bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient Two-Dimensional Numerical Modeling of Asymmetric Curing Process
Authors: Mensah Patrick F. , Soysal Omer , Li Guoqiang , Jana Amitava , Stubblefield Michael A.
Published: January 2009

Modeling of a heat-activated coupling process of fiberglass reinforced epoxy composite pipe with a copper nickel 90/10 (Cu 90% Ni 10%) alloy pipe was investigated in this study. A nonlinear-coupled two-dimensional heat diffusion model was used to capture the essentials of in-situ thermal transport during the curing process through the thickness of the prepreg wrapping layers. The resulting nonlinear boundary value problem was solved using an Alternating Direction Implicit (ADI) finite difference model (FDM). Transient temperature distributions and degree of cure were predicted for the prepreg layers with and without a heating source at the side of the alloy pipe. A reasonable agreement was found between the predicted temperatures and the experimental results. Measures to improve the curing quality of prepreg layers were discussed based on the modeling results.
Piezoelectric Materials as Microelectromechanical Devices for Structural Engineering Applications
Authors: Piazza Gianluca , Driga Mircea , Fowler David
Published: January 2009

Smart systems have recently been used for active control of vibration in structural engineering applications. One class of components often used in these systems includes piezoelectric materials, whose two electromechanical direct and converse effects allow them to play both roles of sensors and actuators. This paper presents the analytical and experimental investigations conducted using piezoelectric materials with polymer concrete as elements of intelligent structures. A piezoelectric film (PVDF) was tested as an embedded stress-strain detector in a polymer concrete beam that was dynamically loaded in axial compression and in flexural configurations. The reliability of the stresses detected via PVDF film was compared with the theoretically predicted values. The results from the comparison are promising, even if some improvements must be adopted in order to apply this technique extensively. Two single-sheet PZT actuators were surface-mounted on a simply supported thin polymer concrete beam. When the beam was transversely excited, oscillations were measured, and they approximately matched predictions by a single-mode Rayleigh-Ritz model under the assumption of Bernoulli-Euler strain distribution.
Roadmap Leading to a Step Change in Profitability Improvement
Authors: Herlyn Folkert J. , Starr Susan C.
Published: January 2009

In today’s volatile market, it is crucial for companies to fine-tune their organizations and processes toward increased profitability and productivity, to have a strategy for continuous improvement, and to institute a means for graduated measurement. In putting together a continuous improvement strategy, a roadmap is essential. The roadmap must be clear and easy to follow. The roadmap that is most easily understood and accepted by an organization is one that is started from a base case, or simplified visualization of the current environment, that is called the ‘As-Is’ case, to the target environment, the ‘To-Be’ case. This roadmap clearly depicts the route to be taken and is based on business process modeling, scoring of actual practices relative to best practice, and gap analysis. A series of activities and process improvements are identified to move towards the desired ‘To-Be’ state of business processes, supporting information technology, and improved methods to measure and review performance. A well-designed roadmap will move the organization in a series of step changes toward higher profitability and productivity.
Evaluation of Topical Approaches to the Implementation of Standardised ERP-Systems
Authors: Ku¨hl Roland W. A. , Kno¨ll H.-D.
Published: January 2009

In spite of the great variety of potential advantages, it is also necessary to illuminate the real effects of Standard Software in practice. Recent studies have revealed that 81% of companies interviewed using SAP, do not fully exploit the software’s ability to optimise business processes, though 61% stated that SAP offers very good process optimisation opportunities.[CS01] Therefore this paper evaluates popular life cycle models with respect to their suitability to implement Standard Software in a process driven way.
Protecting Proprietary Software in the Petroleum Industry
Authors: Winarski Tyson , Nguyen Tuan Ahn
Published: January 2009

The development, management, and exploitation of Intellectual Property is critical to the health and prosperity of the Petroleum Industry. This paper provides a summary of how Petroleum companies can protect their proprietary software. Specifically, this paper will address the risks and benefits associated with protecting proprietary software through copyrights, patents, or trade secrets. With this background, the paper will address how Petroleum Companies can optimally develop, manage, and exploit their Intellectual Property to maximize industry production, efficiency, and profitability.
Experimental Evaluation of Control Fluid Fallback During Off-Bottom Well Control
Authors: Flores-Avila Fernando S. , Smith John Rogers , Bourgoyne Adam T. , Bourgoyne Darryl A.
Published: January 2009

This study measured the liquid fallback during simulated blowout conditions. The purpose of the study was to establish a basis for developing a procedure for controlling blowouts that relies on the accumulation of liquid kill fluid injected while the well continues to flow. The results from full-scale experiments performed with natural gas and water based drilling fluid in a vertical 2787-foot deep research well are presented. The results show that the critical velocity that prevents control fluid accumulation can be predicted by adapting Turner’s model of terminal velocity based on the liquid droplet theory to consider the flow conditions, velocity and properties of the continuous phase when determining the drag coefficient. Similarly, the amount of liquid that flows countercurrent into and accumulates in the well can be predicted based on the concept of zero net liquid flow (ZNLF) holdup.
Recent Advances in Barite Sag Technology
Authors: Dye William M. , Mullen Gregory A. , Ewen Bruce R.
Published: January 2009

The occurrence of barite sag is a well recognized but poorly understood phenomenon in the drilling industry. Industry experts have offered a variety of measuring parameters, based upon empirical data, that only partially correlate with the occurrence of barite sag. The industry’s lack of understanding of the mechanisms and types of barite sag generally result in a poor correlation between laboratory results and field observations of barite sag. The financial impact of barite sag on drilling costs, usually resulting from rig-time lost while circulating and conditioning the mud system, is not trivial. There are reported incidences where recurring barite sag problems have resulted in the loss of drilling projects. The accuracy and relevance of technology utilized to manage barite sag can help reduce drilling costs. In the field barite sag frequently occurs in deviated wells where pipe eccentricity creates conditions conducive to dynamic sag. With the exception of a flow loop, laboratory tests do not simulate field conditions. Historically, laboratory tests characterize density variations arising from a vertical fluid column as static or dynamic sag without proper consideration to angle, pipe eccentricity, annular shear rates and annular flow. This paper reviews traditional and newly-emerging barite sag technology and compares their ability to predict barite sag potential. This potential will be determined under dynamic and static conditions in a sophisticated flow loop configured to match certain field conditions.
Evaluation of a New Thermally Stable Polycrystalline Diamond Material in Soft and Hard Formations
Authors: Zacny Kris A. , Cooper George A.
Published: January 2009

Comparative wear tests were carried out on a new Thermally Stable Polycrystalline Diamond (TSP) composite and Tungsten Carbide (6% Co) (WC) cutters, by machining rock cylinders in an instrumented lathe. Cutting tests were performed on Berea Sandstone and Sierra Granite rocks. It was observed that the new TSP material removes 1.4 times more Berea Sandstone rock than WC and 13 times more Sierra Granite than WC. In addition its volumetric wear is 25 times less in Berea Sandstone and 10 times less in Sierra Granite than WC. WC was also found to have much higher coefficient of friction, which can limit its use in abrasion resistant applications.
Environmental Management Programmes for Onshore Seismic Activity and Exploratory Drilling Operations in South East Trinidad
Authors: Mohammed Avryl A. , van Rijswijck Paul , Dyal Shyam
Published: January 2009

3D Seismic survey of an area approximately 70km2 was conducted in South-East Central Trinidad in the Naparima Mayaro Reserve from January to July 1999. This activity was done with the expectation of drilling exploratory wells for finding commercially viable oil reservoirs as a joint venture operation between Vintage Petroleum Trinidad Limited (formerly Cometra Energy (Canada) Limited) and Petrotrin. The companies initiated a number of proactive Environmental Management Programmes to comply with both local and international regulations. These programmes include: • Preliminary Environmental Impact Assessment Study for Seismic Survey of a 70km2 area. • Environmental Baseline Survey for Seismic Survey inclusive of descriptions of physical, biological and socioeconomic environments, environmental audits, training and monitoring (noise and water quality). • Environmental Impact Assessment for drilling of exploratory well. • Development of Oil Spill Contingency Plan for drilling operations. The implementation of these studies resulted in a number of benefits to the joint venture oil companies, such as: • 100% compliance with Certificate of Environment Clearance Rules and International Association of Geophysical Contractors (IAGC) Guidelines. • Improved corporate image. • Enhanced relationship with Government Agencies. • Improved environmental performance through proper planning. • Trained and empowered workforce in environmental management issues. • Zero oil spills and environmental incidents to date.
Oxygen Consumption as a Measure of Oil Impacted Soil Treatability
Authors: Deuel Lloyd E. , Holliday George H.
Published: January 2009

We know petroleum hydrocarbons degrade in soil via chemical, physical, and biological pathways. Innovative remediation technologies enhance degradation by one or more pathways e.g., in-situ and ex-situ. The typical goal of degradation is to achieve the applicable regulatory criteria. Some, State Agencies, e.g., Louisiana, Texas, require oil total petroleum hydrocarbon (TPH) contamination levels be reduced to ≤10,000 mg/kg. However, other agencies, e.g., New Mexico and California, require oil contamination levels reduced to <1,000 mg/kg. Even 100 mg/kg is not uncommon, e.g., Los Angeles, County, CA. Microbial populations and substrate availability often limit biodegradation at petroleum hydrocarbon levels <1,000 mg/kg. Conventional laboratory biodegradation microcosm studies require an inordinate amount of time to evaluate petroleum hydrocarbon treatability (as measured by loss of analyte) and even more time to optimize treatment parameters that facilitate or improve kinetics (lower half-life values). Two studies discussed here demonstrate the utility of oxygen consumption respirometry in evaluating oil impacted soil treatability. In the first study, oxygen consumption rates were measured after a 1-week incubation period at varying TPH levels (5800 and 1000 mg/kg), carbon:nitrogen (C:N) ratios (100:1 and 25:1), and manure content (0, 0.5, 1.0 and 5.0 percent). Results showed TPH and C:N ratios significant at < 1 percent level and manure significant at < 5 percent level. The second study, a longer-term study (132 day) showed oxygen consumption resulted from degradation of gasoline range (GRO) and diesel range (DRO) fractions of TPH. These studies provide a means of evaluating treatability of low concentrations of petroleum hydrocarbon and a method for assessing treatment options that are passive in nature, but less destructive to the environment.
The Petroleum Refining Regulation in Brazil and the ISO 14000 Standard: Can the Volunteer Become Compulsory?
Authors: da Silva George Rodrigues , Tavares Marina Elisabete Espinho
Published: January 2009

Firstly, the main regulatory characteristics of the Brazilian petroleum and natural gas industry are presented, with emphasis in the oil refining segment. Secondly, it is stood out the binomial “technical standards” versus “regulation acts.” It is worth to point out that the last ones are compulsory and they can be written considering technical standards as a basis. Finally, it is outlined the Brazilian Petroleum National Agency strategy for elaboration of refinery regulations, focusing on the adopted prescriptions for environment damage prevention and protection.
Gas Re-Injection in the Laminaria and Corallina Fields, Timor Sea: Established Techniques, New Environmental and Commercial Benefits
Authors: Gordon David M. , Ryan Scott A. , Twartz Steve K.
Published: January 2009

This paper describes a gas re-injection project designed with the dual objectives of emissions reduction and enhanced oil recovery in an Australian offshore oil field. While gas injection for enhancing oil recovery is common oilfield practice, there are fewer projects that look exclusively at greenhouse gas (GHG) control (either by sequestration or emission reduction), although there is increasing environmental awareness in the industry on the benefits of doing so. The predominant contribution to total GHG CO2-e emissions is from flaring. Significant reductions in flaring have been achieved since completion of commissioning of injection. Flare CO2 emissions at the beginning of 2000 (February-March) reduced from approximately 163,000 tonnes per month to an average of approximately 26,000 tonnes per month over the remainder of 2000, and to 9,800 tonnes per month, over the first half of 2001. GHG efficiency, evident in the ratio of GHGs emitted per tonne of hydrocarbon produced, reduced from approximately 0.4 tonnes CO2-e per tonne of total hydrocarbon produced before injection to 0.08 after injection over the remainder of 2000, and to 0.06 over the first half of 2001. Miscible displacement is expected to add around 6 million barrels to ultimate recovery from the Corallina reservoir. The use of stored gas as a fuel is expected to achieve significant reductions in operational expenditure later in field life.
Surface Water Quality in Onshore E&P Activities in State of Espi´rito Santo, Brazil
Authors: Fontanelli Glauco F.
Published: January 2009

This paper analyses which parameters may be in fact contributing for changing in water quality in Suruaca coastal lowland region, north of Espirito Santo, Brazil (Fig. 1). It is a low and plain area, with freatic level near surface, highly deforested, where there is a dominance of activities such as petroleum exploration and production, extensive cattle breeding and plantations of eucalyptus trees. Water quality monitoring surveys that have been carried out comprise 27 parameters at total, and some anomalies have been reported. From bibliographic search and interview with people who know the area, main economic activities in the region are defined, as well as raw materials utilized by them. Raw materials are analised by means of leaching, solubility, X-ray diffraction and X-ray fluorescence. Thus, it is tried to find links between parameters with anomalous concentrations and economic activities. Besides human sources, there are natural sources that are also contributing for changing the water quality of the region, but they are only mentioned in this paper. This paper shows that not all parameters analised need a continuity of monitoring, since both the characteristics of the economic activities placed in the studied area and the monitoring results give this away. On the other hand, there are other parameters that demand deeper researches, since they occur at concentrations higher than expected. For these latter parameters are related, as possible, the activities more likely of being contributing for its presence with concentrations above the allowable level. It is not possible to evaluate the origin of the anomalous concentrations for barium, lead and mercury.
A Review of National Pollutant Discharge Elimination System Discharge-Permit Requirements for EPA Region 6
Authors: Finley Patrick J.
Published: January 2009

During oil and gas extraction in the Gulf of Mexico (GOM), water and pollutants are produced from wells. The Environmental Protection Agency (EPA) has mandated a permit system to help control the discharge of these waters into the GOM. The National Pollutant Discharge Elimination System (NPDES) contains both requirements and standards for discharge in offshore Texas and Louisiana federal waters. This review summarizes permit (GMG290000) requirements, effluent limitations, standard conditions, and monitoring requirements for NPDES general permits in EPA Region 6.
A Management Plan for the Offshore Disposal of Drilling Muds and Cuttings in Brunei: A Receiving Environment Based Approach
Authors: Hickey T. Earle , Seymour Mike M. J. , Sayle Stephen D.
Published: January 2009

An offshore survey and environmental assessment was conducted on the Brunei continental shelf offshore oil and gas concession area in 2000–2001. The results of the comparison of the environmental effects of previous ocean disposal of oilbased mud (OBM), water-based mud (WBM) and ester-based synthetic mud (ESBM) was used to prepare guidelines for atsea disposal of mud and cuttings based on the sensitivity of the receiving environment. The ranking, in terms of sensitivity of environmental components are as follows: 1) Shallow coral reefs; 2) Deep reefs; 3) Juvenile shrimp nursery areas; 4) Adult shrimp shallow coastal areas; 5) Adult shrimp mid-shelf areas; 6) the Brunei continental shelf; and, 7) Continental slope and deep water. Detailed instructions are presented for the handling and disposal of WBM and ESBM for each offshore zone. The guidelines are presented in a user-friendly format and provide: description of the environmental zone and it’s sensitivity; the disposal management strategy including options for disposal in order of preference; and requirements for planning, disposal and recommended monitoring and follow-up.
Use of Multiphase Meters in Process Control for Oil Field Well Testing: Performance Enhancement Through GVF Control
Authors: Marrelli Jack D. , Mohan Ram S. , Wang Shoubo , Gomez Luis , Shoham Ovadia
Published: January 2009

First oil production from a deep-water oil field is to be achieved by the installation of an Initial Development System (IDS). Well testing is required for field development and reservoir management. The well testing system requires high accuracy oil and water rates to provide the data needed for decision analysis in ongoing drilling programs. The well testing system must also be integrated with other platform operations such as well clean up after drilling. The concept of a certain type of multiphase meter in a feedback control loop with conventional separation technology for process control is simulated to extend the capabilities of both technologies. The principle of GVF control as a supplementary to level control system has been developed for performance enhancement of oil field well testing. Concepts demonstrated here can also be easily applied as retro-fits to existing separation facilities which show accuracy or upset problems because of the simplicity and compact size of the additional multiphase meter component and non-disruptive supplementary integration with existing level control systems.
Performance and Control of Liquid-Liquid Cylindrical Cyclone Separators
Authors: Mathiravedu Rajkumar , Wang Shoubo , Mohan Ram S. , Shoham Ovadia , Marrelli Jack D.
Published: January 2009

The feasibility of using Liquid-Liquid Cylindrical Cyclone (LLCC©) as a free water knockout device for bulk separation of oil-water mixtures in the field strongly depends on the implementation of control systems due to its compactness, less residence time and possible inlet flow variations. In this investigation, the LLCC control dynamics have been studied extensively both theoretically and experimentally. A linear model has been developed for the first time for LLCC separators equipped with underflow watercut control, which enables simulation of the system dynamic behavior. A unique “direct” control strategy is developed and implemented, capable of obtaining clear water in the underflow line and maintaining maximum underflow rate. Dedicated control system simulations are conducted using Matlab/Simulink® software to simulate the real system dynamic behavior. Detailed experimental investigations are conducted to evaluate the system sensitivity and dynamic behavior of the proposed control strategy. The results demonstrate that the proposed control system is capable of controlling the underflow watercut around its set point by obtaining maximum free-water knockout for a wide range of flow conditions. (inlet water concentration of 40% and an inlet mixture velocity of 1.5 m/s).
A Parametric Study on Natural Frequency of Sandwich Panel Using Refined Shear Model
Authors: Liu Qunli , Zhao Yi
Published: January 2009

The natural frequency of a thick rectangular sandwich panel was studied using refined shear deformation theory. Both faceshheets and core materials are orthotropic. Nonlinear behavior of shear deformation of sandwich panel was described by a proposed polynomial function. The effect of transverse shear modulus of sandwich core on flexural vibration of the panel was investigated. Comparison was made among the classical thin plate theory, low order shear deformation theory and high order refined shear theory. Results from finite element analysis were also provided to verify the theoretical predictions.
Preliminary Development of a Composite Pipe Tee-Joint Using Heat Coupling Technology
Authors: Pang Su-Seng , Sun Liangfeng , Sterling Arthur M. , Jones Randy A.
Published: January 2009

Preliminary study of a composite pipe Tee-joint using heat coupling technology was conducted in this paper. The cutting process of the pipes for the Tee-joint was developed. Because the cutting edges of the pipes were coarse, it is necessary to smooth them. Both epoxy resin and prepreg were applied to the joined areas of the pipes. Shrink tape was also applied to the outside of the prepreg to add pressure and compression force. An optimized cure cycle for the epoxy prepreg used as the bonding materials was determined from the thermal cure analysis. The cure process of the joined pipes by epoxy prepreg was conducted in a specially designed oven. The total cure time was about 138 minutes. Several factors, including the thickness and length of the prepreg applied and the adhesive applied to the joints, have been considered in designing Teejoints. The hydrostatic pressure test results showed that the thickness of the wrapped epoxy prepreg had a very important effect on the quality of the joined pipes in terms of pressure.
Preliminary Analysis of Grid Stiffened Composite Cylinders
Authors: Kidane Samuel , Woldesenbet Eyassu , Li Guoqiang , Helms Jack , Smith Brett H.
Published: January 2009

Stiffened cylindrical shells are major components of Aerospace structure application. Two models were developed for assessing the universal buckling load of a generally cross and horizontal stiffened composite cylinder. The first model uses a simple conservation of volume and direction of stiffener orientation, while the second model analyzes the force and moment interaction of the stiffeners and the shell. Based on these models the A, B and D matrix stiffness parameters were determined for the overall cylinder panel. The buckling load was solved for a particular stiffener configuration by using the energy method. Buckling test was also performed on a stiffened composite cylinder and compared with buckling load results of both analytical models, and conclusions were drawn on the degree of reliability of the models developed. Finally, parametric analysis of some of the important design variables was performed based on the ‘Force Smearing’ model.
Nodal Control in a Vibrating Beam
Authors: Singh Akshay N. , Ram Yitshak M. , Pang Su-Seng
Published: January 2009

A method to achieve nodal control at the point of excitation in a Bernoulli-Euler beam is developed. It is shown that, for a uniform Bernoulli-Euler beam, the steady state motion at the point of excitation can be absorbed by means of a control force determined from displacement information at the point of application. A closed form solution for the control gain is presented.
The Top Ten Myths of Reliability Management
Authors: Hoffman Michael R. (Rick)
Published: January 2009

This paper deals with common errors that occur while implementing and executing plant reliability improvement programs. Case htstories are included to provide real world examples of these problems and the financial impact of mistakes. Recommendations are included to avoid pitfalls. In some cases actual tools are provided to solve the problems.
Effectively Using Risk-Based Inspection Results to Implement a Corrosion Under Insulation Program
Authors: Sanders Joe Don
Published: January 2009

This paper will discuss how to use Risk-Based Inspection (RBI) results to justify and manage a Corrosion Under Insulation (CUI) program that can be validated by using key performance indicators. A step-by step methodology to provide guidance on how to recognize, develop, and implement a CUI remediation program will be shared based on experience from 19 plant sites. Recommendations, based on actual plant experience, are included to facilitate the sharing of best practices and prevention of common errors.
Dealing With Low-Frequency-Welded ERW Pipe and Flash-Welded Pipe With Respect to HCA-Related Integrity Assessments
Authors: Kiefner John F.
Published: January 2009

The new regulations, Part 195 Section 195.452, require that special integrity assessments be made to address potential seam-defect problems in low-frequency-welded ERW (electric-resistance-welded) pipe materials where a failure of such materials could have an impact on a high-consequence area (HCA). The spirit of this requirement appears to require action if, and only if, significant seam-related deficiencies are in evidence or if they can be reasonably anticipated. This leaves open the option of categorizing these types of pipelines by performance such that potentially problematic pipeline segments can be subjected to special (i.e., seam-quality) inspections while those that show little or no propensity for such problems can be subjected to metal loss and deformation inspections only. This document is intended to establish a systematic procedure to permit an operator to characterize the relevant ERW pipe segments as to the likelihood of significant seam-related deficiencies. The author is particularly grateful to Rich Turley of Marathon Ashland Pipe Line LLC for helping to formulate the essential steps in deciding when an integrity assessment is needed. Rich made significant inputs to Figure 1 of this document.
Considerations in Gas Pipeline Commissioning to Prevent Hydrate Formation
Authors: Guo Boyun , Ghalambor Ali , Xue Chengcai
Published: January 2009

Formation of gas hydrates in gas production pipelines is one of the major problems in deepwater development. Most of the research work has focused on the problem during normal operation conditions. However, this problem can arise during pipeline commissioning and get worse after commissioning, even though export gas is dry enough to be considered as a hydrate-free fluid under normal operation conditions. This is because the water content that was left in the pipeline during commissioning can initiate formation of gas hydrates when export gas is introduced into the pipeline. The water content depends on the commissioning procedure and fluids used during the commissioning. This paper presents a systematic method to optimize the commissioning procedure. An application example is also presented.
Performance Analysis of Electric Submersible Pumps (ESP) Handling Two-Phase Mixtures
Authors: Caridad Jose´ , Kenyery Frank
Published: January 2009

Behavior of Electric Submersible Pumps (ESP) handling two-phase flow is a subject of primary concern, especially in the petroleum industry, where significant amounts of free gas may be found in oil wells production. Several attempts have been made in order to predict the performance of such kind of pumps, nevertheless, limited success has been achieved due to the complexity of the flow dynamics inside the impeller. Geometry, gas void fraction (GVF) and suction pressure seem to be the main parameters affecting ESP performance. Furthermore, the higher the GVF of the mixture is, the higher the degradation of head that it is experimented by the pump. This complex phenomena is not well understood so far. In this work, a two fluid model is used in 3D CFD simulations carried out in order to obtain the pressure, liquid velocity and gas velocity fields as well as the GVF distribution in an ESP impeller of known geometry; using flow rates, bubble diameter and GVF at the suction as independent variables and an incompressible fluid hypothesis. The gas pocket in the impeller blade reported from other researchers is obtained and comparison with experimental results has shown good agreement. The obtained variables from the simulations are the cornerstone that allows the prediction of the performance curve of the pump for different GVF and in this way, estimate the head degradation of the pump.
Modeling of Transient Two-Phase Flow in a Well After Startup of Electrical Submersible Pump
Authors: Ruiz-Maldonado Oscar , Fairuzov Yuri V.
Published: January 2009

A numerical model of transient two-phase in a wellbore after startup of electrical submersible pump (ESP) was developed in the present study. The model consists of three modules. The first module, the wellbore model, predicts two-phase gas-liquid flow in the wellbore. The second module describes performance characteristics of centrifugal pumps. The third module, the reservoir model, predicts the variable well inflow after startup of the pump. The wellbore model is based on a drift-flux model (three equation model) of two-phase flow. The relative velocity is determined using a flow regime-dependent slip correlation or a mechanistic steady flow model. Field data collected during a startup of an ESP well were analyzed. This analysis showed that the response of the system to the ESP startup is governed by dynamic interacticn between the well and reservoir. The results obtained can be used for the development of production startup or restart procedures for wells equipped with ESP systems.
Worldwide Field Experience of Mobile Well Testing Services With Multiphase Flowmeters
Authors: Theuveny Bertrand C. , Pithon Jean Francois , Loicq Olivier , Se´ge´ral Ge´rard
Published: January 2009

The paper presents the field performance of mobile multiphase flowmeters in more than 500 well tests during the last three years. The field tests were conducted on land or offshore in a wide range of field operating conditions, such as high flowing pressure, heavy oil, viscous fluids, gas and wet gas, gas volume fraction ranging from 10% to 99.6%, and water to liquid ratio frcm 0 to 100%. An in-depth analysis of the lessons learned shows the benefits and limitations of the technology in comparison to the traditional test separators and illustrates the expected range of accuracies that can be readily achieved in the field environment. Statistics from over 600 comparison tests provide a complete understanding of the accuracies of oil, gas, and water flow rates achieved with the multiphase flowmeter. The dual-energy spectral gamma ray venturi multiphase flowmeter requires the measurements of few basic well site fluid properties. A procedure, detailed in the paper, explains the utilization of a field kit specifically designed for this application when no prior information of fluids is available, which is frequently the case in well testing in new areas. The paper presents how the specifically engineered test-design software provides a rapid-decision tool to the selection of the best well testing solution (multiphase flowmeter or test separator). Finally, some operational recommendations for performance of well tests using multiphase flowmeters shares the experience acquired in these 500 operations performed worldwide.
Unified Model for Gas-Liquid Pipe Flow Via Slug Dynamics: Part 2 — Model Validation
Authors: Zhang Hong-Quan , Wang Qian , Sarica Cem , Brill James P.
Published: January 2009

In Zhang et al. [1], a unified hydrodynamic model is developed for prediction of gas-liquid pipe flow behavior based on slug dynamics. In this study, the new model is validated with extensive experimental data acquired with different pipe diameters, inclination angles, fluid physical properties, gas-liquid flow rates and flow patterns. Good agreement is observed in every aspect of the two-phase pipe flow.
A Slug Damper for Compact Separators
Authors: Kouba Gene E.
Published: January 2009

A common concern with the reduced capacity of compact gas/liquid separators, such as the GLCC©, is that flow fluctuations are passed through the separator with little dampening. Rate sensitive devices, e.g., meters, hydrocyclones, etc., located downstream of the compact separator often have a desired turn-down of less than 10 to 1. However, in slug flow, the instantaneous liquid flow rate in the body of a slug can easily exceed 10 times the average liquid flow rate, with a dynamic range closer to 100 to 1. Consequently, use of the GLCC requires careful consideration of the downstream systems and their susceptibility to flow fluctuations. The slug damper was developed to reduce the magnitude of short period flow fluctuations by providing an inexpensive way of increasing liquid retaining capacity of the inlet piping to the GLCC. These preliminary results show that the slug damper system does indeed dramatically reduce exiting flow rate fluctuations from incoming slug flow. Furthermore, the slug damper performed in a predictable manner with no observed instabilities or unusual operation modes.
A Unified Two-Fluid Model for Multiphase Flow in Natural Gas Pipelines
Authors: Ayala Luis F. , Eltohami Eltohami S. , Adewumi Michael A.
Published: January 2009

A unified two-fluid model for multiphase natural gas and condensate flow in pipelines is presented. The hydrodynamic model consists of steady-state one-dimensional mass and continuity balances for each phase and a combined energy equation to give a system of five first-order ordinary differential equations. The hydrodynamic model is coupled with a phase behavior model based on the Peng-Robinson equation of state to handle the vapor-/liquid equilibrium calculations and thermodynamic property predictions. The model handles single and two-phase flow conditions and is able to predict the transition between them. It also generates profiles for pressure, temperature, and the fluid velocities in both phases as well as their holdups. The expected flow patterns as well as their transitions are modeled with emphasis on the low liquid loading character of such systems. The expected flow regimes for this system are dispersed liquid, annular-mist, stratified smooth as well as stratified wavy.
Effect of 2-Phase Oil-Water Flow and Friction Pressure Loss in the Wellbore on Water Cresting in Horizontal Wells
Authors: Inikori Solomon O. , Wojtanowicz Andrew K.
Published: January 2009

Horizontal well application to mitigate water coning problems have gained wide industry acceptance. However, horizontal wells themselves have not been free from water coning (cresting) problems. A major challenge before industry operators is the effective modeling of water crest development in horizontal wells. More often, mathematical models developed for fluid flow in horizontal pipes have been adopted for modeling horizontal well performance but these have been largely inadequate. This paper presents a more encompassing tool for evaluating the performance of horizontal wells with bottom water drive which incorporates all the effects of perforations, 2-phase liquid-liquid flow and axial influx of fluid into the wellbore. A new value of equivalent pipe roughness function is developed for use in the numerical simulators to accommodate the inadequacies of the current commercial softwares. The empirical results using published data from the North Sea indicate a more practical representation of the phenomenon of water cresting in horizontal wells and the level of severity. Two major factors affected by the application of the new approach are; a reduction in the time to water breakthrough as previously predicted by analytical tools, and an effective representation of the geometry of water cresting in horizontal wells similar to field experiences. The paper also shows that direct application of horizontal pipe models in horizontal well is grossly inadequate. Finally it shows use of horizontal wells in the development of reservoirs underlain by water needs adequate evaluation.
Three Dimensional Stress Analysis and Optimisation of Elevators for Drilling by Photoelasticity
Authors: Abdulaliyev Z. E. , Egrican N. A. , Karadag Vedat
Published: January 2009

Elevators designed to suspend tubing and drilling pipes in tripping operations are complex structures in petroleum drilling processes. Due to complexity of structure of elevators designed to suspend tubing in tripping operations used in oil well service, many stress geometrical concentration zones occur, and the three dimensional stresses can’t be calculated accurately with sufficient precision and easily by analytical and numerical procedures. To determine and optimise the real stresses occurring at these structures, the photoelasticity method is used reliably. Three dimensional models made from optically sensitive materials and freezing of strains technique are applied to analyse the stresses throughout in the present analysis. The obtained results can be applied to test the currently existing package programmes and to write new computer algorithmes for the related systems.
Lateral and Torsional Vibration Analysis of Elastic Robot Manipulators With Prismatic Joint
Authors: Kalyoncu Mete , Botsalı Fatih M.
Published: January 2009

Lateral and torsional vibrations of a robot manipulator with an elastic arm sliding in a prismatic joint are analyzed. The elastic arm is assumed as an Euler-Bernoulli beam. The mass of the end-effector is assumed as a point mass attached at the end of the elastic arm. The prismatic joint experiences 3-dimensional translational and rotational motion. The prismatic joint is assumed as rigid and frictionless. Rotational inertia of the beam is taken into consideration in obtaining the equations of motion. Elastic deformations are assumed as linear and small displacements. Axial vibrations are not considered but the effect of axial force is taken into account in the analysis. Elastic arm experiences both bending vibrations in two directions and torsional vibrations. The equations of motion are obtained by Lagrange’s equation of motion. Numerical solution of the equations of motion are obtained by Runge-Kutta method. A computer program is developed for implementation of the presented technique. Numerical simulations are presented in the form of graphics. Presented method is found to be versatile in dynamic analysis of elastic robot arms.
New Results on Mesh Adaptation in Space-Time Finite Element Method
Authors: Adelaide Hector , Bohatier Claude , Jourdan Franck
Published: January 2009

In this paper, a new mesh adaptation method which deals with a space-time finite element approach is proposed to solve frictional contact contitions. Firstly, this method is performed on an elementary elastodynamic example and on a contact problem.
Blade Modeling of an Axial Flow Fan Under Vibration Constraints: An Experimental and Analytical Investigation
Authors: Catania Giuseppe , Naldi Giovanni
Published: January 2009

A fan blade automatic modelling and design technique is proposed. Starting from axial flow fan nominal head H, flow rate Q and revolution speed ω, a numerical constrained optimization procedure is proposed. Fluid-dynamic, as well as geometrical, structural and vibration constraints are taken into account in the evaluation of the optimal objective function. Details of the numerical implementation, as well as results concerning a real application example, are reported and discussed.
Non Linear Active Control of the Dynamic Behavior of Bi-Articulated Flexible Structures
Authors: Bochard Ste´phane , Gaudiller Luc , Der Hagopian Johan
Published: January 2009

When vibrating structures are subjected to large displacements, coupling may occur between the vibrations and the displacements inducing possibly strongly non-linear behavior. In this case, linear control algorithms and independent control strategy are no longer suitable. This study deals with the nonlinear control of Bi-articulated structures. A model that combines both finite element (FE) discretization, taking into account strains/electric field coupling, and global behavior is carried out. Multivariable control is carried out by electromechanical and piezoelectric actuators. The control strategy developed consists in weighting the output of parallel state controllers, calculated for the p discretized operating points crossed during the progression of the structure’s dynamic behavior. The multivariable control u is obtained by weighting interpolation functions fi of the linear quadratic control gains Ki of each controller optimized according to large displacements. The first application to Bi-articulated rigid beam systems shows, in comparison with a stable linear control, that non-linear control is by far the better of the two. This is mainly due to increased efficiency of motor torque use. The second application of the proposed nonlinear control algorithm concerns a Bi-articulated flexible beam system modeled by two rigid body modes and five flexible modes. The control obtained is robust regarding both stability and performance. Quasi-steady controlled dynamic behavior is obtained during movement.
Wireless Operation Monitoring System for Polymer Covered Cylinders in Rolling Contact
Authors: Miettinen Juha , Salmenpera¨ Pekka , Ja¨rvinen Ville , Hirvonen Matti
Published: January 2009

Polymer covered cylindrical rolls are typically used in different paper machine sections like in calenders and in coating units. The main reason for the use of soft-coated rolls is that by using the soft rolls the contact area becomes larger. Strongly loaded line contact causes deformations and heat generation in the polymer cover. In paper production process impurities, like paper pieces, may catch on the surface of the roll. Impurities cause locally larger deformation in the cover. The local deformation produces a higher local temperature area, which can cause cracks in the cover, to loosen the cover from the base and to fracture the cover locally. If a local failure happens the fragments of the cover can damage also the other rolls. In this paper an operation monitoring system for on-line monitoring of roll cover is presented. The system is installed in a laboratory pilot roll installation, where the rolling contact consists of a hard and a soft roll. The measurement system consists of on-line measurement of acoustic emission (AE) of the roll. Additionally the temperature distribution of the roll, the ploymer cover and the position angle of the roll are measured. The measurement signal is transferred from the rotating roll via wireless local area network (WLAN) to the measurement computer. The measurement control computer is connected to the LAN of the laboratory and the measurements can be followed and analyzed with different computers and also via Internet. The paper describes the principles of acoustic emission signal processing and analysis and the construction of the wireless Ethernet-based operation monitoring system.
On the Transient Response of the Thrust Bearing
Authors: Kettleborough C. F. , Goldsberry F. L.
Published: January 2009

The transient response of the thrust slider bearing has been studied numerically. Of greatest interest is the mode of boundary layer formation and the subsequent development of the pressure in the supporting film in the slider bearing as it is subject to tangential acceleration. It is planned to study two basic types of bearings — the first being the fixed-shoe type, while the second is the tilting-pd bearing. The bearings are subjected to types of loading (a) a constant load and (b) an inertial load due to the displacement or load on the runner. The computer solution is based on a simplified form of the Navier-Stokes equation in the tangential direction to determine the velocity distribution and a modified form of Reynolds’ equation to determine the pressure distribution along the pad or shoe of the bearing. The resulting formulation is a simple explicit tangential velocity difference equation in time and a fully implicit difference equation solution for the pressure, which is independent of time. The results of this endeavor are quite interesting and significant. For a simple fixed geometry case which allows the supported load to vary, the load versus time curves compare extremely well with previous findings by other investigators using an entirely different mathematical approach. The supporting film is found to be fully developed in the course of a few milliseconds for a step acceleration. For a step deceleration, the squeeze film concept is demonstrated in the flow field. In cases considering inertial loading due to the thrust runner, a tangential acceleration may produce a damped oscillation in the transverse direction. But in all probability, the most interesting discovery was that in a tilting-pad bearing or any simple slider bearing, the center of pressure which corresponds to the pivot point is a function of the film ratio (see equation (I 1)).
Stress Analysis of Composite Tubes Under Tensile Fatigue Loading in a Simulated Seawater Environment
Authors: Lindsey Christopher G. , Masudi Houshang
Published: January 2009

It is the purpose of this study to investigate the effects of fatigue loading on two variations of hybrid composite tubes. The two types of samples are both composed of AS-4D/carbon fibers and e-glass fibers. The key distinctions between the two samples being the orientation and the number of layers. The samples were composed of the following orientations [90/20/90/20/90/20/20/90/20] and [90/90/20/90/20/20/90/20]. The experiment is designed to not only compare the two samples, but to develop some experimental data for a fatigue curve for similar materials. All loading for this experiment takes place in a controlled environment. Both temperature and the specific gravity of the water are measured and controlled.
Unilateral Contact With Friction of Polyhedron Multibody Systems: Numerical Aspects
Authors: Bohatier Claude , Saussine Gilles
Published: January 2009

This paper presents ways for modeling the unilateral contact with friction between solids in order to simulate a collection of polyhedrons during evolution. In a first stage 2D problems of polygon collections are explored, then the friction conditions are easy to take into account by several available equivalent modeling. In a second stage 3D problems of polyhedron collections are considered. The aim of this paper is to propose efficient algorithm to solve the 3D numerical problems in granular material simulations.