Tectonic control on the petrophysical properties of foredeep sandstone in the Central Apennines, Italy

被引:17
|
作者
Smeraglia, Luca [1 ]
Trippetta, Fabio [1 ]
Carminati, Eugenio [1 ,2 ]
Mollo, Silvio [3 ]
机构
[1] Univ Roma La Sapienza, Dipartimento Sci Terra, Piazzale Aldo Moro 5, I-00185 Rome, Italy
[2] CNR, Ist Geol Ambientale & Geoingegneria, Rome, Italy
[3] Ist Nazl Geofis & Vulcanol, Rome, Italy
基金
欧洲研究理事会;
关键词
sandstone; porosity; permeability; seismic velocities; paleostress; Central Apennines; POROUS SANDSTONES; DEFORMATION BANDS; ELASTIC-MODULI; PHYSICAL-PROPERTIES; NORTHERN APENNINES; COMPRESSIONAL WAVES; TRIASSIC EVAPORITES; NAVAJO SANDSTONE; THRUST-BELT; FLUID-FLOW;
D O I
10.1002/2014JB011221
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Petrophysical properties of rocks and their applicability at larger scale are a challenging topic in Earth sciences. Petrophysical properties of rocks are severely affected by boundary conditions, rock fabric/microstructure, and tectonics that require a multiscale approach to be properly defined. Here we (1) report laboratory measurements of density, porosity, permeability, and P wave velocities at increasing confining pressure conducted on Miocene foredeep sandstones (Frosinone Formation); (2) compare the laboratory results with larger-scale geophysical investigations; and (3) discuss the effect of thrusting on the properties of sandstones. At ambient pressure, laboratory porosity varied from 2.2% to 13.8% and P wave velocities (V-p) from 1.5km/s to 2.7km/s. The P wave velocity increased with confining pressure, reaching between 3.3km/s and 4.7km/s at 100MPa. In situ V-p profiles, measured using sonic logs, matched the ultrasonic laboratory measurement well. The permeability varied between 1.4x10(-15)m(2) and 3.9x10(-15)m(2) and was positively correlated with porosity. The porosity and permeability of samples taken at various distances to the Olevano-Antrodoco fault plane progressively decreased with distance while P wave velocity increased. At about 1km from the fault plane, the relative variations reached 43%, 65%, and 20% for porosity, permeability, and P wave velocity, respectively. This suggests that tectonic loading changed the petrophysical properties inherited from sedimentation and diagenesis. Using field constraints and assuming overburden-related inelastic compaction in the proximity of the fault plane, we conclude that the fault reached the mechanical condition for rupture in compression at differential stress of 64.8MPa at a depth of 1500m.
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页码:9077 / 9094
页数:18
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