Rod Pumping Research Articles

Development of a flashlamp-pumped Cr:LiSAF laser operating at 30 Hz

Cr3+:LiSrAlF6 crystals are an interesting laser medium because of their spectroscopic characteristics: They present a broad emission band in the near infrared and can be pumped either by a flashlamp or by diodes. Up to now, their limitation has been mostly due to their poor thermal properties that limit the laser performance either in the repetition rate in a pulsed system or output power in cw systems. We have designed and constructed a flashlamp-pumped laser using a standard rod pumping cavity that avoids most of the heat generated in the pumping process and allows operation at a fairly high repetition rate of 30 Hz with a high average power of 20 W in a conservative operation mode.

Some experiences in heavy and extra heavy oil exploitation in The Orinoco BELT, Venezuela

This work presents an overview of the development strategic followed by Petroleos de Venezuela, S.A. (PDVSA) for the production of the heavy and extra heavy oil in the Orinoco Belt, in Venezuela. Also will be presented the result of a specific integrated study conducted in the larger reservoir (U2-3 MFB 53) located in the Bare Field, in the Ayacucho area. The study consisted in the construction of a geostatistical model 3D, integrating the information of the different disciplines: geophysics, geology, petrophysics and production-reservoir engineering, which allowed the calculation of an OOIP of 5,935 MSTB with greater certainty. It was determined that the paleotopography of the basement controlled the process of sedimentation of the U2-3 basal sands, confirmed by the drilling of vertical wells and by means of the interpretation of the seismic 3D. This concept was applied to relatively undeveloped neighboring areas of the reservoir to identify new development opportunities. A dynamic model of this area was generated to evaluate cold production using horizontal and multilateral wells of long reach. Using the dynamic model, the optimum flowing bottom hole pressure to avoid the early production of gas was determined, in order to maximize the efficiency of the electrosubmersible and progressive cavity pumps. Based on this study, the first horizontal well (MFB-664) of long reach was drilled, which represent a record for PDVSA of 5,070 feet of horizontal section. The initial production for this well was 2,130 bopd. Other record was obtained in the drilling of the multilateral well MFB-667 (two branches) with an overall length of 8,260 feet; the initial production test was 1,820 bopd at minimal draw down. On the other hand, PDVSA also has developed innovative completions that improve recovery of heavy or extra heavy crude oil: Intelligent Completion, Selective Steam Injection Completion and Progressive Cavity/Sucker Rod Pump Optimization Systems

Determination of the loads acting on the pump rod of a water pumping windmill

One of the most delicate parts to size in a water pumping windmill is the pump rod. Indeed, frequent ruptures during the exploitation and experimentation of windmills shows that the determination of the real forces acting on the pump rod is quite difficult to evaluate. The calculation of these forces is traditionally achieved by taking as a maximal force the sum of the static loads. The calculation model used in this article takes into account the hydraulic pressure losses, inertia forces and the shock force caused by the water column on the piston. This will make it possible to better know the forces acting on the pump rod and therefore to perform better sizing.

Development and Field Experience of a New Concept in Sucker Rods Technology

Abstract The Cerro Drag?n oilfield, operated by Pan American Energy, has producing oil wells that use rod pumping systems with average depths of 2,440 m (8,000 ft) and fluid rates as high as 200 m3/d (1,300 bfpd). In this oilfield, the pulling operations exhibited a high incidence of pin breaks, generally located in the 22.23 mm (7/8 in) OD taper that we concluded to be the weakest part of the entire string, as we will show. In order to solve this problem, a new sucker rods design was developed by creating a new non- API 22.23 mm (7/8 in) sucker rod with ends of 25.4 mm (1 in) in order to reinforce the string. This technical work describes the development of this technology, as well as the experience in the field, with excellent results p to the present. Introduction erro Drag?n is an oilfield located in the Golfo San Jorge Basin (see Figure 1). This field has 1,800 oil producing wells, with 1,642 wells lifted by rod pumping systems. Average pump depths are 2,440 m (8,000 ft) with oil producing rates as high as 200 m3/d (1,300 bfpd). In 1988, a secondary recovery project was started. The water injection rate was raised (Figure 2), resulting in higher production rates and consequently higher loads to all of the components (rods, pumping units, etc.) of the lift system. Associated with this increase in the production rates, an increase in failure rates was observed. It was determined that the main cause of this failure rates increase was connection failures; in particular, the 22.23 mm (7/8 in) pin failures. Approximately 18% of the failures were caused by 22.23 mm (7/8 in) pin breaks. As a result, a team was established between the rod supplier and the operating company to work together to improve the fatigue resistance of the 22.23 mm (7/8 in) connection. The result of this teamwork was a new non-API sucker rod with a 22.23 mm (7/8 in) diameter and a threaded connection of 25.4 mm (1 in). Currently, there are 60 rod strings installed, the oldest ones with an operating service life of about four years, and there has been just one failure (the oldest one failed after 1,499 days in service). The installation of the improved sucker rods in 160 wells (thosewith the higher failure rates) will result in savings of almost US$2 MM/year. This paper describes the development of the rods, as well as the experience in the field. Failures History Due to the increase in the IPA (index of interventions per well per year) for wells lifted by rod pumping (Figure 3), work was conducted to understand the different causes of the failures. The first conclusion was that the sucker rod failures were growing at a constant rate, corresponding to the increment in the production rates.

Modelling of Sucker Rod String

Abstract This paper presents a new technique to analyze dynamic behaviour of a sucker rod string used in the oil well industry. The main concept of the proposed approach is to replace the actual complicated system by a simpler one. This needs the output or one-time accurate solutions of the actual system. This problem is solved using D‘Alembert's solution of systems equation and the adaptive filter matrix method developed by the authors. The developed computer program performs the calculations in very short real time with reasonable accuracy, and without extensive hardware and software requirements. It has been proven that it is possible to use the transfer matrix to calculate load-displacement relations a hundred or more times in one stroke. This could be very advantageous in building new well-head controllers and other tools to control the oil wells. Introduction Rod pumping is the oldest and still the most common method of artificial lift used extensively in the oil well industry(1,2). The literature devoted to the analysis of this system is very extensive. There are different computer programs aimed at the analysis and troubleshooting of rod pumping systems(3–5), however, they require fully equipped computer hardware to perform the calculations. These calculations usually take an amount of time that is longer than the period of pumping (one stroke) and cannot be directly used to control the well in real time. In this paper, a transfer matrix method has been proposed to model the dynamic behaviour of the rod of the sucker string. The main concept of the method is to replace the solution of the mathematical model by a simple matrix operation in which the bottomhole force-displacement values are obtained as the product of the vector of the data at the polished rod end by a transfer matrix. This is an extremely fast mathematical operation, which can be performed hundreds of times during the period of one stroke and does not require any sophisticated software. The system transfer matrix for any given oil well is defined only once in advance using the filter matrix method(6–8). The matrix does not change with time and replaces the mathematical model of the analyzed system. Using this technique, the calculations of the bottomhole values can be performed very fast and in a very simple way. These calculations are easy to implement in one microprocessor. In the studies presented here, we found that to create the system transfer matrix, it is enough to replace the real system by a two-segment rod. The simplified model is solved using D‘Alembert's method(9). Using the equivalent model, the transfer matrix is created. Mathematical Modelling To analyze the performance of the oil well, the force and displacement at the polished rod are measured using a dynamometer. Then these data are used as the boundary conditions for the calculation of forces and displacements at the bottom of the rod string that defines the conditions of the pump, effectiveness of pumping, production rate, etc.

Techbits: Status of Artificial Lift: Technology and Applications

Because water injection is extensively used as a secondary-recovery mechanism in mature fields in Argentina, the Applied Technology Workshop (ATW) on Electrical Submersible Pumps (ESPs) and Progressing Cavity Pumps (PCPs) held in Río Negro, Argentina, garnered intense interest. Because high water cuts are either prevalent or expected to occur in many of these fields, 90 attendees convened in San Carlos de Bariloche to enhance their knowledge of artificial systems through discussion of well-optimization issues, various approaches to resolving these issues, and sharing field-application experiences. Fruitful discussion centered on a variety of topics from PCP elastomer problems to candidate-well selection and from the advantages of automation to mechanical failures in ESPs. Discussion on high-temperature issues, paraffin deposition, effects of corrosion, and practices for cost reduction was combined with multiple case studies to further the learning experience. Building Careers Keynote speaker Atilio Massa, Weatherford Vice President–Latin America Operations, posed this question: “What does the oil and gas industry require from artificial lift systems production and products technical personnel?” In the context of service/producer alignment, Massa emphasized applying an iterative methodology for continuous improvements, going deeply into the fully automated cycle of field operations, and building careers to handle that process (i.e., promoting qualification of employees in the use of new technologies, motivating them to receive continuous training, and ensuring that quality, health, safety, and environment standards are followed). A segment of the meeting was devoted to new artificial lift technologies such as the use of hollow rods. Those have been successfully applied in a variety of conditions in conjunction with the use of PCP technology, but a range of questions remain to be answered, including weight reduction and protection against sensitivity to corrosion. Another technical presentation covered sensors. Not yet a common practice in Argentinean fields, use of downhole pressure and temperature sensors was examined from different viewpoints. It was pointed out that new insights on reservoir behavior, and consequently on production, could be gained. And if components of the ESP supply chain could be supplied from different manufacturers (particularly in the field of sensors), the best interpretation could be had (i.e., pump manufacturers understand pumps, and sensor manufacturers know the most about sensors). Performance having been tested in Brazil’s Campos basin, failures and improvements on the ESP downhole subsurface electric round cable were also discussed, along with continuous-rod systems. It was noted that the advantage of continuous-rod systems is the lack of couplings, the main cause of failure in conventional sucker-rod strings. Presenters entertained questions regarding the logistics required to place the equipment in the well and rod life when submitted to flexion stresses. Reduced operating time and cost-reducing effect of rigless completions formed another segment of the agenda. Such a completion requires a rig to run only the bottomhole assembly (ESP, rod pump, and selective injection equipment). Good planning and daily coordination are essential to good results. Suggestions included the use of coiled tubing for the completion and the addition of memory sensors on the mechanical packers.

Daily Monitoring Reduces Cost of Production in Marginal Wells

The economics of a marginal well is highly sensitive to the price of oil and cost of production. Without improvements to production efficiency, marginal wells often must be shut down or risk operating at a loss. Because rod-pumped wells correspond to this pattern, with many of the wells producing less than 10 BOPD, a 4-year system-development effort was undertaken by Petrolects, a California-based engineering consulting firm, and Bakersfield-based independent producer Vaquero Energy to improve production efficiency. The Marginal Expense Oil Well Wireless Surveillance (MEOWWS) oil-production monitoring system is the result of this development effort, primarily funded by the U.S. Dept. of Energy. The system allows marginal wells to be economically monitored daily, allowing operation with near-optimal efficiency. Detection Methods During the first 2 years of the study, small, self-contained, wireless vibration sensors were attached to different sections of rod pump units. Signals induced by vibration of the pumping unit during fluid pounding were transmitted to a base-station computer in the field office. The operator could then identify problem wells by reviewing transmitted data. Statistical analysis of the vibration data was performed, demonstrating that acceleration sensors were able to detect fluid pound when the well was pumped off. Problems encountered during testing of the vibration-detection system included high power usage, which led to short battery life, and the high cost of the sensors. In the third and fourth years of the MEOWWS project, the method used to detect the pump-off condition was re-evaluated in an attempt to overcome the most serious problems encountered during the first phase. Three methods to determine the operating condition of the pumping unit in real time were tested and compared—vibration measurement, acoustic emissions from surface equipment, and flow measurements of produced fluids. Flow measurement was determined to hold the greatest promise for a reliable, economical, easily installed well-operation sensor and was chosen for further investigation. System Development A proprietary method of detecting outflow from a beam pump was conceived by the investigators. The method involves a simple and direct detection of flow through surface piping. A surveillance system was designed to suit the advantages of the flow-detection method: simplicity, reliability, direct monitoring of production, ease of installation, and low cost. The flow sensors are integrated into a well pump surveillance unit (WPSU). Each WPSU contains an inexpensive low-power microcontroller and a 900-MHz spread-spectrum radio modem. The microcontroller interprets readings from the flow sensor, using proprietary software to measure the well’s state of health and the volumetric pumping efficiency. Readings are saved over a period of hours or days. The power requirements of the WPSU are low enough to permit practical battery-powered operation over a period of years without an external electrical supply, eliminating the need for installation of expensive alternating-current power lines or costly and vulnerable solar-power arrays. The WPSU transmits data to a base station located in the field operations office as frequently as is required by the customer’s needs. The system is designed to transmit information on a daily basis, minimizing its contribution to the problem of radio frequency congestion that is increasingly troubling users of supervisory-control and data-acquisition systems. At the base station, readings are compiled by software to a tabular or graphical format that is easily interpreted by operations personnel. Base-station data are made available through a local area network, or across the Internet, by an integrated Web server. Data are also archived for future reference.

Shock Absorber for Oil-Well Sucker-Rod Pumping Unit

The design of the suspension of a polished pump rod with a shelled sucker-rod string shock absorber is described. The typical experimental loop of damping of the shelled shock absorber is shown.

Best Method to Balance Torque Loadings on a Pumping Unit Gearbox

Abstract In general there are three methods available to the operator to determine the net torque loading on a pumping unit's gearbox. Two dynamic methods determine the instantaneous torque throughout the pumping cycle. Method 1 combines the measured surface dynamometer card and calculated torque factors with measured or calculated counterbalance moments from the crank and weights. Method 2 uses measured motor power with motor and drive efficiencies and the pumping unit speed to calculate gearbox torque. The third method combines the counterbalance effect (CBE) with the measured dynamometer loads and the torque factors to compute the net torque on the gearbox. The CBE test is a direct method of determining net gearbox torque at a specific crank position to estimate the maximum counterbalance moment. This static test is where the cranks and counterweights are held level until no upward or downward movement is noticed when the break is released. Field case studies applying all three methods to determining gearbox torque are presented in this paper. The pros and cons of using each method are discussed. Introduction The oldest and most common method of artificial lift used in producing oil wells is sucker rod pumping. In the United States and Canada, sucker rod lift is used in over 85% of artificial lift wells. The sucker rod lift system consists of four components:prime mover;pumping unit;counterbalance to the rod loading; and,sucker rods and associated downhole equipment. The function of the pumping unit is to convert the rotary motion of the prime mover to the vertical reciprocating motion of the polished rod. Therole of the prime mover is to furnish the necessary power to drive the system. To improve efficiency, reduce the size of the prime mover and gearbox, and to load the gearbox more uniformly, the sucker rod pumping mechanism is furnished with some type of counterbalance system, where the counterbalance effect at the polished rod is approximately equal to the buoyant weight of the rods plus half the fluid load on the plunger. Balanced or Unbalanced Gearbox Loading For each complete stroke, the net torque load on the gearbox is cyclic, usually having two maximum peaks and two minimum valleys. The peaks occur during the upstroke and the downstroke, and the valleys occur at the top and bottom of the stroke. For balanced operation, the magnitude of the peaks should be approximately equal. Pumping unit manufacturers use various types of counterbalancing and mechanical features to reduce the peak gearbox torque and to smooth out the cyclic effects of the load. The gearbox is said to be underbalanced or rod heavy if the upstroke peak is greater, whereas the gearbox is said to be overbalanced or weight heavy if the downstroke peak is greater. Since in a rotating system torque and power are directly related, the previous statements can be equally applied to the cyclic nature of the motor power developed during a complete stroke of the pumping unit.

Incremental Recovery Using Dual- Completed Wells in Gas Reservoirs With Bottom Water Drive: A Feasibility Study

Abstract Water drive reduces gas recovery through the mechanism of water coning, which results in liquid loading that kills the wells. Installation of a Downhole Gas Water Separator (DGWS) in the well may prevent liquid loading. This paper presents another solution to this problem: a dual-completed well with downhole water sink (DWS) drainage and injection installation. DWS wells are different from DGWS wells by the inclusion of a second bottom completion that controls water outside the well and prevents a commingled inflow of gas and water to the top completion. DWS wells have been successfully tested in oil reservoirs. This study analyzes the DWS concept for gas wells by comparing simulated performances of a conventional well and a DWS well. The simulation runs were made over a broad range of the initial reservoir pressure and permeability values for a gas reservoir with a large associated aquifer. Also included is a comparison between DGWS and DWS wells at selected conditions. The results demonstrate the considerable advantages of dual completion over conventional wells in low-pressure (subnormal), tight (1 md) reservoirs-a 2.6 fold recovery increase before the wells are killed by excessive water production. The advantage, however, reduces to 10% for a reservoir with normal pore pressure gradient and a permeability of 10 md, and almost disappears for a permeability of 100 md and abnormal reservoir pressure. When compared to DGWS wells, the final gas recovery of DWS wells is the same, but DWS produces the gas 35% sooner than DGWS. The study also identifies the best DWS completion design where top completion is used only for gas production, and bottom completion for inverse gas coning, gravity separation, and water injection. Introduction Water production reduces gas recovery by shortening the well's life. Water could invade the gas well and kill it when a lot of gas may remain in the reservoir. Various concepts and techniques have been used to solve the water-loading problems. Hutlas and Granberry(1) discussed the techniques used in Kansas, Northwestern Oklahoma, and the Texas Panhandle: pumping units, liquid diverters, gas lift, and a concentric dual-tubing string. They concluded that the pumping units are best suited for shallow gas fields with very low permeability, while a combination of liquid-diverter and gas-lift installation would perform best in deeper, higher-pressure fields. Libson and Henry(2) discussed the methods used to control liquid loading in the tight, low-gas rate reservoirs in the Intermediate Shelf area of Southwest Texas: pumping units, plunger lift, a small concentric dual-tubing string, soap injection, and flow controllers. They found the plunger lift and the small concentric dual-tubing string to be effective in wells with low water rates, while pumping units performed best when the liquid rate exceeded 10 BWPD. Stephenson, Rousen, and Rosenzweig(3) evaluated different methods for dewatering (unloading) gas wells in the Box Church Field-a high water-cut gas reservoir in Texas. The methods include rod pumps, soap sticks, swabbing, coiled tubing/nitrogen, venting, plunger lift, and gas lift.

Downhole Beam Pump Operation: Slippage and Buckling Forces Transmitted to the Rod String

Abstract New results for downhole beam or rod pumps from fairly recent test data are in conflict with traditional relationships. Additional testing is in progress. A pump with large plunger/barrel clearance will cause high fluid slippage. A pump with smaller clearance will cause less fluid slippage, but a tighter fit will tend to increase rod buckling at the pump to a greater degree and may lead to advanced pump and rod wear rates. Therefore, it is important to be able to predict pump slippage and also related forces at the downhole pump. Considerations for pump leakage and example calculations are presented using the older and the new pump slippage relationships. A derivation to account for the pump velocity effects on slippage is also presented. The effect of pump clearances on possible rod buckling above the pump is also studied. Further additional possible causes of rod buckling are presented, discussed, and compared. The results will help the reader to decide on sizing pump clearances to provide leakage for pump lubrication without losing too much on pump efficiency. Several ideas on the sources of rod buckling, such as flow through the travelling valve, and the plunger-barrel interaction are presented and compared. A review of methods to combat rod buckling above the pump is presented. Introduction Pump slippage occurs primarily on the upstroke, occurs through the plunger-barrel interface, and serves to lubricate the plungerbarrel action. Usual industry minimum requirements are quoted to be in the range of 2 – 5% of production to provide lubrication. This figure could come under scrutiny when slippage becomes better defined. If the slippage is too large, then the system becomes inefficient. This can be due to a worn plunger-barrel, and/or travelling valve, or sizing the pump with an excessive clearance. Recent tests(1–3) indicate that older equations(4, 5) used by industry for years may have over-predicted the slippage. If verified, then pumps can be sized with larger clearances, reducing plungerbarrel friction, and possibly eliminating some of the compression at the bottom of the rod string without allowing excessive leakage. In this paper, a derivation of the slippage equation is developed, which also gives a contribution to slippage due to plunger velocity. Since buckling considerations may arise from pump clearance and other factors, rod buckling equations are presented and reviewed. Rods buckle due to outside forces acting up against the bottom of the rod string on the downstroke. It is well known that buoyancy forces do not contribute to buckling(6). Thus, only negative "effective" forces that exclude buoyancy contribute to buckling and "true forces" that include buoyancy should not be used when considering buckling. An example of how to calculate the rod projected area and buoyancy induced pressure forces is presented and examples of calculating "true forces" and "effective forces: are also presented. Contributing factors to rod buckling include the force to slide the plunger in the barrel and also the pressure drop across the travelling valve as the pump travels downward.

Fundamental Equations for Dynamic Analysis of Rod and Pipe String in Oil-Gas Wells and Application in Static Buckling Analysis

Abstract A large number of string materials, such as drillstring, pumping rod, tubing, coiled tubing, casing, etc., are used in oil and gas drilling and production. Proper mechanical analyses of these strings are important. This paper analyses the motions of these strings, and establishes the fundamental equations for the dynamic analysis of these strings in oil and gas wells. The fundamental equations have successfully unified all of the differential equations used in the dynamic analysis of rod and pipe strings in oil and gas wells. All of the differential equations present used in the calculation of tension and torque in directional wells, analysis of drillstring vibration, analysis of bottom hole assembly (BHA), analysis of the buckling behaviour of pipe and casing strings, and analysis of sucker rod pumping systems can be obtained just by proper simplification of the fundamental equations. Thus, these equations have broad uses in drilling and production. The buckling of coiled tubing string, drillstring and casing etc., plays an important role in oil drilling and production operations. As a very important application of the fundamental equations, this paper also establishes the differential equations for the buckling of the strings in inclined straight holes. The linear and non-linear mathematical models for buckling of these strings in horizontal sections have been established. The critical forces for helical and sinusoidal buckling in inclined straight holes have been found. The linear and non-linear buckling of the weightless strings has been analysed. Other applications of the fundamental equations in drilling and production have been presented. Introduction Since the pioneering work by Lubinski et al.,(1) the drilling and production industry has gradually come to accept and appreciate the importance of analysis of BHA, drillstring, casing, tubing, pumping rod etc. A large number of differential equations have been established for special analysis(1–20). However, no fundamental equations that unify these differential equations have been established. As an attempt, this paper establishes the fundamental equations for the dynamic analysis of drillstring, BHA, casing, tubing, pumping rod, etc. in oil and gas wells. Lubinski et al.(1) defined the helical buckling behaviour of pipes in vertical wells. However, the post-buckling behaviour of pipe in inclined and horizontal wells is different from that in nearby vertical wells. Knowledge of the configuration of buckled tubular is important to prevent costly failures, to predict whether a tool can be forced along a directional or horizontal well, and to optimize the tubular string. As an important application of the fundamental equations, this paper also establishes the differential equations for the buckling of the string in inclined straight holes. The linear and non-linear mathematical models for buckling of these strings in horizontal sections have been established. The critical forces for helical and sinusoidal buckling in inclined straight holes have been found. The linear and non-linear bucking of the weightless strings has been analysed. Fundamental Equations for Dynamic Analysis of Rod and Pipe String in Oil-Gas Wells Motions of Strings in Oil and Gas Wells

A Universal Method of Determining the Period of a Multifrequency Signal, Represented in Digital Form

A universal method of determining the period of a complex multifrequency signal and a method of generating a signal with a specified period are described. The use of the method to determine the period of a wattmeter diagram when monitoring and diagnosing rod pump equipment is considered.

Prediction of Turbulent Friction in Rod-Pumped Wells

Summary Frictional forces acting on a rod caused by a rod reciprocating in flowing fluid significantly affect the prediction and diagnosis of rod pumping system performance. Available studies of the flow in the tubing combined with moving rods and couplings are limited to laminar flow. The flow is more likely to be turbulent, however, for liquids with low viscosity and for regions near the rod couplings. Therefore in the current study, turbulent flow in the annular region between the stationary tubing wall and the moving rod/coupling is considered. Computational fluid dynamics (CFD) is used to simulate turbulent flow in the annular region with moving rods and couplings. Also, a simplified model using a mixing-length method is developed that is more computationally efficient than the CFD code. The CFD code that uses the standard k–ε model is used to predict turbulent friction factors in the annulus with the moving rods and couplings. The simplified model is developed to predict turbulent friction factors in the annulus with the moving rods. The results from these models are compared with each other and to the available data published. The friction factors between the rod/coupling and fluid can be represented by four parameters: the rod to tubing radius ratio, the coupling to tubing radius ratio, the fluid Reynolds number, and the relative rod velocity.

Development of the Downhole Dynamometer Database

The Downhole Dynamometer Database (DDDB) is a compilation of test data collected by Sandia National Laboratories (SNL) with a set of five downhole memory tools built by Albert Engineering (AE), and deployed in the sucker rod string with sensors to measure pressure, temperature, load, and acceleration. The purpose of the Database is to provide industry with high quality measurements of downhole sucker rod pumping dynamics. A Microsoft Windows-based interface allows users to browse and visualize the more than 40 MB of data, and to extract data from the database for use in their own programs. The database is available upon request from Sandia National Laboratories at http://www.sandia.gov/apt/.

Design and Optimization for Sucker Rod Pumping System in Deviated Wells

Design and Optimization for Sucker Rod Pumping System in Deviated Wells

Effect of structural factors of the cylinder on the reliability of an oil well rod pump

Effect of structural factors of the cylinder on the reliability of an oil well rod pump

125-mJ diode-pumped injection-seeded Ho:Tm:YLF laser

We describe a diode-pumped, room-temperature Ho:Tm:YLF power oscillator with an optical-to-optical efficiency of 0.03. A Q -switched output energy of as much as 125 mJ at 6 Hz with a pulse width of 170 ns was obtained. Single-frequency, nearly transform-limited operation of the laser was achieved by injection seeding. Laser performance as a function of laser rod temperature and pump intensity was also investigated. The high power and high beam quality of this laser make it well suited for use as a coherent wind lidar transmitter on a space platform.

Improved Design of Rod Pump Valves For Thermal And Horizontal Wells-Laboratory And Field Results

Abstract This paper presents results from a multi-participant project conducted by AOSTRA, ARC and industry to improve rod pumping efficiency for thermal and non-thermal oil fields in Alberta. It describes experimental and theoretical investigations on the hydrodynamics of rod pump valves that resulted in improved valve design and increased field production rates; and shows that, two of the most frequent problems encountered in the field are associated with sand and gas/steam inflow and may be alleviated through a better design of pump valves. These problems were examined in the laboratory (ARC) by testing ball-valve hydrodynamics at different GOR and inclination angles. Nineteen different valve designs were investigated using two laboratory facilities. Visual observations regarding critical GOR and inclination angles and quantitative measurements of pressure drop at different pump rates and fluid viscosity were obtained. A diagram, in which measured drag coefficient was plotted versus Reynolds number, was used to capture the steady and unsteady behaviours of the cage-ball systems. This diagram provided a basis for improving valve design. Following discussions of the laboratory findings with the project participants (field operators and manufacturers), and at the instigation of one particular manufacturer, a new valve design (HIVAC) was completed, manufactured and field tested at numerous sites. The field test results showed a significant increase in flow compared to conventional API valves previously used at the same sites. Introduction The design and operation of sucker rod operated bottom hole oil pumps, used in 80 – 90% of artificial lift wells, reached a mature stage during the period 1970 – 1980(1).Improved diagnostic tools for evaluating their performance appeared during the 1980s. These tools included automated dynamometer cards that aided rapid and relatively inexpensive de-convolution and interpretation of load-stroke diagrams(2,3). During the last decade, the development of heavy oil reservoirs in Alberta, Saskatchewan, and Venezuela and the widespread use of horizontal and deviated wells for both conventional and heavy oil reservoirs has imposed additional constraints on sucker rod pump applications. In Alberta, thermal projects have always experienced difficulties with pumping operations. In 1988, a survey conducted by the Alberta Department of Energy-Oil Sands and Research Division (formerly AOSTRA) found that the most common problems encountered were pump seizure (customarily related to sand-laden fluids), and pump inefficiencies due to steam and non-condensible gases(4). A multi-disciplinary team consisting of ADOE-OSRD, ARC, eight major field operators and four rod pump manufacturers in Alberta was formed to address those problems. Although the major objective was to improve existing thermal pumping technology, more general applications to horizontal well and high gas/oil ratio situations were put at a high priority. An overview of the program and its major laboratory achievements during 1988 – 1991 has been discussed elsewhere(4). This paper describes further laboratory observations on valve hydrodynamics with conventional and slanted wells obtained during 1991 – 1992, as well as significant field results achieved using a novel valve design. Equation 1 (available in full paper)

Measurements of a Small Signal Gain Coefficient of Flashlamp Pumped Cr,Tm:YAG and Cr,Tm,Ho:YAG Lasers

We measured the small signal gain coefficient of Cr,Tm:YAG and Cr,Tm,Ho:YAG flashlamp pumped lasers, varying the rod temperature (5–25°C) and pumping energy density (51.3–85.9 J/cm3). The maximum small signal gain coefficients measured for these lasers were 0.144 cm-1 and 0.234 cm-1, respectively. The Cr,Tm,Ho:YAG laser was found to have a two-fold higher gain, and to be more temperature-sensitive than the Cr,Tm:YAG laser.