Separation of azimuthal effects for new-generation resistivity logging tools — Part I

Geophysics ◽  
2010 ◽  
Vol 75 (1) ◽  
pp. E31-E40 ◽  
Author(s):  
Sofia Davydycheva

A symmetrization approach used in new-generation logging-while-drilling (LWD) resistivity tools separates the dipping anisotropy and dipping boundary effects. It deals with couplings between axial transmitters and tilted or transverse receivers. I have investigated the performance of two symmetrization schemes in full 3D scenarios for LWD and rigorously extended them to triaxial induction logging, including couplings between transverse transmitters and transverse receivers. Thus, I apply similar principles of data processing to new-generation wireline and LWD tools. The method enables separation of the formation response from the borehole eccentricity effect, which cannot be ignored for triaxial induction. The technique can accelerate and improve existing methods of formation interpretation by directly determining bed boundary positions, formation anisotropy azimuth, and tool eccentricity direction and by improving visual interpretation of raw tool data. The second objective of my investigation was a brief review of previously published work on a 3D finite-difference (FD) modeling approach, its latest development and its ability to simulate responses of new-generation resistivity tools in general 3D formations. This approach, based on the Lebedev staggered FD grid, handles arbitrary resistivity anisotropy effectively. Its high efficiency encourages its routine use for modeling. In addition, the method enables simultaneous multispacing and multifrequency computing at no cost. It makes the detailed investigation and further development of the separation technique possible.

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. F185-F202 ◽  
Author(s):  
Sofia Davydycheva

Symmetrization/antisymmetrization of tensor resistivity measurements and data rotation technique enable separation of the formation response from the tool eccentricity effect in the borehole. Similar principles of data processing can be applied to tensor measurements acquired by both wireline and logging-while-drilling tools of the new generation. I show how to directly determine the bed boundary positions and the formation anisotropy azimuth and how to perform visual interpretation of raw tool data in the presence of the tool eccentricity. I study the tool behavior in conductive water-based mud boreholes — the situation that requires much more complicated numerical modeling than the case of resistive oil-based mud boreholes. I show when and how the tool eccentricity effect can be separated from the formation response. The separation technique can accelerate and improve existing methods of formation interpretation.


2012 ◽  
Vol 4 (04) ◽  
pp. 439-453 ◽  
Author(s):  
Zhonghua Ma ◽  
Dejun Liu ◽  
Hui Li ◽  
Xinsheng Gao

AbstractA novel, highly efficient and accurate adaptive higher-order finite element method (hp-FEM) is used to simulate a multi-frequency resistivity logging-while-drilling (LWD) tool response in a borehole environment. Presented in this study are the vector expression of Maxwell’s equations, three kinds of boundary conditions, stability weak formulation of Maxwell’s equations, and automatichp-adaptivity strategy. The newhp-FEM can select optimal refinement and calculation strategies based on the practical formation model and error estimation. Numerical experiments show that the newhp-FEM has an exponential convergence rate in terms of relative error in a user-prescribed quantity of interest against the degrees of freedom, which provides more accurate results than those obtained using the adaptiveh-FEM. The numerical results illustrate the high efficiency and accuracy of the method at a given LWD tool structure and parameters in different physical models, which further confirm the accuracy of the results using the Hermes library (http://hpfem.org/hermes) with a multi-frequency resistivity LWD tool response in a borehole environment.


2021 ◽  
Vol 22 (13) ◽  
pp. 6850
Author(s):  
Seyyed Mojtaba Mousavi ◽  
Seyyed Alireza Hashemi ◽  
Sonia Bahrani ◽  
Khadije Yousefi ◽  
Gity Behbudi ◽  
...  

In this review, the unique properties of intrinsically conducting polymer (ICP) in biomedical engineering fields are summarized. Polythiophene and its valuable derivatives are known as potent materials that can broadly be applied in biosensors, DNA, and gene delivery applications. Moreover, this material plays a basic role in curing and promoting anti-HIV drugs. Some of the thiophene’s derivatives were chosen for different experiments and investigations to study their behavior and effects while binding with different materials and establishing new compounds. Many methods were considered for electrode coating and the conversion of thiophene to different monomers to improve their functions and to use them for a new generation of novel medical usages. It is believed that polythiophenes and their derivatives can be used in the future as a substitute for many old-fashioned ways of creating chemical biosensors polymeric materials and also drugs with lower side effects yet having a more effective response. It can be noted that syncing biochemistry with biomedical engineering will lead to a new generation of science, especially one that involves high-efficiency polymers. Therefore, since polythiophene can be customized with many derivatives, some of the novel combinations are covered in this review.


Toxins ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 262
Author(s):  
Qin-Wei Wu ◽  
Josef P. Kapfhammer

The CRISPR-Cas13 system based on a bacterial enzyme has been explored as a powerful new method for RNA manipulation. Due to the high efficiency and specificity of RNA editing/interference achieved by this system, it is currently being developed as a new therapeutic tool for the treatment of neurological and other diseases. However, the safety of this new generation of RNA therapies is still unclear. In this study, we constructed a vector expressing CRISPR-Cas13 under a constitutive neuron-specific promoter. CRISPR-Cas13 from Leptotrichia wadei was expressed in primary cultures of mouse cortical neurons. We found that the presence of CRISPR-Cas13 impedes the development of cultured neurons. These results show a neurotoxic action of Cas13 and call for more studies to test for and possibly mitigate the toxic effects of Cas13 enzymes in order to improve CRISPR-Cas13-based tools for RNA targeting.


2013 ◽  
Vol 365-366 ◽  
pp. 917-920
Author(s):  
De Fa Zhang ◽  
Yi Cong Gao

In recent years, industrial sewing machine intelligence can be increased. Compared with the traditional equipment, the new generation of domestic equipment in the "high efficiency, energy saving, special" has realized great-leap-forward development. In the performance, will towards high precision, high efficiency, high performance, intelligent direction; in function, to the miniaturization, multi-function direction; in the program, to the systematic, integrated direction. The design and development of industrial sewing machine digitization design packaging platform are discussed.


Geophysics ◽  
2018 ◽  
Vol 83 (5) ◽  
pp. D165-D171
Author(s):  
Zhong Wang ◽  
Huaping Wang ◽  
Treston Davis ◽  
Jing Li ◽  
Suming Wu ◽  
...  

Geosteering is a key technique to increase oil- and gas-production rates, especially within a thin reservoir layer. The purpose of geosteering in the production zone is to keep the drilling path in oil- and gas-bearing reservoirs. To keep the drilling system inside the production zone, downhole sensors must be able to detect bed boundaries, which include identifying the boundary location with respect to the sensor and the boundary distance from the sensor. We have developed a directional resistivity logging-while-drilling (LWD) tool for geosteering applications. The directional LWD tool is equipped with a joint-coil antenna composed of an axially polarized coil Rz connected in series with two transversely polarized coils Rx. During a revolution around the axis of the tool, the voltage of the axial coil VRz, voltage of the transverse coils VRx, and tool face angle [Formula: see text], which indicates the boundary direction, can be extracted through curve fitting the total voltage response of the joint-coil antenna. The distance to the boundary can be derived from a 1D inversion. The LWD tool has been tested in several reservoirs in China, and it has a demonstrated capability to provide reliable and accurate estimations of the boundary direction and distance. Field data indicate that the boundary detection depth can reach 2.1 and 1.7 m when the tool is in a sand and shale formation. Using wireline-logging data from surrounding wells as reference, deviations between the reference and the measured distance to the boundary are within 0.2 m.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2136 ◽  
Author(s):  
Bartosz Gil ◽  
Jacek Kasperski

Theoretical investigations of the ejector refrigeration system using hydrofluoroolefins (HFOs) and hydrochlorofluoroolefin (HCFO) refrigerants are presented and discussed. A comparative study for eight olefins and R134a as the reference fluid was made on the basis of a one-dimensional model. To facilitate and extend the possibility of comparing our results, three different levels of evaporation and condensation temperature were adopted. The generator temperature for each refrigerant was changed in the range from 60 °C to the critical temperature for a given substance. The performed analysis shown that hydrofluoroolefins obtain a high efficiency of the ejector system at low primary vapor temperatures. For the three analyzed sets of evaporation and condensation temperatures (te and tc equal to 0 °C/25 °C, 6 °C/30 °C, and 9 °C/40 °C) the maximum Coefficient of Performance (COP) was 0.35, 0.365, and 0.22, respectively. The best performance was received for HFO-1243zf and HFO-1234ze(E). However, they do not allow operation in a wide range of generator temperatures, and, therefore, it is necessary to correctly select and control the operating parameters of the ejector.


2012 ◽  
Vol 134 (06) ◽  
pp. 36-41
Author(s):  
Guy M. Genin ◽  
Ram V. Devireddy

This article reviews the use of mechanical engineering techniques in the field of nano-engineered medicines. Nano-engineered solutions now exist for a range of medical diagnostics, therapeutics, and imaging, and are at the core of many of the current generation of regenerative medicine and tissue engineering strategies. Nanoparticles can be developed to absorb energy with high efficiency from photons of certain frequency ranges. The ability to understand specific diseases such as osteogenesis imperfecta based upon such fundamental analyses has been demonstrated by ASME member Sandra Shefelbine of Imperial College London in collaboration with the Buehler group. The tools of nanotechnology have enabled mechanical engineers to engineer the beginnings of an entirely new generation of cures and therapies, and this article has discussed just a sample. In order to serve as a forum for discussion of these advances ASME is recommissioning the Journal of Nanotechnology in Engineering and Medicine.


2020 ◽  
Vol 6 (45) ◽  
pp. eabb5381
Author(s):  
Weihua Ning ◽  
Jinke Bao ◽  
Yuttapoom Puttisong ◽  
Fabrizo Moro ◽  
Libor Kobera ◽  
...  

Spintronics holds great potential for next-generation high-speed and low–power consumption information technology. Recently, lead halide perovskites (LHPs), which have gained great success in optoelectronics, also show interesting magnetic properties. However, the spin-related properties in LHPs originate from the spin-orbit coupling of Pb, limiting further development of these materials in spintronics. Here, we demonstrate a new generation of halide perovskites, by alloying magnetic elements into optoelectronic double perovskites, which provide rich chemical and structural diversities to host different magnetic elements. In our iron-alloyed double perovskite, Cs2Ag(Bi:Fe)Br6, Fe3+ replaces Bi3+ and forms FeBr6 clusters that homogenously distribute throughout the double perovskite crystals. We observe a strong temperature-dependent magnetic response at temperatures below 30 K, which is tentatively attributed to a weak ferromagnetic or antiferromagnetic response from localized regions. We anticipate that this work will stimulate future efforts in exploring this simple yet efficient approach to develop new spintronic materials based on lead-free double perovskites.


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