Title: Discontinuities in effective permeability due to fracture percolation

Abstract

Motivated by a triaxial coreflood experiment with a sample of Utica shale where an abrupt jump in permeability was observed, possibly due to the creation of a percolating fracture network through the sample, we perform numerical simulations based on the experiment to characterize how the effective permeability of otherwise low-permeability porous media depends on fracture formation, connectivity, and the contrast between the fracture and matrix permeabilities. While a change in effective permeability due to fracture formation is expected, the dependence of its magnitude upon the contrast between the matrix permeability and fracture permeability and the fracture network structure is poorly characterized. We use two different high-fidelity fracture network models to characterize how effective permeability changes as percolation occurs. The first is a dynamic two-dimensional fracture propagation model designed to mimic the laboratory settings of the experiment. The second is a static three-dimensional discrete fracture network (DFN) model, whose fracture and network statistics are based on the fractured sample of Utica shale. Once the network connects the inflow and outflow boundaries, the effective permeability increases non-linearly with network density. In most networks considered, a jump in the effective permeability was observed when the embedded fracture network percolated. We characterize how themore » magnitude of the jump, should it occur, depends on the contrast between the fracture and matrix permeabilities. For small contrasts between the matrix and fracture permeabilities the change is insignificant. However, for larger contrasts, there is a substantial jump whose magnitude depends non-linearly on the difference between matrix and fracture permeabilities. A power-law relationship between the size of the jump and the difference between the matrix and fracture permeabilities is observed. In conclusion, the presented results underscore the importance of fracture network topology on the upscaled properties of the porous medium in which it is embedded.« less

Authors:

Hyman, Jeffrey De'Haven  ^[1];

• Search DOE PAGES for author "Hyman, Jeffrey De'Haven"
• Search DOE PAGES for ORCID "0000-0002-4224-2847"

Karra, Satish  ^[1];

• Search DOE PAGES for author "Karra, Satish"
• Search DOE PAGES for ORCID "0000-0001-7847-6293"

Carey, James William  ^[1];

• Search DOE PAGES for author "Carey, James William"
• Search DOE PAGES for ORCID "0000-0001-8488-2925"

Gable, Carl Walter  ^[1];

• Search DOE PAGES for author "Gable, Carl Walter"
• Search DOE PAGES for ORCID "0000-0001-7063-0815"

Viswanathan, Hari S.  ^[1];

• Search DOE PAGES for author "Viswanathan, Hari S."
• Search DOE PAGES for ORCID "0000-0002-1178-9647"

Rougier, Esteban  ^[1];

• Search DOE PAGES for author "Rougier, Esteban"
• Search DOE PAGES for ORCID "0000-0002-4624-2844"

Lei, Zhou  ^[1]

• Search DOE PAGES for author "Lei, Zhou"
• Search DOE PAGES for ORCID "0000-0002-4965-5556"

---

+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

Wed Jan 31 00:00:00 EST 2018

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:

1419753

Alternate Identifier(s):

OSTI ID: 1548765

Report Number(s):

LA-UR-17-23142
Journal ID: ISSN 0167-6636

Grant/Contract Number:  

AC52-06NA25396; 20170103DR; LA-UR-17-23142; 20150763PRD4

Resource Type:

Accepted Manuscript

Journal Name:

Mechanics of Materials

Additional Journal Information:

Journal Volume: 119; Journal Issue: C; Journal ID: ISSN 0167-6636

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Computer Science; Earth Sciences; Energy Sciences; Mathematics