Anirbid Sircar

Engineering properties of concrete with partial utilization of used foundry sand

Solid wastes generated from manufacturing industries are increasing at an alarming rate and it is consistently increasing. One such industrial solid waste is Used Foundry Sand (UFS). On the other hand, fine aggregates involved in the concrete are generally river sand, which is scarce, high cost and excavation of the river sand that promote environmental degradation. So, there is an urge to find some alternative solution to dispose UFS and to limit the use of river sand. In this research work, river sand was partially replaced by UFS. The percentage replacements were 0, 5, 10, 15, 20 and 25 wt% respectively. Experimental investigations were carried out to evaluate the mechanical, durability and micro-structural properties of M20 concrete at the age of 7, 28 and 91 day. XRD (X-ray Diffraction), EDX (Energy Dispersive X-ray) and optical-microscopic imaging analysis were performed to identify the presence of various compounds and micro cracks in the concrete with UFS. Comparative studies on control mix against trial mix were carried out. It was found that compression strength, flexural strength and modulus of elasticity were approximately constant up to 20 wt% UFS and decreased with further addition. Whereas, split tensile strength was increased after 20 wt% addition but it affects the other properties of concrete. The durability test results showed that the resistance of concrete against abrasion and rapid chloride permeability of the concrete mixture containing UFS up to 20 wt% were almost similar to the values of control mix. The findings suggest that UFS can effectively replace river sand. However, it is recommended that the replacement should not exceed 20 wt%.

A Treatise on Non-Darcy Flow Correlations in Porous Media

Non-Darcy Flow behavior is important for describing fluid flow in consolidated or unconsolidated porous media when abrupt changes in velocity dominates. A criterion or a generalized equation is required to understand this flow behavior in the isotropic/anisotropic carbonate and sandstone reservoirs, and naturally or hydraulically fractured reservoirs. Various correlations and equations have been reviewed in this paper to quantify this non-Darcy coefficient (i.e., beta coefficient) mathematically. It has been observed that this coefficient is highly dependent on rock properties (mainly porosity, permeability and tortuosity). An algorithm to determine the values of the beta coefficient by using the correlations have been presented and coded and converted in to a robust user-friendly simulator. This simulator can take a large amount of data set as input and will generate a large data set of beta values as output. The obtained or calculated beta value is very useful for predicting the change in pressure gradient with respect to velocity and hence can give the best estimate of hydrocarbon production under challenging or adverse pressure drop conditions.

Hydrocarbon resource estimation: a stochastic approach

Genetic algorithm has been used in various applications including reserve estimations in oil and gas industry for the last few decades. It is an effective stochastic inversion technique for optimization problems. The oil and gas industry is a risk based industry due to lot of uncertainties associated in each reservoir parameter used during the reserve estimation process. Detailed analysis of input data is very much important, either for the pre-bid evaluation or after the discovery of hydrocarbons. In this paper, stochastic approach in hydrocarbon resource estimation has been discussed. The algorithm starts with development of initial population and evaluation of the same. In the second step a fitness value is assigned to each individual. The best fit parents are then selected and by crossover and mutation of new populations are generated. The same process is continued until the optimum solution is reached. The efficacy of the algorithm is tested on real data set of seismic and petrophysical data from Cambay basin. The outcome is a range of resource estimates with various probability values.

Model design of condenser for solar assisted geothermal cooling system using software simulation

Condensers are extensively used in refrigeration, air-conditioning and power generation systems. Condenser for the solar assisted geothermal cooling system is designed by using software simulation of condenser’s geometrical and flow parameters. The geothermal cooling system is designed to reduce electricity consumption of compressor during peak hours during the summer period in hot weather condition. The subsurface temperature of the earth around 5–6-m depth is fairly constant throughout the year which fulfills the requirement of cooling inside the building or residence by using water as a heat exchanging medium. Water is circulated in closed loop system buried into subsurface which sinks the heat of refrigerant from condenser inside the subsurface soil. The condenser is designed by comparing results obtained from (1) manual calculation (2) simulation by CHEMCAD software. In order to have a good and optimized design, manual and software-based calculations should be carried out simultaneously and verified with each other. It is found that results obtained from both calculations are approximately same with a minor difference. The geometry and flow parameter of the condenser is determined on the basis of surrounding temperature. The solar panel is used for power generation to reduce electricity consumption by the compressor, pump, and evaporator fan coil. This provides the hybrid solar assisted geothermal cooling system.

A model on dual string drilling: on the road to deep waters

As the offshore market is facing the deepwater production challenges, the Oil and Gas Industry is investing in new technologies to bring down costs needed to effectively exploit reservoirs. Therefore, dual string drilling (DSD) can eliminate the marine riser which would result in exploring oil fields in deep and ultra-deepwater economically. In order for controlling fluid contact with a borehole wall during drilling operations include introducing an outer pipe into a borehole and positioning an inner pipe within the outer pipe axially. The method may further include circulating a drilling fluid to a drill bit using inner pipe and the annulus between the inner pipe and outer pipe. The drilling fluid may be separated from the control fluid by using an annular isolator. The results showed that with DSD approach a lot of time will be saved in order to circulate the kick out of the well. Apart from riserless drilling, DSD has an efficient cutting removal capacity, better annular clearance, elimination of differential sticking, better well stability, better well control parameters, reduction of torque and drag, avoid the dynamic equivalent circulating density gradient, and better extended reach drilling. The novelty of the new dynamics model is in the ability to solve narrow operational margin between pore pressure and fracture pressure as we move into deeper waters.

Mineralogical assemblage of Cambay Shale of North Cambay Basin, Gujarat, India

Shale Gas exploration and production plays an essential role in ensuring energy security and economic stability. Tapping these reserves using cost-effective technologies can really change the India’s energy supply and value chain. Cambay Shale of Cambay Basin has been proved as the most prominent Indian Shale reserve and in this work an attempt has been made to understand the geographical and mineralogical distribution of this Shale. A sample study on Cambay Shale of North Tectonic Block of Cambay Basin has been ascertained to understand the mineralogy, porosity and maturity with respect to depth. The study involves the use of integrated measurement techniques mainly high-pressure porosity (HPP), scanning electron microscopy (SEM) and Fourier transform electron microscopy (FTIR). Approximately, 13 samples were analysed to understand the mineralogy of this shale and it was observed that it is very clayey in nature with major traces of Illite and minor traces of rutile and kaolinite. The other measurements (i.e., SEM and HPP) were done on two specific samples which confirm the presence of clay-rich porous minerals with high organic matter content.

Design of safe well on the top of Atharamura anticline, Tripura, India, on the basis of predicted pore pressure from seismic velocity data

Pore pressure prediction is an essential part of wildcat well planning. In India, Tripura sub-basin is characterised by huge anticlines, normal faults and abnormally pressured formations. These factors push the wildcat well planning in this area into wide margin of uncertainty. Pore pressures were predicted from seismic velocities by using modified Eaton’s method over the synclinal and flank part of Atharamura to understand the pressure succession towards the anticline. These predicted pore pressures on the flank part lead to a reasonable match when plotted with offset well-measured pore pressures. To reduce the uncertainty, fracture pressures were established by various methods such as Hubbert and Willis method and Matthews and Kelly method from predicted pore pressures. But the fracture pressures were predicted with available horizontal stress correlations due to lack of Poisson’s ratio curve for the study area. The mud pressure required to drill the well is calculated using median line principle, and hence drilling mud window is established by assuming virtual tight conditions. The plot of equivalent circulation density versus depth suggests that well can be drilled with two casing policy. But it is found that adding one more casing pipe will ensure the safety of well. Casing pipes were designed on the basis of collapse pressure, burst pressure and tensile load. Finally, a well plan which includes pore pressure, fracture pressure, drilling mud policy, casing policy and kick tolerance graph were proposed to give clear picture on well planning on the top of the anticline in pore pressure point of view.

Conversion of bio-solids (scum) from tannery effluent treatment plant into biodiesel

ABSTRACT The search for a suitable low cost feedstock for the production of biodiesel has resulted in biodiesel being produced from bio-solids (scum) taken from the tannery effluent treatment facility. The effectively extracted oil was subjected to combined esterification and transesterification using an acid catalyst. The process was optimized for parameters like catalyst concentration, temperature, time, oil to methanol molar ratio and stirring rate. The result was the yield of 0.55 kg of biodiesel from 1 kg wet scum. The physicochemical properties of the produced biodiesel are in the acceptable range of fuel used in diesel engines. The paper also addresses the quality issues regarding minor components like heavy metals and aromatic contents.

Kinetic and thermodynamic studies on the extraction of bio oil from Chlorella vulgaris and the subsequent biodiesel production

Abstract This research article investigates the extraction of bio-oil from Chlorella vulgaris algae which is then subjected to biodiesel production. To evaluate the maximum oil content, four different pretreatment methods and solvent systems were inspected. Among them, maximum oil yield was obtained from ultrasonic pretreated biomass followed by methanol and methyl tertiary butyl ether solvent extraction. Physico-chemical properties of the bio-oil were analyzed as per AOAC Official Methods. The experiments were then designed to determine how variation in different process parameters influences extraction. From these results, kinetic and thermodynamic parameters were also analyzed. The positive values of ΔS and ΔH and the negative value of ΔG indicate that this process is endothermic, irreversible and spontaneous, respectively. The extracted bio-oil was then subjected to acid catalyzed reaction for biodiesel production. A yield of 98.2 wt% biodiesel was obtained at the optimized condition. Fuel properties were analyzed as per ASTM methods.

Exploitation and Utilization of Oilfield Geothermal Resources in INDIA

There are plenty of geothermal resources available in existing oil and gas sedimentary basins in India. In recent time oil and gas companies have put their efforts for exploiting and utilizing geothermal resources using various advanced technologies. The paper describes the study of geothermal energy potential in oilfields in India. Considering the existing low and medium temperature geothermal resources, researchers have discussed the possibility of various direct and indirect applications of geothermal energy. The paper also describes the Organic Rankine Cycle (ORC) technique used to generate power from low enthalpy geothermal resources. From the above studies researchers have found that sustainable and economic development of existing oil and gas fields with efficient utilization of geothermal energy sources can reduce the dependency on fossil fuel. It can be done based on the existing infrastructure, technology experience and reservoir information.