Subsurface Fluid Flow: Hydrology of Geothermal Systems

Hydraulic stimulation is the process of initiating fractures in a target reservoir for subsurface energy resource management with applications in unconventional oil/gas and enhanced geothermal systems. The fracture characteristics (i.e., number, size and orientation with respect to the wellbore) determines the modified permeability field of the host rock and thus, numerical simulations of flow in fractured media are essential for estimating the anticipated change in reservoir productivity. However, numerical modeling of fluid flow in highly fractured media is challenging due to the explosive computational cost imposed by the explicit discretization of fractures at multiple length scales. A common strategy for mitigating this extreme cost is to crudely simplify the geometry of fracture network, thereby neglecting the important contributions made by all elements of the complex fracture system.The proposed &#8220;Hierarchical Finite Element Method&#8221; (Hi-FEM; Weiss, Geophysics, 2017) reduces the comparatively insignificant dimensions of planar- and curvilinear-like features by translating them into integrated hydraulic conductivities, thus enabling cost-effective simulations with requisite solutions at material discontinuities without defining ad-hoc, heuristic, or empirically-estimated boundary conditions between fractures and the surrounding formation. By representing geometrical and geostatistical features of a given fracture network through the Hi-FEM computational framework, geometrically- and geomechanically-dependent fluid flow properly can now be modeled economically both within fractures as well as the surrounding medium, with a natural &#8220;physics-informed&#8221; coupling between the two.SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.

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Subsurface fluid flow and its implications for seabed pockmarks and mud volcanoes: An approach of distinct element method (DEM)

10.1190/1.2792894 ◽

2007 ◽

Cited By ~ 1

Author(s):

Huyen Bui ◽

Jack Dvorkin ◽

Amos Nur

Keyword(s):

Fluid Flow ◽

Distinct Element ◽

Distinct Element Method ◽

Mud Volcanoes ◽

Subsurface Fluid ◽

Element Method

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Sediment mobilization deposits from episodic subsurface fluid flow—A new tool to reveal long-term earthquake records?

Geology ◽

10.1130/g37410.1 ◽

2016 ◽

Vol 44 (4) ◽

pp. 243-246 ◽

Cited By ~ 9

Author(s):

A. Reusch ◽

J. Moernaut ◽

F.S. Anselmetti ◽

M. Strasser

Keyword(s):

Fluid Flow ◽

Earthquake Records ◽

Subsurface Fluid ◽

Sediment Mobilization

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Smart proppant concept for monitoring hydraulic fractures

The APPEA Journal ◽

10.1071/aj10036 ◽

2011 ◽

Vol 51 (1) ◽

pp. 527 ◽

Cited By ~ 2

Author(s):

Arcady Dyskin ◽

Elena Pasternak ◽

Greg Sevel ◽

Rachel Cardell-Oliver

Keyword(s):

Fluid Flow ◽

Random Distribution ◽

Energy Content ◽

Low Frequency ◽

Hydraulic Fractures ◽

Low Frequencies ◽

Flow Channels ◽

Monitoring Technique ◽

Smart Actuators ◽

Subsurface Fluid

Monitoring subsurface fluid flow is important in mapping hydraulic fractures and identifying flow channels in reservoirs. A new monitoring technique is proposed whereby fluid is injected with smart actuators capable of organising their pulses to create a combined output with a higher proportion of energy at low frequencies. Ideally, the best results occur when actuators are sequentialised so each next actuator emits its pulse immediately after the previous actuator. The low frequency energy content achieved using sequentialisation is much higher than that achieved with a random distribution of pulses, but is relatively insensitive to practical errors in scheduling and irregular attenuations of amplitudes. Simulations show that actuators can be self-organised into a sequential state by monitoring other actuators’ pulses using the algorithm presented in this paper.

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