Ahmed Jaddoa Al-Heety

This article presents the pre-stack attenuation of multiple noises from a 2-D land seismic survey acquired on the Iraq-Kuwait border in southern Iraq. The processing workflow is performed using the Geovation software from CGG that employs a de-aliased High-Resolution Radon with a non-iterative process for seismic reflection data. First, we apply noise attenuation, surface deconvolution (predictive), and normal move-out (NMO) correction, which is executed using the root-mean-square velocity (RMS velocity) to flatten the primary event, and the Common Mid-Point gathers (CMP gathers) are converted into the Radon domain using a least-squares-parabolic Radon transform. Several tests are performed on some parameters to predict the multiple events using a High-Resolution de-aliased multiple attenuation (RAMUR) algorithm aimed to attenuate multiple events. RAMUR algorithms compute a model of primary and multiple events based on data decomposition into user-defined parabolas and are performed using a high-resolution, de-aliased least-squares method. The Radon transforms separate primary reflection and multiple reflection events in the (τ-q) domain based on move-out differences between primary and multiple events, which are characterized as events with slower velocity. Reflection events relating to parabolas with a higher curvature are counted as multiples, whereas events with smaller are counted as primary events. The RAMUR algorithms subtract the model of multiples from the input gathers. The workflow effectively attenuates reflection-based generated multiples events, which improves the overall seismic response after imaging, and enhances correlation with well information.

Integrated geophysical seismic measurements have been carried out at Al Layyah Power Generation Plant site, Sharjah, United Arab Emirates to determine the geotechnical properties of soil/rocks. The CHST is performed within a group of 3 boreholes, while a DHST is conducted at one site to determine a velocity profile. Active Multichannel Analysis of Surface Waves (MASW) data is carried out along one MASW line with a total length of 40 m. The measurements have been carried out between boreholes BH-03 and BH-04 along the asphaltic road at the study site. The estimating of dynamic soil properties from the outcomes of seismic surveys is discussed utilizing the seismic velocity acquired from the three locations. The processing and analysis of data and correlation with geological information are described based on the comparative evaluates of the corresponding 1D Vs profiles; it is concluded that CHST and DHST data are generally more reliable than MASW data. 1D Vs profiles obtained from MASW, CHST, and DHST are compared and the average Vs of the top 30 m (Vs30) is computed. There are similar up to 30 m of Vs profiles gained in all seismic tests. Consequently, a good quality recording, processing, and interpretation of MASW data allows dependable results and the same classification of the soil. It indicates that the Vp and Vs have a good correlation with the borehole log. Moreover, the site soil classification is found to be C (Very dense soil and soft rock profile) according to the Dubai Municipality Building Code (DIBC-2004) and the International Building Code (IBC 2009).

Noises are common events in seismic reflection data that have very striking features in seismograms, affecting seismic data processing and interpretation. Noise attenuation is an essential phase in seismic processing data, usually resulting in enhancing the signal-to-noise ratio (SNR) and improving the subsurface seismic image. Groundroll presence is a major fashion of significant noise in land seismic surveys. It is a type of coherent noise present in seismograms that appears as linear events, in most cases overlapping the reflections and probably making it challenging to recognise. There are several domains used in noise attenuation techniques. The domain transformations are a complex algorithm used commonly during the processing of seismic data; Therefore, a large number of methods have been developed to attenuate these types of noise to preserve the frequency bandwidth and enhance the SNR of the seismic data. In the time-offset domain, the noise wave such as groundroll and random noises overlap over time; a different domain makes it easier to successfully isolate coherent, random noise and reflection events. We have used effective algorithms in different domains such as (shot, receiver, t-x, f-x, f-k, R-T, and offset class) to attenuate coherent and random noises present in the data. The results indicate that the different domains can reveal features and geological structures that have been masked by the noises present in current data. Because these filtering techniques encourage significant improvements in the final image quality in the 2D seismic section, possibly giving the interpreter an advantage, particularly in structural and stratigraphic interpretation.

Noises are common events in seismic reflection data that have very striking features in seismograms, affecting seismic data processing and interpretation. Noise attenuation is an essential phase in seismic processing data, usually resulting in seismic interpretation improvement that enhances the signal to noise ratio. Groundroll presence is the major fashion of significant noise in the land seismic survey. It is a type of coherent noise present in seismograms that appears as linear events, in most cases overlapping the reflections and probably making it challenging to recognize. There are several domains used in noise attenuation, Domain transformations is a complex algorithms standard tool used commonly used during processing of seismic data and imaging processing, So a large number methods have been developed to attenuate these types of noise. In the time-offset domain, the noise wave such as Groundroll and random noises, overlap each other over time; a different domain makes it easier to successfully isolate coherent, random noise and reflection events. Five steps are introduced to attenuate coherent and random noise, these steps are FDNAT, AGORA, RADMX, SCFIL, DDMED as well as Time-Variant band-pass Filter. The results indicate that the different domains can actually reveal features and geological structures that have been masked by the noises present in current data. because encourage significant improvements in the final image quality in 2-D seismic section, so, these filtering techniques possibly give advantage to the interpreter in particularly in structural and stratigraphic interpretation during the work of interpretation, especially in the exploration and characterizing possible traps.