泵抽油系统井下工况诊断技术

本文根据动力学原理，考虑井眼轨道、抽油杆柱构成、抽油杆与油管的滑动磨擦力及油液的内摩擦力，采用微元矢量分析方法，建立了定向水平井抽油杆柱纵向振动的微分方程，给出了井下动态参数诊断的定解条件。建立了该模型的差分解，编制了计算机软件，并在大庆油田采油五厂得到了较成功的应用。

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。