Summary

This paper presents a new methodology for automated hierarchical model building with the promise of significantly shortening the turnaround time of 3D model building. The characteristics of the methodology are:

· Multi-scale model consistency in seismic to simulation workflows.

· Models consist of 3D volume primitives optionally constrained by faults and horizons.

· The model segmentation captures high geometric complexity in geological bodies, e.g., salt bodies. Gross volume estimates are available in real time.

· The user can interact with the models on a “systemlevel”, i.e., access all volume primitives belonging to specific stratigraphic sequences.

Introduction

Taking on increasingly complex reservoirs and geometries that cannot practically be represented by bounding surfaces, such as top and base horizons (e.g., carbonates, channels, salt...), necessitates a new generation of volume interpretation tools. The truly three-dimensional nature of seismic data makes working in terms of volumes instead of primitive surfaces more attractive and convenient. Volume interpretation also provides better handling of geometries induced by volume properties that are not directly represented in a surface framework. An important requirement of any new interpretation tool is that it must be fast and intuitive to use. Making informed decisions necessitates good data representation, analysis and interaction capabilities, thus, putting high focus on user interface and interaction capabilities. An excellent approach to a more user friendly, high level and informative interpretation system is seen in the recently introduced interpretation paradigm of system level interpretation [2]. There the key idea is to automate the task of extracting low-level primitives, such as horizons and faults, and present the user with an overall system level overview of these pre-generated primitives. This represents a top down approach, where the user starts with the big picture, and zooms in on the smaller details, instead of spending time building the details and maybe never see the bigger picture. The user can then spend time analyzing the data, applying and developing geological knowledge important for the field. This approach to interpretation is orders of magnitude faster than conventional approaches, and in addition offers far superior data analysis capabilities. An equivalent approach for volume interpretation would be the pre-generation of sub-volumes, representing geological objects, combined with analysis and navigation tools. The vision would then be to interpret in terms of geological objects, much like in Figure 1. Being able to select objects, split, group, and label them would provide a much more intuitive approach to volume interpretation as opposed to boundary extraction, construction of associated closed volumes and voxel picking.

Hierarchical model building

Throughout the lifecycle of a reservoir a variety of models are generated and used as a means of representing the information obtained, to understand observations, predict future observations and plan appraisal strategies. The size and detail of these models depend heavily on the maturity of the reservoir, which may be in the exploration, appraisal, development or production phase. Individual models represent various geophysical aspects of a reservoir, such as velocities, facies distributions, porosities, permeabilities, and more.

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