Electrical Submersible Pump Performance Research Articles

Experimental data-driven model development for ESP failure diagnosis based on the principal component analysis

AbstractThe reliable diagnosis of electrical submersible pump (ESP) failure is a vital process for establishing of the optimal production strategies and achieving minimum development costs. Although traditional ammeter charts and nodal analysis are commonly used for ESP failure diagnosis, the techniques have limitations, as it requires manpower and is difficult to diagnose the failure in real-time. Therefore, in this study, ESP failure diagnosis was performed using the principal component analysis (PCA). First, 11 types of 9,955 pieces of data were acquired from a newly constructed ESP experimental system for 300 days. During the experimental period, ESP failure occurred twice with a significant drop in performance: first on day 112 and second on day 271. The PCA model was constructed with the 8,928 pieces of normal status data and tested with the 1,027 pieces of normal and failure status data. Three principal components were extracted from the measured data to identify the patterns of the normal and failure status. Based on the logistic regression method to analyze the efficiency of the PCA model, it was found out that the developed PCA model showed an accuracy of 93.3%. Therefore, the PCA model was found to be reliable and effective for the ESP failure diagnosis and performance analysis.

Maximizing Oil Recovery in a Marginal Oilfield: Niger Delta Case Study

Marginal field development and production are often abandoned by operators because of finding reliable and available equipment and services to enable the field to be developed. These challenges make it difficult to economically produce such fields. This research demonstrates the use of industry-based simulators (PIPESIM, ECLIPSE and PETREL) to design well completion model, Electrical Submersible Pump (ESP). model, simulate, and evaluate the performance of ESP on a typical marginal oilfield. The main objective of this study is to effectively optimize oil production from marginal fields in the Niger Delta using Electrical Submersible Pump (ESP). ECLIPSE software was used for the reservoir description. PIPESIM was used to design the artificial lift system (ESP) for five oil wells and PETREL was used to integrate the whole system for effective production optimization. The performance of ESP wells was simulated and compared with the naturally flowing wells. The results obtained from the production forecast showed that the ESP wells gave superior oil production when compared to natural flowing wells. From the simulation results, it was observed that the cumulative oil recovery without ESP was 33,684,736 stb while that recovered with ESP was 87,751,136 stb (about 261% oil increment). The findings of this study will enable petroleum engineers to design ESP systems and well completion that would effectively optimize oil production from marginal fields in the Niger Delta. Furthermore, the findings of the study will offer new and exciting ways to process and transform abandon oilfields into productive marginal oilfields.

Evaluating the intake plugging effects on the electrical submersible pump (ESP) operating conditions using nodal analysis

The intake plugging of an electrical submersible pump (ESP) has presented a formidable challenge to conventional ESP wells. Attention to cumulative solid deposition is essential since it intensifies the intake plugging severity and impedes ESP performance. We present a new approach to evaluate the ESP performance degradation during increased intake plugging severity. In particular, we employ the intake plugging factor, rate-derating factor, and affinity law to calculate the new ESP speed at different plugging conditions. We used Schlumberger PIPESIM software to perform nodal analysis of the newly calculated ESP speed. The result was validated using the actual field data and compared to the field cases that reported the intake plugging issue. The nodal analysis showed a steady maximum ESP head with zero rate derating at the shut-in point. The intake plugging factor caused a significant reduction in the ESP operating rate and increased pump intake pressure and annulus liquid level. Based on the existing intake plugging field data, we established the quantitative standard for the normal and abnormal intake plugging factor range. The observed results agreed with the field downhole data recorded during the intake plugging problem. We identified that regulating the ESP speed to the reduced operating rate could minimize unexpected pump stoppage. It is also possible to carefully monitor the intake plugging problem by combining the annulus liquid level, the signature of pump intake pressure, and a deadhead test.

Effects of tip clearance on energy performance of three-stage electrical submersible pump

In order to investigate the influence of tip clearance on the energy performance of electrical submersible pump (ESP), numerical simulation and experimental study were carried out. The three-dimensional transient Reynolds-Averaged Navier–Stokes (RANS) equation is solved by using the ANSYS CFX software. The experimental results were used to verify the reliability of the numerical method. The results shown that the increase of tip clearance leads to the decrease of energy performance. The increase of tip clearance leads to a proportional drop in energy performance under part-load flow rate conditions, while the increase of tip clearance leads to a significant loss under large flow rate conditions due to increased leakage. The rotor-stator interaction between the impeller and the diffuser is the main factor for the enhanced turbulence at part-load flow rate conditions, resulting in energy losses. The maximum turbulence intensity along the axial direction in the tip clearance is 4.4 times and 4.7 times of the minimum turbulence intensity at rated flow rate 1.0Qdes and large flow rate 1.4 Qdes operating conditions, respectively. The results could be referred to predict the internal flow loss and optimize the design of ESPs.

Study Reviews ESP Performance in High-Viscosity Applications

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31839, “Understanding ESP Performance Under High-Viscosity Applications and Emulsion Production,” by Luiz Pastre, SPE, Jorge Biazussi, and William Monte Verde, University of Campinas, et al. The paper has not been peer reviewed. Copyright 2022 Offshore Technology Conference. Reproduced by permission. _ Despite its common use as an artificial lift method for heavy-oil developments, electrical-submersible-pump (ESP) system performance in high-viscosity applications is not fully understood. Failure to understand challenges to equipment performance in such conditions can lead to operational inefficiency and equipment failures. The complete paper presents results of single-phase and multiphase tests performed by researchers at the University of Campinas. It also presents operational data, lessons learned, and examples of failures gathered over 10 years of ESP operation in the Peregrino field, a highly viscous, heavy-oil field offshore Brazil operated by Equinor. Peregrino Field The field was discovered in 1994 in the southern part of the Campos Basin offshore Brazil. The discovery lies in shallow waters approximately 120 m deep in Block BM-C-7. Although a large amount of recoverable oil in place (300 million– 600 million bbl) was confirmed, the technology to properly develop the field was not available. A detailed development plan was created to optimize Peregrino heavy-oil production while considering drainage strategy and well design. Recovery and production are maximized in Peregrino by extending the reservoir section length. As a result, every well in Peregrino is drilled with a long horizontal section inside the reservoir and completed with openhole gravel-pack lower completions. This strategy resulted in the longest wells in Brazil, with a record of 8613 m measured depth (MD) total length, with 2272 m MD in the horizontal section. To improve the effectiveness of sand control and avoid solids production, gravel is pumped to fill the annular space between the 8½-in. openhole section and the 5½-in.-outer-diameter screens. Inside the reservoir, water flows at a much higher velocity than viscous crude does. Therefore, inflow control devices are deployed in the lower completion to limit water flow into the wellbore at selected wells. To make gravel-pack operation feasible in such a configuration, sacrificial screens are installed in the bottom of the lower completion string. An artificial lift method is required to produce the heavy and viscous oil from the field and maintain commercial rates when pressure support and production declines. ESPs proved to be the most-efficient method for this application.

Optimal design and performance improvement of an electric submersible pump impeller based on Taguchi approach

Electric submersible pump (ESP) is the core artificial lift equipment to pump production oil from underground or deep sea to the surface. Its energy efficiency significantly affects global oil market and energy consumption. To explore the effects of the impeller meridian profile on the hydraulic performance, a typical multi-stage ESP with medium specific speed was taken as the research object. Based on the statically determinate control of the shroud and hub profiles, eight parameters of the impeller meridian profile were selected as the key factors. By taking head and efficiency as optimization targets, 27 schemes were designed according to the Taguchi approach. The effect analysis method was employed to determine the primary and secondary order of the parameters. The linear relationship between the meridional parameters and the optimization target was analyzed based on regression analysis. The results show that the design of the intersection line of the front and rear shrouds in the impeller meridian has great effects on the ESP performance. The optimal model shows a significant improvement on both of efficiency and head compared with the original model. The head increases 3.5% and the efficiency increases 6.1%. This study provides new inspiration to optimize the hydraulic design of ESPs to achieve higher efficiency and lower energy consuming.

Experimental Study on the Performance of Electrical Submersible Pump Operating with Ultraviscous Oil

Summary The production of high-viscosity crude oil can be challenging owing to portfolio limitations and lack of energy efficiency in artificial lift systems, especially for ultraheavy oil in deepwater fields. In recent decades, the electrical submersible pump (ESP) has improved significantly, and this technology is commonly applied in this context. However, few studies in the literature discuss the behavior of these pumps with nonconventional oils such as ultraviscous ones. This work investigates the performance of a 10-stage ESP, when it operates with a single-phase flow of ultraviscous oil. For this purpose, an experimental circuit was set up; the pump was submitted to tests in which the viscosity of the fluid varied from 8 to 4,170 cp and rotational speed between 1,200 and 3,500 rev/min. A subsequent analysis compared the pump’s experimental viscous performance and the theoretical performance calculated by the methods available in the literature. This analysis highlighted the lack of precision of the existing correction performance models, and new empirical correlations are proposed to correct the ESP performance with viscous fluid. There were doubts at first as to the possibility of ultraviscous block, but the ESP model tested handled fluid with a viscosity up to 4,170 cp. Finally, the performance parameters of the ESP were calculated using a phenomenological 1D model based on the loss analysis developed by the authors, which revealed good results and a powerful tool to adjust the size of the ESP for definitive production system.

New correlations for predicting two-phase electrical submersible pump performance under downhole conditions using field data

AbstractElectrical Submersible Pump (ESP) is one of the major Artificial Lift methods that is reliable and effective for pumping high volume of fluids from wellbores. However, ESP is not recommended for applications with high gas liquid ratio. The presence of free gas inside the pump causes pump performance degradation which may lead to problems or even failure during operations. Thus, it is important to investigate effect of free gas on ESP performance under downhole conditions. At present, existing models or correlations are based on/verified with experimental data. This study is one of the first attempts to develop correlations for predicting two-phase gas–liquid pump performance under downhole conditions by using field data and laboratory data. Field data from three oil producing wells provided by Strata Production Company and Perdure Petroleum LLC. as well as experimental data obtained from experimental facility at Production and Drilling Research Project—New Mexico Tech were used in this study. Actual two-phase pump differential pressure per stage is obtained from experiments or estimated from field data and was normalized using pump performance curve. The values are compared to pump performance curve to study the relationships between pump performance and free gas percentage at pump intake. Correlations to predict ESP performance in two-phase flow under downhole and experimental conditions was derived from the results using regression technique. The correlation developed from field data presented in this study can be used to predict two-phase ESP performance under downhole conditions and under high gas fraction. The results from the experimental data confirm the reliability of the developed correlation using field data to predict two-phase ESP performance under downhole conditions. The developed correlation using the laboratory data predicts quite well the two-phase pump performance at the gas fraction of less than 15% while it is no longer reliable when free gas fraction is more than 15%. The findings from this study will help operating companies as well as ESP manufacturers to operate ESPs within the recommended range under downhole conditions. However, it is recommended to use the proposed correlation on reservoirs with conditions similar to those of the three presented wells.

Predictive Approach to Perform Fault Detection in Electrical Submersible Pump Systems.

It has been a great challenge for the oil and gas industry to timely identify any electrical submersible pump (ESP) abnormal performance to avoid ESP failure. Given the high cost of the ESP failure, more and more real-time surveillance systems are applied to monitor ESP performance to generate alarms in the case of failures. This paper presents a robust principal component analysis (PCA) model to perform fault detection for ESP systems continuously. A three-dimensional plot of scores of principal components was used to observe different patterns during the stable and failure periods. 47 cases of actual failure events and 40 cases of stable operating events were tested on the robust PCA model to generate prediction results. The testing results demonstrate that the robust PCA model has managed to identify 20 failure events before the actual failure time out of the 47 failure cases and has successfully distinguished all the 40 stable operating wells. This study has concluded that PCA has the potential to be used as a monitoring platform to recognize dynamic change and therefore to predict the developing failures in the ESP system.

Real-time Performance Monitoring of Electrical Submersible Pumps in SAGD Process

Electrical submersible pump (ESP) is one of the preferred artificial lift systems in upstream oil production because of its wide operating range and endurance to harsh operating environments. In Alberta Canada, about two-thirds of steam assisted gravity drainage (SAGD) wells are equipped with ESPs. Keeping the ESPs long-term operational is one of the primary challenges faced by the operators. ESP failures are a common problem due to various reasons, such as, harsh operating conditions, improper installations, etc. Therefore, the real-time monitoring of ESP performance is indispensable as it can prevent unscheduled well shutdowns and enable preventative maintenance. In this work, aiming at the development of reliable ESP performance monitoring in SAGD process, a monitoring strategy based on a multivariate statistical technique is proposed. The strategy includes a novel first-principles based feature extraction approach, an online model update strategy and a new health index to evaluate ESP health conditions in real time. Test results on real ESP datasets are presented to highlight the efficacy of the proposed algorithm.

Energy characteristics and optimal design of diffuser meridian in an electrical submersible pump

Electrical submersible pump (ESP) is widely used as an artificial lifting machinery in the petroleum production and geothermal usage. Its energy efficiency is related to the amount of produced oil and affects the global energy consumption. This study aimed to improve the energy performance of a typical three-stage ESP. Through the combination of Taguchi methods and numerical simulations, the diffuser meridian within ESP was geometrically optimized by setting the head and efficiency under design flow condition as the evaluation index. On the basis of the Bessel curve characteristics, the line patterns of hub and shroud within the ESP diffuser meridian were parameterized to preliminary extract the necessary factors of Taguchi test. Finally, the influence priority of different factors on the optimization was analyzed to guide the subsequent ESP optimization. Comparison of the performance and the internal flow field of models before and after optimization revealed that the Taguchi test is remarkably helpful in optimizing the meridian within ESP diffuser. This work provides new ideas for optimizing the meridian of main hydraulic components within ESPs to achieve higher efficiency and lower energy consuming.

Experimental investigation on the performance of Electrical Submersible Pump (ESP) operating with unstable water/oil emulsions

Electrical Submersible Pump (ESP) is one of the most commonly used artificial lift methods in petroleum production, due to its capacity to operate in several conditions with two or three-phase flows. When the ESP operates with emulsion flow, its performance is degraded, and operational instabilities occur. Therefore, this paper aims to carefully investigate phase inversion and to present, by the first time, the effective viscosity of unstable mineral oil/water emulsions, within the ESP. The first part of this work analyzes the phase inversion phenomenon for two oil types in three viscosities, five ESP rotational speeds, and three mixture flow rates. Logistic functions were fitted using the dimensionless head as a water cut function to determine the phase inversion within the ESP. The continuous phase inversion model, developed for emulsion pipe flow, did not present a satisfactory agreement to flow conditions tested. An indirect method to determine the emulsion effective viscosity within the ESP was proposed, which was obtained from the water/oil emulsion performance curves. The viscous performance data were used to determine the parameters of a dimensionless head empirical model for the tested ESP. Thus, the calculated values were compared with the effective viscosity obtained with oil and water emulsions, as well as the ESP performance, operating with emulsion and oil, which provides similar values for low rotational speeds. The different behavior of the effective viscosity between the pipeline flow and within the ESP was observed for water-in-oil emulsions and may be related to the high centrifugal field in the ESP.

A Holistic Approach in Establishing a Structured Framework to Maximize Production Availability through Integrated ESP Key Performance Indicators

Summary Managing large-scale electrical submersible pump (ESP) operations and assessing their performance can be a challenging task. Diverse operational environments, widely spread geographical areas, large ESP populations, and different service providers are some of the complications facing operators. Nonetheless, it is vital to the success of any artificial lift project to establish a performance evaluation structure that can effectively capture deficiencies and highlight improvements. While many operators focus on run life statistics as the central key performance indicator (KPI) for ESPs, these types of statistics may not be sufficient in providing meaningful information to decision makers. Other important ESP performance parameters include ESP shutdowns (both planned and unplanned), restart time of tripped ESPs, commissioning time, failure rate, and the number of premature ESP failures. Thus, a comprehensive study was jointly initiated between an oil operator and ESP vendors to establish KPIs that drive improvements in all aspects. The selected KPIs were developed in a structure that ultimately focuses on maximizing production availability and revenue generation. By constructing the ESP KPI framework, subpar performance areas were clearly visible by both the operator and the service provider. Decision makers were able to identify and act on fields that lag in performance while exerting efforts to improve underperforming service providers. Furthermore, regular meetings were conducted to review the established KPIs and recommend some action items, which might focus on either technical or operational solutions. Finally, KPI targets were set on the basis of the review of historical trends and were assigned to be challenging yet relevant and attainable. The followed practice can prove to be successful in forming a common ground where service providers can quantify losses by the operator as a result of ESP performance deficiencies. Comprehensive data collection and keeping of ESP trips, failures, and replacements are critical to the success of this work. Regular review of field reports and well performance are imperative to accurately compute the various KPI formulas. In fact, many of the KPI calculations can be automated to capitalize on the available communication networks installed in the field to improve ESP monitoring and accurately assess their performance.

Comparative analysis of an electrical submersible pump's performance handling viscous Newtonian and non-Newtonian fluids through experimental and CFD approaches

Electrical Submersible Pumps (ESPs) are among the most common artificial lifting methods employed nowadays in the O&G industry. This work aims to carry out an exhaustive analysis of the performance and flow features of a multistage ESP when handling Shear-Thinning non-Newtonian fluids, which are commonly found in mature, heavy oil wells. Currently, no studies have been conducted for multistage centrifugal pumps operating under such conditions. In this study, water, two Newtonian oils of different viscosities, and two non-Newtonian fluids, consisting of two CMC solutions in water (0.5% and 1% w/w), were tested. The testing facility consisted of a four-stage ESP located in a closed-loop arrangement in which the flowrate could be freely manipulated. Experimental measurements were taken to determine the pressure rise and power consumption by the ESP's motor. The CFD model was validated against experimental data collected in this study. The CFD head rise was in excellent agreement against the experimental data for water, with MSE of 4.91%. Good agreement was also observed, with a slight overprediction, for the pump's efficiency, with an MSE of 10.6%. The non-Newtonian fluids best fitted the Cross viscosity model. CMC 0.5% obtained a 12% higher average head rise than that of CMC 1%, despite the latter exhibiting a more pronounced Shear-Thinning trend (higher Cross time constant). It was found that the non-Newtonian fluids tested out-performed, in terms of head rise, the Newtonian oils by an average of 23.5%, and 11.4% against the heavier and the lighter oil, respectively. This improved performance was observed despite the non-Newtonian range of effective viscosities being over one or more orders of magnitude higher than the oils' dynamic viscosities. Furthermore, it was noted that the pump's performance with both non-Newtonian fluids did not deteriorate as rapidly as it did for the viscous oils. This lead to a shift in the BEP towards higher flowrates for the non-Newtonian fluids. This observation was supported by the CFD effective viscosity profiles, which showed a decline in the viscosity as the flowrate increased. CFD proved to be a valuable tool to analyze and understand in depth the viscosity variations and flow features throughout the pump's domain and their connection with the global performance observed for the ESP.

Empirical Model for Heat Transfer of Electric Submersible Pump (ESP) Motor at Oil Producer Well

Motor operating temperature at wells equipped with Electric Submersible Pump (ESP) need to be monitored to maintain ESP performance run life. Not all producer wells equipped with temperature sensor, so it considered necessary to build mathematic model to estimate motor operating temperature. Model of heat transfer to predict motor operating temperature is developed based on empirical equation method. Parameter and variable data obtained from producer wells include water cut, viscosity, specific gravity, operating temperature, ampere and voltage. Procedure to calculate viscosity is ASTM D-88 and procedure to calculate specific gravity is ASTM D-5002.
 From 18 wells data obtained from the field, calculated reynolds numbers indicate turbulent flow regime with reynold numbers more than 4,000. Nusselt number were calculated using multiple linear regression with result of Nu = 0.06 * Re0.65 * Pr0.36 with error of 1.3% from downhole sensor measurement. The comparison with similar research also provided that use different Nusselt number empirical equation.
 The conclusion from the research showing that empirical approach by using specific constants to predict Nusselt number can be used to predict more accurate heat transfer coefficient with error 1.3%. Higher water cut fluid flow need lower fluid velocity to achieve motor operating temperature below motor limit temperature with fluid velocity above 0.3 m/s.

A Review of Experiments and Modeling of Gas-Liquid Flow in Electrical Submersible Pumps

As the second most widely used artificial lift method in petroleum production (and first in produced amount), electrical submersible pump (ESP) maintains or increases flow rate by converting kinetic energy to hydraulic pressure of hydrocarbon fluids. To facilitate its optimal working conditions, an ESP has to be operated within a narrow application window. Issues like gas involvement, changing production rate and high oil viscosity, greatly impede ESP boosting pressure. Previous experimental studies showed that the presence of gas would cause ESP hydraulic head degradation. The flow behaviors inside ESPs under gassy conditions, such as pressure surging and gas pockets, further deteriorate ESP pressure boosting ability. Therefore, it is important to know what parameters govern the gas-liquid flow structure inside a rotating ESP and how it can be modeled. This paper presents a comprehensive review on the key factors that affect ESP performance under gassy flow conditions. Furthermore, the empirical and mechanistic models for predicting ESP pressure increment are discussed. The computational fluid dynamics (CFD)-based modeling approach for studying the multiphase flow in a rotating ESP is explained as well. The closure relationships that are critical to both mechanistic and numerical models are reviewed, which are helpful for further development of more accurate models for predicting ESP gas-liquid flow behaviors.

Combined effects of viscosity and surface roughness on electric submersible pump performance

An electric submersible pump that lifts crude oil from well bore is a type of multi-stage centrifugal pump. The unexpected wellbore conditions like change in pumping fluid viscosity and sand production severely affect pump performance and eventually lead to breakdown. The present study proposes a numerical approach to understand the effects of fluid viscosity and surface roughness of the flow passages in an electric submersible pump at design and off-design conditions. A three-dimensional numerical analysis was carried out by solving Reynolds-averaged Navier–Stokes equations with shear stress transport turbulence model to characterize performance of the pump. The pumping fluids, i.e., water and crude oils of different viscosities were analyzed for different surface roughness ( Ks) values. The model predictions were compared with a theoretical one-dimensional model for the effect of viscosity and surface roughness. It was found that the disc-friction and the skin-friction losses are sensitive hydraulic losses of which the disc-friction loss increases with increase in viscosity, whereas skin-friction loss decreases with increase in surface roughness at high viscosity. The combined effect of viscosity and roughness showed a complicated behavior and eventually an improvement in pump performance at a higher surface roughness compared to a smoother and lowers surface roughness.

Numerical Study on Electrical-Submersible-Pump Two-Phase Performance and Bubble-Size Modeling

Summary The electrical submersible pump (ESP) is widely used in the petroleum industry to maintain high crude-oil production rate. Its performance deteriorates with the increase of gas entrainment. Previous studies showed that bubble size is an important factor affecting ESP boosting pressure under multiphase flow. In this paper, a novel indirect approach is proposed to obtain the representative bubble sizes inside a rotating ESP impeller by matching numerical-simulation results with experimental performance curves. A 3D computational-fluid-dynamics (CFD) model is implemented on a three-stage ESP geometry to simulate the pump-pressure increment under various flow conditions. By use of structured hexahedral grids and the frozen-rotor technique, the mesh independence and numerical accuracy are verified. ESP boosting pressure in single-phase simulations is found to match well with experimental data. For two-phase simulations, the Eulerian-Eulerian model is used. At low inlet gas volumetric fractions (GVFs), the numerically simulated pump-pressure increment using constant bubble sizes agrees well with experimental measurements. At higher GVFs, the simulation results deviate from experimental pump-performance curves considerably. By increasing bubble sizes, the simulated ESP performance can be tuned to match experimental results. Through this process, a bubble-size change trend with varying GVFs is obtained. A mechanistic model that is based on the maximum stable bubble in a rotating turbulent flow field is developed to correlate the CFD simulated bubble sizes. Further, numerical-simulation results incorporating the proposed bubble-size prediction model agree well with experimental data.

CFD simulation and experimental study of oil viscosity effect on multi-stage electrical submersible pump (ESP) performance

In this study, the oil viscosity effect on ESP performance is investigated by experimental study and computational fluid dynamics (CFD) simulations. Oils with different viscosities are flowed through a DN1750ESP at varying flow rates and rotary speeds. The temperature is maintained at different levels with a heat exchanger circulated by cold water. The pressure increase over the 3rd stage as well as total 7 stages in ESP is measured with differential pressure transducers. The same geometries, fluid properties and flow characteristics are implemented into CFD simulations. The three-dimensional (3D), steady-state Reynolds-Averaged Navier–Stokes (RANS) equations with standard SST (shear stress transport) turbulence models are solved in ANSYS CFX by employing frozen-rotor technique. With high-quality structured hexahedral mesh, the simulated pressure increment is compared with corresponding experimental results. Flow structures inside ESP impeller and diffuser channels are analyzed. At pump best efficiency point (BEP), the boosting pressure decreases 30–40% when oil viscosity increases from 10 cp to 100 cp. ESP becomes ineffective when oil viscosity is higher than 200 cp. With oil viscosity increasing, pump H-Q performance curve becomes more linear. CFD simulation reveals that the recirculation flow at impeller blade trailing edge is more prominent at lower liquid flow rates.

High Temperature and High Pressure ESP Performance Testing System Design

With the development of oilfield exploration, the performance of electric submersible pump (ESP) has been enhanced very fast. It requires testing techniques develop at the same time. The most outstanding question is the testing of high temperature and pressure ESP. A testing well was drilled in Daqing in 1992. It keeps the water liquid state on 150 centigrade by high pressure. This system can simulate operational mode 3000 meters under the ground. But many new ESPs have been produced these years. The quondam testing system couldnt meet the testing requirement. A new testing system is desiderated eagerly. This paper developed a high temperature and pressure ESP testing experimentation system. Hydraulic/thermodynamic analysis calculation has been carried on. Friction resistance from constant pressure point to the suction inlet of hot water pump and the ESP in heating-forced cycle and experimentation primary cycle are calculated respectively. Keeping the water liquid state on 180 centigrade, constant pressure value was fixed on 2.5 MPa. The heat load is calculated including the heat that the water in the system and the equipment need and the heat loss. In order to protect ESP from emanating too much heat to keep the temperature and pressure of the system steady, heat exchange system has been designed. Cold load and heat exchange square have been calculated. Friction resistance and the size of the cold water cistern have been calculated. These provide necessary academic foundation for the testing experimentation of high temperature and pressure ESP.