Pump Barrel Research Articles

Analysis of the flow and thermal-fluid–solid coupling of crude oil in circular pipe caused by variable pressure gradient

Abstract Globally, enhanced oil recovery (EOR) has become a pressing issue as the demand for crude oil continues to increase. This study investigates the flow and thermal-fluid–solid coupling of crude oil in a rod pump during hot water recovery and obtains the maximum recovery of crude oil in a vertical pipeline through numerical analysis. The pressure gradient in the pump barrel was first developed and deduced based on the ideal gas state equation and Bernoulli’s equation. According to the rheological experiment results, it was proven that the light crude oil conforms to the Newtonian constitutive equation. Subsequently, the momentum equation of crude oil flowing in the pipeline and fluid–solid coupling heat transfer equations were established and solved using the finite difference method. The effects of the thermal recovery temperature T w , wall thickness c, and stroke time n of the rod pump on flow Q are discussed. In particular, the flow Q within 1 min first increases and then slows down with the increase in stroke time n and reaches its maximum value at n = 7 r/min. Furthermore, flow Q decreases with an increase in c but increases as T w increases; c = 1.2 cm, T w = 363 K is the best oil recovery scheme.

DEVELOPMENT OF DOWNHOLE PUMP VALVE ASSEMBLY

The purpose of the work is modernization of the valve, in order to increase reliability, wear resistance, increase the pump flow and reduce the load on the rod string, as well as improve durability. The sucker rod pump is one of the most popular and extensively utilized artificial lift systems. It is a frequently chosen option for lifting oil because of its fundamental simplicity, low operating costs, and adaptability in power supply. In the long run of oil production history, sucker-rod pumping was the first option—and frequently the only option—when artificial lift was required. For this reason, the oldest and most popular method of producing oil wells worldwide is sucker-rod pumping. Since the steel used to make rods has limited strength, sucker-rod pumping is typically thought of as a way to raise moderate to low liquid production rates from shallow to medium well depths due to depth restrictions. Since the correct working of the standing and traveling valves is largely responsible for an efficient pumping operation, valves are regarded as the heart of the sucker-rod pump. The extremely high differential pressures across the valve during pumping necessitate a highly dependable sealing action between the ball and the seat. Small initial flaws in the sealing surfaces or subsequent corrosion- or abrasion-related problems result in greater liquid slipping and a quick decline in valve function because of fluid cutting. Subsurface pumps using traditional ball-and-seat valves suffer a number of basic operational issues: • Because of the greatly high number of pumping cycles per day, the sealing surfaces may sustain significant damage from the frequent collision of the two parts against one another. • In deviated wells, valve wear is uneven and can cause premature failure. • Typical cage constructions, meant to limit impact damage, typically restrict the flow area available through the valve and can be the source of pumping inefficiencies due to low fillage of the pump barrel. Keywords: sucker rod pumps, downhole pump, traveling valve, standing valve, valve assembly.

Exploring the effects of water content on friction behavior and mechanism of DLC films in oil production environment based on molecular dynamics simulation and first-principles calculations

To provide atomic-level insights for improving the service life of the Sucker Rod Production System (SRPS) in the harsh oil extraction environment, we attempted to investigate the friction and wear behavior of the FeFe model (conventional steel plunger pump barrel) and the DLC-Fe model (DLC-coated plunger pump barrel) in the oil extraction environment through molecular dynamics (MD) simulations and first-principles calculations. The results show that the interaction force between the conventional steel plunger and the light oil chain increases significantly as the crude oil moisture content increases. The shear strain of friction layer is intensified, severely limiting its wear resistance in the harsh oil extraction environment. Interestingly, due to the weaker interaction with the light oil chain, the plunger-pump barrel system coated with DLC films exhibited excellent frictional performance. Further studies showed that the passivation of C-suspension bonds on the films surface in the crude oil effectively improved the shear resistance of the DLC friction layer with the increase of water molecules. The related results provide a theoretical support for the practical engineering application of DLC film on the surface of oil well pump plunger.

Modeling and characteristic analysis of viscous resistance in annulus gap of coalbed gas well drainage pump

The viscous resistance caused by the relative motion of plunger and pump barrel is an important factor in the dynamic analysis of the drainage and production mechanism during coalbed methane exploitation. Existing studies mostly focus on deep well (1000–3000 m) large-displacement pump (usually 80–300 m3/d), and the interstitial medium is mainly crude oil. Regression fitting is mainly carried out based on empirical formula or experimental simulation method, without considering the characteristics of shallower coalbed gas well (400–800 m) small-displacement pump (<10 m3/d). The variation of the clearance between plunger and barrel and the variation of viscous resistance between plunger and barrel are not revealed. Based on the Navier-Stokes equation and Newton's internal friction law, a mathematical model of the annular viscous resistance between the plunger and the pump barrel is established, and an analytical method is used to describe the influence of stroke times, annular clearance, and differential pressure between the upper and lower plungers on the viscous resistance. The results show that the plunger stroke is directly proportional to the variation range of viscous resistance, and low stroke is beneficial to reduce the viscous resistance. The effect of differential pressure between upper and lower plunger of rod pump on viscous resistance of small displacement coalbed gas well is significantly greater than that of plunger running speed. The annular clearance is directly proportional to the differential pressure between the upper and lower parts of the plunger, the inertia force of the plunger, and the shear force of the moving fluid. The annular viscous resistance model between plunger and pump barrel is helpful to improve the calculation accuracy of suspending point load of coalbed gas well pumping unit, analyze the working condition of coalbed gas drainage gas production process, and provide basis for the optimization design of coalbed gas well rod pump clearance.

Analysis of Pump Efficiency and Feed Flow Under the Condition of Flexible Rate

In this paper, a flexible method of optimizing the velocity of plunger is presented by selecting important oil well production parameters through orthogonal test and combining the oil well parameters and the structural parameters of the pump barrel. In order to explore the influence of the motion rate of the optimized flexible plunger on the pump efficiency, the motion law curves of the plunger before and after the optimization were compared, and the pump efficiency before and after the optimization was theoretically analyzed. The flow rate and pump efficiency of the pump before and after optimization were simulated by the model. Finally, the pumping unit experimental system is used to test the pumping pump fluid production before and after optimization. The results show that the pump efficiency under the optimized flexible rate is 3.7% higher than that before the optimization without considering other factors. The model simulation analysis shows that the mass flow rate of the pump in a single swabbing period under the condition of optimized flexible rate is increased, and the pump efficiency is increased by 4.9% compared with that before optimization. The experimental results of the pumping unit experimental system show that the fluid yield under the optimized flexible rate is higher than that before the optimization, and the maximum increase is 4.1%. The experimental results are consistent with the theoretical analysis results.

Viscoelastic Representation of the Operation of Sucker Rod Pumps

The issues of leakage with respect to the clearance between the pump plunger outer surface and the pump barrel inner surface and other operational conditions have been revisited in this paper. Both Poiseuille flow rate due to the pressure difference and Couette flow rate due to the plunger motion have been considered. The purpose of this study is to explore the possibility of representing the entire downhole pump system with a simple viscoelastic model. We have explored both Kelvin and Maxwell viscoelastic models along with the dynamic behaviors of a mass point attached to the viscoelastic model. By using the time-dependent polished rod force measured with a dynamometer as the input to the viscoelastic models, we have obtained the displacement responses, which match closely with the actual measurements in experiments and operations. Further study and experiments have been planned and partially implemented in the McCoy School of Engineering at Midwestern State University, a member of the Texas Tech University System.

In Situ Synthesis of (M:Nb,Ta)C/Ni35 Composite Coating Cladded on 40Cr Steel.

To improve the wear and corrosion resistance of the pump barrel material (40Cr steel), a (M:Nb,Ta)C/Ni35 composite cladding coating by in situ synthesis of composite carbides was conducted. The effects of ceramic micro-particles content on the phase composition, microstructure of the coating, structural characteristics of (M:Nb,Ta)C and the tribology and electrochemical corrosion behavior were systematically studied. The increase of ceramic micro-particles changed the morphology of (M:Nb,Ta)C with the size from sub-micron to micron. The (M:Nb,Ta)C dispersed along the grain boundary inhibits the growth of the grains. During friction, the spherical structure exhibited a rolling lubrication effect and the petal structure provided a stronger attachment ability to resist the shear. The corrosion occurred at the grains, exhibiting corrosion pits, in which the high content ceramic micro-particles were relatively shallow. Moreover, a few dot corrosion pits were distributed along the grain boundaries without (M:Nb,Ta)C. Therefore, to improve the corrosion resistance, a thin composite carbide coating with good wear and corrosion resistance was prepared.

抽油泵内筒材料激光熔覆高熵合金的热力耦合仿真研究

抽油泵内筒材料激光熔覆高熵合金的热力耦合仿真研究

On Leakage Issues of Sucker Rod Pumping Systems

The issues of leakage with respect to the clearance between the pump plunger outer diameter and the pump barrel inner diameter and other operation conditions have been revisited in this paper. Both Poiseuille flow rate due to the pressure difference and Couette flow rate due to the plunger motion have been considered. The purpose of this study is to better understand the nature of the leakage with respect to pressure difference, eccentricity, and motion related to the plunger of typical sucker rod pump systems. More specifically, based on the newly derived relaxation time scales for transient solutions of the governing Navier–Stokes equations, the quasi-static nature of relevant measurement techniques is confirmed for the current production systems. This key observation is also demonstrated with a computational model using the experimentally measured pressure difference and the plunger movement.

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.

고점성 액체용 스크루 펌프 개발

One method of conveying the reactants in reactors is to use a screw pump. In this study, we fabricated and experimented with a screw pump based on a general extruder. In a typical extruder, the pitch of the screw flights is the same and the diameter of the screw shaft increases gradually. However, an extruder with an increased shaft diameter is disadvantageous because it is difficult to combine it with the screw flights and shaft. The screw pump in this study had the same diameter and decreased the pitch of the screw flights, thus making it easier to manufacture a screw pump. In this study, we confirmed the flow rate of the screw pump manufactured using an extruder and analyzed experimental results. We estimated the difference between the theoretical and the experimental values as the leakage flow that occurs at the clearance between the screw flight and the pump barrel.

Analysis of the performance indicators of oil well sucker-rod pumps

The paper notes that as the depths of operated wells grow, the application of cable and pulley mechanisms becomes preferable as compared to the existing pumpjacks. A generalized theoretical analysis of the kinematics of cable and pulley drives is set forth. The authors present the general theoretical analysis of the kinematics of the above mechanisms, as well as the results of computer calculations based of the developed equations for a number of cases. Further analysis of the results showed that the crank mechanisms of a rope pulley have “smooth” kinematics. The research resulted in a proposed invention of the design of mast-type oil well sucker-rod pump drive with lower steel intensity and power consumption that would allow increasing the performance of sucker-rod pumps.The Purpose of this article consists in finding a utility model of a pump for the well rod in order to ensure the environmental safety of the equipment. That is achieved by lightening the metal structure of the pump with rotary stem and energy consumption is reduced. In the context of this problem, some calculations were performed in order to prove the system’s dependability. Based on the performed calculations it was established that the light structure can be used instead of the old heavy structure being its environmentally safe version. Experimental studies conducted by AzINMASH Research and Design Institute of Petroleum Engineering (Baku, Azerbaijan) indicate the feasibility of normal operation of sucker-rod pumps under the condition that n∙S = 54÷60 m/min. The authors examined the dependence between the peak output Q and the number of strokes n for various standard pumpjack sizes. The analysis of the parameters shown that the value of the product n∙S in the existing pumpjacks is below the recommendations based on experimental data, i.e. there is a tangible opportunity of increasing the productivity by extending the stroke of the rod hanger center, since well pump barrels may be as long as 6 to 7 meters. Estimates show that while studying the kinematics of long-stroke drives the changes in the length of the rope may be practically disregarded due to the displacement of the rope-to-pulley contact point. This simplifies the formulas that describe the kinematics of this type of long-stroke drives. Using the resulting formulas, comparative computer calculations for various cases were performed. It is shown that cable and pulley mechanisms have “softer” kinematics. The calculations confirmed the advisability of modification of the pump’s design that ensured reduced pollution of environment and energy savings. The future world will need renewable sources of energy, more power-efficient oil and gas production, minimal or zero pollution of the environment, thus the proposed solution appears to be of relevance. The authors propose a more productive design of sucker-rod pump that is easy to install and maintain at oil and gas production facilities. That can be achieved based on the calculations mentioned above.

The numerical simulation of entire sucker rod string buckling with couplings in vertical wells

A new model is built to study the buckling of a rod string with couplings in the vertical well considering two important loads: the axial distribution load along the rod and the concentrated load at the bottom. Firstly, the calculation method for the axial distribution load of the sucker rod string is established based on a wave equation of longitudinal vibration. And, the simulation results show that the axial distribution load of sucker rod string has an obvious non-uniform distribution characteristic. The friction force between the plunger and the pump barrel (FFPPB), which is an important part of the concentrated load at the bottom, is improved based on both the Newtonian fluid (NF) and the non-Newtonian power law fluid (NNPLF) by using the Flunent software. In view of the above improvement of the computational method, a simulation model of the entire rod string buckling with couplings is established. Under the assumption that the coupling is taken as a radial constraint boundary, the two-point boundary value problem (BVP) algorithm is used to solve the differential equation, and the least square method is used to establish the continuity conditions on the supporting point of coupling. The simulation results show that the eccentric state of the plunger (eccentricity ratio $$\upvarepsilon =0\sim 1$$) has a significant influence on the eccentric wear area between the rod-tubings, which should be taken into account in the practical calculation. And compared without couplings, the contact pressure between the sucker rod string and the tubing is transferred to the couplings, which fits the engineering reality. Further, the simulation result implies the centralizers should be installed firstly near the couplings in order to protect the couplings better. The new method lays the theoretical foundation for the further studying the rod wear life and the design of the eccentric wear prevention.

Prediction and Analysis of Polished Rod Dynamometer Card in Sucker Rod Pumping System with Wear

In the oil production process, the wear of friction pairs in sucker rod pumping installations will increase over time, which leads to the failure of the sucker rod pumping system. In order to study the effect of wear on the sucker rod pumping system, a wear model between the plunger and pump barrel was established. By analyzing the wear law, the wear volume and wear time of the pump barrel were calculated under abrasive wear. The forces of the sucker rod microunit were analyzed, and the wave equation of the sucker rod was established. Based on the given boundary and initial conditions, a mixed difference method was used to solve the equation. Taking the no. L2111 well of an oilfield as an example, the change curves of the wear volume and wear time with abrasive particle diameter were plotted, and the polished rod dynamometer card considering wear was predicted. The results showed that the increased clearance caused by wear will reduce the polished rod load on upstroke of the sucker rod pumping system, which could provide a theoretical basis for the next fault diagnosis.

An Investigation on the Hardness and Wear Rate of Surface Alloyed AISI304 Stainless Steel with Ti using GTA as Heat Source

Background: Stainless steels are mainly used where prevention of corrosion attack is the main criteria, but low surface hardness and high wear rate are key obstacles to extensive application. Methods: The surface alloying of AISI 304 stainless steel with titanium was carried out using the heat generated from the Gas Tungsten Arc (GTA). Experiments were conducted by varying the GTA parameters and the optimal parameter was determined. Composition of the surface alloyed layer was analysed using atomic emission spectrometer. The Ti alloyed surface layers were characterized using SEM imaging/EDAX analysis. Findings: Composition of the surface alloyed layer was analysed using atomic emission spectrometer and the results confirmed an increase in the Ti content on the surface layer when compared to the composition of the substrate. The EDAX analysis showed that intermetallic alloys are present in the Ti alloyed surface layers. The microhardness was measured using the Vickers microhardness testing machine and the hardness increased from 267.5 HV for the substrate to 2098 HV for the surface alloyed layer. The wear was measured using the pin-on-disk wear tester and the wear rate decreased from 14.78 x 10 -4 mm 3 /m for the substrate to 1.84 x 10 -4 mm 3 /m for the surface alloyed layer. The observation of the microstructure revealed that there is grain refinement in the Ti alloyed surface layer. Applications: The modified specimens can be used as medical implants, control rods in nuclear power plants, pump barrels petrochemical industry. This method can be used to improve the properties in specific area of a product.

Simulation and Experimental Studies on Optimum Barrel Length for High Impact Penetrator

The primary purpose of this project is about simulation and experimental studies for optimum barrel length of a high impact penetrator.This project uses the concept of two-stage light gas gun modified by using shaped charge at the first stage. Sacrificial barrel is the important part for this project. The combination of sacrificial barrel with piston serves to compress the air along the barrel at appropriate pressure. It produces sufficient amount of pressure to rupture the rupture disc and the pressure will force the projectile to travel through the barrel. There is some parameter to be investigated such as volume of air in pump barrel, strength of rupture disc and location of the piston in the sacrificial barrel. Some method is use such as calculation to determine the suitable length for the sacrificial barrel and the thickness of the rupture disc. The parameter will be use to perform simulation that will result in amount of the pressure and velocity of projectile that can be produced. The comparison result from simulation and experimental testing on the condition of sacrificial barrel and piston is obtained in this study. The significance of this project is more on the cost because this project only uses an atmospheric air as a mechanism to launch a projectile. More than that, high impact penetrator can reduce space because it is smaller compare to light gas gun.

Research of the cavitation performance of the condensate pump

Condensate pump is an important part of power plant circulation systems, which is used to pump condensate water. Because the condensate water pressure is very low, the first impeller of the condensate pump must have a good cavitation performance. Numerical simulation was employed to study the first impeller cavitation performance. The first impeller was set in the condensate pump barrel, and the double suction casing was kept, the parts after the double suction casing was simplified as tube. The simplicity can guarantee the inlet and outlet conditions of the impeller. Based on the RANS and SST k − ω turbulence model, CFD software was used to simulate the condensate pump at different working conditions. The numerical simulation shows that cavitation occurred at the suction side of the blades closing to the leading edge. The cavitation performance of the impeller was predicted based on the numerical calculation. Comparing with the experimental results, the numerical simulation result is smaller than that of the experiment in small flux, and the cavitation performance trend is agreed with that of the experiments.

Structural Design for Oil Well Pump with Soft Sealing and Small Diameter Piston

For the low pumping demand of daily production per well of low permeability oilfield, a diameter of 25mm soft sealing small diameter piston-type subsurface pump is designed, and an external traveling valve to ensure that the valve still application of standard parts is adopted, while reducing the pump barrel diameter. In order to solve the problems of pump leakage increasing with wear, automatically compensate for soft seal ring is adopted in piston design. The liquid pressure of the pump barrel is changed in the pump working process, so that the sealing ring is deformed outwardly. When the pump reaches the upper stroke, the gap between the pump barrel and the piston reduced, and further improve the sealing effect. The innovation of structure and the selection of new materials can reduce the difficulty of pump processing, as well as can extend the maintenance cycle. This paper introduces the overall structure and sealing characteristics of soft sealing small diameter piston-type subsurface pump. If the soft sealing small diameter piston-type subsurface pump and real-time variable frequence control technique of pumping unit combined, a more reasonable machine rod pump combination can be provided to achieve ultra-low permeability oilfield stripped well efficiently pumping.

Numerical Simulation of the Effects of Scanning Velocity on the Process of Laser Transformation Hardening on the Inner Wall of Pump Barrel

This study establishes a 3-D finite element model for the numerical simulation of laser transformation hardening on inner wall of pump barrel through a finite element code-SYSWELD. The change of thermal mechanical parameters with temperature is considered. The temperature field, metallurgy transformation and distribution of residual stress are predicted. The effect of scanning velocity on the temperature, martensite fraction and distribution of residual stress are studied. The results show that peak temperature in the hardened zone reaches to 1067.0°C and the maximum heating and cooling rate of hardened zone are 1.24×104°C/s and 3.68×103°C/s. After treatment, martensite can be obtained as a main phase in the hardened zone whose fraction increases with the decrease of scanning velocity. Compressive stress could be acquired in the hardened zone while the peak of tensile stress exists in the HAZ.

Structure Optimization and Strength Analysis of CBM Special Anti-Clogging Drainage Pump

There are abundant coal bed methane resources in China, and recovery technology is considered a very important part in the development of coal bed methane. At present, coal bed methane production areas are still adopting the tubing liner pump, but because of the special working environment, in the pumping process, the fine breeze (sand) and other solid particles entering into the pump barrel is likely to cause the pump stuck, pipe string buried by sand and other issues. In view of the above problems, based on the ordinary tubing liner pump, through the increase of the anti-litter bypass style traveling valve housing and fixed valve housing, outside liner jacket, sand reservoir and liquid in tee joint measures we developed a new type of CBM special anti-clogging drainage pump and adopted finite element analysis software ANSYS to complete key parts of strength calculation. The use of this pump will effectively reduces the blocking of fine coal particles (sand) and other solid particles, decreases the pump's checking operation and workload of sand bailing, consequently improves efficiency, reduces overall operating costs.