Identification of Paleo-Volcanic Rocks on Seismic Data

Abstract

IntroductionWhile exploring for hydrocarbons in rift related basins, volcanics, volcaniclastic deposits or their erosional products are common lithologies. The presence of rock types derived from volcanism and/or affected by post-volcanic re-deposition may lead to complex lithologies with complex diagenetic overprints at the reservoir level. Partial or complete reservoir substitution, alteration by circulating hot fluids and addition of mineral components have led to a number of unsuccessful wells, both in exploration and field development projects. Furthermore, volcanic rocks may form lateral seals or migration barriers, providing both positive and negative impact on the petroleum system. Non-permeable volcanic layers can seal the top of the reservoir, preventing it from breaching, or they can build a migration barrier for the fluid on its way from the source rock into the trap. In most cases, highly varied lithologies with wide ranges of inherent rock properties occur. It is therefore essential to understand the distribution of volcanics in the vicinity of the reservoir. Published examples of volcanic reflectors identifiable from seismic data are still very sparse, and there is no systematic compilation of information and knowledge available. Free air gravity maps, as well as other potential field methods, may show anomalies caused by volcanic and sub volcanic bodies if they are really massive geobodies. Unfortunately, the majority of volcanic features are rather thin (some tens of meters thick). At a reservoir depth of more than 3 km the resolution of standard potential field data is not good enough to delineate the individual units. A close cooperation of specialists from different disciplines is required in order to resolve specific problems related to seismic interpretation and reservoir prediction within such a complex environment. Sedimentology and fieldwork studies of recent analogues provide the basis for recognition of the depositional environment used for seismic interpretation. Special seismic processing must be utilized to calculate attributes from prestack data, showing amplitude variations with increasing offset from the energy source (commonly referred to as AVO analysis). These data are interpreted using results from rock physics analysis -elastic parameters of different lithology types and seismic forward modeling. The AVO analysis is used to support the lithology identification from seismic geometries. The input for the rock physics is delivered by the petrophysicist -log derived properties and interpretations. Petrography is used for provenance analysis, as well as analysis of diagenesis and fabric. In many cases, this turns out to be the key to understanding the anomalous AVO behavior of sandstones. Finally, sequence stratigraphy relates the different levels of sandstones to periods with and without volcanic activity. www.intechopen.comUpdates in Volcanology -A Comprehensive Approach to Volcanological Problems 182 Our experience from working in different basins around the world has shown tha...

The Manihiki Plateau—A multistage volcanic emplacement history

“…This resulted in numerous volcanic features like extrusion centers, which are characterized by distinct seismic facies depending on the flow nature. This seismic facies comprises characteristics such as geometry [ Klarner and Klarner , ; Magee et al ., ; Planke et al ., ], e.g., parallel flows (Figures a and b), subparallel flows (Figures a and b) [ Uenzelmann‐Neben et al ., ], and amplitude characteristics, e.g., lateral alteration of strong and weak amplitudes (Figures a–c) [ Klarner and Klarner , ; Planke et al ., ].…”

“…We interpret these sharply defined features with strong amplitudes to represent volcanic flows emerging from various vents. Additionally, we interpret the zones of weak amplitudes (e.g., Figure b, CDPs 9300, 8400, and 8000) to result from magmatic chimneys [ Klarner and Klarner , ], which fed the so‐called main emplacement volcanism (pre‐R7). We suggest that the sequence topped by intrabasement reflection band IB1 represents a volcanic flow unit deposited prior to R7.…”

“…A parasitic cone occurs within the secondary volcanism (R6) at the western flank of the main vent right next to a deep depression in which DSDP Leg 33 Site 317[Shipboard Scientific Party, 1976] is located.Geochemistry, Geophysics, Geosystems 10.1002/2015GC005852 which are characterized by distinct seismic facies depending on the flow nature. This seismic facies comprises characteristics such as geometry[Klarner and Klarner, 2012;Magee et al, 2013;Planke et al, 2000], e.g., parallel flows(Figures 3a and 3b), subparallel flows(Figures 4a and 4b)[Uenzelmann-Neben et al, 1999], and amplitude characteristics, e.g., lateral alteration of strong and weak amplitudes(Figures 4a-4c)[Klarner and Klarner, 2012;Planke et al, 2000].…”

Variation in style of magmatism and emplacement mechanism induced by changes in basin environments and stress fields (Pannonian Basin, Central Europe)

“…With the advancement of 3D seismic cubes a great number of studies have been published on various subvolcanic features from well‐studied different continental margins (Hansen & Cartwright, ; Holford, Schofield, Macdonald, Duddy, & Green, ; Jackson, ; Jackson, Schofield, & Golenkov, ; Lee, Young, Yoon, Kim, & Yoo, ; Magee Jackson, & Schofield, ; Planke, Rasmussen, Rey, & Myklebust, ; Suleiman, Magee, Jackson, & Fraser, ; Zhao et al, ). Papers mainly focused on identifying and characterizing various intrusive and extrusive features and their implications on the evolution of sedimentary basins and petroleum systems (Holford et al, ; Klarner & Klarner, ; Lee et al, ; Planke et al, ). The numerical and analogue modelling of volcanic intrusions and their emplacement mechanism has also been in the forefront of investigations for a long time (Chevalier & Woodford, ; Malthe‐Sørenssen, Planke, Svensen, & Jamtveit, ; Pollard & Johnson, ; Polteau, Ferre, Planke, Neumann, & Chevallier, ).…”

“…| 381 EAGE PETRIK ET al. and extrusive features and their implications on the evolution of sedimentary basins and petroleum systems (Holford et al, 2013Klarner & Klarner, 2012;Lee et al, 2006;Planke et al, 2005). The numerical and analogue modelling of volcanic intrusions and their emplacement mechanism has also been in the forefront of investigations for a long time (Chevalier & Woodford, 1999; Malthe-Sørenssen, Pollard & Johnson, 1973;Polteau, Ferre, Planke, Neumann, & Chevallier, 2008).…”