Nonlinear distortion of signals radiated by vibroseis sources

Лебедев, А. В.; Beresnev, Igor A.

doi:10.1190/1.1778240

Cited by 53 publications

(27 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, the contact region is typically much softer than the other parts of the interacting bodies ͑the baseplate and the consolidated material below͒; as a result, the deformations in this intermediate region are large enough to change the spectrum of radiation considerably. A model of such a contact and its effect on radiation were discussed by Lebedev and Beresnev ͑2004͒. In the equivalent scheme of the vibroseis source ͑Lerwill, 1981; Sallas and Weber, 1982;Sallas, 1984;Safar, 1984͒, this nonlinearity can be accounted for by introducing a contact spring with the rigidity K c = −dF c /dx ͑Lebedev and Beresnev, 2004͒, where x ϵ z 2 − z 3 , F c is the restoring force from the contact deformation, and z 1 , z 2 , and z 3 are the displacements of the reaction mass, baseplate, and the ground beneath the plate, respectively ͑Figure 1͒. The system of equations governing the source then becomes ͑Leb-edev and Beresnev, 2004͒…”

Section: Model Formulation -Bimodular and Smooth Profiles Of Contact mentioning

confidence: 99%

Model parameters of the nonlinear stiffness of the vibrator-ground contact determined by inversion of vibrator accelerometer data

2006

Self Cite

View full text Add to dashboard Cite

Analysis of vibroseis data shows that harmonic distortion in the ground-force signal may exceed the primary distortions in the hydraulic system. This can be explained by the baseplate-ground contact nonlinearity created by the deformations of the contact roughness. We separated the nonlinear distortion generated in the hydraulics from that generated at the contact. We then formulated an inverse problem for resolving the parameters of the nonlinear contact rigidity, based on the equivalent model of the nonlinear source and the comparison of predicted and observed harmonic levels. The inverse problem was solved for models of bilinear contact and the contact with the rigidity smoothly varying between two asymptotic values, using data obtained on sandy soil. Rigidities changing between approximately 10 9 N/m in compression and 6 ϫ 10 8 N/m in tension were resolved from the inversion for both models, although the smooth nonlinear-rigidity model is a better approximation. The analysis shows the adequacy of the equivalent mechanical source model used for the description of nolinear distortions in real soil-baseplate coupled systems.

show abstract

Section: Model Formulation -Bimodular and Smooth Profiles Of Contact mentioning

confidence: 99%

Model parameters of the nonlinear stiffness of the vibrator-ground contact determined by inversion of vibrator accelerometer data

2006

Self Cite

View full text Add to dashboard Cite

show abstract

“…The stress field of the circular baseplate-ground system under the action of a harmonic disturbance can be obtained from (5). To determine the vertical displacement component of the circular baseplate ( , 0, ) with = 0, the distribution of the reaction force imposed on the bottom of the baseplate needs to be determined.…”

Section: Wave Displacement Field Of a Circular Baseplate Under Amentioning

confidence: 99%

“…The other way is to improve the performance of fundamental components in the vibrator mechanical and hydraulic system [14,15]. Although improvements of individual components in the vibrator system are seen [5][6][7][8][9][10][11][12][13][14][15][16], the theoretical progress on the seismic vibrator design moves very slowly. This is because the dynamics between the vibrator and ground coupling are unclear.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dynamic Characteristics Analysis of a Seismic Vibrator-Ground Coupling System

Liu

Huang

et al. 2017

Shock and Vibration

View full text Add to dashboard Cite

A mathematical model to describe the seismic vibrator and ground coupling is proposed based on dynamic analyses of the vibrator baseplate structure and properties of soil. This mathematical model is solved using Newmark's method. It produces reasonable results and the trend of amplitude envelope follows the experimental data. With this model, characterization of the vibrator-ground coupling is performed. Modal analysis study shows that the motions between the vibrator reaction mass and baseplate experience a combination of a first-order vibration mode and a second-order vibration mode. The corresponding frequencies of two vibration modes are located at 2.77 Hz and 488.7 Hz, respectively. As the frequency goes up, the motion behavior of the reaction mass and baseplate is dominated by the second-order vibration mode. It is realized that the second-order vibration mode is responsible for the phase difference between the input sweep signal and the output force signal. Furthermore, the impact of the coupling system parameters on the vibrator output force is also investigated. It is observed that the vibrator output force decreases as the sweep frequency increases. The weight ratio of the reaction mass and the baseplate has an impact on the vibrator output force.

show abstract

“…the pilot, to a seismic signal linearly, see for example Martin and Jack (1990), Walker (1995), Lebedev and Beresnev (2004), Lebedev et al (2006), Meunier (2011) and Wei and Phillips (2012). The non-linearity in the total system, figure 1, contributes to the distortion of the source wavelet from the pilot, as well as from its estimates measured at the source.…”

Section: Introductionmentioning

confidence: 99%

Influence of Drive Level on the Fundamental Vibrator Signal

Noorlandt¹,

Drijkoningen²,

Faber³

2013

London 2013, 75th Eage Conference en Exhibition Incorporating SPE Europec

View full text Add to dashboard Cite

SUMMARYIn this abstract we show the influence of vibrator drive level on the signal it produces. For that purpose a field survey was carried out using an INOVA's AHV-IV vehicle with a modified 266kN (60.000 lbf) vibrator. A single linear sweep was repeated at 10 different drive levels ranging from 5 to 90% at two locations. Each drive level was repeated 10 times and each run was repeated twice per location. In total 400 sweeps were carried out. From this data set we conclude that; the vibrator signal is very repeatable for a given setting; the repeatability is less comparing different runs with the same setting; the ground-base plate interaction depends on the drive level in a non-linear way and not taking these effects into account produce arrival time and amplitude errors in seismic records.

show abstract

Nonlinear distortion of signals radiated by vibroseis sources

Cited by 53 publications

References 18 publications

Model parameters of the nonlinear stiffness of the vibrator-ground contact determined by inversion of vibrator accelerometer data

Model parameters of the nonlinear stiffness of the vibrator-ground contact determined by inversion of vibrator accelerometer data

Dynamic Characteristics Analysis of a Seismic Vibrator-Ground Coupling System

Influence of Drive Level on the Fundamental Vibrator Signal

Contact Info

Product

Resources

About