Analysis of Two Neighboring Miocene Paleo-Turbidite Systems in a Complex Deep-Water Environment: Implications for Biostratigraphic Techniques Used in Gulf of Mexico Petroleum Exploration Studies

Biostratigraphic techniques are commonly used in shallow environments of the Gulf of Mexico basin for depositional history modeling in petroleum exploration applications. Extending these interpretations to deep-water settings, where the structural and depositional history is more complex, is problematic. A localized study area was used for a case-analysis of a typically complex deep-water study area. A dataset of seismic, well-log, and biostratigraphic information was used to: (a) assess accuracy of the biostratigraphic interpretations produced by Fillon (2005), (b) determine specific pitfalls of micropaleontology as a tool in this environment, and (c) provide guidelines for the application of biostratigraphic data in the deep-water. Results indicate that the previous depo-history modeling did not account for local complexity, thus lessening utility at the petroleum exploration scale. Future studies in this environment should account for sections transported down-dip, isolation of depocenters, autocyclic variability, and reduce reliance on the condensed section as a chronostratigraphic tool

Exploring the seismic expression of fault zones in 3D seismic volumes

Acknowledgments The seismic interpretation and image processing has been run in the SeisLab facilty at the University of Aberdeen (sponsored by BG, BP and Chevron) Seismic imaging analysis was performed in GeoTeric (ffA), and Mathematica (Wolfram research). Interpretation of seismic amplitudes was performed Petrel 2014 (Schlumberger). We thank Gaynor Paton (Geoteric) for in depth discussion on the facies analysis methodology and significant suggestions to improve the current paper. We thank the New Zealand government (Petroleum and Minerals ministry) and CGG for sharing the seismic dataset utilized in this research paper. Seismic images used here are available through the Virtual Seismic Atlas (www.seismicatlas.org). Nestor Cardozo and an anonymous reviewer are thanked for their constructive comments and suggestions that strongly improved the quality and organization of this paper.Peer reviewedPostprin

Mass transport processes and deposits in offshore Trinidad and Venezuela, and their role in continental margin development

textMass transport complexes (MTC) form a significant component of the stratigraphic record in ancient and modern deep water basins. One such basin, the deep marine margin of eastern offshore Trinidad, situated along the obliquely converging boundary of the Caribbean and South American plates and proximal to the mouth of the Orinoco River, is characterized by catastrophic shelf margin processes, intrusive and extrusive mobile shales, active tectonics and possible migration and sequestration of hydrocarbons. Major structural elements found in the deep water slope regions include: large transpressional fault zones along which mobile shales extrude to form seafloor ridges; fault-cored anticlinal structures overlain by extrusive seafloor mud volcanos; shallow-rooted sediment bypass grabens near the shelf break; and normal and counterregional faults. A data volume consisting of 10,708 km2 of several merged 3D seismic data volumes enable subseafloor interpretation of several mass transport event deposits and the erosional surfaces that form their boundaries. The data shows numerous mass transport complexes which are characterized by chaotic, mounded seismic facies and fanlike geometries. Their extent (up to 2017 sq. km) and thickness (up to 250 m) is strongly influenced by seafloor topography. Depositional and erosional architectures identified with these units includes: large magnitude lateral erosional edges, thrust faulting, linear basal scours, side-wall failures, flow geometries, possible displaced blocks and chaotic matrix material. Active tectonism in the region, high sedimentation rates associated with the Orinoco Delta System, and abundant unstable gas hydrates suggest the presence of higher frequency mechanisms at work for MTCs generation than sea-level fluctuations alone. Three types of mass transport complexes are identified in offshore Trinidad; shelfattached systems that were fed by shelf edge deltas whose sediment input is controlled by sea level fluctuations, slope- attached systems which occur when upper slope sediments catastrophically fail due to gas hydrate disruptions, earthquakes and/or storm activity, and locally detached systems formed when local instabilities in the sea floor trigger small collapses. Such classification of the relationship between slope mass failures and the sourcing regions enables an understanding of the nature of initiation, length of development history, petrography and petrophysics of MTC’s. In addition, a collection of morphometric parameters of MTCs from different continental margins are analyzed in order to better understand their causal mechanisms, and to establish whether systematic morphometric parameters characterize these deposits across different tectonic settings. Observations suggest that there is a clear relationship between morphometric parameters of MTC and their causal mechanisms.Geological Science

Seismic Texture Applied to Well Calibration and Reservoir Property Prediction in the North Central Appalachian Basin

Enhancing seismic interpretation capabilities often relies on the application of object oriented attributes to better understand subsurface geology. This research intends to extract and calibrate seismic texture attributes with well log data for better characterization of the Marcellus gas shale in north central Appalachian basin. Seismic texture refers to the lateral and vertical variations in reflection amplitude and waveform at a specific sample location in the 3-D seismic domain. Among various texture analysis algorithms, here seismic texture is characterized via an algorithm called waveform model regression utilizing model-derived waveforms for reservoir property calibration. Altering the calibrating waveforms facilitates the conversion of amplitude volumes to purpose-driven texture volumes to be calibrated with well logs for prediction of reservoir properties in untested regions throughout the reservoir.;Seismic data calibration is crucial due to the resolution and uncertainty in the interpretation of the data. Because texture is a more unique descriptor of seismic data than amplitude, it provides more statistically and geologically significant correlations to well data. Our new results show that seismic texture is a viable attribute not only for reservoir feature visualization and discrimination, but also for reservoir property calibration and prediction. Comparative analysis indicates that the new results help better define seismic signal properties that are important in predicting the heterogeneity of the unconventional reservoir in the basin. Provisions of this research include a case study applying seismic texture attributes and an assessment of the viability of the attributes to be calibrated with well data from the Marcellus Shale in the north central Appalachian basin. Examples from this study will provide insight in its capabilities in practical applications of seismic texture attributes in unconventional reservoirs in the Appalachian basin and other basins around the world

Transfer function design based on user selected samples for intuitive multivariate volume exploration

pre-printMultivariate volumetric datasets are important to both science and medicine. We propose a transfer function (TF) design approach based on user selected samples in the spatial domain to make multivariate volumetric data visualization more accessible for domain users. Specifically, the user starts the visualization by probing features of interest on slices and the data values are instantly queried by user selection. The queried sample values are then used to automatically and robustly generate high dimensional transfer functions (HDTFs) via kernel density estimation (KDE). Alternatively, 2D Gaussian TFs can be automatically generated in the dimensionality reduced space using these samples. With the extracted features rendered in the volume rendering view, the user can further refine these features using segmentation brushes. Interactivity is achieved in our system and different views are tightly linked. Use cases show that our system has been successfully applied for simulation and complicated seismic data sets