Stabilizing biopolymers in water-based drilling fluids at high temperature using antioxidants, a formate salt, and polyglycol

Biopolymers degrade in water-based drilling fluids when exposed to high temperatures for some time, thus leading to hole-cleaning problems such as stuck pipe. To stabilise biopolymers in drilling fluids, the mechanisms by which they degrade at elevated temperatures must be understood. The degradation mechanisms of thermally labile biopolymers, therefore, include acid-catalysed hydrolysis and oxidation-reduction (redox) reactions. In this paper, an attempt is, therefore, made to investigate whether the combination of anti-oxidants, formate salt, and polyglycol could stabilise biopolymers in water-based drilling fluids with pH 8 to 10 above 200°C. Novel clay-based drilling fluids were formulated with sodium carbonate, sodium bicarbonate, biopolymers, antioxidants, a formate salt, a defoamer and polyglycol. The rheological properties of the drilling fluid formulations were measured using Model 800 and Model 1100 viscometers before and after hot-rolling dynamically in a roller oven for sixteen hours to condition the fluids. Presented results showed that xanthan gum in bentonite-water suspension remained stable up to 1000°C, and konjac gum in bentonite-water suspension remained stable up to 65°C. Experimental data also indicated that after dynamic aging for 16 hours, the antioxidant, formate salt and polyglycol increased the stability temperatures of the biopolymers - konjac gum and xanthan gum – in water-based drilling fluid formulations above 200°C. The best additives package that increased the stability temperatures of the biopolymers was potassium formate, sodium erythorbate, and 0.7% polyethene glycol. This additive package also maintained the suspension capability of the drilling fluid formulations. These additives can, therefore, be used to stabilise water-based drilling fluids containing biopolymers in the 150-232°C temperature range without using expensive and formation damaging synthetic polymers

Water-based drilling fluids for high-temperature applications and water-sensitive and dispersible shale formations

This study examines the effectiveness of sodium erythorbate, potassium formate, and polyethylene glycol for the formulation of high-performance water-based drilling fluids. High-performance water-based drilling fluids are environmentally-friendly, remain stable when exposed to high temperatures, and retard problems associated with reactive shale. A biopolymer, diutan gum, is used as drilling fluid viscosifiers in the preparation of drilling fluid formulations. The viscosities of the drilling fluid formulations with pH 8-10 were measured using Model 1100 viscometer before and after aging dynamically in a roller oven for sixteen hours. Shale rock samples were characterised using scanning electron microscope photos while X-ray diffraction analysis was used to identify the mineral contents of the shale samples. Shale dispersion tests were carried out by aging shale cuttings in an inhibitive drilling fluid formulation and in freshwater dynamically in a roller oven for 16 hours at 120°C. The percentage recovery of shale rocks after dynamic aging was determined. Experimental data indicated that the diutan gum stability temperature in bentonite water-suspension after aging for 16 hours was 115°C. Experimental data also indicated that the mud formulations with the additives - sodium erythorbate, potassium formate, and polyethylene glycol - retained their viscosities up to 232°C. The additives, therefore, significantly retarded the degradation of the biopolymer and other mud additives up to 232°C. The result from the shale dispersion test showed that the shale cuttings recovered from freshwater was 78%; with drilling fluids formulated with the additives, the shale cuttings recovered were 100%. This new fluid system which is stable at high temperatures and inhibits shale dispersion can meet high temperature and shale formation drilling requirements

Experimental investigation of methane-water and methane-brine IFT measurements using pendant drop (rising bubble) method

Gas hydrate formation involves low molecular gas mass transfer to a cage-like structure formed by water molecule under low temperature and high-pressure conditions. Gas hydrate is considered a problem if it develops along a pipeline. In order to solve the problem of gas hydrate formation in the pipeline, there is a need to understand the Interfacial Tension (IFT) behaviour at gas-water interface. This paper presents an experimental investigation of IFT of methane bubble in distilled water and varying concentration of salt (NaCl) using pendant drop (rising bubble) method. The results obtained shows that the IFT decreases with an increase in temperature and pressure. This decreasing trend shows that IFT existing at CH4 – H2O interface is a function of temperature and pressure. Additionally, the concentration of 2.9, 5.6, 8.2 and 10.7wt% NaCl resulted in an average increase of the IFT of the CH4-H2O system in 1.46, 2.57, 3.51 and 4.24 mN.m-1 respectively

The Methods to Improve Quality of Service by Accounting Secure Parameters

A solution to the problem of ensuring quality of service, providing a greater number of services with higher efficiency taking into account network security is proposed. In this paper, experiments were conducted to analyze the effect of self-similarity and attacks on the quality of service parameters. Method of buffering and control of channel capacity and calculating of routing cost method in the network, which take into account the parameters of traffic multifractality and the probability of detecting attacks in telecommunications networks were proposed. The both proposed methods accounting the given restrictions on the delay time and the number of lost packets for every type quality of service traffic. During simulation the parameters of transmitted traffic (self-similarity, intensity) and the parameters of network (current channel load, node buffer size) were changed and the maximum allowable load of network was determined. The results of analysis show that occurrence of overload when transmitting traffic over a switched channel associated with multifractal traffic characteristics and presence of attack. It was shown that proposed methods can reduce the lost data and improve the efficiency of network resources.Comment: 10 pages, 1 figure, 1 equation, 1 table. arXiv admin note: text overlap with arXiv:1904.0520

Properties of a Low-Carbon Binder-Based Mortar Made with Waste LCD Glass and Waste Rope (Nylon) Fibers

Carbon dioxide emissions are one of the problems that arouses the interest of scientists because of their harmful effects on the environment and climate. The construction sector, particularly the cement industry, is a significant source of CO2. On the other hand, solid waste constitutes a major problem facing governments due to the difficulty of decomposing it and the fact that it requires large areas for landfill. Among these wastes are LCD waste glass (WG) and used rope waste. Therefore, reusing these wastes, for example, in concrete technology, is a promising solution to reduce their environmental impact. Limited studies have dealt with the simultaneous utilization of glass waste as a substitute for cement and rope waste (nylon) fiber (WRF). Therefore, this study aimed to partially replace cement with WG with the addition of rope waste as fibers. Thirteen mixtures were poured: a reference mixture (without replacement or addition) and three other groups containing WG and WRF in proportions of 5, 15 and 25% by cement weight and 0.25, 0.5 and 0.75% by mortar weight, respectively. Flow rate, compression strength, flexural strength, dry density, water absorption, dynamic modulus of elasticity, ultrasonic pulse velocity and electrical resistivity were tested. The results indicate that the best ratio for replacing cement with WG without fibers was 5% of the weight of cement. However, using WRF increased the amount of glass replacement to 25%, with an improvement in strength and durability characteristics

Influence of mechanical activation on the behavior of green high-strength mortar including ceramic waste

Solid waste management is a significant environmental issue for countries because of the need for huge landfills. The ceramic tile waste powder (CWP) is one of the wastes. Conversely, cement production, the main ingredient in concrete, emits large quantities of greenhouse gases, a significant environmental concern. Therefore, substituting some of the cement in concrete with CWP is an issue that deserves investigation to reduce the environmental impact of both materials. Accordingly, this study aims to investigate the influence of the grinding time and proportion of CWP as a substitute for cement on the properties of high-strength mortar (HSM). Three grinding times (10, 15, and 20 minutes) and three replacement percentages (10%, 20%, and 30% by weight) for CWP were adopted for each time. Ten mixtures (including the reference mixture) were executed. The fresh (flow rate), mechanical (compressive strength) durability (ultrasonic pulse velocity, dynamic elastic modulus, water absorption, density, percentage of voids and electrical resistivity) and microstructural properties were examined. The life cycle assessment (LCA) was also addressed. The results showed that the mechanical activation had a pronounced effect on the durability properties (especially water absorption and percentage of voids) more than on the compressive strength. Generally, a sustainable HSM (with more than 70 MPa of compressive strength) can be produced in which 30% of the cement was replaced with CWP with almost comparable performance to the CWP-free mortar. Furthermore, LCA results showed that mortars containing 30% CWP ground for 15 mins (GT15CWP30) had the lowest GWP per MPa

Potential Use of Rendering Mortar Waste Powder as a Cement Replacement Material: Fresh, Mechanical, Durability and Microstructural Properties

The difficulty of decomposing solid waste over time has made it a significant global problem because of its environmental impact and the need for large areas for disposal. Among these residues is the waste of the rendering mortar that is produced (falls to the ground) while applied to wall surfaces. The quantity of these materials may reach 200 to 500 g/m2. As a result of local urban development (in Iraq), thousands of tons of these wastes are produced annually. On the other hand, the emission of greenhouse gases in the cement industry has had a great environmental impact. One of the solutions to this problem is to reduce the cement content in the mix by replacing it with less emissive materials. Residues from other industries are considered a relatively ideal option due to their disposal on the one hand and the reduction of harmful emissions of the cement industry on the other hand. Therefore, this research aims to reuse rendering mortar waste powder (RMWP) as a possible alternative to cement in mortar. RMWP replaced the cement in proportions (0, 10, 15, 20, 25, and 30% by weight). The flow rate, flexural and compressive strengths, ultrasonic pulse velocity, bulk density, dynamic modulus of elasticity, electrical resistivity, and water absorption tests of the produced mortar were executed. Microstructural analysis of the produced mortar was also investigated. Results indicated that, for sustainable development, an eco-friendly mortar can be made by replacing cement with RMWP at a rate of 15%, resulting in a 17% decrease in compressive strength while maintaining or improving durability properties. Moreover, the microstructure became denser and more homogeneous in the presence of RMWP

Hypertrophic pyloric stenosis: tips and tricks for ultrasound diagnosis

We describe a systematic approach to the ultrasound (US) examination of the antropyloric region in children. US is the modality of choice for the diagnosis of hypertrophic pyloric stenosis (HPS). The imaging features of the normal pylorus and the diagnostic findings in HPS are reviewed and illustrated in this pictorial essay. Common difficulties in performing the examination and tips to help overcome them will also be discussed