A New Approach for Predrilling the Unconfined Rock Compressive Strength Prediction

Nabaei, M.; Shahbazi, Khalil

doi:10.1080/10916461003752546

Cited by 17 publications

(3 citation statements)

References 24 publications

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“…The unconfined compressive strength is a parameter with importance regarding wellbore stability prediction with geomechanical models [6,31,38,39]. There are two ways to determine the unconfined compressive strength: 1. derivation from a series of triaxial measurements (C 0 ; cf.…”

Section: Alternative Methods Of Parameter Determinationmentioning

confidence: 99%

“…31,32), or to different ways of parameter determination (Eqs. 25,38). The presented data set and empirical relations, however, give new and comprehensive information about mechanical and physical properties of sedimentary and volcanic rocks valid for the NWGB.…”

Section: Comparison With Previous Studiesmentioning

confidence: 99%

“…With logging-while-drilling data the initially computed geomechanical model can be continuously adapted to the conditions at depth. For such geomechanical modelling, the uniaxial compressive strength (UCS) is the most important geomechanical input parameter Nabaei and Shahbazi, 2012;. There already exist several software approaches for building and updating geomechanical models (Settari and Walters, 2001; geomechanics software, e.g.…”

Section: Introductionmentioning

confidence: 99%

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Outcrop analogue studies of rocks from the Northwest German Basin for geothermal exploration and exploitation

Reyer¹

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Rock heterogeneities in terms of layering and fault zones are common phenomena in sedimentary basins such as the Northwest German Basin (NWGB). At geothermal projects, these heterogeneous rock properties affect many issues associated with exploration, drilling, and reservoir stimulation. This thesis investigates how high resolution data from outcrop analogues can be used to improve predictions of both normal fault structure and rock mechanical conditions at greater depths.To better understand normal fault structure and associated fracture systems in sedimentary rocks of the NWGB, 58 outcrop-scale normal fault zones were analysed in detail. The focus was on fracture orientations, densities, apertures and lengths, separately for fault damage zones and host rocks, as well as structural indices. Pronounced differences between carbonate and clastic rocks were found, and mainly in carbonate rocks clear damage zones with increased fracture densities occur. While the maximum aperture is similar for both rock types, the percentage of fractures with large apertures is much higher in the damage zones. In carbonate rocks, damage zone fractures may differ significantly in orientation from that in the host rocks. In clastic rocks, fractures show a similar orientation in both fault damage zones and host rocks. Structural indices indicate that normal fault zones in carbonate rocks are more damage-zone dominated and have more profound effects on enhancing permeability in fluid reservoirs than those in clastic rocks. Based on measured Young's moduli and fracture density distributions, effective stiffnesses E e within normal faults are calculated and yield a significantly smaller stiffness decrease for clastic-rock damage zones compared with carbonate rocks. 6 PrefaceThis thesis entitled "Outcrop Analogue Studies of Rocks from the Northwest German Basin for Geothermal Exploration and Exploitation: Fault Zone Structure, Heterogeneous Rock Properties, and Application to Reservoir Conditions" was written simultaneously to the project "Heterogeneous rock properties, drilling efficiency and fracture propagation" which is part of the collaborative research program gebo (Geothermal Energy and High Performance-Drilling) funded by Niedersächsisches Ministerium für Wissenschaft und Kultur and Baker Hughes. It is the result of work that was done initially as research assistant (May 2009 to October 2010), followed by almost three years as doctor student at the Geoscience Centre of the Georg-August-

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Section: Alternative Methods Of Parameter Determinationmentioning

confidence: 99%