TY - JOUR T1 - Comparison of three fracture sampling methods for layered rocks JF - International Journal of Rock Mechanics and Mining Sciences [1997] Y1 - 2010 A1 - Alex K Manda A1 - Stephen B Mabee KW - #StaffPubs KW - Big Quarry KW - carbonates KW - case studies KW - data acquisition KW - data processing KW - dolomite KW - Door Peninsula KW - fractures KW - geographic information systems KW - ground water KW - information systems KW - joints KW - layered materials KW - mapping KW - methods KW - movement KW - multiple scanline method KW - northeastern Wisconsin KW - numerical models KW - permeability KW - sampling KW - selection method KW - simulation KW - single scanline method KW - statistical analysis KW - Structural geology 16 KW - style KW - three-dimensional models KW - United States KW - Wisconsin AB - Three methods of fracture data collection are tested against each other in layered dolomitic rocks to evaluate the effectiveness of each method in sampling fracture properties. The methods tested are the single scanline method (SSM), selection method (SM), and multiple scanline method (MSM). Finite element techniques were first used to build a base model with the exact locations, sizes and orientations of each fracture observed in the natural fracture network. Then, a second set of models were stochastically generated using statistics from each sampling technique. For each network, the overall fracture intensity was used to assess the effectiveness of each sampling technique in capturing the real fracture properties. Fracture network permeability was also calculated for each of two directions to evaluate the transmissive properties of the networks. Although all three methods produced good matches of relative intensity and permeability between natural and synthetic fractures, the results reveal that a well-placed scanline performed the best at recreating natural fractures. However, the results from one variation of the SSM were only slightly better than the results from both versions of the SM. In general, the SSM provides the best results but possibly at heavy costs in time and labor, whereas the SM gives comparable results with less expenditure of energy and time. Thus, the SM is an adequate technique and recommended for use at large outcrops or where time, access or budget constraints are a concern. PB - Elsevier : Oxford-New York, International CY - International VL - 47 SN - 13651609 UR - http://www.sciencedirect.com/science/article/pii/S1365160909001804 IS - 22 N1 - Accession Number: 2010-041538; Language: English; Coordinates: N441500N452000W0865600W0880000; Coden: IJRMA2; Collation: 9; Publication Types: Serial; Updated Code: 201023; Illustration(s): illus. incl. 4 tables; Number of References: 25; Reviewed Item: Analytic JO - International Journal of Rock Mechanics and Mining Sciences [1997] ER - TY - JOUR T1 - A method of estimating bulk potential permeability in fractured-rock aquifers using field-derived fracture data and type curves JF - Hydrogeology Journal Y1 - 2013 A1 - Alex K Manda A1 - Stephen B Mabee A1 - David F Boutt A1 - Cooke, Michele L. KW - #StaffPubs KW - aquifers KW - boundary conditions KW - eastern Massachusetts KW - fractured materials KW - fractures KW - ground water KW - Hydrogeology 21 KW - massachusetts KW - Nashoba terrane KW - naturally fractured reservoirs KW - numerical models KW - permeability KW - prediction KW - pump tests KW - simulation KW - two-dimensional models KW - United States AB - A method is devised for estimating the potential permeability of fracture networks from attributes of fractures observed in outcrop. The technique, which is intended as a complement to traditional approaches, is based on type curves that represent various combinations of fracture lengths, fracture orientations and proportions (i.e., intensities) of fractures that participate in flow. Numerical models are used to derive the type curves. To account for variations in fracture aperture, a permeability ratio (R) defined as the permeability of a fracture network in a domain divided by the permeability of a single fracture with identical fracture apertures, is used as a dependent variable to derive the type curves. The technique works by determining the point on the type curve that represents the fracture characteristics collected in the field. To test the performance of the technique, permeabilities that were derived from fractured-rock aquifers of eastern Massachusetts (USA) are compared to permeabilities predicted by the technique. Results indicate that permeabilities estimated from type curves are within an order of magnitude of permeabilities derived from field tests. First-order estimates of fracture-network permeability can, therefore, be easily and quickly acquired with this technique before more robust and expensive methods are utilized in the field. Copyright 2012 Springer-Verlag Berlin Heidelberg PB - Springer : Berlin - Heidelberg, Germany CY - Federal Republic of Germany VL - 21 SN - 1431217414350157 UR - http://link.springer.com/article/10.1007%2Fs10040-012-0919-2 IS - 22 N1 - Accession Number: 2013-055373; Language: English; Coordinates: N421500N424500W0704500W0714500; Collation: 13; Publication Types: Serial; Updated Code: 201334; Illustration(s): illus. incl. 4 tables, geol. sketch maps; Number of References: 41; Reviewed Item: Analytic JO - Hydrogeology Journal ER -