Nanofibers of cobalt manganese oxide (CoMn 2 O 4) were grown using an electrospun technique. Structural and microstructural characterizations confirm the formation of phase pure CoMn 2 O 4 with high porosity. The potential application of CoMn 2 O 4 nanofibers as an electrode material for energy storage device was studied using cyclic voltammetry and galvanostatic charge-discharge measurements. A specific capacitance of 121 F/g was observed with enhanced cyclic stability. Furthermore, an energy storage device was fabricated by sandwiching two electrodes separated by an ion transporting layer. The device showed a specific capacitance of 241 mF/cm 2 in 3M NaOH electrolyte. The effect of temperature on the charge storage properties of the device was also investigated for high temperature applications. The device showed about 75% improvement in the charge storage capacity when the temperature was increased from 10 to 70 o C.This research suggests that nanofibers of CoMn 2 O 4 could be used for fabrication of energy storage devices which could operate in a wide temperature range with improved efficiency.

A good primary cementing job governs in a great part the producing performance of a well. Successful zonal isolation, which is the main objective of any cementing job, primarily depends on the right cement design. The resin-based cement system, which is a relatively new technology within the oil industry has the potential to replace conventional cement in critical primary cementing applications. This paper describes the lab-testing and field deployment of the resin-based cement systems. The resin-based cement systems were deployed in those well sections where a potential high-pressure influx was expected. The resin-based cement system, which was placed as a tail slurry was designed to have better mechanical properties as compared to the conventional cement systems. The paper describes the process used to get the right resin-based cement slurry design and how its application was important to the success of the cementing jobs. The cement job was executed successfully and met all the zonal-isolation objectives. The resin-based cement's increased shear bond strength and better mechanical properties were deemed to be instrumental in providing a reliable barrier that would thwart any future issues arising due to sustained casing pressure (SCP). This paper describes the required lab-testing, lab-evaluation, and the successful field deployment of the resin-based cement systems.

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It is of prime importance for a drilling fluid to have good and optimal rheology in order to achieve good hole-cleaning and have good barite sag resistance. Invert emulsion drilling fluids with organoclay as a viscosifier sometimes fail to maintain sufficient rheology during drilling due to the thermal degradation of organoclay with time and temperature. Thus, there was a need to develop a drilling fluid with optimal rheology sufficient to give good hole cleaning and barite sag resistance in high temperature and pressure conditions. This paper describes the formulation of invert emulsion drilling fluids formulated with a synergistic rheology modifier combination comprising of two different additives viz. rheo1 and rheo2. Invert emulsion fluids formulated with either rheo1 or rheo2 did not show good and optimal rheology required for successful drilling. However, the synergistic effect of these two additives rheo1 and rheo2 resulted in fluids with low PV and enhanced yield point and low end rheology thereby increasing their capacity for better hole-cleaning and barite-sag resistance. The effectiveness of this rheology modifier combination was shown by formulating 68pcf low density, 90pcf medium density and 120pcf high density invert emulsion drilling fluids. The 68pcf, 90pcf and 120pcf fluids were hot rolled at 250°F, 300°F and 325°F respectively. Rheology of the 120pcf invert emulsion fluid was measured across high temperature and pressure range. The paper also describes the contamination and static aging studies of 90pcf and 120pcf fluids at 300°F and 325°F respectively. 68pcf, 90pcf and 120pcf invert emulsion drilling fluids formulated with the novel rheology modifier combination of rheo1 and rheo2 showed optimal rheology and low HTHP fluid loss. Static aging studies of 90pcf and 120pcf fluids at 300°F and 325°F respectively showed that the fluids were resistant to barite sag. Contamination studies of 90pcf fluid showed that the contaminants have minimal effect on the rheology and filtration properties of the invert emulsion fluid. HTHP rheology of the 90pcf invert emulsion fluid shows consistent rheology across high temperatures and pressures. The paper thus demonstrates the superior performance of the rheology modifier combination to achieve good rheological and filtration properties.

The properties of the selected drilling fluid must be carefully planned to have minimal effects on the near-wellbore pore spaces. Proper mixing, monitoring, and maintenance of the drilling fluid throughout the drilling operations are as critical as the careful planning. Solids control equipment should be operated to remove the cuttings and maintain the density and rheological properties consistent. The characteristics of an effective reservoir fluid system include stability at high pressures and temperatures, proper and stable density, good filtration control, ability to transport cuttings, and minimal damage to formation pore spaces, Davidson et al. 1997. Selection of the most suitable drilling fluid additives takes into consideration numerous factors such as downhole conditions (pressure and temperature), formation type and petro physical properties, and the objective of the drilling operation. The experimental work in this paper involved rheological properties, thermal stability, API and HT/HP filtration and acid filter cake removal efficiency. Tangentional flooding showed that water based Mn3O4 drill-in fluid has the highest return permeability compared to the typical drill-in fluids (KCl/CaCO3/Barite and potassium drill-in fluids). Potassium formate drill-in fluid filtrate was not compatible with brine. This incompatibility explained its low return permeability in spite of its low solids content. Oil based drilling fluid was developed and tested with good acceptable results. Filter cake removal efficiency was showing more than 95%, indicating its removable formation damage.