Theories and Applications of Pulsed-Jet Drilling With Mechanical Specific Energy

SPE Journal ◽  
2016 ◽  
Vol 21 (01) ◽  
pp. 303-310 ◽  
Author(s):  
Wei Minghui ◽  
Li Gensheng ◽  
Shi Huaizhong ◽  
Shi Shuaishuai ◽  
Li Zhaokun ◽  
...  

Summary Mechanical specific energy (MSE) is the amount of energy required to destroy a unit volume of rock. The main work of this study is to bring the hydraulic energy of a pulsed jet into an MSE model and further analyze the mechanism of improving the rate of penetration (ROP) for pulsed-jet drilling on the basis of the model. Laboratory experiments are used to obtain the relationship of bit hydraulic horsepower between pulsed jet and continuous jet, and then the MSE model of pulsed-jet drilling is established. According to the MSE theory, the major mechanisms of improving ROP in pulsed-jet drilling are changing the breaking strength of rock and improvement of downhole-cuttings-cleaning efficiency. Field tests and data presented in this study showed that this model could be used to evaluate drilling efficiency and identify abnormal conditions for pulsed-jet drilling. All tests were operated with similar parameters and on the same drilled formation. The field results illuminate that pulsed-jet drilling has higher drilling efficiency compared with conventional drilling. Moreover, the specific patterns for abnormal conditions can be detected in real time in the process of pulsed-jet drilling. This model is less ambiguous as well as robust. Therefore, it could provide theoretical support for the wide application of pulsed-jet drilling.

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Haibo Shi ◽  
Fereidoon Shahidi ◽  
Jiankang Wang ◽  
Yan Huang ◽  
Ye Zou ◽  
...  

Abstract Developing efficient and promising tenderising techniques for postmortem meat is a heavily researched topic among meat scientists as consumers are willing to pay more for guaranteed tender meat. However, emerging tenderising techniques are not broadly used in the meat industry and, to some degree, are controversial due to lack of theoretical support. Thus, understanding the mechanisms involved in postmortem tenderisation is essential. This article first provides an overview of the relationship of ageing tenderisation and calpain system, as well as proteomics applied to identify protein biomarkers characterizing tenderness. In general, the ageing tenderisation is mediated by multiple biochemical activities, and it can exhibit better palatability and commercial benefit by combining other interventions. The calpain system plays a key role in ageing tenderisation functions by rupturing myofibrils and regulating proteolysis, glycolysis, apoptosis and metabolic modification. Additionally, tenderising techniques from different aspects including exogenous enzymes, chemistry, physics and the combined methods are discussed in depth. Particularly, innovation of home cooking could be recommended to prepare relatively tender meat due to its convenience and ease of operation by consumers. Furthermore, the combined interventions provide better performance in controlled tenderness. Finally, future trends in developing new tenderising techniques, and applied consideration in the meat processing industry are proposed in order to improve meat quality with higher economical value. Graphical abstract


Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4920 ◽  
Author(s):  
Bang Du ◽  
Xiaolan Qiu ◽  
Lijia Huang ◽  
Songlin Lei ◽  
Bin Lei ◽  
...  

Circular synthetic aperture radar (CSAR) has a 360° observation capability on the central observation scenario. A typical way to process CSAR imaging is to cut data into small sub-apertures because most targets are only coherent at a very small observation angle. There are many sub-aperture imaging methods after development in recent years. The back-projection algorithm is widely used because it is simple and can be applied to an arbitrary trajectory. Because of the limitation of the Nyquist sampling frequency and influence of the antenna sidelobe, azimuth ambiguity is a phenomenon that may occur in the radar imaging process. The existing researches typically choose the back-projection (BP) imaging area according to the SAR platform flight path and the antenna beam width. The limitation of the CSAR imaging area and its azimuth ambiguity region are rarely analyzed theoretically. This paper focus on the sub-aperture imaging of CSAR, based on the BP algorithm, which derives the relationship of azimuth ambiguity with CSAR parameters such as the pause repeat frequency (PRF), slant range angle, velocity of radar platform, etc. This paper proposes an equation for the calculation of the azimuth ambiguity region and analyzes the limitations, which provides theoretical support for CSAR parameter design, imaging area selection, and azimuth ambiguity analysis.


2021 ◽  
pp. 1-17
Author(s):  
Abbas Roohi ◽  
Rahman Ashena ◽  
Gerhard Thonhauser ◽  
Thomas Finkbeiner ◽  
Laurent Gerbaud ◽  
...  

Abstract This work investigates the drilling performance by reaming while drilling (RWD) using a dual-body bit and compared it with conventional drilling by a standard drilling bit. The dual-body bit consisted of a 2.45-in pilot bit located at a short distance ahead of a 2.47*3.97-in reamer. Conducting a series of drilling experiments at a simulation drilling rig with full monitoring sensors, we further studied the drilling performance as a function of the distance between the pilot bit and the reamer which affect mud diffusion and the resultant change in pore pressure and stress. A method was devised to eliminate the drill-string vibration and its effect on the drilling performance and the energy consumed. The mechanical specific energy (MSE) calculated for each case was considered as a drilling performance indicator. Using two laboratory experiments as well as analytical thermo-poro-elastic calculations of the Mechanical Specific Energy (MSE), the MSE changes were monitored and recorded. Comparison of this drilling performance indicator was used in both the RWD and the conventional drilling assembly to analyze the effect of RWD. Based on the results, with increasing the distance between the pilot bit and reamer, there is an increase in improvement of drilling performance in terms of MSE reduction. The best drilling performance indicator (MSE reduction of 84%) was observed with the distance between the pilot bit and the reamer of 43.3 cm. This is considered a novel finding in reaming while drilling.


2021 ◽  
Vol 30 (1) ◽  
Author(s):  
Tuan Minh Tran ◽  
Quang Huy Nguyen

In recent years, experimental and numerical researches on the effect of blasting pressure on the stability of existing tunnels was widely obtained. However, the effect of the blasting pressure during excavation a new tunnel or expansion old tunnels on an existing tunnel has disadvantages and still unclear. Some researches were carried out to study the relationship of the observed Peak Particle Velocity (PPV) on the lining areas along the existing tunnel direction, due to either the lack of in situ test data or the difficulty in conducting field tests, particularly for tunnels that are usually old and vulnerable after several decades of service. This paper introduces using numerical methods with the field data investigations on the effect of the blasting in a new tunnel on the surrounding rock mass and on the existing tunnel. The research results show that not only predicting the tunnel lining damage zone under the impact of blast loads but also determination peak maximum of explosion at the same time at the surface of tunnel working.


2007 ◽  
Vol 11 (1) ◽  
pp. 75-96 ◽  
Author(s):  
Ricardo Corrêa Gomes ◽  
Luciana de Oliveira Miranda Gomes

This paper proposes a theoretical framework for investigating stakeholder theory in organizations. The organizations theory can be understood in three theoretical models: rationalist, natural and open systems. These models are presented to justify that organizations should be analyzed taking into account that social system aspects and the natural and open system models are employed. The applications of this paper rely upon the theoretical framework which is based on an extensive literature review comprising environment based theories. This paper would be of help to researchers examining the whole set of the relationship of organizations with their environment instead of only the relationships with external agents. Employing the theoretical basis presented in this analysis, the researcher will be able to identify both feasible theoretical sources for his/her studies and useful approaches for carrying on his/her investigations. The paper presents theories for explaining the organization's behavior and performance as being influenced by stakeholders who inhabit its environment. Resource dependence and institutional theory are employed to give theoretical support to the stakeholder. At the end of the paper, a diagram representing the theoretical framework is presented.


2021 ◽  
Author(s):  
Mengjie Li ◽  
Weijian Du

Abstract Whether the environmental regulation policy can achieve the double dividend of pollution control and employment promotion is a problem worthy of further discussion. This paper studies the effect of environmental regulation on employment scale and employment structure. Based on the matching data, the empirical results show that environmental regulations enhance the employment scale of enterprise. From the perspective of employment structure, labor redistribution, which is caused by environmental regulation, is mainly reflected in the employment creation and employment destruction effects, which lead to the optimization of the employment structure. Further research shows that environmental regulations expand employment scale but have different impacts on the employment structure in the developed and undeveloped regions of China. In addition, internal and external factors, such as enterprise innovation and institutional environment, may affect the relationship of environmental regulation and employment of enterprise. This paper provides theoretical support for the promotion of the construction of ecological civilizations and the solving of the employment dilemma.


2012 ◽  
Vol 572 ◽  
pp. 317-321
Author(s):  
Xian Jia ◽  
Zhi Bing Chu ◽  
Qing Xue Huang ◽  
Li Feng Ma

Rolling-cut bilateral shear is a sort of auxiliary equipment with arc upper blade performing pure rolling over flat lower one. The working principle are characterized as up-and-down movement of upper blade by crank shaft, after the rotation caused by the phase difference between two shafts, which makes upper blade rotate to adapt to steel shearing with different thickness. Through analysis the processing of rolling-cut bilateral shear and make the shearing mechanism simplify 8-linkage, and then the kinetics formula of shearing mechanism was established. The relationship of crank shaft length of rolling-cut bilateral shear in shearing process and movement trace of upper blade (shearing overlapping) was obtained as well as the change rule of length of linkage over upper blade, which provides the theoretical support for the design of rolling-cut bilateral shear.


1995 ◽  
Vol 27 (Supplement) ◽  
pp. S209
Author(s):  
S. Fujita ◽  
W. F. Brechue ◽  
C. F. Kearns ◽  
B. W. Kingston ◽  
M. L. Pollock

2013 ◽  
Vol 401-403 ◽  
pp. 1068-1073
Author(s):  
Bo Hang Liu ◽  
Xiao Xia Liu ◽  
Shi Jie Zhang

The video detection technology is a very active branch in the research field of machine vision, and the detection of vehicle trajectory by the stationary camera has become more and more important. However, there is little research on the measurement error of left-turn vehicles trajectory.This paper not only studies the relationship between the measurement error and longitudinal distance; but also relationship of measurement error and transverse distance. Their mathematical models are constructed and each of the variables in the models is analyzed. Then in the case analysis of certain intersection, the experimental results have shown that the proposed funtions can describe the relationship between measurement error and the parameters. It can provide the theoretical support for the measurement error problems of obtaining trajectory by video detection.


HortScience ◽  
2011 ◽  
Vol 46 (6) ◽  
pp. 838-840 ◽  
Author(s):  
James D. McCreight ◽  
Michael D. Coffey

A new strain of cucurbit powdery mildew incited by Podosphaera xanthii (Castagne) Braun & Shishkoff (formerly Sphaerotheca fuliginea), designated race S, is virulent on all the commonly used melon (Cucumis melo L.) powdery mildew race differentials and first appeared on melon in Yuma, AZ, and Imperial Valley, CA, in 2003. Melon PI 313970 (C. melo var. acidulus) was resistant to P. xanthii race S in 2003 and subsequent years. Inheritance of resistance to P. xanthii race S was studied in two naturally infected, replicated field tests in Imperial Valley in 2005 and 2009 using the parents and F1, F2, and reciprocal backcross generations from crosses of PI 313970 with powdery mildew-susceptible ‘Top Mark’. Resistance to race S was recessive: all F1 and BCTM individuals were susceptible. One recessive gene, designated pm-S, conditioned resistance to race S in the F2 and BCPI. The relationship of pm-S to the previously reported recessive and codominant genes in PI 313970 for resistance to P. xanthii races 1, 2, 2U.S., 3, 3.5, 4.5, and 5 remains to be determined.


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