Offset panel

Geophysics ◽  
1984 ◽  
Vol 49 (8) ◽  
pp. 1140-1152 ◽  
Author(s):  
Thomas K. Fulton ◽  
K. Michele Darr

The offset panel is a display of basic seismic data which combines single‐channel profiles from successive offsets (source‐to‐receiver distances) into one format. The profiles are displayed one below another and arranged vertically by offset and horizontally by common‐depth‐point. This arrangement allows for comparison of variations observed at one offset to those at another offset. Alteration of the data due to near‐surface geologic variations generates geometric patterns on the display which are different from patterns due to changes in seismic source or receiver. This display has utility in data processing to verify field recording geometry, monitor the seismic source (primarily a marine application), and determine processing parameters. It aids data interpretation by allowing for the detection of an anomalous velocity zone in the near‐surface which may affect deeper structural interpretation. Utilization of the offset panel in identification of shallow events of high amplitude also allows identification of shallow drilling hazards in the marine environment with conventional seismic data.

Geophysics ◽  
1989 ◽  
Vol 54 (11) ◽  
pp. 1384-1396
Author(s):  
Howard Renick ◽  
R. D. Gunn

The Triangle Ranch Headquarters Canyon Reef field is long and narrow and in an area where near‐surface evaporites and associated collapse features degrade seismic data quality and interpretational reliability. Below this disturbed section, the structure of rocks is similar to the deeper Canyon Reef structure. The shallow structure exhibits very gentle relief and can be mapped by drilling shallow holes on a broad grid. The shallow structural interpretation provides a valuable reference datum for mapping, as well as providing a basis for planning a seismic program. By computing an isopach between the variable seismic datum and the Canyon Reef reflection and subtracting the isopach map from the datum map, we map Canyon Reef structure. The datum map is extrapolated from the shallow core holes. In the area, near‐surface complexities produce seismic noise and severe static variations. The crux of the exploration problem is to balance seismic signal‐to‐noise ratio and geologic resolution. Adequate geologic resolution is impossible without understanding the exploration target. As we understood the target better, we modified our seismic acquisition parameters. Studying examples of data with high signal‐to‐noise ratio and poor resolution and examples of better defined structure on apparently noisier data led us to design an acquisition program for resolution and to reduce noise with arithmetic processes that do not reduce structural resolution. Combining acquisition and processing parameters for optimum structural resolution with the isopach mapping method has improved wildcat success from about 1 in 20 to better than 1 in 2. It has also enabled an 80 percent development drilling success ratio as opposed to slightly over 50 percent in all previous drilling.


Geophysics ◽  
2020 ◽  
Vol 85 (2) ◽  
pp. V169-V181 ◽  
Author(s):  
Daniele Colombo ◽  
Diego Rovetta ◽  
Ernesto Sandoval-Curiel ◽  
Apostolos Kontakis

We have developed a new framework for performing surface-consistent amplitude balancing and deconvolution of the near-surface attenuation response. Both approaches rely on the early arrival waveform of a seismic recording, which corresponds to the refracted or, more generally speaking, to the transmitted energy from a seismic source. The method adapts standard surface-consistent amplitude compensation and deconvolution to the domain of refracted/transmitted waves. A sorting domain specific for refracted energy is extended to the analysis of amplitude ratios of each trace versus a reference average trace to identify amplitude residuals that are inverted for surface consistency. The residual values are either calculated as a single scalar value for each trace or as a function of frequency to build a surface-consistent deconvolution operator. The derived operators are then applied to the data to obtain scalar amplitude balancing or amplitude balancing with spectral shaping. The derivation of the operators around the transmitted early arrival waveforms allows for deterministically decoupling the near-surface attenuation response from the remaining seismic data. The developed method is fully automatic and does not require preprocessing of the data. As such, it qualifies as a standard preprocessing tool to be applied at the early stages of seismic processing. Applications of the developed method are provided for a case in a complex, structure-controlled wadi, for a seismic time-lapse [Formula: see text] land monitoring case, and for an exploration area with high dunes and sabkhas producing large frequency-dependent anomalous amplitude responses. The new development provides an effective tool to enable better reservoir characterization and monitoring with land seismic data.


Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. IM37-IM49 ◽  
Author(s):  
Sanyi Yuan ◽  
Jinghan Wang ◽  
Tao Liu ◽  
Tao Xie ◽  
Shangxu Wang

Phase information of seismic signals is sensitive to subsurface discontinuities. However, 1D phase attributes are not robust when dealing with noisy data. In addition, variations of seismic phase attributes with azimuth are seldom explored. To address these issues, we have developed 6D phase-difference attributes (PDAs) derived from azimuthal phase-frequency spectra. For the seismic volume of a certain azimuth and frequency, we first construct stacked phase traces at each common-depth point along a certain decomposed trending direction. Then, the 6D PDA is extracted by calculating the complex-valued covariance at a 6D phase space. The proposed method enables characterization of the subsurface discontinuities and indicates seismic anisotropy. Moreover, we provide one q-value attribute obtained by singular value decomposition to describe the variation intensity of PDA along different azimuths. Simulated and field wide-azimuth seismic data sets are used to illustrate the performance of the proposed 6D PDA and the derived q-value attribute. The results show that PDA at different frequencies can image various geologic features, including faults, fracture groups, and karst caves. Our field data example shows that PDA is able to discern the connectivity of karst caves using large-azimuth data. In addition, PDA along different azimuths and the q-value attribute provide a measurement of azimuthal variations, as well as the anisotropy. Our 6D PDA method can be used as a potential tool for wide-azimuth seismic data interpretation.


2020 ◽  
Author(s):  
Young Jun Kim ◽  
Snons Cheong ◽  
Deniz Cukur ◽  
Dong-Geun Yoo

<p>In marine seismic surveys, various acquisition systems are used depending on the survey purpose, target depth, survey environment, and conditions. A 3D survey of oil and/or gas exploration, for instance, require large-capacity air-gun arrays and six or more streamers with a minimum length of 6 km. In contrast, a high-resolution seismic survey for the shallow-water geological research and engineering needs a small capacity source such as air-gun, sparker, and boomer, deployed with a single-channel or multi-channel (24-channel) streamers. The main purpose of our seismic survey was to investigate the Quaternary geology and stratigraphy of offshore, Korea. Because the Quaternary is the most recent geological period, our target depth was very shallow at about 50 m below the sea-bottom. We used a high-frequency seismic source including a sparker of 2,000 J capacity or a 60 in<sup>3</sup> mini GI-gun and an eight-channel streamer with a 3.125 m group interval or a single-channel streamer that included 96 elements. To compare the resolution of seismic data according to the seismic source, a boomer or sparker systems were used with the single-channel streamer on a small survey ship. The seismic data processing was performed at the Korea Institute of Geoscience and Mineral Resources (KIGAM) with ProMAX, and the data processing and resolution of each survey were compared based on their acquisition systems.</p>


2016 ◽  
Vol 2 (3) ◽  
Author(s):  
Delyuzar Ilahude ◽  
Lukman Arifin

From the total magnetic anomaly and single channel seismic data interpretation on the systematic mapping in the Tanjung Selor waters, east Kalimantan, are shows correlation almost similar between magnetic anomaly with the seismic data records. The magnetic anomaly value and seismic data profiles are show that the many fault and fold structures identification in the research area. The total magnetic anomaly result which are presented of the magnetic basement. Dari Anomali magnet total dan data seismik dangkal saluran tunggal pada pemetaan sistematik di perairan Tanjung Selor, Kalimantan timur, menunjukkan hubungan yang hampir mirip antara nilai anomali magnet total dengan data seismik. Profil anomali magnet dan data seismik dangkal menunjukkan banyaknya struktur sesar dan perlipatan teridentifikasi di daerah penelitian. Anomali magnet total hasil penelitian ini lebih cenderung menggambarkan intensitas magnet batuan dasar.


2020 ◽  
Vol 35 (2) ◽  
Author(s):  
Muhammad Zulfikar ◽  
Noor Cahyo Dwi Aryanto ◽  
Andi Agus Nur ◽  
Ildrem Syafri

Bangka Island is one of the islands in Indonesia which is traversed by Southeast Asia granitoid belt. This belt stretches from Burma (Myanmar) to Bangka Belitung. This granitoid has potential as a source rock of mineral that carrying tin and rare earth element. At present, mapping of granitoid rocks to the waters area is rarely published, so acoustic basement mapping is necessary to do in order to determine the distribution of granitoids in Toboali waters. The research method used is a single channel seismic with an energy source of 300 joules. The sound source uses a single plate boomer, so it has a high enough resolution but the penetration is not deep enough. Acoustic basement in Toboali waters varies in depth from 15 - 75 ms or getting deeper south. When viewed from the continuity of the acoustic basement, it is estimated that the granitoid is 7 km from the nearest coastline.


Geophysics ◽  
1968 ◽  
Vol 33 (5) ◽  
pp. 711-722 ◽  
Author(s):  
E. B. Davies ◽  
E. J. Mercado

Several writers have proposed the use of multichannel filters for the elimination of coherent noise on seismic records. One filter of this type which can be constructed is a multichannel Wiener filter which has a multichannel input and a single channel output. In this form, it is applicable to data collected for vertical or horizontal common‐depth‐point stack processing. The choice of desired output characteristics for this Wiener filter is flexible and, for example, can be tuned to correspond to multichannel deconvolution. The results of the application of filters of this type to field and synthetic data, in general, show little if any advantage over single‐channel deconvolution. This failure appears to be connected with the low cross coherence of both noise and reflection signal on field‐recorded, common‐depth‐point traces.


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