Vertical Cable Seismic (VCS) Survey for Buried Hydrothermal Sulfide Deposit

Asakawa, Eiichi; Tara, Kenji; Murakami, Fumitoshi; Tsukaraha, Hitoshi; Mizohata, Shigeharu

doi:10.4043/26583-ms

Cited by 4 publications

(3 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, we establish the reference velocity model by accurate velocity analysis on common scatter point (CSP) gathers. In practice, constructing CSP gathers from common receiver gathers is an initial process of Kirchhoff pre-stack migration (Bancroft and Xu, 1999). By this processing, we can address large elevation changes and the travel times for the source and receiver ray paths can be computed to the actual locations.…”

Section: Rtm Is Suitable For Vcs Imagingmentioning

confidence: 99%

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

et al. 2021

View full text Add to dashboard Cite

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.

show abstract

Section: Rtm Is Suitable For Vcs Imagingmentioning

confidence: 99%

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

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Derived from defence research, the VCS method was successfully applied to conduct offshore seismic survey, for highquality subsalt imaging [3,7], for low-angle fault scarp imag-ing and assessment of remaining exploration potential [8], for hydrothermal deposit exploration [5], for seafloor massive sulphide survey [9][10][11][12], and for natural gas hydrate exploration [4,[13][14][15]. All these applications reveal that the VCS technique is an effective approach to exploiting and developing the complex offshore oil and gas fields, which can provide superior seismic image compared with conventional marine seismic method.…”

Section: Introductionmentioning

confidence: 99%

Hydrate-Bearing Sediment Imaging of Ghost Reflection in Vertical Cable Seismic Data Using Seismic Interferometry

Wang

Liu

et al. 2022

Geofluids

View full text Add to dashboard Cite

Marine vertical cable seismic (VCS) collects seismic waves by hydrophone array vertically suspended in seawater to prospect the offshore geological structure and monitor the reservoir. Due to its irregular source-receiver geometry, the primary imaging has narrow illustration coverage. Here, we proposed a cross-correlation transformation based on ghost wave interferometry. This method can transform the ghost reflections from the vertical cable seismic profile into the virtual surface seismic primaries just like those excited by the source and recorded by marine seismic towed-streamer below sea surface. After processing these virtual primaries with conventional method, we can obtain the ghost reflection imaging section with high resolution which effectively extend the illustration footprints in the subsurface. By application of this transform, virtual primaries are generated from the first-order ghost reflections of the actual VCS data. Then, migration of these virtual primaries provides a high-resolution image of hydrate-bearing sediments.

show abstract

“…In 2010, the successful development of an autonomous VC detection system with a detection depth of 100-2000 m further advanced the applicability of VC data processing technology. Then, a joint VC and submarine source was first applied in 2013 to conduct 3D seismic exploration within the Okinawa Trough to investigate vulcanization, thereby providing valuable seismic data for structural studies of mineral deposits (Asakawa et al, 2012;.…”

mentioning

confidence: 99%

The Sensitive Properties of Hydrate Reservoirs Based on Seismic Stereoscopic Detection Technology

Liu

Xing

Qin

et al. 2020

Acta Geologica Sinica (Eng)

View full text Add to dashboard Cite

Higher‐precision determinations of hydrate reservoirs, hydrate saturation levels and storage estimations are important for guaranteeing the ability to continuously research, develop and utilize natural gas hydrate resources in China. With seismic stereoscopic detection technology, which fully combines the advantages of different seismic detection models, hydrate formation layers can be observed with multiangle, wide‐azimuth, wide‐band data with a high precision. This technique provides more reliable data for analyzing the distribution characteristics of gas hydrate reservoirs, establishing velocity models, and studying the hydrate‐sensitive properties of petrophysical parameters; these data are of great significance for the exploration and development of natural gas hydrate resources. Based on a velocity model obtained from the analysis of horizontal streamer velocity data in the hydrate‐bearing area of the Shenhu Sea, this paper uses three VCs (longitudinal spacing of 25 m) and four OBSs (transverse spacing of 200 m) to jointly detect seismic datasets consisting of wave points based on an inversion of traveltime imaging sections. Accordingly, by comparing the differences between the seismic phases in the original data and the forward‐modeled seismic phases, multiangle coverage constraint corrections are applied to the initial velocity model, and the initial model is further optimized, thereby improving the imaging quality of the streamer data. Petrophysical elastic parameters are the physical parameters that are most directly and closely related to rock formations and reservoir physical properties. Based on the optimized velocity model, the rock elastic hydrate‐sensitive parameters of the hydrate reservoirs in the study area are inverted, and the sensitivities of the petrophysical parameters to natural gas hydrates are investigated. According to an analysis of the inversion results obtained from these sensitive parameters, λρ, Vp and λμ are simultaneously controlled by the bulk modulus and shear modulus, while Vs and μρ are controlled only by the shear modulus, and the latter two parameters are less sensitive to hydrate‐bearing layers. The bulk modulus is speculated to be more sensitive than the shear modulus to hydrates. In other words, estimating the specific gravity of the shear modulus among the combined parameters can affect the results from the combined elastic parameters regarding hydrate reservoirs.

show abstract

Vertical Cable Seismic (VCS) Survey for Buried Hydrothermal Sulfide Deposit

Cited by 4 publications

References 5 publications

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

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

Hydrate-Bearing Sediment Imaging of Ghost Reflection in Vertical Cable Seismic Data Using Seismic Interferometry

The Sensitive Properties of Hydrate Reservoirs Based on Seismic Stereoscopic Detection Technology

Contact Info

Product

Resources

About