Texture mounded

Chemical evidence consists of detailed chemical analysis of the corrosion products and any biological mounds present at or near the corrosion site. Evaluation of the chemistry of the liquid phase and its variability, both spatially and with time in relation to corrosive attack, is necessary. The important factors are color, texture, odor, and distribution of materials and organic and inorganic chemistries. 

Most of the hydrocarbons (gas and oil) occur in sedimentary rocks that were generated in different depositional environments (e.g. river charmels, delta systems, submarine fans, carbonate mounds and reefs). Seismic waves penetrating into and reflected within sedimentary rock bodies yield a seismic image of their external shape and of their internal texture. Therefore, the analysis of the external shape of seismic bodies and its internal textures, which is called seismic facies analysis [2], helps to specify the depositional environment of the investigated sedimentary rocks. An analysis of the seismic facies is a must in seismic interpretation to determine the depositional environment and to locate potential reservoirs, especially in complex oilfields. 

The following of this chapter explains (1) the principals of seismic facies analysis, (2) what kind of principal external shapes and internal textures are desirable to extract, and, (3) what kind of strategy should be developed to achieve an automatic mapping of the specified features. The attention of this chapter is directed to carbonate mounds of the Barents Sea and their seismic facies. 

Chaotic Texture (Figure 9). A chaotic texture is characterised by discontinuous, discordant reflections suggesting a disordered arrangement of reflection surfaces. Chaotic textures can represent a wide range of features like slumped areas, reefs and carbonate mounds, cut-and-fiU channel complexes, and highly faulted and folded areas. 

Fig. 10. Different channel fiU textures (a) onlap fill, (b) mounded onlap fill, (c) divergent fill, (d) prograded fiU, (e) chaotic fiU, and (f) complex fill (modified after...

Channels can show different types of textures due to various Ailing mechanisms and size, aspect ratio, sinuosity, etc. We can differentiate onlap All, prograded fill (progradational clinoforms can have all the shapes described in Subsection 4.2), mounded onlap fill (in this case the channel top is convex upward), chaotic fill, divergent fill, and complex fill. 

Fig. 11. Different textures of mounds upward complex, and (c) chaotic.

Internally mounds can consist of different textures each reflecting different environments, ranging from volcanoes to reefs Mitchum et al. [2] differentiate six main textures of mound. However, we will focus here mainly on the external shape and on a few basic textures. 

Concave Upward Simple. The texture of the mound consists of a stack of concave upward events. Surrounding events show a pronounced onlap onto the mound surface. This texture can be typical for volcanoes. 

Concave Upward Complex. The texture consists of a complex arrangement of parallel and wavy events. The seismic events surrounding the mound show onlap. This texture is characteristic for submarine fans. 

Fig. 13. [Reproduced in colour in Plate 2 on page 421.] Segmentation of a two-dimensional inline of the Barents Sea data set into different shapes and textures. This figure shows that a manual interpretation is challenged when it comes to defining the lateral boundaries of the mound shape in two dimensions, not mentioning...

Introduction to Seismic Texture 4.6 Mounded Textures in Other Settings... 

A. Carrillat, T. Randen, L. Spnneland, and G. Elvebakk (2002) Automated mapping of carbonate mounds using 3D seismic texture attributes. Proceedings of the Society of Exploration Geophysicists, Annual Meeting. 

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