Introduction
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Subjects
Technical issues that are tackled by the people related to SFERA show a wide spectrum represented by hydrocarbon E&P Companies, Service Companies, and Academic World representatives, which treat geological, geophysical, geomechanical and engineering aspects of faulted and fractured rocks. From what has issued from previous meetings on the subject and numerous research papers, ongoing projects and project proposals, we can roughly group these aspects in the following list of categories:

Data Collection, Management, and Analyses

Scale of the data (micron to tens of km’s), 1D, 2D, 3D

Provenance: different sources and instruments, different providers

Data Base: Numerical, GIS, 3D location in a Shared Earth Model

Analysis: Which Parameters to describe and classify?

Geomechanical data acuisition

Static Conceptual Geological Model: descriptive relationships and genesis
Numerical Parameters on Reservoir-Prospect scale;

Definition through special analyses, 3D Seismic, attributes

SEM Model: – Balancing (2D, 3D) – backward model, kinematics of the system
Analogue Modelling: build and test hypothesis, material science
Numerical Mechanical Simulation of Deformation: build and test hypothesis
Modelling of fracture network (DFN, DFFN)

Three types (Probabilistic, Deterministic; Geological Drivers)
Pre – syn- post- deformation fault and fracture networks

Extraction of parameters: static/geometrical and dynamic for continuous models

Fracture Porosity, Permeability, Matrix Blocks, Sigma factor

Definition of the simulation grid: Static Dynamic Conceptual Model

Take small faults and fractures into account?

Dynamic Simulation: well test scale, reservoir scale-well interference.
Feed-back with well tests, learning process

All these categories are listed in an order which also reflects the Workflow followed to tackle the problem of faulted and fractured reservoirs, a workflow for which a general diagram was designed during the 2000 Society of Petroleum Engineers (SPE) Forum in St. Maxime, hereby reproduced in this Introduction Chapter (Figure 1 below).

Present day Situation
Many ongoing projects involve combinations of efforts of University, Industry and Consultancy companies, which is reflected also in the larger ongoing Consortia which study aspects of outcrop analogues, numerical simulations and analogue experiments.
In the usage of classical subsurface observation tools such as core, Log, and Seismics, reviews of the state of the art and refinements of existing technologies discuss a number of new techniques which developments show that the quality of the subsurface knowledge on fault and fracture patterns is rapidly increasing. Examples are the use of magnetic anisotropy of core samples, recognition of new features in Log data such as pinnate joints, the inversion of paleostress using core and Log data sets, and seismic anisotropy. More and more emphasis is put on the recognition of present day stress field (“neostress”), and its application in the recognition of critically stressed faults and fractures in order to predict the anisotropy of the permeability of the system.

Many studies today show validity of the use of outcrop analogues and how they are integrated with reservoir studies. It can clearly be recognised that the focal points of many current Research Projects are now directed towards the definition of rules that link depositional facies models to conceptual fault and fracture models and excellent examples are shown of the first results of this approach. Many projects reflect the interest in this approach and it is, therefore, also not surprising that most of the emphasis today of studies of outcrop analogues regard carbonate rocks, which could be related both to current tendency of economic interest and to the lack of information and concepts on these geologic environments which existed just a few years ago. Integrating these empirical data sets of mechanical stratigraphy with geomechanical forward modelling (analogue experiments and numerical simulations) and backward modelling (2D and 3D balancing, stress and strain history reconstruction) seems to have become the key to successful prediction of larger scale patterns, although clearly new conflicting scientific hypothesis have arisen (e.g. current debates on relation between fault/fracture patterns and anticline geometry and bed curvature). One of the key points also discussed in previous meetings and subject of the latest research papers which may be the seed for the generation of innovative solutions is the distinction between “pre-tectonic” and “syn-tectonic” features, also known as “pre-syn and post-folding” patterns. Let us not forget that it would be hard to find a completely non-fractured rock on the face of our Earth, and most rocks are only very slightly deformed!

Experiments and numerical simulations show us various aspects of the neo-formation, propagation and remobilisation of different types of faults and fractures, and we seem to be more and more capable of understanding differences in mechanical material behaviour and relationships with all kinds of parameters which characterise the stress and strain history, and, who knows, we might in the near future even be able to define, describe, and understand the difference between objects such as joints, faults, cracks, fractures, ruptures, cleavage, shear bands, etc…

The use of numerical simulations of discrete fracture models in different stages of the workflow and the integration with dynamic data sets is shown and reviewed, the problems of upscaling and static and dynamic parameter extraction for mono/dual porosity/permeability, and bi/tri-phase flow simulations, especially in relation to EOR/IOR design, gas and water injection schemes, flood design, etc.. More and more studies show that fracture patterns should be viewed as complex and highly heterogeneous, compartment defining reservoir elements that may both be enhancing and/or impeding flow. It is clear that only sensible combinations of statistical and probabilistic models, with data and model driven approaches can provide the accuracy necessary to represent the “interesting”, or we may say “effective” part of the conceptual model numerically, optimising time and investments in the different stages of reservoir development, and the meeting provides and excellent occasion to discuss the challenge of exploring the frontiers of where Science and Technology stand and can contribute Today.

Definitions
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Dictionary

Fowler, H.W. & F.G. Fowler (1958); The concise Oxford Dictionary of current English. Fourth Edition revised by E. McIntosh, Oxford at the Clarendon Press., Oxford University press., Amen House, London E.C.4, Oxford, Great Britain, 1958.

Fr_c’ture, n., & v.t. & i. 1. Breaking, breakage, esp. of bone or cartilage (COMPOUND2 ~ ); surface shown by mineral when broken with hammer; substitution of diphthong, diphthong substituted, for simple vowel owing to influence of following consonant. 2. vb. Cause ~ in, break continuity of, crack (t. & i.). [F, f. L fractura (FRACTION, -URE)]

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Geo-scientific Nomenclature; Thesaurus

Visser, W.A.. (1980); Geological nomenclature. Royal Geological and Mining Society of the Netherlands. Bohn, Scheltema & Holkema, Utrecht, Martinus Nijhoff, The Hague, Boston, London, 1980.

Fracture (0469); Mineralogy; p. 35
The breaking of a mineral other than along planes of cleavage or parting. The fracture of a mineral can be described in terms of conchoidal (shell-like), fibrous, uneven, etc.
Breuk / Cassure; Fracture / Bruch / fractura

Fracture (0541); Crystallography; p. 40
The breaking of a crystal other than along cleavage planes.
Breuk / Fracture / Bruch / Fractura

Fracture (1494); Fracturing; p. 112
General term for a surface along which loss of cohesion has taken place.
Breuk / Fracture / Bruch / Fractura

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Related terms