Assessment and Modelling of Wear prediction and Bit Performance for Roller Cone and PDC Bits in Deep Well Drilling

Drilling is one of the important aspects in the oil and gas industry due to the high demand for energy worldwide. Drilling time is considered as the major part of the operations time where the penetration rate (ROP) remains as the main factor for reducing the time. Maximizing ROP to lower the drilling cost is the main aim of operators. However, high ROP if not controlled may impact on the well geometry in terms of wellbore instability, cavities, and hole diameter restrictions. Accordingly, more time is needed for the other operations that follow such as: pool out of hole (POOH), casing running, and cementing. Bit wear is considered as the essential issue that influences in direct way on the bit performance and reduce ROP. Predicting the abrasive bit wear is required to estimate the right time when to POOH to prevent any costly job to fish any junk out to the surface. The two-common types of bits are considered in the research, rock bits (roller cone bits) and Polycrystalline Diamond Compact bits (PDC). This study focuses more on PDC bits because about 60% of the total footage drilled in wells worldwide were drilled by PDC bits and this is expected to reach 80% in 2020. The contribution of this research is to help reducing the drilling cost by developing new tools not to estimating the time when to POOH to surface but also to measure the wear and enhance the accuracy of prediction the bit efficiency. The work is broken down into four main stages or models to achieve the objective: The first stage; estimating of the rock abrasiveness and calculate the dynamic dulling rate of the rock bit while drilling. The second stage; estimating the PDC abrasive cutters wear by driving a new model to determine the mechanical specific energy (MSE), torque, and depth of cut (DOC) as a function of effective blades (EB). The accuracy of the predicted wear achieves 88% compared to the actual dull grading as an average for bits used in five wells. The third stage; modifying the previous MSE tool to develop a more accurate approach; effective mechanical specific energy (EMSE), to predict the PDC bit efficiency in both the inner and outer cone to match the standard bit dulling. The fourth stage; predicting ROP while PDC drilling in hole by accounting three parts of the process: rock drillability, hole cleaning, and cutters wear. The results achieve an enhancement of about 40% as compared to the available previous models. Consequently, the developed models in this study provide a novelty on understanding in more details the bit rock interface process and gain an idea of the relationship between the drilling parameters to enhance the bit performance and avoid damaging the bit. This is basically about optimisation the controllable factors such as: weight on bit (WOB), rotary speed (RPM), and flow rate. The result is the reduction in time losses and the operations cost. To ensure reliability and consistency of the proposed models, they were validated with several vertical oil wells drilled in Libya. The results from the validation of the models are consistent with the real field data. The research concludes that the developed models are reliable and applicable tool for both: to assist decision-makers to know when to pull the bit out to surface, and also to estimate the bit performance and wear

Shifted Jacobi spectral collocation method with convergence analysis for solving integro-differential equations and system of integro-differential equations

This article addresses the solution of multi-dimensional integro-differential equations (IDEs) by means of the spectral collocation method and taking the advantage of the properties of shifted Jacobi polynomials. The applicability and accuracy of the present technique have been examined by the given numerical examples in this paper. By means of these numerical examples, we ensure that the present technique is simple and very accurate. Furthermore, an error analysis is performed to verify the correctness and feasibility of the proposed method when solving IDE

Approximate solutions for solving nonlinear variable-order fractional Riccati differential equations

In this manuscript, we introduce a spectral technique for approximating the variable-order fractional Riccati equation (VO-FRDEs). Firstly, the solution and its space fractional derivatives is expanded as shifted Chebyshev polynomials series. Then we determine the expansion coefficients by reducing the VO-FRDEs and its conditions to a system of algebraic equations. We show the accuracy and applicability of our numerical approach through four numerical examples. &nbsp

Noise-robust method for image segmentation

Segmentation of noisy images is one of the most challenging problems in image analysis and any improvement of segmentation methods can highly influence the performance of many image processing applications. In automated image segmentation, the fuzzy c-means (FCM) clustering has been widely used because of its ability to model uncertainty within the data, applicability to multi-modal data and fairly robust behaviour. However, the standard FCM algorithm does not consider any information about the spatial linage context and is highly sensitive to noise and other imaging artefacts. Considering above mentioned problems, we developed a new FCM-based approach for the noise-robust fuzzy clustering and we present it in this paper. In this new iterative algorithm we incorporated both spatial and feature space information into the similarity measure and the membership function. We considered that spatial information depends on the relative location and features of the neighbouring pixels. The performance of the proposed algorithm is tested on synthetic image with different noise levels and real images. Experimental quantitative and qualitative segmentation results show that our method efficiently preserves the homogeneity of the regions and is more robust to noise than other FCM-based methods

A Segmentation Strategy for Structures with Common Mode Coupling

The level of electromagnetic coupling to electronic devices can vary widely from one device to another. When considering the induced voltage from an incoming plane wave on printed circuit boards (PCBs) and their attached cable harnesses, there is significant variety in the configuration of the devices that could be seen. This encourages the use of segmentation, so that the components of these devices (PCBs, connectors, and harnesses) can be modeled separately to alleviate simulation burden. This allows for a more flexible model and a \u27toolbox\u27 to construct devices with. The goal of this work is to use segmentation to model the external electromagnetic radiation from these devices. The radiation pattern and reciprocity theory can later be used to calculate the voltage coupled from an incident plane wave. Most realistic devices exhibit strong common mode (or antenna mode) coupling that cannot be ignored during segmentation. When segmenting such structures, a multi-modal approach is needed to incorporate coupling from both the common (CM) and differential (DM) modes and to allow these currents to flow properly between the blocks. This work introduces the concept by segmenting a simple dipole, which requires the common mode only, and then applies the complete methodology to a more complicated structure that requires the incorporation of both modes

A Fast Cascading Method for Predicting the Coupling from External Plane Waves to Pcbs

The radio frequency (RF) coupling to electronic devices impacts their EMC performance. The functionalities of a working electronic device may be disrupted when the electromagnetic (EM) coupling reaches a certain level. Studies of the EM coupling to printed circuit boards (PCBs) are therefore essential for RF susceptibility and EMC purposes. For decades, researchers focused on the analytical modeling of EM coupling to transmission lines. However, when it comes to more realistic PCBs the analysis usually still relies heavily on full-wave simulations because of the complexity of the structures and the lack of analytical solutions. Using a traditional full-wave modeling approach, however, could take hours to investigate the EM coupling from the external plane wave to the structure for one incident angle of arrival and polarization. In this paper, we present a methodology using reciprocity that allows for rapid estimation of the voltage induced in the terminations for multiple incident angles of the incoming plane wave and load values based on just one full-wave simulation. This reciprocity-based method is combined with a segmentation technique to enable the capability of studying the coupling to more realistic PCBs. For the cases studied here, estimates could be found in minutes using this approach rather than hours using a full-wave simulation. Estimates were within 2-3 dB of estimates using full-wave simulations for a simple trace structure. Accuracy was not as good for individual angles of arrival of an incident RF wave to a complicated structure including two integrated circuit (IC) packages connected by a trace, but statistical estimates of coupling were within 2-3 dB

Genetic analysis of male sterility genes in different A and B sorghum lines

Hybrid seed production requires use of cytoplasmic male sterility (CMS). Without this system, hybrid seed production would not be economically feasible. There is, therefore, need for developing A and B sorghum lines, as an essential step for development of hybrid sorghum industry. A genetic study of male sterility in different A and B sorghum ( Sorghum bicolor (L.) Moench) lines was conducted at the research farm Institute for Agriculture Research in Samaru and Kadawa. Chi-square test revealed goodness-of-fit to single gene of observed proportion of sterile and fertile plants to the expected ratio in all the backcross generations, thereby upholding the assumption of single gene inheritance for the traits studied. Stability of male sterile genes across generations of backcrosses indicated that sterility was inherited 68 to 95% among the different genotypes. Based on high number of sterile plants, crosses 159 x 160 and 421 x 422 are the best in terms of breeding potential for male sterility.La production des semences hybrides n\ue9cessite l\u2019utilisation de la st\ue9rilit\ue9 m\ue2le cytoplasmique (CMS). Sans ce syst\ue8me, la production des semences hybrides ne serait pas \ue9conomiquement faisable. Il y a donc, un besoin pour d\ue9velopper des lign\ue9es A et B du sorgho, comme une \ue9tape essentielle dans le d\ue9veloppement d\u2019industrie de sorgho hybride. Une \ue9tude g\ue9n\ue9tique de la st\ue9rilit\ue9 m\ue2le dans diff\ue9rentes lign\ue9es A et B du sorgho ( Sorghum bicolor (L.) Moench) a \ue9t\ue9 conduite \ue0 la ferme d\u2019exp\ue9rimentation de l\u2019Institut des Recherches Agricoles de Samaru et Kadawa. Le test de Chi-carr\ue9 a r\ue9v\ue9l\ue9 la qualit\ue9 d\u2019association d\u2019un seul g\ue8ne de la proportion observ\ue9e de plants st\ue9riles et fertiles au ratio observ\ue9 dans les g\ue9n\ue9rations de r\ue9trocroisement, ainsi soutenant l\u2019hypoth\ue8se de l\u2019h\ue9ritage d\u2019un g\ue8ne pour les traits \ue9tudi\ue9s. La stabilit\ue9 de g\ue8nes de la st\ue9rilit\ue9 m\ue2le \ue0 travers les g\ue9n\ue9rations du r\ue9trocroisement a indiqu\ue9 que la st\ue9rilit\ue9 \ue9tait h\ue9rit\ue9e entre 68 \ue0 95% entre les diff\ue9rents g\ue9notypes. Sur la base du nombre \ue9lev\ue9 de plantes st\ue9riles, les croisements 159 x 160 et 421 x 422 sont les meilleurs en termes du potentiel d\u2019am\ue9lioration g\ue9n\ue9tique pour la st\ue9rilit\ue9 m\ue2le

The application of deep eutectic solvent ionic liquids for environmentally-friendly dissolution and recovery of precious metals

publisher: Elsevier articletitle: The application of deep eutectic solvent ionic liquids for environmentally-friendly dissolution and recovery of precious metals journaltitle: Minerals Engineering articlelink: http://dx.doi.org/10.1016/j.mineng.2015.09.026 content_type: article copyright: Copyright © 2015 The Authors. Published by Elsevier Ltd.© 2015 Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

A simple method for extracting both active oily and water soluble extract (WSE) from Nigella sativa (L.) seeds using a single solvent system

The current study provides a way of extraction for both active NSO and WSE from Nigella sativa seeds using 98% methanol. About 1 kg of ground seeds was macerated by 1:2.5 w/v (g/mL) for 72 hours. After rotary evaporation and 7 days of continuous drying and chilling at 50 and 4 °C, NSO and WSE were obtained at the same instant. Solubility tests of 24 solvents and 11 thin layer chromatographic analyses while 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging assay of NSO (73.66) , WSE (33.32) and NSO + WSE (78.22) against ascorbic acid (IC50 = 4.28 mg/mL) was performed. WSE was found to be highly soluble in water and 5% NaOH exhibiting the same Rf value of 0.95 for EtOH:DMSO (9:1) against the honey. WSE has revealed more than twofold higher anti-oxidant activity than others. Formulation of WSE with Tualang honey may provide better targeted hydrophilic drug delivery systems