Papers by Author: R. Nagarajan

Abstract: Oil and Gas industry is going through a phase where there is an increased demand of energy sources (particularly oil and gas) and reduced production due to mature oilfields. There is a need for new technologies which can help improve production from the reservoir and develop new fields. Nanotechnology offers promising solution for the same. Nanotechnology is the study of science of materials at nanoscale which help in enhancing the performance of processes. Nanoparticles are the nanosized materials in the range of 1-100 nm. Nanoparticles have high specific surface area and unique properties, such as high adsorption potential and heat conductivity. These particles when mixed with base fluids, also called as nanofluids, and used for several application related to upstream oil and gas industry, help improve the performance of several processes. The use of nanoparticle in exploration and production is an attractive tool for petroleum engineers that have been improved by many researchers in recent years. This paper discusses about how the nanotechnology plays an important role in an upstream oil and gas industry which includes exploration, drilling, and completion, production and enhanced oil recovery operation.

Abstract: Megasonic cleaning traditionally refers to use of acoustic fields in the 800 kHz 1 MHz range to remove contaminants adhered to surfaces immersed in liquid media. However, even fields driven by frequencies in the > 400 kHz regime exhibit virtually all characteristics of conventional megasonics. These include: unidirectional pumped flow of liquid (acoustic streaming) normal to the transducer, at velocities that scale as square of frequency; and, a near-absence of cavitational phenomena associated with ultrasonic cleaning. For the latter reason, megasonic cleaning is preferred over ultrasonics when attempting to remove contaminants from delicate, fragile, erodible or feature-rich surfaces. Silicon wafer cleaning in semiconductor manufacturing, integrated circuit cleaning, and printed circuit board cleaning have utilized megasonics (with appropriate chemistry) for several decades. The megasonic frequency offers the additional benefit of a very thin boundary layer over the immersed surface, which effectively exposes even sub-micron and nanodimensional particles to the flow of the cleaning liquid.

Abstract: Cavitation erosion is predominant in pipelines for liquid transportation, causing damage to pipe wall, impeller and their accessories. The present study is focused on development of cavitation -wear resistant nano-ceramic particle-reinforced polymer matrix material; and on study of its feasibility to be used as lining material in hydraulic transportation. The polymer/nano composite is fabricated using power ultrasound in all three process steps: synthesis of nano-dimensional particles of white fused alumina (WFA) from micron size particles, optimized blending and finally reinforcement into poly methyl methacrylate (PMMA) matrix. The effect of ultrasonic parameters on nanocomposite/ virgin polymers (like polyethylene and polypropylene) is studied by measuring mass loss of the materials and suspension turbidity during exposure time. At low frequency (20-60 kHz), cavitation intensity is predominant; this effect is utilized for fabricating sub-micron particles, and for performing accelerated cavitation erosion tests. At high frequency, acoustic streaming is predominant; this effect is utilized for blending and reinforcing of the nano ceramic particles into polymer matrix. The size and quantity of the particles generated by cavitation erosion was analyzed by Laser Particle Size Analyzer (20 nm-1400 micron range). The nano-composite coupons were analyzed before and after the ultrasonic erosion test using SEM. It is concluded that lowfrequency sonication is a viable option for cavitaton erosion testing of ceramic/polymer composites.