Andrej Bóna

Andrej Bóna
Curtin University · Western Australian School of Mines

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142
Publications
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861
Citations

Publications

Publications (142)
Poster
Full-text available
DAS and geophone work on fundamentally different principles; therefore, it is reasonable to question whether these systems can obtain the same information about the same physical properties. In addition, borehole geophones and DAS have different factors that affect the amplitude of measured signal. We bring the data recorded with geophones and DAS...
Article
Orthotropic velocity models are commonly considered as to have the lowest complexity (or highest symmetry) that can realistically describe the combined effect of Earth’s velocity heterogeneity in the vertical and in the horizontal (radial) directions. Velocity heterogeneity in the vertical direction is commonly caused by horizontal stratification o...
Conference Paper
Full-text available
Full-waveform inversion (FWI) is a powerful tool for building property images/volumes. It uses the complete seismic wavefield (transmitted, reflected and converted waves) to build the models of subsurface physical properties. We conducted a feasibility study of a 2D elastic FWI applied to synthetic and field single offset vertical seismic profile (...
Article
Recent advancements in DAS technology open new ways for borehole-based seismic monitoring of CO 2 geosequestration. Compared to 4D surface seismic monitoring, repeated VSP surveys with DAS receivers reduce the cost and invasiveness of time-lapse CO 2 monitoring considerably. However, standard borehole imaging techniques cannot provide the same leve...
Article
The quality and accuracy of a seismic image can be significantly affected by anisotropy. When anisotropy is significant, neglecting it can lead to smearing of the image, dispositioning of reflections, and distortion of amplitudes. Thus, it is imperative to estimate anisotropy and take it into account, especially for long‐offset or wide‐azimuthal se...
Article
Full-text available
Monitoring of passive seismic sources generated by mining activities and hydraulic fracturing has an important role in hazard analysis and in development of unconventional reservoirs. Surface arrays are vastly used in such monitoring scenarios with the advantage of wider spatial monitoring aperture, thus monitoring larger volumes over downhole arra...
Article
Full-text available
Acoustic energy emitted by drill bits can be recorded by geophones on the surface and processed for an image of the subsurface using seismic interferometry methods. Pilot sensors record bit signals on the drill rig and play an important role in processing geophone traces for the image. When pilot traces are not available, traces of the nearest geop...
Article
Full-text available
Acoustic energy emitted by drill bit can be recorded by geophones on the surface and processed for an image of the subsurface using seismic interferometry methods. Pilot sensors record bit signal on the drill rig and play an important role in processing geophone traces for the image. When pilot traces are not available, traces of the nearest geopho...
Article
This study aims to assess the ability of shallow distributed acoustic sensing (DAS) to serve as a cost-effective seismic sensor array for permanent monitoring applications. To this end, as part of the CO2CRC seismic monitoring program, a fibre-optic DAS array was deployed alongside a permanently buried geophone array at the Otway Project site (Vict...
Article
Full-text available
Spatial aliasing is an unwanted side effect that produces artifacts during seismic data processing, imaging and interpolation. It is often caused by insufficient spatial sampling of seismic data and often happens in CMP (Common Mid-Point) gather. To tackle this artifact, several techniques have been developed in time-space domain as well as frequen...
Article
Distributed Acoustic Sensing (DAS) is an optical interferometric method for acquisition of acoustic and seismic signals. It uses laser pulses that travel along the length of a fibre-optic cable and backscatter as they encounter small inconsistencies in the fibre. Impinging seismic waves cause strain on the cable, resulting in differences in phase o...
Article
This work studies seismic response of injection of super-critical CO2 in Perth Basin, WA for the purpose of CO2 sequestration. We aim to propose the most suitable way of monitoring and verification of such storage. To this end, we generated synthetic seismic datasets based on static geological models reflecting various hypothesis about the subsurfa...
Article
Seismic methods are frequently used for the purpose of monitoring of time-lapse changes introduced by CO2 sequestration. Surface seismic is often considered as the main tool for monitoring. Vertical Seismic Profile (VSP) is occasionally applied as an auxiliary method. Standard VSP data processing workflow does not provide a quantitative estimate of...
Article
Complex structure of the subsurface in hard rock environment often complicates traditional processing and interpretation of seismic datasets based on the analysis of reflected waves. Full-waveform inversion (FWI), in turn, utilizes the whole wavefield, including the transmitted waves and reflections, to build the models of physical properties (such...
Article
Vertical seismic profiling (VSP) is commonly used in the oil and gas industry for better subsurface imaging and characterisation, as well as for providing depth calibration for surface seismic. The use of VSP in mineral exploration and mine planning is not very common mostly due to the small diameter and stability of the boreholes, as well as the r...
Article
Full-text available
Human body is a miracle machine created by the creator. It’s happens different types of Biological, chemical and physical activities inside and outside. In this research trying to describe functions of electrons on human body, adverse effect of it on human body, free electron and Free radical functions, Grounding of human body, neutralize of static...
Article
Full-text available
Distributed Acoustic Sensing (DAS) uses standard telecommunication fibre optic cables to detect acoustic and seismic signals. The technique utilises optical time-domain reflectometry; a “light-box” measures the light backscattered from a series of laser pulses emitted into the fibre. As seismic waves impinge on the cable, the fibre is strained, cau...
Article
Distributed acoustic sensing (DAS) can revolutionize the seismic industry by using fiber-optic cables installed permanently to acquire on-demand vertical seismic profile (VSP) data at fine spatial sampling. With this, DAS can solve some of the issues associated with conventional seismic sensors. Studies have successfully demonstrated the use of DAS...
Article
The elastic properties of crystalline rocks can be estimated from ultrasonic measurements on the powders of crushed rocks produced by the drilling process. To determine the elastic properties of grains from properties of powder packs, we study the dependence of their ultrasonic wave velocities on pressure. From this dependency, using the Hertz‐Mind...
Conference Paper
Reservoir monitoring usually involves a combination of seismic surveys acquired using a large array of seismic receivers and mobile sources to image the subsurface changes. Such surveys rely on accurate positioning of both source points and receivers. Permanent reservoir monitoring seeks to overcome the limitations of the conventional approach, suc...
Article
Distributed acoustic sensing (DAS) is a rapidly developing technology particularly useful for the acquisition of vertical seismic profile (VSP) surveys. DAS data are increasingly used for seismic imaging, but not for estimating rock properties. We have developed a workflow for estimating elastic properties of the subsurface using full-waveform inve...
Article
During the last decade, distributed acoustic sensing (DAS) has emerged as a new technology for seismic acquisition. DAS has the potential to reduce the cost of permanent monitoring operations over time as it offers long equipment survivability and requires minimum maintenance. However, broad adoption of DAS technology still faces some challenges, s...
Article
Vertical seismic profile (VSP) is one of the technologies for monitoring hydrocarbon production and CO2 geosequestration. However quantitative interpretation of time-lapse VSP is challenging due to its irregular distribution of source-receiver offsets. One way to overcome this challenge is to use full waveform inversion (FWI), which does not requir...
Article
Most seismic processing algorithms generally consider the sea surface as a flat reflector. However, acquisition of marine seismic data often takes place in weather conditions where this approximation is inaccurate. The distortion in the seismic wavelet introduced by the rough sea may influence (for example) deghosting results, as deghosting operato...
Article
A common acquisition scenario in microseismic monitoring is the deployment of large areal receiver arrays at or near the surface. This recording geometry has the advantage of providing coverage of the source's focal hemisphere as well as characterization of the arrival time moveout curve; however, the accuracy of many location techniques applied to...
Article
Diffractions carry valuable information about local discontinuities and small scale objects in the subsurface. They are still not commonly used in the process of geological interpretation. Many diffraction imaging techniques have been developed and applied for isotropic media while relatively few techniques have been developed for anisotropic media...
Article
Full-text available
In this paper, we are proposing a new methodology of 2D seismic acquisition and processing that aims to improve imaging of complex 3D geological environments. The method requires a simultaneous acquisition along two parallel receiver lines. The adapted processing highlights locations of the reflectors that are out of vertical plane by filtering the...
Article
The primary objective of seismic exploration in a hard rock environment is the detection of heterogeneities such as fracture zones, small-scale geobodies, intrusions, and steeply dipping structures that are often associated with mineral deposits. Prospecting in such environments using seismic-reflection methods is more challenging than in sedimenta...
Article
Full-text available
Seismic imaging techniques often require an input velocity model. Velocity analysis is one of the most critical stages in seismic data processing. Standard ways to find the velocity model from seismic data in the time domain are constant velocity stack and semblance velocity analysis that may be time consuming and labor intensive. Oriented/velocity...
Conference Paper
As mineral deposits are bounded to hard rock environment, seismic method suffers from near surface complex wave propagation effect. We applied and compared two wave extrapolation redatuming techniques, namely finite-difference and common focus point, methods with the aim to improve imaging by removing propagation footprints form near surface. Redat...
Article
Agood seismic velocity model is required for many routine seismic imaging techniques. Velocity model building from seismic data is often labor intensive and time consuming. The process becomes more complicated by taking nonhyperbolic traveltime estimations into account. An alternative to the conventional time-domain imaging algorithms is to use tec...
Conference Paper
Diffraction imaging is a useful tool for seismic reservoir characterization because it can provide additional information about small-scale heterogeneities. Diffractions and reflections coexist on seismic data. Because the latter often mask diffractions, a separation procedure is required. Plane-wave destruction workflow has been proven to be an ef...
Article
Quantitative interpretation of seismic data depends upon the amplitude analysis of reflected waves. However, the quality of the image obtained can be significantly affected by attenuation and anisotropy in the overburden. Therefore, the insights into the magnitude, sources and spatial distribution of these parameters may prove to be substantial for...
Conference Paper
Diffractions carry valuable information about local discontinuities and small scale objects in the subsurface. They are still not commonly used in the process of geological interpretation. Many diffraction imaging techniques have been developed and applied for isotropic media while relatively few techniques have been developed for anisotropic media...
Article
Diamond-impregnated drill bits are known to be low energy vibration seismic sources. With the strong interference from the drill rig, it is difficult to obtain the drill-bit wavefield with a surface receiver array. To overcome the challenge of surface wave interference generated from the rig for seismic-while-drilling (SWD), we need to separate the...
Article
SUMMARY There are two types of passive seismic monitoring: downhole and surface monitoring. In this paper, we introduce a new surface monitoring technique that does not require trigger time and any seismic velocity information prior to imaging. Therefore, this technique can be considered as a velocity independent monitoring technique. We have calcu...
Article
SUMMARY Reciprocity principle has been used in a number of seismic applications. This principle relates the two wave fields with interchanged source and receiver locations, where the radiation patterns of the source and receiver are interchanged as well. In extending this principle to be used in real-world scenarios where radiation patterns vary in...
Article
SUMMARY We used laser Doppler interferometer for measuring the displacement on the sample surface. These measurements allow us to clearly separate different wave types, whose picked travel times are used for estimation of VTI anisotropy parameters. One of the observations in this study is the very strong amplitude of critically refracted SP wave at...
Article
SUMMARY Velocity analysis is one of the most critical stages in seismic data processing and the velocity errors influence the accuracy of the imaging. The conventional workflows, to obtain the migration velocity model, are generally labour intensive and time consuming. An experienced processor is needed to pick the velocities in the velocity spectr...
Article
SUMMARY We present a feasibility study of using passive seismic data for imaging of diffractors. Imaging and characterisation of seismic diffractors is important for many applications of seismic methods, including carbon geosequestration, since in sedimentary setting the diffractors are associated with terminations of layers at faults, as well as e...
Article
Seismic monitoring feasibility analysis performed for a particular site usually involves the prediction of the time-lapse seismic signal and an assessment of the detectability of such a signal. In order to do this, level and other characteristics of time-lapse noise should also be known. In general, the observed time-lapse noise is spatially correl...
Conference Paper
Passive seismic events are generally made by fault displacement, drilling, and hydraulic fracturing during high-pressure fluid injection into boreholes. There are two general configurations of seismic receiver arrays for passive seismic event monitoring: surface and down-hole. Surface arrays provide a larger aperture and hence greater coverage of t...
Article
). ( ) ( ( ) ) √( ) SUMMARY Most of the migration techniques require an input velocity model. Velocity analysis is one of the most critical stages in seismic data processing. Standard ways to find the velocity model are constant velocity stack and Semblance velocity analysis, which can be time consuming and labour intensive. In this work, we introd...
Conference Paper
Full-text available
In this study, we analyse the accuracy of layer-stripping method to use P-wave reflection traveltimes in transverse isotropic media with vertical axis of symmetry (VTI) to estimate interval anisotropic parameters that are required for seismic processing. We also present a synthetic Walkaway VSP example in which a comparison can be made between the...
Conference Paper
We investigate the possibility to image and characterise the different types of diffractors – such as point, line, and edge – and separate them from reflections by limiting the aperture around the tangent point between the diffraction hyperbola and the relfection traveltime surface. To this end, we look at the tangents of the diffraction hyperbola...
Conference Paper
During Stage 2 of the Otway CCS Australian project it is planned to inject a small, up to 15,000 tonnes of gas, into a saline aquifer located at depth of 1500 m. In CO2 sequestration, the ability to detect CO2 plumes is one of the main purposes of using time-lapse seismic imaging. The detectability of CO2 in seismic time-lapse surveys relies on two...
Conference Paper
The assessment of subsurface architecture and location of faults is key information in CO2 geosequestration projects. The 3D seismic survey has been acquired as a part of the SW Hub CCS project in vicinity of potential future CO2 injection sites. The acquisition was carried out within the Harvey and Waroona Shires about 150 km south-east from Perth...
Article
We compared and analyzed hard-rock drilling elastic energy emission between diamond-impregnated coring and reverse- circulation (RC) percussion drilling methods from an experiment at Brukunga, South Australia. The two drilling mechanisms generated very different seismic wavefields. This comparison emphasized their energy radiation differences and s...
Article
A diamond drill bit is usually considered to be an inadequate seismic vibration source. To detect and use weak drillbit- generated seismic wavefields in hard-rock drilling, we compared different coherency measures between a conventional method of semblance and a generalized multiple signal classification (MUSIC) algorithm. We tested the detectabili...
Conference Paper
Fine layering is known to cause both seismic anisotropy and attenuation. However both effects depend on the contrast between elastic properties of adjacent layers. Previous analysis of well log data suggests in typical sedimentary environments even with layer contrast of 30%, both layered-induced anisotropy and attenuation are negligibly small. Nev...
Book
Full-text available
"I thought I knew everything I needed to know about characteristics and their role in the solution of partial differential equations. After reading this book, I discovered that I was wrong. The authors draw us along on an incredible mathematical journey by starting from simple examples and moving on to progressively more sophisticated examples. Thu...
Article
Hard rock seismic exploration normally has to deal with rather complex geological environments. These types of environments are usually characterized by a large number of local heterogeneity (e.g., faults, fracture zones, and steeply dipping interfaces). The seismic data from such environments often have a poor signal-to-noise ratio because of the...