Numerical Study of Cuttings Transport of Nanoparticle-Based Drilling Fluid

Cuttings transportation from the drill bit, through the annulus, to the surface is one of the most important functions performed by drilling fluid. The prediction of drilling fluid's performance to transport cuttings in the annulus is very complex task due to the presence of numerous parameters. Nanoparticles (NPs) have been recently introduced into drilling fluid to engineer its properties and enhance its performance. Nevertheless, the lifting capacity has not been sufficiently investigated. The understanding of the influence and the mechanisms responsible for the improvement in cuttings transport process can further advance the application of NPs for drilling fluids. Computational fluid dynamics (CFD) is widely used as a numerical technique in handling complex multiphase flow problems in different operational conditions. The present work has taken the advantages of CFD to computationally analyze the influence of NPs and the effects of various parameters such as drilling fluids rheology, flow rate, pipe rotation, cuttings density, shape, concentration, and drilling fluids-cuttings particle coupling regimes on the cuttings transport in a vertical wellbore. The CFD simulation is carried out by using transient solver of ANSYS-FLUENT commercial code. The dense discrete phase model is used to overcome the main shortcomings of previous Eulerian based approaches. Good agreement has been achieved between the simulation and the published experimental results. It showed that the fluid viscosity and cuttings transport process can be significantly enhanced by adding nanomaterials to the fluid, and the process is highly influenced by cuttings characteristics such as in situ concentration, shape, and density

Security-oriented cloud computing platform for critical infrastructures

The rise of virtualisation and cloud computing is one of the most significant features of computing in the last 10 years. However, despite its popularity, there are still a number of technical barriers that prevent it from becoming the truly ubiquitous service it has the potential to be. Central to this are the issues of data security and the lack of trust that users have in relying on cloud services to provide the foundation of their IT infrastructure. This is a highly complex issue, which covers multiple inter-related factors such as platform integrity, robust service guarantees, data and network security, and many others that have yet to be overcome in a meaningful way. This paper presents a concept for an innovative integrated platform to reinforce the integrity and security of cloud services and we apply this in the context of Critical Infrastructures to identify the core requirements, components and features of this infrastructure

Latency reduction by dynamic channel estimator selection in C-RAN networks using fuzzy logic

Due to a dramatic increase in the number of mobile users, operators are forced to expand their networks accordingly. Cloud Radio Access Network (C-RAN) was introduced to tackle the problems of the current generation of mobile networks and to support future 5G networks. However, many challenges have arisen through the centralised structure of C-RAN. The accuracy of the channel state information acquisition in the C-RAN for large numbers of remote radio heads and user equipment is one of the main challenges in this architecture. In order to minimize the time required to acquire the channel information in C-RAN and to reduce the end-to-end latency, in this paper a dynamic channel estimator selection algorithm is proposed. The idea is to assign different channel estimation algorithms to the users of mobile networks based on their link status (particularly the SNR threshold). For the purpose of automatic and adaptive selection to channel estimators, a fuzzy logic algorithm is employed as a decision maker to select the best SNR threshold by utilising the bit error rate measurements. The results demonstrate a reduction in the estimation time with low loss in data throughput. It is also observed that the outcome of the proposed algorithm increases at high SNR values

Chickpea

The narrow genetic base of cultivated chickpea warrants systematic collection, documentation and evaluation of chickpea germplasm and particularly wild Cicer species for effective and efficient use in chickpea breeding programmes. Limiting factors to crop production, possible solutions and ways to overcome them, importance of wild relatives and barriers to alien gene introgression and strategies to overcome them and traits for base broadening have been discussed. It has been clearly demonstrated that resistance to major biotic and abiotic stresses can be successfully introgressed from the primary gene pool comprising progenitor species. However, many desirable traits including high degree of resistance to multiple stresses that are present in the species belonging to secondary and tertiary gene pools can also be introgressed by using special techniques to overcome pre- and post-fertilization barriers. Besides resistance to various biotic and abiotic stresses, the yield QTLs have also been introgressed from wild Cicer species to cultivated varieties. Status and importance of molecular markers, genome mapping and genomic tools for chickpea improvement are elaborated. Because of major genes for various biotic and abiotic stresses, the transfer of agronomically important traits into elite cultivars has been made easy and practical through marker-assisted selection and marker-assisted backcross. The usefulness of molecular markers such as SSR and SNP for the construction of high-density genetic maps of chickpea and for the identification of genes/QTLs for stress resistance, quality and yield contributing traits has also been discussed

Gr-Al2O3 Nanoparticles-Based Multifunctional Drilling Fluid

Various chemical additives are used in drilling fluids to improve drilling efficiency and increase oil production. Dispersing nanoparticles as additives in drilling mud is one of the more promising techniques that could help solve many difficulties of drilling operations. However, the existing research in this field is insufficient and suffers from numerous inconsistent outcomes. This study aims to discover and evaluate the impact of graphite-alumina hybrid nanoparticles on the rheology, thermal properties, zeta potential, and electrical conductivity of water-based drilling fluids. This study shows that that the addition of nanoparticles improves the effectiveness of water-based mud (WBM), both in static and dynamic situations due to the establishment of an appropriate gel structure that can be easily broken under low shear stress. Furthermore, these nanoparticles improve the degree and the speed of structural recovery by reducing the relaxation time, which is necessary to avoid the sedimentation of weighting materials and drilled cuttings. Besides, nanoparticle seeded fluid improves the effective thermal conductivity of conventional drilling fluids, and the highly charged suspension resulting from the addition of nanoparticles is desirable for drilling operations. It is also observed that nanoparticles could penetrate through the porous wall of the wellbore and clog the pores, forming a thin and impermeable cake that reduces drilling fluid loss. When properly engineered, nanoparticles could significantly improve the performance of conventional drilling fluids

Examination of drill pipe corrosion in water-based drilling fluids under wellbore conditions

Drill-pipe corrosion is a critical issue for any drilling operation, particularly under high-pressure, high-temperature downhole conditions. However, most laboratory studies have been conducted under ambient and static conditions, with only a few downhole studies based on flow loop showing inconsistent results. In this study, we proposed a novel simple method to simulate pipe corrosion/erosion in a reservoir-like environment under both the static and dynamic conditions and investigated the influences of wellbore conditions, including temperature, pressure and salinity of water-based drilling fluids, on the corrosion behaviour of the drill pipe. The results showed that the erosion effect of the drilling fluid (without drilled cuttings) was negligible. Furthermore, we found that the corrosion rate increased with an increase in the temperature, pressure and rotational speed; however, it decreased with an increase in the salinity. In addition, the proposed method can be used to simulate other complicated conditions

Non-intrusive user identity provisioning in the internet of things

The Internet of Things (IoT) represents an evolutionary vision and a new era of such smart environments that encompass all identifiable things in a dynamic and interacting network of networks. Each user has wide interactions with a huge number of entities. It would be impractical to require users to confirm themselves every time they cross various network boundaries, as the frequent verification process would disrupt the users’ normal activities and degrades the overall performance. This paper presents a service provisioning framework for IoT that relies on verifying user identity using a non-intrusive method of monitoring and inferring certain types of user activities. The framework helps in supporting the purpose of the IoT for being smart, boundless, easier and safer to improve people’s lives. The proposed framework reduces the risk of identity theft that results from losing user devices, where the user identity is usually stored. It copes with the loss of the user’s ID or people impersonating other people, and raises an alarm to block an intruder from being verified as a legitimate user

Security-oriented cloud computing platform for critical infrastructures

The rise of virtualisation and cloud computing is one of the most significant features of computing in the last 10 years. However, despite its popularity, there are still a number of technical barriers that prevent it from becoming the truly ubiquitous service it has the potential to be. Central to this are the issues of data security and the lack of trust that users have in relying on cloud services to provide the foundation of their IT infrastructure. This is a highly complex issue, which covers multiple inter-related factors such as platform integrity, robust service guarantees, data and network security, and many others that have yet to be overcome in a meaningful way. This paper presents a concept for an innovative integrated platform to reinforce the integrity and security of cloud services and we apply this in the context of Critical Infrastructures to identify the core requirements, components and features of this infrastructure