The continuous demand for oil and gas forces the petroleum industry to develop new and cost-effective technologies to increase recovery from new fields and enhance extraction from existing fields. Subsea wet gas compression stands out as a promising solution for increasing production capacity, utilizing remote regions and reducing costs. A prerequisite for successful oil and gas production utilizing subsea wet gas compressors is operability. This includes the system’s ability to cope with operational changes, without having to shut down. One of the fundamental operational changes is the liquid content in the inlet pipe, which may fluctuate considerably at certain time intervals. The current study investigates how changes in liquid content impacts compressor performance. An experimental test campaign has been performed at the Norwegian University of Science and Technology (NTNU). The test facility is an open loop configuration consisting of a single shrouded centrifugal impeller, a vaneless diffuser and a symmetrical circular volute. The main objectives were to document how the presence of liquid impacts the compressor characteristics and further, how the operating point moves within the characteristics when solely subjected to an increase of liquid content. The compressor was exposed to liquid contents ranging from gas mass fraction 1.0 to 0.60. The test reveals that the compressor pressure ratio at wet conditions is higher in comparison to dry conditions. Care should be taken when analysing stability and surge margins at variations in fluid liquid content. Further, the compressor behaves in a predictable manner, revealing several linear trends, when subjected to stepwise changes in liquid content from a fixed operating point.

The Measurement While Drilling (MWD) tool is used by oil and gas industry to provide the directional survey information while drilling. With rig rates exceeding $1 million per day and wells that are drilled at depths of over 30,000 ft (9144 m), operators needs to have an MWD tool that can self-power itself to provide high data rates and strong signal strength. Among different types of MWD tool, the Continuous Mud-Pulse Telemetry (C-MPT) can generate high data rates and signal strength. The C-MPT has a rotating valve that propagates signal upstream through the drilling fluid in the drill string. However, the ability to power a C-MPT for the MWD tool using the existing hydraulic forces of the drilling fluid has not been extensively researched. The focus of this study was to propose the 2-lobe and 3-lobe turbo siren designs that can provide power to an alternator while maintain high data rates and signal strength. All turbo siren designs are based on a vein, rotor, and stator. The turbo siren systems were manufactured with 3D printing. An experimental wind tunnel was designed and built to simulate the downhole drilling environment. The testing results of the turbo siren systems are presented and discussed, including no-load rotation speed (RPM), stall torque, power and data rate. The results provide the guidance for the optimization of the self-powered MWD turbo siren design.

An Arrhenius relationship is employed to develop a model for prediction of gas permeation in the polymeric materials. A permeation cell was designed to measure the gas permeation. The permeation of Helium was examined over a range of low to high temperature and pressure conditions. The results of the experiments were used to verify the accuracy of the prediction model. The obtained model was successful in predicting gas permeation rate at two different pressures. The results showed that pressure’s effect is insignificant on models. The predicted results for different pressure were close, and both models can be used to obtain an approximation for gas permeation rate for the examined material where no experimental data exists.

Norwegian industries are constantly assessing new technologies and methods for more efficient and safer production in the aqua cultural, renewable energy, and oil and gas industries. These Norwegian offshore industries share a common challenge: to install new equipment and transport personnel in a safe and controllable way between ships, farms and platforms. This paper deploys the Moving Frame Method (MFM) to analyze the motion induced by a crane and controlled by a gyroscopic inertial device mounted on a ship. The crane is a simple two-link system that transfers produce and equipment to and from barges. An inertial flywheel — a gyroscope — is used to stabilize the barge during transfer. The MFM describes the dynamics of the system using modern mathematics. Lie group theory and Cartan’s moving frames are the foundation of this new approach to engineering dynamics. This, together with a restriction on the variation of the angular velocity used in Hamilton’s principle, enables an effective way of extracting the equations of motion. This project extends previous work. It accounts for the dual effect of both the crane and the stabilizing inertial device. Furthermore, this work allows for buoyancy and motor induced torques. Furthermore, this work displays the results in 3D on cell phones. The long-term results of this work leads to a robust 3D active compensation method for loading/unloading operations offshore. Finally, the interactivity between the crane and the stabilizing gyro anticipates the impending time of artificial intelligence when machines, equipped with on-board CPU’s and IP addresses, are empowered with learning modules to conduct their operations.

Multiphase flow is commonly found in almost every process related to oil and gas industry. The precise prediction of the flow behavior is essential to provide safe and efficient hydrocarbon recovery. An accurate characterization of multiphase flow plays a major role in well design optimization and development of successful production and transportation facilitiess. Even though the hydrodynamic behavior of multiphase flow in various pipe geometries typically found in the industry has been widely studied, there is still very little known about the flow pattern and hydrodynamic conditions presented in horizontal annular geometry. Current work presents Computational Fluid Dynamics (CFD) simulation of two-phase oil-water flow in horizontal concentric annuli using different turbulence models and Eulerian-Eulerian continuous-disperse interphase drag model. Water was modelled as disperse phase, while oil was considered as continuous phase. Effect of water droplet diameter in the interphase model is extensively discussed in this paper. Results of the simulations are compared to the experimental data for a variety of liquid velocities and water cuts.

Multiphase flows are encountered in many engineering problems. Particularly in the oil and gas industry, many applications involve the transportation of a mixture of oil and natural gas in long pipelines from offshore platforms to the continent. Numerical simulations of steady and unsteady flows in pipelines are usually based on one-dimensional models, such as the two-fluid model, the drift-flux model and the homogeneous equilibrium model. The 1991’s version of the well-known and widely-used commercial software OLGA describes a system of non-linear equations of the two-fluid-model type, with an extra equation for the presence of liquid droplets. It is well known that one-dimensional formulations may be physically inconsistent due to the loss of hyperbolicity. In these cases, the associated eigenvalues become complex numbers and the model loses physical meaning locally. This paper presents a numerical study of the 1991’s version of the software OLGA, for an isothermal flow of stratified pattern, in a horizontal pipeline. For each point of interest in the stratified-pattern flow map, the eigenvalues are numerically calculated in order to verify if the eigenvalues are real and also to assess their signs. The results indicate that the model is conditionally hyperbolic and loses hyperbolicity in a vast area of the stratified region under certain flow conditions. Even though the model is not unconditionally hyperbolic, some simulations here performed for typical offshore pipeline flows are shown to be in the hyperbolic region.

In oil and gas industry, machineries and mechanical components are designed with high reliability to meet the demand of the oil field. Rotating machinery is a widely used equipment and any failure of critical components within the machinery could lead to delays and large expenses. Failure of rotary seal is one of the foremost causes of breakdown in rotary machinery and such a failure can affect the other process operations in oil and gas plants. Assessing seal degradation and severity estimation are very important for maintenance decision-making. Extracting meaningful and sensitive features that can show seal degradation from raw signals is a challenging task of degradation assessment. However, no extensive works are dedicated in this area of seals. In this paper, we perform accelerated aging and testing to capture the behavior of seals through their cycle of operation and demonstrated a statistical time domain feature based approach for extracting the sensitive features that can show seal degradation. Out of eleven statistical features extracted, seven extracted features such as mean, RMS, maximum, squared mean rooted absolute amplitude, impulse factor, crest factor, margin factor are found to be significant factors which have a potential to differentiate severity levels in seals. The findings from our work show that our approach has a potential to assess the severity in seals. As a possible extension, extracted features can be used to build a classification model to classify severity in seals which could be of great interest to the users and manufacturers of rotary seals.

The ongoing research for model choice and selection has generated a plethora of approaches. With such a wealth of methods, it can be difficult for a researcher to know what model selection approach is the proper way to proceed to select the appropriate model for prediction. The authors present an evaluation of various model selection criteria from decision-theoretic perspective using experimental data to define and recommend a criterion to select the best model. In this analysis, six of the most common selection criteria, nineteen friction factor correlations, and eight sets of experimental data are employed. The results show that while the use of the traditional correlation coefficient, R 2 is inappropriate, root mean square error, RMSE can be used to rank models, but does not give much insight on their accuracy. Other criteria such as correlation ratio, mean absolute error, and standard deviation are also evaluated. The Akaike information criterion, AIC has shown its superiority to other selection criteria. The authors propose AIC as an alternative to use when fitting experimental data or evaluating existing correlations. Indeed, the AIC method is an information theory based, theoretically sound and stable. The paper presents a detailed discussion of the model selection criteria, their pros and cons, and how they can be utilized to allow proper comparison of different models for the best model to be inferred based on sound mathematical theory. In conclusion, model selection is an interesting problem and an innovative strategy to help alleviate similar challenges faced by the professionals in the oil and gas industry is introduced.

Multi-phase flow is encountered in multiple industrial disciplines including oil and gas industry starting from the reservoirs, production tubes, well heads, separators and transportation systems comprehending risers & onshore/offshore transportation pipelines. The complex nature & instability of slug flow where pressure, temperature, velocities and flow rates oscillate lead to high fatigue loads on mechanical elements in pipelines. The prediction of the two-phase flow pattern inside pipelines is crucial in extending the life of the pipeline. This paper proposes the first numerical approach for predicting the vibration of a three-dimensional pipeline with an elbow due to two-phase flow using one-way fluid-structure interaction technique using the commercial software ANSYS. The unsteady Reynolds-averaged Navier-Stokes equations with three turbulent models are used to model the fluid domain. The finite element analysis is used to model the pipeline by using shell elements. The two-phase mixture superfacial velocities inside the pipeline were identified by measuring the acceleration response of the surface of the pipe. Modal analysis is performed to check the variation of the pipeline natural frequency with the water content in the flow. The simulation results were validated with experimental data. Based on the simulation results, a numerical method for the measuring of the two-phase flow rates is proposed.

Floating Production, Storage and Offloading (FPSO) units are floating vessels used by the oil and gas industry offshore for the production and processing of hydrocarbons as well as storage of oil. It is equipped with the required facilities to produce, process, and store produced fluids. Among the equipment on board of the FPSO are pumps used to inject water or pump crude oil. This FPSO is fitted with seven positive displacement pumps powered by diesel engines; three for water injection and four for power fluid. At the exhaust of the driving engines, stainless steel bellows experienced frequent failures on a monthly basis; thereby, incurring a huge financial overburden on operating companies. Therefore, the aim of this paper is to explore the possibility of identifying some remedies to overcome this problem. The paper discusses the root causes of bellow failures attached to the exhaust system of a diesel engine on board of an FPSO. Effect of vibration, temperature, corrosion, and vessel rolling on the bellow structural response were investigated to identify the root causes of failure. A finite element modeling of the problem under study was conducted by taking into account the combined effect of thermo-mechanical loads. It was found that the thermal stress was well below the allowable stress. In addition, vibration analysis of the bellow-engine system revealed that the fundamental frequency of the bellow was way below the engine’s natural frequency. However, it was found that the vessel’s rolling generated an elevated stress that can cause failure of the bellow in a very short period time. The paper also presents some possible solutions to remedy or delay failure from occurring frequently as in this case.

API rated flanges [1] are used in oil and gas industries frequently. The current practice is to select a flange and its seal/gasket from a tabulated range of load and area of application. Some applications may require a unique flange or seal for a pressure and temperature that is not listed on the table. To design such non-API flange (geometry such as thickness, number of bolts, bolts pattern, etc. are different from API flange) that meets system requirements is a challenge. Currently there is no standard available as per authors knowledge to design non-API flange. Therefore, in this study, a finite element analysis with new acceptance criterion for the 5”-15-ksi non-API flange connection for different pressure and temperature has been performed. Elastic-plastic finite element analysis method is used to check the leak tightness [2]. A fatigue calculation based on elastic-plastic analysis with twice yield method as per ASME Section VIII, Division 2 [3], sec. 5.5.4, has also been performed. A new acceptance criterion based on industry practices are used for leak tightness. The contact pressure and contact pressure band width are used to check the leak tightness. The results showed that for all load cases seals have enough contact pressure and contact pressure band width to prevent leakage and they meet the acceptance criteria. The calculated fatigue life was found more than the required life for an application.

Energy pipelines require regular inspection and health monitoring against defects, cracks, and corrosion due to the fluid pipe interaction and external environment conditions. Accurate and efficient pipeline inspection is extremely important to the oil and gas industry. Inspection of pipelines is usually carried out either internally using smart pigs and tethered robots or externally with limited inspection options. Internal inspection has many limitations and external inspection is still primitive. However, external inspection has the advantage of being carried out without interruption of the production process. In this paper, a novel design for an autonomous robot for pipeline external inspection is presented. Although, the proposed design is developed mainly to fit a magnetic flux leakage based inspection technique, the robot modular design will fit other inspection methods and applications with minimal design modifications. The proposed robot is designed to carry multiple hall effect sensors and allow adjustment of the radial distance between the sensors and the pipe surface. Also, the robot is able to scan different size pipes and maintain constant distance from the pipe surface. A prototype is fabricated using 3D printer and standard fasteners to evaluate the workability of the proposed design. The initial testing of the developed prototype showed that the robot can be made to move at a constant speed without slipping. The design details and the prototype elements are delineated in this paper.

Modeling of heat loss from offshore buried pipelines is one of the prime concerns for Oil and Gas industries. Offshore Oil and Gas production and thermal modeling of buried pipelines in arctic regions are challenging tasks due to environmental conditions and hazards. Flow properties of Oil and Gas flowing through the pipelines in arctic regions are also affected due to freezing around pipelines. Solid formation in the production path can have serious implications on production. Heavy components of crude oil start to precipitate as wax crystal when the fluid temperature drops. Gas hydrates also form when natural gas combines with free water at high pressure and low temperature. Pipeline burial and trenching in some offshore developments are now one of the prime methods to avoid ice gouge, ice cover, icebergs, and other threats. Long pipelines require more thermal management to deliver production to the sea surface. Significant heat loss may occur from offshore buried pipelines in the forms of heat conduction and natural convection through the seabed. The later can become more prominent where the backfill soil is loose or sandy. The aim of this paper is to provide an insight of modeling and conducting the experiments using different parameters with numerical analysis results support to investigate the heat loss from offshore buried pipelines. This paper also provides validation of the outputs from benchmark tests with analytical models available for theoretical shape factor at constant temperature and constant heat flux boundary conditions. These theoretical models have limitations such as the assumption of uniform soil properties around the buried pipeline, isothermal outer surface of the buried pipeline and soil surface. Degree of saturation of surrounding medium can play a significant role in the thermal behavior of fluid travelling through the backfill soil. This paper presents several steady states and transient response analysis describing some influential geotechnical parameters along with test procedures and numerical simulations using CFD to model the heat loss for different parameters such as burial depth, backfill soil, trench geometries etc. This paper also shows the transient response for several shutdown (cooldown) tests performed in the saturated sand medium. The statistical and uncertainty analysis performed from the experimental outputs also ensure the legitimacy of the experimental model. The outcomes of this research will provide valuable experimental data and numerical predictions for offshore pipeline design, heat loss from buried pipelines in offshore conditions, and efficient model to mitigate the flow assurance issues e.g. wax and hydrates.

Solids suspension has broad applications in the oil and gas industry (i.e., sand production, cuttings transportation during drilling, and barite sag in drilling fluids). The conventional modeling approaches for solids suspension and transportation include mechanics models (i.e., layer models) and computational fluid dynamics (CFD) based Eulerian-Lagrangian models. One of the most important assumptions for these approaches is that the solid particles have uniform size, which is not true in the actual applications. The computational fluid dynamics/discrete element method (CFD-DEM) approach can track each single particle in the system; however, the computational time is not practical for industrial applications. This paper presents a relatively simple Eulerian approach for characterizing solids suspension in multiphase flow systems. The multiphase flow equations are derived by using a proper averaging procedure without considering interphase mass transfer. A proposed new solids suspension model, which is based on the fluid-solid interaction and kinetic theory, account for multiple solids sizes in the flow. The suspension characterizations for particles with different sizes are considered by introducing a particle size distribution function, which also captures detailed particle distribution and fluid/particle and particle/particle interactions. Therefore, a more realistic solids transportation prediction can be achieved. A simulation package is developed by solving the model using the finite difference method. The boundary-fitted coordinate system is applied to integrate the irregular geometry caused by drillpipe eccentricity and a packed solids bed. The influence of the solid phase on the carrier fluid is considered, and solid-liquid two-way coupling is implemented. The simulation package has been used for transient hole cleaning simulations during drilling. Simulation results show that cuttings’ backsliding makes the hole cleaning process in intermediate inclined wells different from that in horizontal and highly inclined wells. The cuttings movement in this part of the well follows the two-steps-forward, one-step-back routine. Well packoff is also captured by the program for improper hole cleaning operations in an intermediated inclined position. Transient hole cleaning tests were conducted on a 90 ft long, 8 × 4.5 in. flow loop. Experimental data are compared with the simulation results, and good matching is obtained. This method can also be used as a general tool for solids suspension and transportation simulation in multiphase systems.

Two phase flows occur in many engineering problems, especially in the nuclear, gas and petroleum industries. In oil and gas applications, specifically, a mixture of oil and natural gas is transported in pipelines from offshore platforms to the continent. The prediction of how the flow behaves in time as it moves along the pipe is extremely important, mainly during the pipeline design stage or regular operation. This paper presents simulations for stratified gas-liquid two-phase flow in a horizontal pipeline that is subject to the temperature gradients that exist in the bottom of the ocean, and the resulting heat transfer process that may lead to wax formation and deposition. A one-dimensional two-fluid mathematical model was employed that includes conservation equations of mass and momentum for each fluid and one energy equation for the mixture of liquid and gas. The problem was formulated as an initial-boundary value problem of the hyperbolic type and it was solved using the Flux Corrected Transport (FCT) numerical method, which is second-order accurate in space, coupled with an explicit discretization in time that is first-order accurate. The FCT method is appropriate to solve problems characterized by hyperbolic equations that may contain discontinuities and shock waves, and it presents small dispersive effects. The results showed excellent accuracy results when compared to commercial software widely used in the oil and gas industry.

Oil-water dispersed flow, in which one of the phases either water or oil is dispersed into the other phase, which is the continuous phase, occurs commonly in Petroleum Industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties and other factors. Production equipment, such as pumps and chokes, generate shear in oil-water mixture flow, which has a strong effect on phase inversion phenomena. In this study, based on the newly acquired data on a gear pump, the relationship between phase inversion region and shear intensity are discussed and the limitation of current phase inversion prediction model is presented.

Quantification of oil droplet shearing in produced water treatment facilities is a crucial aspect of operations for the oil and gas industry. In this paper, a detail mathematical modeling of droplet breakage and coalescence using a Population Balance Method (PBM) is addressed. The PBM models the dynamics of droplet size distribution due continuous interactions between individual droplets (such as coalescence and breakup). An understanding of the PBM in regards to the conservation of mass of dispersed droplets is also developed. A stand-alone PBM is used for calculating coalescence and breakage rates in a system having homogeneous mixture and constant turbulent energy dissipation. A coupled computational fluid dynamics-PBM approach is also implemented in a hydrocyclone to examine the local rates of droplet breakup and coalescence. Effects of the turbulent intensity and the interfacial tension of an oil-water mixture and the volume fraction of the dispersed phase on the time evolution of volume fraction distribution and Sauter mean diameter are examined. Results show that, for typical fluid properties associated with produced water, droplet-droplet coalescence is dominant over droplet breakage when the turbulent energy dissipation (ε) is small; the opposite is found for regions associated with high energy dissipation. In a hydrocyclone, the rate of droplets shearing is significant near the entry and at the inlet chamber; this rate decreases downstream. The research outcomes based on the stand-alone PBM and coupled CFD-PBM approaches allow us to identify and redesign the critical part of the water treating facilities to minimize shearing of dispersed droplets.

Frequently, Two-phase flow occurs in petroleum industry. It takes place on production and transportation of oil and natural gas. Initially, the most common patterns for vertical flow are Bubble, Slug, Churn and Annular Flow. Then, for horizontal flow, the most common patterns are Stratified Smooth, Stratified Wavy, Elongated Bubble, Slug, Annular, Wavy Annular and Dispersed Bubble Flow. It is also known that after separation, each fluid is carried through pipes, so oil is moved long distances. However, as it is known, the oil energy diminishes on the way. For that reason, it is needed a pumping station for keeping the oil flow energy high for proper movement. Additionally, that fluid is transported through a network, so fittings are present, like elbows, “T” and “Y” junctions, and others. As known, on a piping network, the losses can be classified in two groups: large and localized. The former consists on losses due to wall roughness-fluid interaction. The latter is related with fittings. This study is focused on 45° “Y” junctions. The main purpose of this study is to simulate the fluid flow on a 45° “Y” junction, using a 0.1143 m diameter 2 m length pipe, in which a 0.0603 m diameter 1 m length pipe confluences, using oil-gas as the working fluid, considering Dispersed Bubble Pattern. It can be attributed a “K” flow loss coefficient for each path, from each entry to the exit of the junction. For the Two-Phase Flow, it was supposed a horizontal Dispersed Bubble Pattern, which takes place at very high liquid flow rates. So the liquid phase is the continuous phase, in which the gas phase is dispersed as discrete bubbles. Particularly three API Grades were considered for the oil, corresponding to three main types of continuous phase. For the numerical model, it was generated several non-structured grids for validation, using water as a fluid. Then the simulations were carried out, using non-homogenous model, with oil and gas, changing the gas void fraction, and the superficial velocities for gas and liquid. A commercial package was used for numerical calculations. It was encountered that changing the value of the referred variables, in some cases the exit pressure of the “Y” junction diminishes. For validation of the results, a literature model was used for comparing both “K” loss coefficients: numerically and from the bibliography. It is important to highlight that these results, permit to analyze a way of diminishing the fluid energy losses in a Two-Phase oil-gas piping network, particularly in 45° “Y” junctions which represents economically saving.

The continuous demand for oil and gas pushes the petroleum industry to develop new technologies in order to increase production and exploit existing fields. The wet gas process, based on direct compression of unprocessed well stream subsea is a powerful means to expand the extraction of crude oil and gas and reach remote regions. Consequently centrifugal compressors are key elements that need to be developed in this area. Since no commercial subsea compressors are available and the liquid phase inside the standard process has to be avoided, it is essential to fully understand the machine behaviour, particularly investigate the presence of a gas-liquid mixture. Because of liquid impact, the performance of compressors and consequently the margin of stability may have to be modified. Here, delayed instability inception should be identified. An ongoing research programme is conducted at the Norwegian University of Science and Technology (NTNU) concerning the influence of wet gas on performance and aerodynamic stability. An open loop wet gas test rig is designed and employed in an experimental campaign. The main goal of this study is the visualisation of flow in a vaneless diffuser by means of special windows in Plexiglas, in correspondence with the diffuser and volute. Most attention is focused on the behaviour that leads to unstable phenomena, like stall and surge, in order to expose wet effects. Interactions between the diffuser and volute will also be taken into account. Simultaneously, the analysis will be supported by measurements from high-response dynamic pressure sensors. A fast Fourier transform (FFT) examination will be realised, in order to identify characteristic frequencies of unsteady events.

As easily recoverable hydrocarbon resources are depleting, the oil and gas industry focuses more on producing oil and gas from ultra-deep, tight and scattered pockets of reserves. However, these recoveries are not only difficult and expensive, but also require the development of new technologies and materials that can meet stringent requirements regarding operation in sub-surface environment. The emergence of expandable tubular in the late 1990s has opened a new avenue for oil and gas wells design and remediation processes. However, these tubular go through large expansion in diameter at kilometers depths in onshore and offshore wells. This alters the post expansion mechanical and microstructural properties of the tubular that may lead to premature failure during operation. The idea of understanding such variations revolve around complex mechanisms occurring at micro level including multiphase microstructure, grains sizes and morphology, and crystallographic orientations. Initial grains morphology and distribution of phases, and the subsequent changes due to the expansion process lead to significant variations in material properties at macro level. Optical micrographs showed that the expandable tubular material is composed of fine grained microstructure of ferrite phase with some traces of martensite and plate-like structures. Induced martensite results from the phase transformation of metastable austenite induced by thermomechanical processing applied during the manufacturing stage. A reasonable presence of martensite phase in the tubular material enhances its structural integrity, collapse and burst strengths, as well as provides a safeguard against possible mechanical failures such as buckling. On the other hand, the ferrite phase is a soft phase and its presence improves the formability of the tubular resulting in higher expansion ratio. It was also observed that the grains size is affected by the tubular expansion. The presence of elongated grains in the microstructure is due to the excessive deformation as well as the crystallographic reorientation of grains due to the course of tubular expansion. However, no strong texture has been found in the expanded tubular material, which may be attributed to the complex nature of loadings induced during the expansion process. In order to understand the influence of tubular expansion process on mechanical properties of tubular, samples from un-expanded and expanded sections of the tubular (expanded at 16%, 20% and 24% of the tubular original inner diameter) are investigated using standard mechanical testing procedures. Mechanical testing results revealed an increase in yield strength, ultimate tensile strength and hardness, whereas ductility and impact toughness tend to decrease. Fracture surface analysis of fractured tensile samples has also been done using scanning electron microscope (SEM). At lower expansion ratio, fracture surface micrographs revealed a predominantly ductile nature of failure with clusters of fine microscopic dimples intermingled with voids. However, at higher expansion ratio, the test specimens revealed a mixed mode of failure with both brittle and ductile features.