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Journal : Scientific Contribution Oil and Gas

The Linear and Non-Linear Background Energy Approach in The Seismic S/N Ratio Enhancement Imam Setiaji Ronoatmojo; Yarra Sutadiwiria; Muhammad Burhannudinnur; Dewi Syavitri
Scientific Contributions Oil and Gas Vol. 46 No. 2 (2023): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.46.2.318

Abstract

Side-swept is often understood as a side sweep of seismic waves that occurs on the surface. This understanding creates confusion when considering that side-swept is a part of linear function, in fact side-swept could be in the form of sweeping waves from the reflector on the side, so side-swept is a non-linear function like a signal. The implications for noise reduction with the t-p transformation becomes more complex. The elimination of side-swept in this study, relies on an application using an algorithm developed by Hampson (1987). Initial data conditioning preparation should be needed to clarify the difference between linear and non-linear functions through static refraction correction and velocity analysis, then coherent noise elimination (ground-droll) is carried out through f-k domain transformation, as well as random noise through f-x domain transformation. Side-swept is eliminated in t-p domain. Energy observation shows the remaining noise energy caused by coherent noise, random noise and non-linear side-swept functions. It proves that it is difficult to remove a non-linear function that overlaps the reflector signal. The best step is to minimize coherent (linear) noise and random noise by consistently using an amplitude correction indicator on the surface and performing velocity analysis especially for the suspected power spectrum as an effort to attenuate side-swept wave interference on the reflector signal. Finally, the signal restoration efforts due to non-linear noise attenuation, is carried out by surface consistent deconvolution
The Influence of Side-Slip Velocity on Subsurface Displacement Imam Setiaji Ronoatmojo; Muhammad Burhannudinnur; Yarra Sutadiwiria; Dewi Syavitri
Scientific Contributions Oil and Gas Vol. 47 No. 2 (2024): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

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Abstract

This research aimed to determine the influence of side-slip velocity on subsurface displacement during seismic data acquisition. Anisotropy constants were used to determine the depth migration process before stack, which showed inadequate results after data validation. Therefore, the forward modeling of a medium, which comprised anisotropy constants of normal and offset raytracing was conducted to address this problem. The configuration of source to receiver were orthogonal and slant. The results showed that the migration process failed to resolve the geological structures of the position shifting. The configuration of source to receiver were orthogonal and slant. The results show the better continuity of slant and the influence of complex geological structures controls the position shifting, which could not be resolved by the migration process. It could be seen from the random distribution of the normal shift of group velocity and phase velocity, as well as the CDP – CRP shift. It produced wave azimuth rotation in a discontinuity plane, such as fault and anticline ridge. This azimuth rotation was strongly suspected to cause inaccurate anisotropy constants implementation in pre-stack depth migration process. Keywords: side-slip velocity, anisotropy constants, migration, normal displacement, CDP-CRP displacement
Updated Geochemical Characterization of Hydrocarbon Potential of Surface Sample in Lariang-Karama Sub-Basin, West Sulawesi, Indonesia Yarra Sutadiwiria; Muhammad Taufiq Fathaddin; Imam Setiaji Ronoatmojo; Dewi Syavitri; Cahyaningratri P.R.; Barona Belladesta; Yeftamikha Yeftamikha; Andy Livsey
Scientific Contributions Oil and Gas Vol. 47 No. 2 (2024): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The Lariang-Karama Sub-Basin is situated within the Makassar Basin, located in the West Sulawesi region. It has source of rocks which has the potential to produce hydrocarbons and to become a target for new field discoveries in hydrocarbon exploration activities. It is on this basis that the authors are interested in conducting research in the Makassar Basin area and its surroundings, which has been carried out since 2017. This is a comprehensive literature review study from 2017 to 2022, focusing on the origin and composition of biomarkers, paleogeography of facies sources from oil seeps (2017-2018), paleofacies and biomarker characteristics of Paleogene to Neogene rocks (2019), contribution of terrestrial materials based on geochemical and biostratigraphic analysis (2020), tectonic processes occurring in the basin, and geochemical characterization of source rocks in the research area (2022). The FS-12 surface sample in shale may belong to the Kalumpang Formation, located in West Sulawesi. The results of TOC analysis were 0.62%, indicating sufficient quantity. Based on the results of the cross plot between HI values of < 50 and Tmax of 499 °C, the category was found to be overmature and could not produce hydrocarbons. The results of this research, along with those of previous research and the latest geochemical study, were obtained in the West Sulawesi region and the eastern Makassar Strait. These findings consisted of marine shale source rocks in West Sulawesi and lacustrine shale source rocks in the eastern Makassar Strait