scholarly journals On the development of high-frequency torsional impact drilling techniques for hard formation drilling

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878160 ◽  
Author(s):  
Liping Tang ◽  
Xiaohua Zhu
Keyword(s):  
High Frequency ◽  
Laboratory Experiments ◽  
Control Method ◽  
State Of The Art ◽  
Theoretical Background ◽  
Stick Slip ◽  
Real Time Measurement ◽  
Deep Wells ◽  
Hard Formation ◽  
Active Control Method

Stick-slip vibration is a big problem that the drilling of deep wells has to face, especially for drilling of tough formations. This type of vibration leads to failure problems, reduces the rate of penetration, and lowers the borehole quality. Suppression techniques for stick-slip vibration, for example, active control method based on real-time measurement, play important roles in improving the drilling efficiency. The high-frequency torsional impact drilling, however, provides a cheaper and more stable way to mitigate stick-slip in many conditions. This work is aimed to study the high-frequency torsional impact generator, which is used to achieve the function, for this new technique. First, state-of-the-art of high-frequency torsional impact generator is studied by schematically illustrating the existing four structures and their operating principles, followed by comments for these structures. Second, theoretical background of the high-frequency torsional impact drilling is presented, showing how the high-frequency torsional impact generator works to mitigate stick-slip and improve drilling efficiency. Finally, an optimally designed high-frequency torsional impact generator is schematically described. It is an improved version of the assembly of United Diamond and the improvements are based on results of a series of laboratory experiments.

Analysis of stick-slip reduction for a new torsional vibration tool based on PID control

2019 ◽  
Vol 234 (1) ◽  
pp. 82-94 ◽  
Author(s):  
Jialin Tian ◽  
Yi Zhou ◽  
Lin Yang ◽  
Shuhui Hu
Keyword(s):  
Torsional Vibration ◽  
Pid Control ◽  
Control Method ◽  
Field Tests ◽  
Rock Breaking ◽  
Drill String ◽  
Viscosity Reduction ◽  
Stick Slip ◽  
Deep Wells ◽  
Reduction Characteristics

The phenomenon of stick-slip vibration is widespread in the exploration of deep and ultra-deep wells. It causes the reduction of the mechanical drilling rate and wastes the driving energy. Besides, it also accelerates the aging and failure of the drill strings and threatens the safety of drilling seriously. In order to effectively control the stick-slip vibration of the drill string, a new type of torsional vibration tool is proposed in this paper firstly. Then, the theoretical model of the drill string system based on the tool is established. And then, the viscosity reduction characteristics of the new torsional vibration tool are studied by the PID control method. Finally, field tests were carried out in comparison with simulation. The results show that the new torsional vibration tool can reduce the stick-slip vibration. And the two PID control equations can both control the drill bit speed in real time through changing the turntable speed. The results also have important reference significance for reducing and controlling the stick-slip vibration of the drill string and improving the rock-breaking efficiency.

Development of a high-frequency torsional impact generator for improving drilling efficiency

2013 ◽  
Vol 228 (11) ◽  
pp. 1968-1977 ◽  
Author(s):  
Xiaohua Zhu ◽  
Liping Tang
Keyword(s):  
High Frequency ◽  
Oil And Gas ◽  
Impact Frequency ◽  
Element Analysis ◽  
Stick Slip ◽  
Deep Wells ◽  
Experimental Apparatus ◽  
The Finite Element Analysis ◽  
Drilling Technology ◽  
The Impact

The drilling of deep wells has to face problems to suppress stick-slip vibrations, especially for tough formations. Such problems induce frequent tool failures and poor well quality. Torsional impact drilling is an emerging drilling technology for improving the productivity of oil and gas by mitigating the stick-slip vibration. In this paper, a high-frequency torsional impact generator has been developed in order to investigate this drilling technology. Mechanism of torsional impact as a means of stick-slip mitigation is studied. Structure and operating principle of the tool have been presented. The finite element analysis approach is utilized in the analysis of applicability of the impact unit which is most significant for the tool. The analysis indicates that the impact unit operates successfully. An experimental apparatus is developed to examine the applicability of the proposed numerical method to the analysis of the impact unit. Laboratory tests with different impact frequency are conducted with the apparatus. It is verified that the impact system operates regularly, and high-frequency torsional impacts are generated. In addition, impact parameters of the apparatus which will be helpful to the study of the high-frequency torsional impact drilling are obtained.

scholarly journals Efficient Rank-Based Diffusion Process with Assured Convergence

2021 ◽  
Vol 7 (3) ◽  
pp. 49
Author(s):  
Daniel Carlos Guimarães Pedronette ◽  
Lucas Pascotti Valem ◽  
Longin Jan Latecki
Keyword(s):  
Diffusion Process ◽  
Learning Strategies ◽  
State Of The Art ◽  
Representation Learning ◽  
Theoretical Background ◽  
High Dimensional ◽  
Visual Features ◽  
Learning Approaches ◽  
Previous Decade ◽  
Asymptotic Complexity

Visual features and representation learning strategies experienced huge advances in the previous decade, mainly supported by deep learning approaches. However, retrieval tasks are still performed mainly based on traditional pairwise dissimilarity measures, while the learned representations lie on high dimensional manifolds. With the aim of going beyond pairwise analysis, post-processing methods have been proposed to replace pairwise measures by globally defined measures, capable of analyzing collections in terms of the underlying data manifold. The most representative approaches are diffusion and ranked-based methods. While the diffusion approaches can be computationally expensive, the rank-based methods lack theoretical background. In this paper, we propose an efficient Rank-based Diffusion Process which combines both approaches and avoids the drawbacks of each one. The obtained method is capable of efficiently approximating a diffusion process by exploiting rank-based information, while assuring its convergence. The algorithm exhibits very low asymptotic complexity and can be computed regionally, being suitable to outside of dataset queries. An experimental evaluation conducted for image retrieval and person re-ID tasks on diverse datasets demonstrates the effectiveness of the proposed approach with results comparable to the state-of-the-art.

scholarly journals Sub-THz and THz SiGe HBT Electrical Compact Modeling

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1397
Author(s):  
Bishwadeep Saha ◽  
Sebastien Fregonese ◽  
Anjan Chakravorty ◽  
Soumya Ranjan Panda ◽  
Thomas Zimmer
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
Silicon Germanium ◽  
High Frequency ◽  
State Of The Art ◽  
Sensitivity Study ◽  
Compact Modeling ◽  
Process Technology ◽  
Very High Frequency ◽  
Sige Hbt ◽  
Frequency Behavior

From the perspectives of characterized data, calibrated TCAD simulations and compact modeling, we present a deeper investigation of the very high frequency behavior of state-of-the-art sub-THz silicon germanium heterojunction bipolar transistors (SiGe HBTs) fabricated with 55-nm BiCMOS process technology from STMicroelectronics. The TCAD simulation platform is appropriately calibrated with the measurements in order to aid the extraction of a few selected high-frequency (HF) parameters of the state-of-the-art compact model HICUM, which are otherwise difficult to extract from traditionally prepared test-structures. Physics-based strategies of extracting the HF parameters are elaborately presented followed by a sensitivity study to see the effects of the variations of HF parameters on certain frequency-dependent characteristics until 500 GHz. Finally, the deployed HICUM model is evaluated against the measured s-parameters of the investigated SiGe HBT until 500 GHz.

scholarly journals Model predictive control for autonomous ground vehicles: a review

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Shuyou Yu ◽  
Matthias Hirche ◽  
Yanjun Huang ◽  
Hong Chen ◽  
Frank Allgöwer
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
High Performance ◽  
Control Method ◽  
Theoretical Background ◽  
Future Research ◽  
Centralized Control ◽  
Ground Vehicles ◽  
Uncertain Environments ◽  
Autonomous Ground Vehicles

AbstractThis paper reviews model predictive control (MPC) and its wide applications to both single and multiple autonomous ground vehicles (AGVs). On one hand, MPC is a well-established optimal control method, which uses the predicted future information to optimize the control actions while explicitly considering constraints. On the other hand, AGVs are able to make forecasts and adapt their decisions in uncertain environments. Therefore, because of the nature of MPC and the requirements of AGVs, it is intuitive to apply MPC algorithms to AGVs. AGVs are interesting not only for considering them alone, which requires centralized control approaches, but also as groups of AGVs that interact and communicate with each other and have their own controller onboard. This calls for distributed control solutions. First, a short introduction into the basic theoretical background of centralized and distributed MPC is given. Then, it comprehensively reviews MPC applications for both single and multiple AGVs. Finally, the paper highlights existing issues and future research directions, which will promote the development of MPC schemes with high performance in AGVs.

High average power coherent femtosecond pulse combining system based on an all fiber active control method

2018 ◽  
Vol 15 (7) ◽  
pp. 075101 ◽  
Author(s):  
H L Yu ◽  
Z X Zhang ◽  
X L Wang ◽  
R T Su ◽  
H W Zhang ◽  
...  
Keyword(s):  
Active Control ◽  
Femtosecond Pulse ◽  
Control Method ◽  
Average Power ◽  
High Average Power ◽  
Active Control Method

Comparison of Times of Synchronization of Chaotic Burke-Shaw Attractor with Active Control and Integer and Optimum Fractional-Order Pecaro Carroll Method

2021 ◽  
Author(s):  
Ali Durdu ◽  
Yılmaz Uyaroğlu
Keyword(s):  
Active Control ◽  
Fractional Order ◽  
Chaotic Attractor ◽  
Secure Communication ◽  
Chaotic Systems ◽  
Control Method ◽  
Initial Conditions ◽  
Data Communication ◽  
Experimental Results ◽  
Active Control Method

Abstract Many studies have been introduced in the literature showing that two identical chaotic systems can be synchronized with different initial conditions. Secure data communication applications have also been made using synchronization methods. In the study, synchronization times of two popular synchronization methods are compared, which is an important issue for communication. Among the synchronization methods, active control, integer, and fractional-order Pecaro Carroll (P-C) method was used to synchronize the Burke-Shaw chaotic attractor. The experimental results showed that the P-C method with optimum fractional-order is synchronized in 2.35 times shorter time than the active control method. This shows that the P-C method using fractional-order creates less delay in synchronization and is more convenient to use in secure communication applications.

The Investigation of the Optimization Scheme of the Low-cycle Fatigue Cropping Based on the Acoustic Emission Technique

2021 ◽  
Author(s):  
Yujian Ren ◽  
Jingxiang Li ◽  
Yuanzhe Dong ◽  
Dong Jin ◽  
Shengdun Zhao
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
Control Method ◽  
Low Cycle Fatigue ◽  
Control Strategies ◽  
Low Frequency ◽  
Loading Frequency ◽  
Cycle Fatigue ◽  
Al 6061 ◽  
Whole Process

Abstract High efficiency and good section quality are two main objectives of metal bar cropping. A suitable control method can help to achieve both goals. An investigation of the control method of low-cycle fatigue cropping (LCFC) based on the acoustic emission (AE) technique has been proposed in this study. Ring-down counts and kurtosis are used to monitor the whole process of LCFC. The results showed that kurtosis is more suitable for monitoring the LCFC process and as a critical parameter to optimize the control method than ring-down counts in the noisy factory environment.Moreover, three types of materials are studied in this experiment; by combine with the AE results, macroscopic images and microscopic images of sections, characteristics of various LCFC stages are obtained. The results also indicated reduce the area of the transient fracture zone is the key to improve the section quality. Reducing the load frequency before the unstable crack propagation stage will beneficial to realize the goals. Based on the evaluation of kurtosis, an optimized control method is presented, and two control parameters: transient time T and the critical value of the slope of kurtosis C are determined. For 16Mn, 1045 and Al 6061, the T is 5s, 10s, and 1s, respectively. For 16Mn, 1045, and Al 6061, the C is 100, 300, and 0, respectively. Two parameters, h and S, are used to evaluate the section quality and four control strategies are compared. The results indicate the optimal control methods can improve the section quality effectively. The influence trend of reducing loading frequency is investigated by further comparison. It can be seen as the frequency decreases, the efficiency of the section quality improving decreases. In order to realize the optimal results, different control strategies are adopted for different materials. Strategy 1 (high frequency is 20Hz，high frequency thought the whole process), strategy 2 (high frequency is 20Hz，low frequency is 8.33Hz), and strategy 3 (high frequency is 20Hz，low frequency is 6.67Hz) is suitable for Al 6061, 1045, and 16Mn, respectively.

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