Experimental Study on the Characteristics of VIV and Whirl Motion of Rotating Drill Pipe

2013 ◽  
Author(s):  
Tomoya Inoue ◽  
Chang-Kyu Rheem ◽  
Masanori Kyo ◽  
Hide Sakaguchi ◽  
Miki Y. Matsuo
Keyword(s):  
Experimental Study ◽  
Drill Pipe ◽  
Low Frequency ◽  
Rotating Cylinder ◽  
Water Tank ◽  
Scientific Drilling ◽  
Model Experiments ◽  
Drilling Operations ◽  
Pipe Rotation ◽  
Direction Opposite

During drilling operations, the scientific drilling vessel Chikyu encounters vortex-induced vibration (VIV) of the riser during riser drilling as well as that of the drill pipe during riserless drilling. The characteristics of the VIV of the drill pipe will differ from those of the riser because the drill pipe rotates during operations. Therefore, investigating the characteristics of the VIV during drill pipe rotation is important. In this paper, the results of model experiments that show the characteristics of the VIV of a rotating drill pipe and drill pipe whirl are described. The authors conducted model experiments on the VIV response of a rotating cylinder in a water tank to observe the motion of the rotating cylinder. The results confirmed that rotating affects the characteristics of the VIV. When the rotating frequency of the drill pipe was low, the VIV resonated with the rotation; as the rotating frequency increased, the frequency of the VIV decreased. In addition, a self-excited whirl motion was also observed during the experiments. This “drill pipe whirl,” which rotated in the direction opposite to the rotation of the drill pipe at a low frequency, was larger in amplitude than the VIV. The results demonstrate that rotation of the drill pipe affects the characteristics of the VIV and generates the whirl motion.

scholarly journals The effect of drill–pipe rotation on improving hole cleaning using polypropylene beads in water-based mud at different hole angles

2019 ◽  
Vol 10 (3) ◽  
pp. 1253-1262 ◽  
Author(s):  
A. Katende ◽  
B. Segar ◽  
I. Ismail ◽  
F. Sagala ◽  
H. H. A. R. Saadiah ◽  
...  
Keyword(s):  
Buoyancy Force ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Drilling Mud ◽  
Hole Cleaning ◽  
Drag Forces ◽  
Water Based ◽  
Drilling Operations ◽  
Cost Efficient ◽  
Pipe Rotation

AbstractHole cleaning is always a problem, particularly during drilling operations, and drilling fluid plays an important role in transporting drill cuttings through an annular section of wellbore to the surface. To transport the cuttings, a water-based mud with added polypropylene beads was selected since it is environmentally friendly and cost efficient. The polypropylene beads help to transport cuttings by providing an additional buoyancy force that lifts the cuttings to the surface via the influence of collision and drag forces. This experiment was performed using a 20 ft test section, 10 ppg drilling mud and 0.86 m/s annular velocity in a laboratory scale rig simulator, and the concentration of polypropylene beads was varied from 0 to 8 ppb. As the concentration of polypropylene increases, the cutting transport ratio also increases. It was observed that the fewest cuttings are lifted at a critical angle of 60°, followed by 45°, 30°, 90° and 0°. Additionally, cutting sizes had moderate effects on the cutting lifting efficiency, where smaller cutting sizes (0.5–1.0 mm) are easier to lift than larger cutting sizes (2.0–2.8 mm). Furthermore, a study of buoyancy force and impulsive force was conducted to investigate the cutting lifting efficiencies of various concentrations of polypropylene beads. This lifting capacity was also assisted by the presence of polyanionic cellulose (PAC), which increases the mud carrying capacity and is effective for smaller cuttings. The results show that in the presence of pipe rotation, the cutting lifting efficiency is slightly enhanced due to the orbital motion provided by the drill pipe for better hole cleaning. In conclusion, polypropylene beads combined with pipe rotation increase the cutting transport ratio in the wellbore.

scholarly journals Research and Fabrication of Broadband Ring Flextensional Underwater Transducer

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1548
Author(s):  
Jiuling Hu ◽  
Lianjin Hong ◽  
Lili Yin ◽  
Yu Lan ◽  
Hao Sun ◽  
...  
Keyword(s):  
High Speed ◽  
Structural Parameters ◽  
Low Frequency ◽  
Flexural Vibration ◽  
Underwater Acoustic Communication ◽  
Voltage Response ◽  
Water Tank ◽  
Spherical Cap ◽  
Finite Element Software ◽  
Underwater Transducer

At present, high-speed underwater acoustic communication requires underwater transducers with the characteristics of low frequency and broadband. The low-frequency transducers also are expected to be low-frequency directional for realization of point-to-point communication. In order to achieve the above targets, this paper proposes a new type of flextensional transducer which is constructed of double mosaic piezoelectric ceramic rings and spherical cap metal shells. The transducer realizes broadband transmission by means of the coupling between radial vibration of the piezoelectric rings and high-order flexural vibration of the spherical cap metal shells. The low-frequency directional transmission of the transducer is realized by using excitation signals with different amplitude and phase on two mosaic piezoelectric rings. The relationship between transmitting voltage response (TVR), resonance frequency and structural parameters of the transducer is analyzed by finite element software COMSOL. The broadband performance of the transducer is also optimized. On this basis, the low-frequency directivity of the transducer is further analyzed and the ratio of the excitation signals of the two piezoelectric rings is obtained. Finally, a prototype of the broadband ring flextensional underwater transducer is fabricated according to the results of simulation. The electroacoustic performance of the transducer is tested in an anechoic water tank. Experimental results show that the maximum TVR of the transducer is 147.2 dB and the operation bandwidth is 1.5–4 kHz, which means that the transducer has good low-frequency, broadband transmission capability. Meanwhile, cardioid directivity is obtained at 1.4 kHz and low-frequency directivity is realized.

Scaling Formulae for the Wellbore Hydraulics Similitude with Drill Pipe Rotation and Eccentricity

2021 ◽  
Author(s):  
Thad Nosar ◽  
Pooya Khodaparast ◽  
Wei Zhang ◽  
Amin Mehrabian
Keyword(s):  
Power Law ◽  
Flow Rate ◽  
Annular Flow ◽  
Rotation Speed ◽  
Drilling Fluid ◽  
Drill Pipe ◽  
Flow Loop ◽  
Annular Flows ◽  
Fluid Rheology ◽  
Pipe Rotation

Abstract Equivalent circulation density of the fluid circulation system in drilling rigs is determined by the frictional pressure losses in the wellbore annulus. Flow loop experiments are commonly used to simulate the annular wellbore hydraulics in the laboratory. However, proper scaling of the experiment design parameters including the drill pipe rotation and eccentricity has been a weak link in the literature. Our study uses the similarity laws and dimensional analysis to obtain a complete set of scaling formulae that would relate the pressure loss gradients of annular flows at the laboratory and wellbore scales while considering the effects of inner pipe rotation and eccentricity. Dimensional analysis is conducted for commonly encountered types of drilling fluid rheology, namely, Newtonian, power-law, and yield power-law. Appropriate dimensionless groups of the involved variables are developed to characterize fluid flow in an eccentric annulus with a rotating inner pipe. Characteristic shear strain rate at the pipe walls is obtained from the characteristic velocity and length scale of the considered annular flow. The relation between lab-scale and wellbore scale variables are obtained by imposing the geometric, kinematic, and dynamic similarities between the laboratory flow loop and wellbore annular flows. The outcomes of the considered scaling scheme is expressed in terms of closed-form formulae that would determine the flow rate and inner pipe rotation speed of the laboratory experiments in terms of the wellbore flow rate and drill pipe rotation speed, as well as other parameters of the problem, in such a way that the resulting Fanning friction factors of the laboratory and wellbore-scale annular flows become identical. Findings suggest that the appropriate value for lab flow rate and pipe rotation speed are linearly related to those of the field condition for all fluid types. The length ratio, density ratio, consistency index ratio, and power index determine the proportionality constant. Attaining complete similarity between the similitude and wellbore-scale annular flow may require the fluid rheology of the lab experiments to be different from the drilling fluid. The expressions of lab flow rate and rotational speed for the yield power-law fluid are identical to those of the power-law fluid case, provided that the yield stress of the lab fluid is constrained to a proper value.

scholarly journals An EEG Experimental Study Evaluating the Performance of Texas Instruments ADS1299

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3721 ◽  
Author(s):  
Usman Rashid ◽  
Imran Niazi ◽  
Nada Signal ◽  
Denise Taylor
Keyword(s):  
Experimental Study ◽  
Mixed Models ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Low Frequency ◽  
Low Power Consumption ◽  
Motor Tasks ◽  
Negative Peak ◽  
Eeg Data ◽  
Healthy Participants

Texas Instruments ADS1299 is an attractive choice for low cost electroencephalography (EEG) devices owing to its low power consumption and low input referred noise. To date, there have been no rigorous evaluations of its performance. In this EEG experimental study we evaluated the performance of the ADS1299 against a high quality laboratory-based system. Two self-paced lower limb motor tasks were performed by 22 healthy participants. Recorded power across delta, theta, alpha, and beta EEG bands, the power ratio across the motor tasks, pre-movement noise, and signal-to-noise ratio were obtained for evaluation. The amplitude and time of the negative peak in the movement-related cortical potentials (MRCPs) extracted from the EEG data were also obtained. Using linear mixed models, no statistically significant differences (p > 0.05) were found in any of these measures across the two systems. These findings were further supported by evaluation of cosine similarity, waveform differences, and topographic maps. There were statistically significant differences in MRCPs across the motor tasks in both systems. We conclude that the performance of the ADS1299 in combination with wet Ag/AgCl electrodes is analogous to that of a laboratory-based system in a low frequency (<40 Hz) EEG recording.

scholarly journals Large‐scale experiments of the borehole instability on shale formation influenced by drill pipe rotation

2019 ◽  
Vol 7 (6) ◽  
pp. 2895-2920 ◽  
Author(s):  
Yuanwei Sun ◽  
Meng Meng ◽  
Xiaodong Dai ◽  
Yuanfang Cheng ◽  
Yanli Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Drill Pipe ◽  
Shale Formation ◽  
Pipe Rotation
Sign in / Sign up

Export Citation Format

Share Document