Improved Workflow for Fault Detection and Extraction Using Seismic Attributes and Orientation Clustering

Faults represent important analytical targets for the identification of perceptual ground motions and associated seismic hazards. In particular, during oil production, important data such as the path and flow rate of fluid flows can be obtained from information on fault location and their connectivity. Seismic attributes are conventional methods used for fault detection, whereby information obtained from seismic data are analyzed using various property processing methods. The analyzed data eventually provide information on fault properties and imaging of fault surfaces. In this study, we propose an efficient workflow for fault detection and extraction of requisite information to construct a fault surface model using 3D seismic cubes. This workflow not only improves the ability to detect faults but also distinguishes the edges of a fault more clearly, even with the application of fewer attributes compared to conventional workflows. Thus, the computing time of attribute processing is reduced, and fault surface cubes are generated more rapidly. In addition, the reduction in input variables reduces the effect of the interpreter’s subjective intervention on the results. Furthermore, the clustering method can be applied to the azimuth and dip of the fault to be extracted from the complexly intertwined fault faces and subsequently imaged. The application of the proposed workflow to field data obtained from the Vincentian oil field in Australia resulted in a significant reduction in noise compared to conventional methods. It also led to clearer and continuous edge detection and extraction

Sedimentary characteristics and processes of submarine mass-transport deposits in the Ulleung Basin and their relations to seismic and sediment physical properties

Special issue Advancements in Understanding Deep-Sea Clastic Sedimentation Processes.-- 17 pages, 17 figures, 2 tables.-- This research is a contribution of ‘Studies on Gas Hydrate Resource Assessment and Characterization of Chimney Structures in the Ulleung Basin’ and also a part of the project titled ‘Marine Geological and Geophysical Mapping of the Korean Seas’Three successive Pliocene MTD units (M2, M3, and M4 in ascending order) in the Ulleung Basin are characterized by continuous strong-amplitude negative basal reflections with transparent to chaotic internal seismic facies. Mapping of these MTD units in a dense 2-D grid of seismic reflection data reveals that each MTD unit generally thickens upslope to a maximum of 113 m and wedges out downslope against a structurally uplifted pre-existing surface. Although the source failure scars cannot be traced on the slope, the minimum runout distances of the MTD units from the base of the upper slope near the 1000 m isobath are estimated to be > 120 km. Each MTD unit is characterized in the logging-while-drilling (LWD) data by a gradual increase in bulk density, P-wave velocity, and resistivity values at the basal part and an abrupt decrease at the lower boundary. Nine sedimentary facies are identified in the MTD units, which indicate a variety of mass-transport processes such as sliding with brittle to plastic deformations and high-to low-viscosity debris flows. Vertical distribution of sedimentary facies shows a repeated generalized pattern in all MTD units. The pattern is interpreted to represent initial deep failures involving sand-prone consolidated sediments near the shelf break and successive shallow failures involving soft heterogeneous muddy sediments that were deposited in a deeper downslope area. The presence of sand-prone mass-transport deposits accounts for the basal densification and strong-amplitude negative basal reflections. Absence of such sand-prone basal parts in MTDs at other locales implies unpredictability of lithologic characteristics in MTDs with similar seismic reflection signaturesSamples and data for this study were acquired by onboard and post-cruise analyses of the 2nd Ulleung Basin Gas Hydrate Drilling Expedition (UBGH2), which was funded by Ministry of Knowledge Economy of Korea (MKE). [...] SH Lee is supported by the Basic Program (PE99534) of Korea Institute of Ocean Science and TechnologyPeer Reviewe

Characteristics and origins of long-runout submarine mass-transport deposits in the Ulleung Basin revealed from drilling and 2-D grid seismic reflection data

Korean Geological Society Conference, 26 October 2016, Pyeongchang, South KoreaPeer Reviewe

Characterization of Thin Gas Hydrate Reservoir in Ulleung Basin with Stepwise Seismic Inversion

Natural gas hydrates (GHs) filling sand layer pores are the most promising GHs that can be produced via conventional mechanisms in deep-sea environments. However, the seismic tracking of such thin GH-bearing sand layers is subject to certain limitations. For example, because most GH-bearing sand layers are thin and sparsely interbedded with mud layers, conventional seismic data with a maximum resolution of ~10 m are of limited use for describing their spatial distribution. The 2010 Ulleung Basin drilling expedition identified a relatively good GH reservoir at the UBGH2-6 site. However, the individual GH-bearing sand layers at this site are thin and cannot therefore be reliably tracked using conventional seismic techniques. This study presents a new thin layer tracking method using stepwise seismic inversion and 3D seismic datasets with two different resolutions. The high-resolution acoustic impedance volume obtained is then used to trace thin layers that cannot be harnessed with conventional methods. Moreover, we estimate the high-resolution regional GH distribution based on GH saturation derived from acoustic impedance at UBGH2-6. The thin GH layers, previously viewed as a single layer because of limited resolution, are further subdivided, traced, and characterized in terms of lateral variation