Hydraulic Vibrators Research Articles

To the question of the study of a vibration device to eliminate seizures during the construction of oil and gas wells

The drilling process is one of the most expensive steps in the construction of an oil well. Therefore, methods that reduce drilling costs without compromising the quality of well construction are always in demand by oil companies. As a rule, specialists in the field of drilling seek to increase the rate of penetration, reduce the number of round trips, eliminate accidents due to tool breaks, ensure uniform weight on bit, reduce time spent on eliminating complications, etc. Among these approaches, a special place is occupied by the technology of using vibration devices to prevent sticking of the drill string. The article presents theoretical studies of the operation of the device for dynamic impact on the bottomhole, allowing to assess the influence of design factors on its operation. The performed studies allow us to recommend the use of the device in a single bottomhole assembly to create pulsating flushing and dynamic loading of the bit. The obtained research results can be used in the design of downhole assemblies of various sizes with hydraulic vibrators for drilling wells. Keywords: Well Drilling; Horizontal Section; Sticking; Weight On Bit; Device; Vibration; Friction.

A new generation low-frequency seismic vibrator

Extending the vibroseis acquisition bandwidth toward very low frequencies (below 5 Hz) can be very beneficial for land seismic exploration. However, most conventional hydraulic vibrators have physical limitations as well as harmonic distortion in the vibrator mechanical and hydraulic systems that limit the ground-force output at low frequencies. To enhance the low-frequency range, the vibrator output force must be increased with an improved signal-to-noise ratio. An improved design of the vibrator mechanical and hydraulic system becomes very necessary to achieve this goal. With this goal, a newly designed low-frequency vibrator is developed and field-tested. Experimental results find that this new generation low-frequency vibrator can produce the recoverable seismic data with a low-frequency range from 1 to 4 Hz.

A dynamic mesh-based approach to analyse hydrodynamic interactions between a fluidic hammer and drill bit

The main goal of this study was to reveal the hydrodynamic interactions between a fluidic hammer and drill bit. For this purpose, a computational fluid dynamics analysis based on a dynamic mesh technique was used instead of the conventional steady analysis. The results show that the effect of the drill bit on the performance of the fluidic hammer is negligible. However, the fluidic hammer has a significant effect on the bit hydraulics. The flow fluctuation caused by the fluidic hammer can significantly influence the bottom-hole flow fields and upwards flow velocity in annular space. It is also found that the flow fluctuation ratio is nearly constant during the variation of total inlet flow rate, while it can be largely affected by the mass of the steel mass block, piston diameter, and piston rod diameter. To improve the borehole cleaning, the lowest average velocity in the annular space during flow fluctuation should be higher than the critical velocity or the corresponding velocity associated with the desired cutting concentration. The conclusions can also serve as a reference for the study of other hydraulic hammers or vibrators.

The construction of a simple portable electromagnetic vibrator from commercially available components

ABSTRACTSince its introduction in the late 1950s, hydraulic vibrators have become the dominant source for land seismic surveys. The hydraulic vibrators typically used for commercial land seismic acquisition, however, are large, costly to operate and expensive to purchase. This inhibits their use for small‐scale and short‐duration surveys as well as Vibroseis research. In this paper we describe, in detail, the construction of a portable vibrator from commercially available components for a cost of less than $US2,000. Data shows that the vibrator is able to successfully transmit sweeps from 15 to 180 Hz with different spectral contents. The vibrator produces a stronger signal than a sledgehammer and we estimate its output to be around 1 kN. The frequency content of the data was concentrated at lower frequencies (<100 Hz) and the ground‐roll was far more energetic than that produced using a sledgehammer.

The effects of inter‐vibrator interference on vibrator performance

ABSTRACTThe output from the hydraulic vibrators typically used for land seismic surveys is controlled by monitoring the acceleration measured by accelerometers mounted on the reaction mass and baseplate. The considerable energy output by such vibrators, which are coupled with the sensitivity of the accelerometers used, results in crosstalk if more than one vibrator is being used. In this paper, we present the results of a field experiment in which we measured the crosstalk between two adjacent vibrators. We found that the level of crosstalk was approximately ‐20 dB when the vibrators were adjacent but decreased with increasing frequency and separation. This result has implications for measurements of vibrator performance, source‐signature deconvolution, and in particular, estimates of the total energy output by a fleet of vibrators.

Errata

Geophysical ProspectingVolume 58, Issue 3 p. 539-539 Free Access Errata This article corrects the following: On the accuracy of the ground force estimated in vibroseis acquisition Christos Saragiotis, Péter Scholtz, Claudio Bagaini, Volume 58Issue 1Geophysical Prospecting pages: 69-80 First Published online: December 11, 2009 Source measurement effect on high fidelity vibratory seismic separation Nirupama Nagarajappa, David Wilkinson, Volume 58Issue 1Geophysical Prospecting pages: 55-68 First Published online: October 30, 2009 How do hydraulic vibrators work? A look inside the black box John J. Sallas, Volume 58Issue 1Geophysical Prospecting pages: 3-18 First Published online: October 30, 2009 Reflection point sideslip and smear in imaging below dipping anisotropic media Rob Vestrum, Don Lawton, Volume 58Issue 4Geophysical Prospecting pages: 541-548 First Published online: December 1, 2009 First published: 26 March 2010 https://doi.org/10.1111/j.1365-2478.2010.00878.xAboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat In [[1] ] equation (3) currently reads: (3) It should read: (3) The only error has to do with the term F that should have appeared as lower case f to represent the instantaneous frequency in Hz, as defined in the sentence above this equation. In [[2] ] some symbols are missing. On page 56, equation (1) currently reads: (1) It should read: (1) The following sentence published on page 58: For example, if the response of vibrator 2 during sweep 2 is delayed by seconds with respect to sweep 1 response, then the value of k for element [2, 2] of the matrix A (Fig. 3b) would be e−i2πf. Should read: For example, if the response of vibrator 2 during sweep 2 is delayed by τ seconds with respect to sweep 1 response, then the value of k for element [2, 2] of the matrix A (Fig. 3b) would be e−i2πfτ. In [[3] ] equation (3) reads: (3) It should read: (3) q has been defined earlier in the text as a quantity that models the frequency-dependent effects (other than the Earth itself) due to the receivers, recording equipment, attenuation etc., while here the quantity models the actual groundforce and should therefore be g. In [[4] ] the incorrect caption for Fig. 8 was published. The correct caption for this figure should read: Figure 8 Isotropically migrated stacks of limited-offset ranges from the 15° model data: a) near offsets from 0–1300 m, b) mid offsets from 1300–2600 m, c) far offsets from 2600–4500 m. The horizontal line represents the model position of the reflector. The vertical markers indicate an estimate of the horizontal position of the reflector edge on each of the three limited-offset images: near, mid and far. REFERENCES [1] Sallas J.J. 2010. How do hydraulic vibrators work? A look inside the black box. Geophysical Prospecting 58, 3– 17. doi:10.1111/j.1365-2478.2009.00837.xWiley Online LibraryWeb of Science®Google Scholar [2] Nagarajappa N. and Wilkinson D. 2010. Source measurement effect on high fidelity vibratory seismic separation. Geophysical Prospecting 58, 55– 67. doi:10.1111/j.1365-2478.2009.00839.xWiley Online LibraryWeb of Science®Google Scholar [3] Saragiotis C., Scholtz P. and Bagaini C. 2010. On the accuracy of the ground force estimated in vibroseis acquisition. Geophysical Prospecting 58, 69– 80. doi:10.1111/j.1365-2478.2009.00851.xWiley Online LibraryWeb of Science®Google Scholar [4] Vestrum R. and Lawton D. 2009. Reflection point sideslip and smear in imaging below dipping anisotropic media. Geophysical Prospecting. doi:10.1111/j.1365-2478.2009.00849.xWiley Online LibraryWeb of Science®Google Scholar Volume58, Issue3May 2010Pages 539-539 ReferencesRelatedInformation

How do hydraulic vibrators work? A look inside the black box

ABSTRACTIn order to have realistic expectations of what output is achievable from a seismic vibrator, an understanding of the machine's limitations is essential. This tutorial is intended to provide some basics on how hydraulic vibrators function and the constraints that arise from their design. With these constraints in mind, informed choices can be made to match machine specifications to a particular application or sweeps can be designed to compensate for performance limits.

An electrical marine vibrator with a flextensional shell

A completely new electro-mechanical marine Vibroseis concept is introduced that uses a flextensional shell with a uniquely developed form. Two controllable output resonances achieve a very high efficiency and repeatability, with a typical frequency bandwidth of 6-100 Hz. The marine vibrator can be used as a standard towed acoustic source in shallow water, or as a stationary source in transition zone environments. It is particularly significant that the vibrator requires only an electrical power supply, cannot leak hydraulic fluids, is easily transported, and is suitable for applications requiring very low environmental impact. A marine vibrator will provide several environmental advantages. Vibrator technology spreads the net source energy over a long period, reducing the acoustic power in comparison to impulsive sources. This is attractive for applications where high peak power may be problematic. This fact was established by the original hydraulic vibrators developed previously. An electrical marine vibrator offers even more advantages than hydraulic vibrators. There is no need for heavy equipment and hydraulic systems that can cause hydraulic oil spills. As the electrical vibrator requires only an electrical power supply it can be easily transported to different vessels and locations without any costly installations and potential environmental hazards. The marine vibrators discussed here have been tested as a standard towed acoustic source in shallow water, and as a stationary source in transition zone environments (4-6 ft of water). These applications are particularly well suited for this type of source.

Optimal Vibration Stimulation to the Neck Extensor Muscles Using Hydraulic Vibrators to Shorten Saccadic Reaction Time

Optimal vibration stimulation to the neck extensor muscles using hydraulic vibrators to shorten the saccadic reaction time was examined. Subjects were 14 healthy young adults. Visual targets (LEDs) were located 10 degrees left and right of a central point. The targets were alternately lit for random durations of 2-4 seconds in a resting neck condition and various vibration conditions, and saccadic reaction times were measured. Vibration amplitude was 0.5 mm in every condition. The upper trapezius muscles were vibrated at 40, 60, 80, and 100 Hz in a sub-maximum stretch condition in which the muscles were stretched at 70% of maximum stretch. In addition, the muscles were vibrated at 60 Hz with the muscles maximally stretched, with 70% vertical pressure without stretching, and with vibration applied to the skin in the same area as the muscle vibration. At 60, 80, and 100 Hz at 70% maximum stretch, saccadic reaction time shortened significantly compared with the resting neck condition. However, no significant difference in the reaction time was observed among the frequencies. The saccadic reaction times in the maximum stretch condition, muscle pressure condition, and skin contact condition did not differ significantly from that in the resting neck condition. Vibration stimulation to the trapezius with 60-100 Hz frequencies at 0.5 mm amplitude in the sub-maximum stretch condition was effective for shortening saccadic reaction time. The main mechanism appears to be Ia information originating from the muscle spindle.

Piezoelectric seismic vibration device and method

A vibrator and method for transmitting seismic signals into the earth to obtain data on various subsurface characteristics. The vibrator is driven with piezoelectric transducers which can operate below 500 Hz, and can produce better signal resolution at higher frequencies than is possible with hydraulic vibrators. The piezoelectric vibrators can be used in various embodiments at the earth's surface, within a borehole, or while permanently buried in the earth.

High Frequency Hydraulic Vibrators

Hydraulic vibrators which are powerful, cheap and compact are described and theory for their performance prediction is given. They are of use where high forces are required on structures of high dynamic stiffness at frequencies up to 1 kHz.

Paper 7: Hydraulic Vibrators in Automobile Testing with Special Reference to the Rootes Suspension Parameter Rig

The principles of the conventional high performance hydraulic vibrator and its operating characteristics are described. An examination is made of the limitations involved and compared to the limitations of electro-magnetic and mechanical vibrators to show significant areas where the hydraulic vibrator has worthwhile advantages. Mention is made of typical applications of hydraulic vibrators to vehicle testing and development. However, a substantial part of the paper is devoted to a specific installation, being a rig primarily designed for the measurement and study of vehicle suspension. This suspension parameter rig essentially consists of four long stroke hydraulic vibrators set in substantial pedestals so that the tyre contact patches of a vehicle may be individually supported and fed vertical inputs. The rig and its associated instrumentation is described in some detail as are its various modes of use from static to dynamic testing up to around 100 Hz. Much of the work carried out on the rig is directly or indirectly associated with vehicle ride. In addition to the ability to feed in single and repetitive waveforms at different phase relationships, road inputs may be simulated.

Tyre and Vehicle Vibration

An installation specifically designed for the measurement and analysis of vibrations generated at the tyre to road contact, of vibration through tyre, vehicle suspension and body structure is described. Results of tests on rolling drums, including tests on drums with special test surfaces and tests on hydraulic and electromagnetic vibrators designed to feed vibrations into the tyre at ground contact are given. As the hydraulic vibrator is capable of vibrations in the three directions, vertical, longitudinal and lateral, examples of the attenuation during transmission through tyre and suspension are given. Road test recording equipment is available and it uses the analysis equipment installed for the laboratory installation of vibrators and drums: elimination of long delays in analysis is given attention.