The Feasibility of Permanent Land Seismic Monitoring with Buried Geophones and Hydrophones

Bakulin, Andrey; Burnstad, Roy; Jervis, Michael; Kelamis, Panos G.

doi:10.3997/2214-4609.20148785

Cited by 8 publications

(13 citation statements)

References 1 publication

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“…We apply the deconvolution-convolution method to the field data from Saudi Arabia (Bakulin et al, 2012). The seismic data were acquired with a single surface vibrator sweeping every 7.5 m and recorded by receivers buried at 30 m depth with 30 m inline spacing (Figure 1).…”

Section: Field Data Examplementioning

confidence: 99%

“…In cases where a significant fold is required for imaging, burial of a large number of sources can be inefficient and costly. Recently, an experiment was conducted in a challenging desert environment with surface sources and shallow buried receivers (Bakulin et al, 2012). Using downhole sensors allowed removing a significant amount of receiver-side 4D noise.…”

Section: Introductionmentioning

confidence: 99%

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Improving Repeatability of Land Seismic Data Using Virtual Source Approach Based on Multidimensional Deconvolution

Alexandrov¹,

Neut²,

Bakulin³

et al. 2015

Proceedings

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SUMMARYWe present a new redatuming workflow developed for improving the repeatability of seismic data and designed specifically to account for changes in the source signatures or variations in downgoing fields in general. The new approach is based on the virtual source method with the same potential for reducing nonrepeatability, associated with acquisition geometry changes and variations in the near surface. To correct for changes in the source wavelet between surveys, we suggest deconvolving the virtual source gather of the monitor survey with the point-spread function (PSF) of the same survey, and immediately convolving with the PSF of the base or reference survey. The PSF governs the radiation pattern of the virtual source. Trying to completely deconvolve the effects of individual PSFs on each virtual source response may degrade repeatability due to possible amplification of noise. Instead, we try to equalize radiation patterns of the virtual sources across all repeat surveys by reassigning a new reference PSF to all surveys. We apply the deconvolution-convolution method to a field 4D dataset with buried receivers and demonstrate significant improvement in repeatability.

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Section: Field Data Examplementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improving Repeatability of Land Seismic Data Using Virtual Source Approach Based on Multidimensional Deconvolution

Alexandrov¹,

Neut²,

Bakulin³

et al. 2015

Proceedings

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show abstract

“…The repeatability of a land seismic survey is affected by the ambient noise (weather conditions, machinery), variation of the source generated noise pattern, velocity variations in the shallow subsurface, source‐receiver positioning, variations in acquisition parameters, geophone coupling, and other factors. (Bakulin et al, ). All these factors may cause the time‐lapse seismic signal to be below the detectable level.…”

Section: Introductionmentioning

confidence: 99%

“…Using permanent buried installations could be particularly beneficial onshore, where the presence of complex overburden, rapid variations in source generated noise, seasonal variations and highly variable ambient noise are commonplace. In order to evaluate various acquisition geometry configurations for onshore monitoring, such as the depth of the buried array or the type of receiver, a comprehensive onshore field experiment was recently conducted in Saudi Arabia (Bakulin et al, ). The study demonstrates the importance of the depth of buried receivers in the presence of the complex near‐surface.…”

Section: Introductionmentioning

confidence: 99%

Burying receivers for improved time‐lapse seismic repeatability: CO2CRC Otway field experiment

Shulakova

Pevzner

Dupuis

et al. 2014

Geophysical Prospecting

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4D seismic is widely used to remotely monitor fluid movement in subsurface reservoirs. This technique is especially effective offshore where high survey repeatability can be achieved. It comes as no surprise that the first 4D seismic that successfully monitored the CO2 sequestration process was recorded offshore in the Sleipner field, North Sea. In the case of land projects, poor repeatability of the land seismic data due to low S/N ratio often obscures the time‐lapse seismic signal. Hence for a successful on shore monitoring program improving seismic repeatability is essential. Stage 2 of the CO2CRC Otway project involves an injection of a small amount (around 15,000 tonnes) of CO2/CH4 gas mixture into a saline aquifer at a depth of approximately 1.5 km. Previous studies at this site showed that seismic repeatability is relatively low due to variations in weather conditions, near surface geology and farming activities. In order to improve time‐lapse seismic monitoring capabilities, a permanent receiver array can be utilised to improve signal to noise ratio and hence repeatability. A small‐scale trial of such an array was conducted at the Otway site in June 2012. A set of 25 geophones was installed in 3 m deep boreholes in parallel to the same number of surface geophones. In addition, four geophones were placed into boreholes of 1–12 m depth. In order to assess the gain in the signal‐to‐noise ratio and repeatability, both active and passive seismic surveys were carried out. The surveys were conducted in relatively poor weather conditions, with rain, strong wind and thunderstorms. With such an amplified background noise level, we found that the noise level for buried geophones is on average 20 dB lower compared to the surface geophones. The levels of repeatability for borehole geophones estimated around direct wave, reflected wave and ground roll are twice as high as for the surface geophones. Both borehole and surface geophones produce the best repeatability in the 30–90 Hz frequency range. The influence of burying depth on S/N ratio and repeatability shows that significant improvement in repeatability can be reached at a depth of 3 m. The level of repeatability remains relatively constant between 3 and 12 m depths.

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“…In recent years, we can notice an emerging acquisition design in industry which makes use of downhole sensor arrays (e.g. Bakulin et al (2012)). Inspired by marine acquisition designs that make use of recordings at multiple depth levels for successful wavefield decomposition (e.g.…”

Section: Introductionmentioning

confidence: 99%

Wavefield Decomposition of Field Data, Using a Shallow Horizontal Downhole Sensor Array and a Free-surface Constraint

et al. 2014

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SUMMARYSeparation of recorded wavefields into downgoing and upgoing constituents is a technique that is used in many geophysical methods. The conventional, multi-component (MC) wavefield decomposition scheme makes use of different recorded wavefield components. In recent years, land acquisition designs have emerged that make use of shallow horizontal downhole sensor arrays. Inspired by marine acquisition designs that make use of recordings at multiple depth levels for wavefield decomposition, we have recently developed a multi-depth level (MDL) wavefield decomposition scheme for land acquisition. Exploiting the underlying theory of this scheme, we now consider conventional, multi-component (MC) decomposition as an inverse problem, which we try to constrain in a better way. We have overdetermined the inverse problem by adding an MDL equation that exploits the Dirichlet free-surface boundary condition. To investigate the successfulness of this approach, we have applied both MC and combined MC-MDL decomposition to a real land dataset acquired in Annerveen, the Netherlands. Comparison of the results of overdetermined MC-MDL decomposition with the results of MC wavefield decomposition, clearly shows improvements in the obtained one-way wavefields, especially for the downgoing fields.

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The Feasibility of Permanent Land Seismic Monitoring with Buried Geophones and Hydrophones

Cited by 8 publications

References 1 publication

Improving Repeatability of Land Seismic Data Using Virtual Source Approach Based on Multidimensional Deconvolution

Improving Repeatability of Land Seismic Data Using Virtual Source Approach Based on Multidimensional Deconvolution

Burying receivers for improved time‐lapse seismic repeatability: CO2CRC Otway field experiment

Wavefield Decomposition of Field Data, Using a Shallow Horizontal Downhole Sensor Array and a Free-surface Constraint

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