TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractNanotechnology application can revolutionalise the additive characteristics and behaviour by tuning particle properties to meet certain operational, environmental, and technical requirements. Hence, the nanotechnological research leading to create some tailored made nanoparticles could be a promising step change research for smart fluids development for different industrial applications. These particles are ultra fines in nature, usually larger than an atom cluster but smaller than ordinary micro particles and thus have very high specific surface area with enormous area of interactions. Due to nano-scale particle dimension, the nano-type fluid additives have both external as well as internal inhibition potential, require a very low additive concentration and thus expected to provide superior fluid properties at a drastically reduced additive concentration.Nano-particles with high thermal stability and affinity to acid gases such as H 2 S and CO 2 will help meet the technical challenges of sour gas environment, deep and geothermal drilling and thus expected to complete a well economically and safely with a drastic reduction in oil and gas exploration and exploitation risk. Identification, screening, selection, and/or development of nontoxic, environment friendly and biodegradable nano-particle-based drilling fluids are expected to meet the current as well as the future environmental norms and regulations for drilling and production in deep water and sensitive environments.This paper provides a detailed description of the likely benefits of emerging nano-particle-based additives in smart fluid design for oil and gas field application, especially for a new generation of drilling and drill-in, completion, stimulation, fracturing, etc fluids for trouble-free drilling, completion and production of oil and gas resources.

Current experience shows, it is often impossible to fulfill certain functional tasks that are essential in challenging drilling and production environments using conventional macro and micro type fluid additives due to their inadequate physical, mechanical, chemical, thermal and environmental characteristics. Hence, the industry is looking for physically small, chemically and thermally stable, biologically degradable, environmentally benign chemicals, polymers or natural products for designing smart fluids to use virtually in all areas of oil and gas exploration and exploitation. Due to totally different and highly enhanced physio-chemical, electrical, thermal, hydrodynamic properties and interaction potential of nanomaterials compared to their parent materials, the nanos are considered to be the most promising material of choice for smart fluid design for oil and gas field application. This paper describes the formulation and preliminary test results of several nano-based drilling fluids. The recently developed nano-based fluids were formulated using a blend of nanos and nanostabiliser to study the rheological and filtration properties and evaluate its suitability for oil and gas field application. Initial mud formulation indicates that development of a functionally viable, physically stable and homogeneous and also long lasting nano-based drilling mud is difficult using water or salt water as the fluid phase. However, use of a suitable viscosifier at a right concentration and adoption of a special preparation method lead to the formulation of a nano-based drilling mud with desirable rheological and filtration properties along with the gelling behavior and mudcake quality. Initial test results indicate that the newly developed nano-based drilling mud produces suitable high and low end rheological properties including gelling characteristics and thus expected to fulfill its functional task during drilling and after cessation of drilling.

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Treatment of air streams contaminated with volatile organic compounds in a biofilter under transient and steady-state conditions of operation is described with a mathematical model. The model incorporates convection and dispersion in the gas phase, partial coverage of the solid support, interphase mass transfer between the gas and the aqueous biofilm with an equilibrium partition at the interface followed by diffusion, direct adsorption to the exposed uncovered solid adsorbent media, transfer between the biofilm and the solid support, and biological reactions in both the biofilm and the adsorbent. The model equations were solved numerically by the method of orthogonal collocation using a MATLAB computer code. The effects of pollutant dispersion in the gas phase, specific surface area available for mass transfer, thickness of the biofilm, and adsorptive capacity of the solid support on the biofilter performance were investigated in detail. The steady-state removal efficiency appears to be nearly independent of gas-phase dispersion of the pollutant in the normal industrial range of operations. Results also indicate that the biofilter performance is a strong function of specific surface area for mass transfer and biofilm thickness. Simulation results further suggest that higher adsorptive support media are capable of handling load fluctuations irrespective of the rate of reaction in the adsorbed phase.