scholarly journals A Comparison Study on Near-surface High-resolution Seismic Data by Different Source and Geophone Types

2011 ◽  
Vol 32 (6) ◽  
pp. 674-686
Author(s):  
Hyoung-Soo Kim ◽  
Young-Seuk Keehm
Geophysics ◽  
2020 ◽  
pp. 1-57
Author(s):  
Daniele Colombo ◽  
Ernesto Sandoval ◽  
Diego Rovetta ◽  
Apostolos Kontakis

Land seismic velocity modeling is a difficult task largely related to the description of the near surface complexities. Full waveform inversion is the method of choice for achieving high-resolution velocity mapping but its application to land seismic data faces difficulties related to complex physics, unknown and spatially varying source signatures, and low signal-to-noise ratio in the data. Large parameter variations occur in the near surface at various scales causing severe kinematic and dynamic distortions of the recorded wavefield. Some of the parameters can be incorporated in the inversion model while others, due to sub-resolution dimensions or unmodeled physics, need to be corrected through data preconditioning; a topic not well described for land data full waveform inversion applications. We have developed novel algorithms and workflows for surface-consistent data preconditioning utilizing the transmitted portion of the wavefield, signal-to-noise enhancement by generation of CMP-based virtual super shot gathers, and robust 1.5D Laplace-Fourier full waveform inversion. Our surface-consistent scheme solves residual kinematic corrections and amplitude anomalies via scalar compensation or deconvolution of the near surface response. Signal-to-noise enhancement is obtained through the statistical evaluation of volumetric prestack responses at the CMP position, or virtual super (shot) gathers. These are inverted via a novel 1.5D acoustic Laplace-Fourier full waveform inversion scheme using the Helmholtz wave equation and Hankel domain forward modeling. Inversion is performed with nonlinear conjugate gradients. The method is applied to a complex structure-controlled wadi area exhibiting faults, dissolution, collapse, and subsidence where the high resolution FWI velocity modeling helps clarifying the geological interpretation. The developed algorithms and automated workflows provide an effective solution for massive full waveform inversion of land seismic data that can be embedded in typical near surface velocity analysis procedures.


2008 ◽  
Author(s):  
Tariq Alkhalifa ◽  
Ramzy AlZayer ◽  
and Majed AlMalki

2017 ◽  
Vol 5 (4) ◽  
pp. SR23-SR33 ◽  
Author(s):  
Xin Cheng ◽  
Kun Jiao ◽  
Dong Sun ◽  
Zhen Xu ◽  
Denes Vigh ◽  
...  

Over the past decade, acoustic full-waveform inversion (FWI) has become one of the standard methods in the industry to construct high-resolution velocity fields from the seismic data acquired. While most of the successful applications are for marine acquisition data with rich low-frequency diving or postcritical waves at large offsets, the application of acoustic FWI on land data remains a challenging topic. Land acoustic FWI application faces many severe difficulties, such as the presence of strong elastic effects, large near-surface velocity contrast, and heterogeneous, topography variations, etc. In addition, it is well-known that low-frequency transmitted seismic energy is crucial for the success of FWI to overcome sensitivity to starting velocity fields; unfortunately, those are the parts of the data that suffer the most from a low signal-to-noise ratio (S/N) in land acquisition. We have developed an acoustic FWI application on a land data set from North Kuwait, and demonstrated our solutions to mitigate some of the challenges posed by land data. More specifically, we have developed a semblance-based high-resolution Radon (HR-Radon) inversion approach to enhance the S/N of the low-frequency part of the FWI input data and to ultimately improve the convergence of the land FWI workflow. To mitigate the impact of elastic effects, we included only the diving and postcritical early arrivals in the waveform inversion. Our results show that, with the aid of HR-Radon preconditioning and a carefully designed workflow, acoustic FWI has the ability to derive a reliable high-resolution near-surface model that could not be otherwise recovered through traditional tomographic methods.


2021 ◽  
Author(s):  
Bjarne Almqvist ◽  
Maria Ask ◽  
Linus Brander ◽  
Stefan Buske ◽  
Christoph Büttner ◽  
...  

<p>Increasing the effectiveness of exploration for mineral resources is vital to meet future societal, economic and environmental challenges. Effective exploration drilling for mineral resources is an area where industrial innovation plays an important role. Measurements-while-drilling, data acquisition and next generation logging sondes represent three important areas that need development in the mineral exploration sector. Despite this need, there is a lack of test beds that allow to test novel drilling equipment. This limits the development and implementation of equipment with technology that has been proven, but does not yet fulfil the requirements of a product on the commercial market. Although a variety of test sites exist throughout Europe, they are constrained to existing infrastructure, which limits users to pre-existing conditions that may not fit their purpose or need. The I-EDDA-TC provides a unique environment for the development of drilling, and related, equipment used for exploration of mineral resources.</p><p>The regional geology around the test center site is dominated by Svecokarelian age granitoid intrusive and acid volcanic rocks (rhyolites) that strike east-west and dip sub-vertical. During 2019 and 2020, two boreholes were drilled at the test center site, as part of an EIT Raw Materials upscaling project. The first borehole is a fully cored 970 m deep borehole drilled with diamond bit (HQ dimension). The second borehole was drilled in the late summer of 2020, and is a 200 m deep percussion-drilled borehole with ~220 mm diameter. Here we present a preliminary synthesis of results from a geophysical survey, borehole logging and geological logging of drill core.</p><p>In summer 2019 a comprehensive geophysical surveying program was performed at the site, including 3D high resolution seismic, 2D deeper seismic with a large vibrator source, a series of high-resolution resistivity profiles and magnetic profiles. The 3D seismic data provided detailed velocity information in the near-surface at the site, allowing interpretation of depths to the groundwater table and bedrock in 3D. Data gained from two downhole logging campaigns provides a robust base for the detailed differentiation and characterization of the formations. A first look on the data shows well defined correlations amongst the various geophysical downhole parameters. Geological logging focused both on material properties (e.g. mineralogy, grain-size, texture, alteration and mineralization) and rock mass (joints and RQD). Magnetic susceptibility and ultrasonic pulse velocity were measured at regular intervals along the full core length, and 66 specimens were prepared and analysed with respect to porosity, density, abrasivity, major chemical elements, indirect tensile strength and uniaxial compressive strength. The integrated analysis of core data, surface and borehole seismic data, and the continuous logging profiles allows for the 3-dimensional characterization of the underground below the test center platform, as well as provides reference data for assessment of work conducted at the site (e.g. development of geophysical instruments, testing of drillabilaty and wear on drill bits). Our results will be open access published so that data can be compared to drilling and instruments test of commercial and academic parties utilizing this testing facility in future.</p>


2022 ◽  
Vol 12 (2) ◽  
pp. 584
Author(s):  
Sherif M. Hanafy

Near-surface high-resolution seismic mapping is very important in many applications such as engineering and environmental. However, the conventional setup of the seismic technique requires planting geophones, connecting cables, and then collecting all equipment after completing the survey, which is time-consuming. In this study, we suggest using a land-streamer setup rather than the conventional setup for fast, accurate, and high-resolution near-surface seismic surveys. Only one field data set is recorded using both the conventional and the land-streamer setups. The recorded data is then compared in terms of time, frequency, wavenumber domains, and acquisition time. Following this, we compared the accuracy of the subsurface mapping of both setups using a synthetic example. The results show that the conventional setup can reach deeper depths but with lower accuracy, where the errors in imaging the local anomalies’ widths and thicknesses are 77% to 145% and 35% to 50%, respectively. The land-streamer setup provides accurate near-surface results but shallower penetration depth, here the errors in the anomalies’ widths and thicknesses are 5% to 12% and 10% to 20%, respectively.


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