Inter-stage performance and energy characteristics analysis of electric submersible pump based on entropy production theory

The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance.

Energy Consumption Analysis and Optimization of Electric Submersible Pump System

Electric submersible pumps account for a considerable proportion in the development of the Bohai Oilfield. Improving the system efficiency of the electric submersible pump wells, ensuring that the units operate in the high-efficiency zone, is essential. Analysis shows that the efficiency of the electric submersible pump system depends on the wear and tear of each component of the submersible pump equipment, the setting of operational parameters, and more importantly, the production status and daily management level of the oil well. Therefore, improving the structural performance of the submersible pump product, optimizing the parameters setting of the oil well, strengthening daily management, establishing a scientific management system, and improving the production management process and system can effectively improve the production efficiency and economic benefits of the oil well, and further achieve the goal of energy saving and emission reduction. In addition, it is necessary to actively promote the concept and technology of energy saving and emission reduction, encourage oilfield enterprises to explore effective measures to reduce the energy consumption of the electric submersible pump system by strengthening the scientific management system, and achieve a green, low-carbon, and high-quality development of oilfield production to achieve the unity of economic benefits, social benefits, and environmental benefits. This article applies the above measures in the P oilfield to achieve energy optimization of submersible electric pump systems, reducing the daily power consumption of single well submersible electric pump systems by 371 kWh per day, increasing the submersible electric pump's lifespan by 200 days, generating considerable project benefits.

Pressure pulsation in stages of electric submersible pump at shut-off under various speeds

Electric submersible pumps were widely used in agricultural fields,petroleum and various other industries. The pressure pulsation caused fatigue failure due to vibration in electric submersible pump and affects the life and performance of its system. The objective of this study was to experimentally investigate the characteristics of pressure pulsation which were generated at various stages of a multistage electric submersible pump during closed valve operation at different speeds. An electric submersible pump with five stages was selected for conducting experiments. A variable frequency drive( VFD)was used to operate the electric submersible pump at five different speed settings from 40 to 60 Hz. Piezoresistive pressure transducers were mounted at each stage of the electric submersible pump to capture the unsteady pressure signals. At each speed setting,the electric submersible pump was operated at the shut-off condition and the signals of unsteady pressure from all the five stages were captured. A fast fourier transformation( FFT) was carried out on the pressure signals to convert into frequency domain.From the spectra of pressure pulsation signals,the characteristics of pressure pulsation are obtained for each stage and for various speed settings which were then used to understand its variation with speed and stages.

Development and Application of a Surface High-pressure Injection Device Using a Submersible Electric Pump

Injection recovery is an important measure for increasing the oil recovery rate of an oil field. One way is that centrifugal pumps or plunger pumps are used in an injection station to responsible for injection over a large area under the same pressure. This method is ineffective for low-permeability layers. For the oilfields in dispersed distribution in the marginal areas of Daqing, the low water-absorbing section needs an injection with a high delivery pressure and a low discharge capacity; another way is to install the submersible electric pump upside down, but because the submersible electric pump and the motor are underground, it is difficult for installation and maintenance. Introduced in this paper is the development and application of a surface high-pressure injection device with a submersible electric pump. Bysuccessful resolving some problems, such as the axial force of the submersible electric pump, sealing, level regulation of the pump, coaxiality and vibration, the device has the good points of running smoothly, moving easily, installation and maintains quickly and long period of running. This device can effectively solve the injection of the low water-absorbing section and of oilfields in dispersed locations. The recovery rate of oilfields is also enhanced.

Effective Electrical Submersible Pump Management Using Machine Learning

Artificial lift plays an important role in petroleum industry to sustain production flowrate and to extend the lifespan of oil wells. One of the most popular artificial lift methods is Electric Submersible Pumps (ESP) because it can produce high flowrate even for wells with great depth. Although ESPs are designed to work under extreme conditions such as corrosion, high temperatures and high pressure, their lifespan is much shorter than expected. ESP failures lead to production loss and increase the cost of replacement, because the cost of intervention work for ESP is much higher than for other artificial lift methods, especially for offshore wells. Therefore, the prediction of ESP failures is highly valuable in oil production and contributes a lot to the design, construction and operation of oil wells. The contribution of this study is to use 3 machine learning algorithms, which are Decision Tree, Random Forest and Gradient Boosting Machine, to build predictive models for ESP lifespan while using both dynamic and static ESP parameters. The results of these models were compared to find out the most suitable model for the prediction of ESP life cycle. In addition, this study also evaluated the influence factor of various operating parameters to forecast the most impact parameters on the duration of ESP. The results of this study can provide a better understanding of ESP behavior so that early actions can be realized to prevent potential ESP failures.

气液两相条件下叶片开孔对电潜泵性能和内部流场的影响

为了研究电潜泵内部流动机理,从而改善高含气工况下电潜泵的气液混输性能,文中基于欧拉-欧拉非均相流模型,对不同入口含气率工况下叶片开孔前后的气液两相流动特性进行了数值模拟分析,探究了气液两相流条件下叶片开孔对电潜泵性能和内部流场的影响.结果表明,在纯水工况以及低含气率、小流量工况下,叶片开孔会降低电潜泵性能;但是叶片开孔可以改善电潜泵在大流量下的气液混输性能.叶片开孔后会改变叶轮内部压力分布,使电潜泵叶轮内部平均压力升高,进而改善叶轮内部流态.叶片开孔后会冲散气相聚集,使气体分布更加均匀,叶轮流道内涡核分布明显减少,减少了能量耗散.该研究为改善电潜泵气液混输性能提供了理论依据.

煤层气L型水平井电潜螺杆泵井清防砂工艺技术创新及应用

套管完井压裂投产的煤层气L型水平井出砂严重,倒置式电潜螺杆泵举升工艺受压裂砂影响故障频繁,影响了连续稳定排采,因此确定了倒置式电潜螺杆泵排采过程中由于压裂砂导致的故障点,并针对性创新应用了井筒内、导流罩及泵内清砂工艺技术,同时优化防砂管柱设计,确保了连续稳定排采。

地浸采铀工艺中电潜泵内流场数值模拟研究

电潜泵是我国地浸采铀工艺中实现浸出液有效提升的主要装备,但目前针对介质举升状态下电潜泵水力部件内部流场作用机制的研究较少。试验以叶轮-导叶内部结构为研究对象,应用CFD方法对介质流动特性开展非定常分析,研究了叶轮和叶轮出口段内部的压力脉动变化规律,并利用瞬态流场数据对叶轮截面压力流场进行动模态分解(DMD)与压力流场重构,揭示了介质举升状态下由动静干涉引起的压力脉动周期性变化规律与动静部件距离对动静干涉强度的影响规律。结果表明,叶片通过频率值与快速傅里叶变换(FFT)频率值基本一致。试验结果可对减少由压力脉动引发的泵体无效震动、优化电潜泵水力部件结构参数和提升系统效率提供一定理论参考。

新型潜油电泵轴承支持架拆装装置的研究与应用

潜油电泵在油田机械采油方面应用非常广泛,由于长期在井下工作,潜油电泵结垢腐蚀、磨损现象严重需要进行检维修,但在机组拆卸时,存在轴承支持架拆卸困难、员工劳动强度大、工作效率低等问题。由移动平台(移动小车、启动柜、电动机、减速机、安全护罩、机械手)和固定平台组成的潜油电泵轴承支持架拆装装置,作业中改变了拆卸方式,移动平台的电器部分,实现拆装自动化,解放了人工,机械手定位准确,综合消减了人工操作带来的安全隐患,固定平台支撑稳固牢靠,均达到安全操作目的。应用于1000余台次的潜油电泵轴承支持架拆装维修,累计创效42.6万元,该项探索提高了安全操作系数和工作效率,对同类设备拆装作业具有良好的借鉴意义。

出砂油井潜油电泵叶轮结构优化

潜油电泵应用于出砂油井时,砂粒对离心泵叶轮磨损严重,导致增压性能降低,甚至机组失效。为了明确叶轮磨损规律,优化叶轮结构参数,开展了含砂条件叶轮磨损特性仿真分析。建立了全尺寸离心泵几何模型,利用六面体结构化网格进行网格划分,基于CFD数值模拟技术,优选RNG k-ε湍流模型和离散相模型模拟固-液两相流场,以冲蚀磨损率为评价指标,通过SIMPLEC算法进行求解。实验采用正交设计方法,解决多因素敏感分析的交互影响。结果表明:出口宽度对叶轮磨损影响最大,叶包角、入口宽度和叶片数次之,出口宽度越大,冲蚀磨损率越小。最优叶轮结构参数为出口宽度21.1 mm、叶包角90°、叶片数10、入口宽度13.6 mm,相比于原泵型叶轮结构,新叶轮几何形态更发散。研究成果对同类油井泵型选择提供了参考依据,也为潜油电泵制造商开展防砂优化设计提供了理论支撑。

电潜离心泵内流场及外特性的数值模拟分析

针对目前油田使用的两种不同叶导轮结构的电潜离心泵,包括传统径向流泵和聚驱用混向流泵,采用计算流体动力学(CFD)研究方法,建立电泵内流场的数值仿真,在流量80~200m^(3)/d范围内,研究泵输送不同运动黏度为1~40mm^(2)/s介质时特性差异。在介质黏度为1和40mm^(2)/s,流量为80~180m^(3)/d工况下,使用FLUENT软件选用标准k-ε湍流模型和SIMPLE算法进行求解,分析两种泵在不同工况下的内部流场变化规律,通过流场分析探究叶轮结构对泵外特性的影响机制。仿真得到泵的扬程、效率曲线,发现泵性能出现变化的工况点与叶轮内流场分析结果相对应,并根据泵叶轮的内流场分布和泵的性能曲线分析两种泵所适用的工况。结果表明,径向流泵适用于大流量和高黏度工况,混向流泵适用于较低流量和中低黏度工况,为不同工况下泵的选择及泵的优化提供理论依据。

电潜螺杆泵入口处气液比动态变化特性分析

随着油田开发的不断深入,螺杆泵采油技术得到进一步发展与完善,近年来,在高含气和稠油等非常规油气藏中也得到广泛应用,但由于游离气和溶解气的存在,气体进入泵内会影响螺杆泵的工作性能和使用寿命。针对这种情况,综合考虑油气水三相流体对螺杆泵运行工况的影响,结合钻井液密度、生产气油比、含水率和气体状态方程,建立了螺杆泵入口处的气液比计算模型,并以大港油田J36-6和J36-8油井的生产数据进行模拟分析。结果表明,在动液面高度一定的情况下,增加下泵深度有利于降低泵入口处的气液比,高密度、高含水和低生产气油比是保证泵入口气液比较低的关键。

电潜泵气液两相流工况水力增压性能预测模型

电潜泵自20世纪以来广泛应用于海上和非常规油气田,来提高油井的生产效率,是一种革命性的油田生产方法,主要适用于自然压力和能量不足的井。潜水离心泵最初是用于抽取矿井中积水而开发的。阿迈斯·阿鲁图诺夫开发了第一台用于油井生产的电潜泵。此后电潜泵逐渐在石油行业中广为人知并流行起来。然而,电潜泵对流动条件非常敏感,为了提高其耐受性、效率、可靠性以及适应恶劣和复杂的井下流动条件,电潜泵经历了许多重大的技术改进。目前电潜泵通常由电动机、密封和一系列离心泵级组成,非常适合于高产的深井和偏斜井中,也常用于非常规井,如页岩油井。因此,电潜泵的耐气性、粘度影响以及长期开采能力已经引起了重大关注。由于其内部流动规律复杂,两相混输风险高,高粘/气液两相流工况下耐受极限和长效开采能力受限,严重制约了电潜泵在深水和非常规油气田安全高效开采中的运用。本文基于欧拉方程,利用最佳流速概念推导回流、摩擦和泄漏等损失,提出了适用于井下旋转电潜泵复杂工况下增压性能预测的理论模型。针对气液两相流动,该模型基于离心场中两相的力学分析,建立旋转叶轮内部体含气率模型,并根据流型选择曳力系数,计算两相滑移效应,修正混合相密度,进而提升扬程预测的准确性。模型预测和实验数据的对比验证了该模型预测的精度和可靠性均高于文献中常见的计算方法。本文所提出的方法可准确预测油的粘度、含水乳化液和气液流对泵性能的影响。该模型可帮助泵工程师开发新的电潜泵几何形状,同时帮助人工举升工程师改进油井完井举升工艺设计。

不同级数电潜泵失速演化及级间差异性研究

当电潜泵在小流量工况下运行时会出现失速现象,并出现一系列的负面影响,严重影响机组的安全性和稳定性。为了研究失速工况下电潜泵内部的旋涡演化及其级间差异性,文中对单级、两级和三级电潜泵进行数值模拟研究,重点讨论了设计工况、临界失速及深度失速工况下电潜泵的内外特性。结果表明:在设计工况和临界失速工况下,首级叶轮流道内部出现多个旋涡结构,次级与末级叶轮内流动顺畅。在深度失速工况下,单级、两级和三级电潜泵首级叶轮内部均存在着大尺度的回流涡,并伴随着强烈跨流道溢流现象;流道内部各种旋涡聚集糅杂形成涡团,对流道出口处产生严重阻塞。电潜泵首级叶轮进口处大尺度旋涡结构、各级叶轮同步失速以及导叶内强烈的分离涡共同导致扬程骤降,同时造成极高的能量损失。该研究为完善电潜泵设计方法提供了理论基础。

煤层气井电潜螺杆泵故障识别与治理对策

L型套管压裂水平井在低渗或深部煤层气田开发上具有很大的技术优势,电潜螺杆泵举升工艺为水平井排采的重要方式之一,具有排量大,设备占地面积小,调参方便,自动化程度高等技术优势。通过现场270余口井的排采实践,发现该类泵型存在卡泵、烧泵等5类故障,分析总结了各类故障发生前后的生产特征及原因,提出4类针对性预防及后期治理对策,研究结果为电潜螺杆泵在沁水煤层气田的稳定排采奠定了基础,同时也为其他煤层气区块的开发提供了借鉴经验。

国产变频器在海上石油平台中的应用

海上石油平台建设中的变频器应用,对变频控制效果提升有促进作用。因此,在对国产变频器在海上石油平台的应用进行研究中,根据平台设备需求,充分考虑工况、配电条件以及检修等因素对变频器应用的影响,分析国产变频器的实际应用方式,并设计国产变频器的应用方案,旨在实现国产变频器在海上石油平台中的应用效果提升。

某海上低渗油藏油井电潜泵卡泵损坏机理分析

针对某海上低渗油藏油井电潜泵故障率高情况,深入研究发现低产电潜泵井生产波动较大,电潜泵叶轮磨损严重,以及部分高含水油井存在出砂和结垢,堵塞流体通道等因素,引起电泵卡泵过载停机,提出改进电潜泵结构、合理生产制度和防垢防砂举措等方法,有效降低了电潜泵井卡泵故障率。

潜油电泵生产系统优化与实践

海上油气田多应用电潜泵采油,随着油田不断开发,油藏地质条件发生较大变化,不合理的电潜泵生产系统,导致泵效率降低、无用功增加、机采成本增加、产量下降、故障率升高。为精准预判电泵是否处于健康运行状态,在保证产量不减的前提下,做到早发现、早干预、早处理、及时调整优化电泵井生产系统,提高泵效、降低电泵功率,降低机采成本、降低潜油电泵井故障率、降低修井检泵外委费用、减少躺井时间、降低桶油成本、提高电泵井综合时率,达到降本增效、提高油气田开发的经济效益。

煤层气井排采设备适应性分析

排采设备的选择是否合理是保障煤层气井连续、稳定、合理排采的前提条件。煤层气井井型种类多,部分井轨迹复杂,采用的主要排采设备有杆式抽油泵、管式抽油泵、顶驱螺杆泵、电潜螺杆泵、水力同心型无杆泵等多种。根据不同排采设备不同的排采原理,以及它们的优缺点和适用条件,对它们在潘庄区块不同条件的煤层气井的应用情况,从检泵周期、检泵原因以及防偏磨、防煤粉、能否满足沉没度要求等多角度进行了适应性分析,总结出了考虑地面、井筒、储层、费用等多因素条件下各排采设备对煤层气井的适用条件,为潘庄区块及类似煤层气井排采设备的优选提供了重要的参考价值。

矿用气动潜水泵自动限速控制系统设计

气动潜水泵的稳定性和安全性都优于传统电动潜水泵,然而在气动潜水泵抽不到水时,会造成轻载或空载,容易出现失控现象。基于出口节流调速原理,根据液位传感器能否检测到水面,通过继电器的开/关来控制电磁阀的换向,气动潜水泵自动限速控制系统调节气动泵排气出口流量大小。这样可以限制空载状态下气动涡轮潜水泵的转速,防止空载导致的失控现象。同时在预定时间内,系统自动停止运行,有负载时自动启动,从而达到节能和减少环境污染的目的。通过模拟试验和工业试验,成功实现了气动潜水泵的自动限速,进一步提高了矿用潜水泵监测的自动化程度。