Distribution and Nature of Fault Architecture in a Layered Sandstone and Shale Sequence: An Example from the Moab Fault, Utah

We examined the distribution of fault rock and damage zone structures in sandstone and shale along the Moab fault, a basin-scale normal fault with nearly 1 km (0.62 mi) of throw, in southeast Utah. We find that fault rock and damage zone structures vary along strike and dip. Variations are related to changes in fault geometry, faulted slip, lithology, and the mechanism of faulting. In sandstone, we differentiated two structural assemblages: (1) deformation bands, zones of deformation bands, and polished slip surfaces and (2) joints, sheared joints, and breccia. These structural assemblages result from the deformation band-based mechanism and the joint-based mechanism, respectively. Along the Moab fault, where both types of structures are present, joint-based deformation is always younger. Where shale is juxtaposed against the fault, a third faulting mechanism, smearing of shale by ductile deformation and associated shale fault rocks, occurs. Based on the knowledge of these three mechanisms, we projected the distribution of their structural products in three dimensions along idealized fault surfaces and evaluated the potential effect on fluid and hydrocarbon flow. We contend that these mechanisms could be used to facilitate predictions of fault and damage zone structures and their permeability from limited data sets.

[1]  Thérèse Granier.  Origin, damping, and pattern of development of faults in granite , 1985 .

[2]  L. Durlofsky,et al.  Computing Permeability of Fault Zones in Eolian Sandstone from Outcrop Measurements , 2002 .

[3]  F. Lehner,et al.  The emplacement of clay smears in synsedimentary normal faults: inferences from field observations near Frechen, Germany , 1997 .

[4]  S. Martel.  Formation of compound strike-slip fault zones, Mount Abbot quadrangle, California , 1990 .

[5]  P. Eichhubl,et al.  Focused fluid flow along faults in the Monterey Formation, coastal California , 2000 .

[6]  A. Aydin,et al.  A new process-based methodology for analysis of shale smear along normal faults in the Niger Delta , 2003 .

[7]  B. Tikoff,et al.  Competency contrast, kinematics, and the development of foliations and lineations in the crust , 2002 .

[8]  Grant M. Skerlec,et al.  Evaluating Top and Fault Seal , 1999 .

[9]  Frederick M. Chester,et al.  Implications for mechanical properties of brittle faults from observations of the Punchbowl fault zone, California , 1986 .

[10]  A. Aydin,et al.  Three-dimensional visualization of normal fault segmentation and its implication for fault growth , 2000 .

[11]  Robert J. Knipe,et al.  Juxtaposition and Seal Diagrams to Help Analyze Fault Seals in Hydrocarbon Reservoirs , 1997 .

[12]  W. F. Brace,et al.  A note on brittle crack growth in compression , 1963 .

[13]  S. G. Roberts,et al.  Numerical simulation of departures from radial drawdown in a faulted sandstone reservoir with joints and deformation bands , 1998, Geological Society, London, Special Publications.

[14]  Richard G. Gibson,et al.  Fault-Zone Seals in Siliciclastic Strata of the Columbus Basin, Offshore Trinidad , 1994 .

[15]  Paul Segall,et al.  Mechanics of discontinuous faults , 1980 .

[16]  James P. Evans,et al.  Fault zone architecture and permeability structure , 1996 .

[17]  Robert J. Knipe,et al.  Faulting, fault sealing and fluid flow in hydrocarbon reservoirs: an introduction , 1998, Geological Society, London, Special Publications.

[18]  R. Knipe.  The Influence of Fault Zone Processes and Diagenesis on Fluid Flow: Chapter 10: DIAGENESIS AND FAULTS , 1993 .

[19]  M. Antonellini,et al.  Effect of Faulting on Fluid Flow in Porous Sandstones: Petrophysical Properties , 1994 .

[20]  D. Pollard,et al.  Fluid flow in discrete joint sets: Field observations and numerical simulations , 1999 .

[21]  M. Antonellini,et al.  Effect of Faulting on Fluid Flow in Porous Sandstones: Geometry and Spatial Distribution , 1995 .

[22]  Arvid M. Johnson,et al.  Development of faults as zones of deformation bands and as slip surfaces in sandstone , 1978 .

[23]  Terry Engelder,et al.  2 – JOINTS AND SHEAR FRACTURES IN ROCK , 1987 .

[24]  G. Mandl,et al.  The Role Of Faults In Hydrocarbon Migration And Trapping In Nigerian Growth Fault Structures , 1978 .

[25]  R. Gabrielsen,et al.  Parameters that control the development of clay smear at low stress states: an experimental study using ring-shear apparatus , 2002 .

[26]  Atilla Aydin,et al.  Fractures, faults, and hydrocarbon entrapment, migration and flow , 2000 .

[27]  Guozhu Zhao,et al.  Analysis of minor fractures associated with joints and faulted joints , 1991 .

[28]  F. Lehner,et al.  On a mechanism of clay smear emplacement in synsedimentary normal faults , 1991 .

[29]  A. Aydin,et al.  Anatomy of a normal fault with shale smear , 1996 .

[30]  J. Caine,et al.  Fault Zone Architecture and Fluid Flow: Insights from Field Data and Numerical Modeling , 2013 .

[31]  N. Davatzes,et al.  Overprinting faulting mechanisms in high porosity sandstones of SE Utah , 2003 .

[32]  Urban S. Allan,et al.  Model for Hydrocarbon Migration and Entrapment Within Faulted Structures , 1989 .

[33]  J. Walsh,et al.  The Field Geology of the Moab Fault , 1996 .

[34]  R. Sibson.  Conditions for fault-valve behaviour , 1990, Geological Society, London, Special Publications.

[35]  Richard H. Sibson,et al.  Fault rocks and fault mechanisms , 1977, Journal of the Geological Society.

[36]  M. Takahashi,et al.  Permeability change during experimental fault smearing , 2003 .

[37]  Louis J. Durlofsky,et al.  Representation of Fault Zone Permeability in Reservoir Flow Models , 2001 .

[38]  D. Faulkner,et al.  The gas permeability of clay-bearing fault gouge at 20°C , 1998, Geological Society, London, Special Publications.