Development of Vertical Cable Seismic System

Asakawa, Eiichi; Murakami, Fumitoshi; Sekino, Y.; Okamoto, Taku; Ishikawa, K.; Tsukahara, H.; Shimura, T.

doi:10.3997/2214-4609.20148328

Cited by 17 publications

(5 citation statements)

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“…Vertical cable seismic use vertical hydrophone array moored on the sea bottom to record the seismic waves for complex geological structures imaging (Krail, 1991(Krail, , 1993(Krail, , 1994Leach, 1997;Ikelle & Wilson, 1999;Asakawa et al, 2012Asakawa et al, , 2014Wang et al, 2019Wang et al, , 2021. Owing to the unique field acquisition, ghost reflections can be classified into receiver ghosts, source ghost and source-receiver ghost with respect to their raypaths as shown in Figure 1.…”

Section: Receiver Ghosts In Vertical Cable Seismic Surveymentioning

confidence: 99%

Application of deconvolution interferometry to receiver ghost reflection in vertical cable seismic survey

Wang

Liu

et al. 2023

Geophysical Prospecting

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Marine vertical cable seismic is to probe targets near the submarine with use vertical hydrophone array suspending in deep sea water. Despite imaging of primary reflections from vertical cable seismic data can provide seismic profiles with high resolution, its submarine illumination is much narrower than that of conventional towed-streamer seismic owing to the irregular geometry. In view of the fact that imaging of multiples can provides better subsurface illumination with fine resolution, we present a strategy for imaging of receiver ghost reflections from vertical cable seismic data, based on seismic interferometry by deconvolution. This method can convert first-order receiver ghosts into virtual primaries from the towed-streamer data without velocity model and sourcereceiver position. We illustrate the deconvolution interferometry for the receiver ghost reflections with the real vertical cable seismic data in Shenhu area, South China Sea and further obtain virtual primary reflections. Finally, we use these virtual primaries to successfully construct a stacked image and obtain a post-stack migration image with conventional seismic data process method. This stacked and migrated image significantly extends the submarine illumination with higher resolution and it is useful in characteristics recognition of hydrate-bearing sediments and free gas.

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Section: Receiver Ghosts In Vertical Cable Seismic Surveymentioning

confidence: 99%

Application of deconvolution interferometry to receiver ghost reflection in vertical cable seismic survey

Wang

Liu

et al. 2023

Geophysical Prospecting

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“…Texaco built vertical cables in the late 1980s and early 1990s and conducted vertical cable acquisition experiments in the Gulf of Mexico (Krail, 1994; 1997), which provided clear reflection at the edge of the salt dome and below the salt. In 2009, JGI Inc. developed an integrated VCS acquisition system for hydrothermal deposit exploration and studied corresponding data processing methods (Asakawa et al., 2012). In 2013, Ocean University of China and Guangzhou Marine Geological Survey Bureau of China Geological Survey jointly developed VCS technology for gas hydrate exploration.…”

Section: Amplitude Versus Offset Analysis Of Gas Hydrate Using the Br...mentioning

confidence: 99%

Study on multicomponent Amplitude Versus Offset forward modelling of thin layer gas hydrate using the Brekhovskikh equation

Zhang

Gao

Wang

et al. 2023

Geophysical Prospecting

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Amplitude Versus Offset forward modelling plays a crucial role in identifying gas hydrate reservoirs. However, since gas hydrates commonly exist in thin intermediate seafloor layers, traditional Amplitude Versus Offset techniques based on the Zoeppritz equation with the semi‐infinite medium assumption may not accurately depict the reflection amplitude of hydrates. In this paper, multi‐component Amplitude Versus Offset forward modelling using the Brekhovskikh equation was performed to simulate the Amplitude Versus Offset response of thin‐layered gas hydrate reservoirs more accurately. The numerical experiments demonstrate that the overall trends of the P‐wave and S‐wave Amplitude Versus Offset curves calculated by the Brekhovskikh equation and the Zoeppritz equation are consistent under various reservoir thicknesses, porosities and hydrate saturations, but the Amplitude Versus Offset curves calculated by the Brekhovskikh equation reveal more details. When the angle is greater than 30°, the gradient of the P‐wave Amplitude Versus Offset curve calculated from the Brekhovskikh equation as a function of hydrate saturation and porosity is greater than that calculated by the Zoeppritz equation, whereas the S‐wave Amplitude Versus Offset is not sensitive to changes in hydrate reservoir parameters. To further validate the Brekhovskikh equation in practical Amplitude Versus Offset analysis of gas hydrates, a geological model of gas hydrates is established based on logging data in the South China Sea. Subsequently, the bottom simulation reflection Amplitude Versus Offset of the P‐wave was computed using the Brekhovskikh equation and the Zoeppritz equation. Comparison with the actual vertical cable seismic data indicates that the Amplitude Versus Offset curve using Brekhovskikh equation is more consistent with the amplitude trend than the Zoeppritz equation. This finding suggests that the Brekhovskikh equation holds great potential for establishing an Amplitude Versus Offset identification marker for gas hydrates and improving seismic data interpretation in gas hydrate exploration.

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“…As vertical cable is fixed near the seafloor, the source vessel could shoot along the surveying lines in any azimuth. In addition, VCS acquisition can use various marine sources, such as sparkers and air-gun (Asakawa et al, 2012). In fact, VCS exploration can be considered a multi-offset vertical seismic profiling (VSP).…”

Section: Marine Vertical Cable Seismic Exploration General Conceptmentioning

confidence: 99%

“…However, VCS has not been widespread used for resource survey owing to its expensive acquisition system and unique processing method. In 2009, JGI Inc. started to develop an integrated VCS acquisition system for hydrothermal deposit exploration and research on corresponding data processing and analysis technique (Asakawa et al, 2012). They carried out the VCS experiment in Lake Biwa and obtained high-resolution 3D images which are better than the conventional surface seismic.…”

Section: Introductionmentioning

confidence: 99%

Reverse Time Migration of Vertical Cable Seismic Data to Image Hydrate-Bearing Sediments With High Resolution

et al. 2021

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Marine vertical cable seismic (VCS) is a promising survey technique for submarine complex structure imaging and reservoir monitoring, which uses vertical arrays of hydrophones deployed near the seafloor to record seismic wavefields in a quiet environment. Recently, we developed a new type of distributed VCS system for exploration and development of natural gas hydrates preserved in shallow sediments under the seafloor. Using this system and air-gun sources, we accomplished a 3D VCS yield data acquisition for gas hydrates exploration in the Shenhu area, South China Sea. In view of the characteristics of VCS geometry, we implement reverse time migration (RTM) on a common receiver gather to obtain high-resolution images of marine sediments. Due to the unique acquisition method, it is asymmetrical for the reflection path between the sources and the receivers in the VCS survey. Therefore, we apply accurate velocity analysis to common scatter point (CSP) gathers generated from common receiver gathers instead of the conventional velocity analysis based on common depth point gathers. RTM with this reliable velocity model results in high-resolution images of submarine hydrate-bearing sediments in deep water conditions. The RTM imaging section clearly shows the bottom simulating reflector (BSR) and also the reflection characteristics of the hydrate-bearing sediments filled with consolidated hydrates. Moreover, its resolution is relative to that of acoustic logging curves from the nearby borehole, and this imaging section is well consistent with the synthetic seismogram trace generated by the logging data. All these results reveal that VCS is a great potential technology for exploration and production of marine natural gas hydrates.

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Development of Vertical Cable Seismic System

Cited by 17 publications

References 0 publications

Application of deconvolution interferometry to receiver ghost reflection in vertical cable seismic survey

Application of deconvolution interferometry to receiver ghost reflection in vertical cable seismic survey

Study on multicomponent Amplitude Versus Offset forward modelling of thin layer gas hydrate using the Brekhovskikh equation

Reverse Time Migration of Vertical Cable Seismic Data to Image Hydrate-Bearing Sediments With High Resolution

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