Hydraulic borehole characterization through the application of moment methods to fluid conductivity logs

Löw, Simon; Kelley, V.A.; Vomvoris, S.

doi:10.1016/0926-9851(94)90051-5

Cited by 9 publications

(6 citation statements)

References 14 publications

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“…Since the 1990s, several authors have successfully used SBDTs to develop methods of determining the hydraulic properties of flowing fractures in boreholes (e.g., Tsang et al 1990; Löw et al 1994; Evans 1995; Brainerd and Robbins 2004; Doughty and Tsang 2005; West and Odling 2007). These studies all involved analysis of results obtained under pumped conditions that disturbed the ambient head distributions and induced vertical flow.…”

Section: Introductionmentioning

confidence: 99%

A Tracer Methodology for Identifying Ambient Flows in Boreholes

et al. 2011

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Identifying flows into, out of and across boreholes is important for characterising aquifers, determining the depth at which water enters boreholes, and determining the locations and rates of outflow. This study demonstrates how Single Borehole Dilution Tests (SBDTs) carried out under natural head conditions provide a simple and cheap method of identifying vertical flow within boreholes and determining the location of in-flowing, outflowing and cross-flowing fractures.Computer simulations were used to investigate the patterns in tracer profiles that arise from different combinations of flows. Field tracer tests were carried out using emplacements of a saline tracer throughout the saturated length of boreholes and also point emplacements at specific horizons. Results demonstrated that SBDTs can be used to identify flowing fractures at the top and bottom of sections of vertical flow, where there is a change in vertical flow rate within a borehole, and also where there are consistent decreases in tracer concentration at a particular depth. The technique enables identification of fractures that might be undetected by temperature and electrical conductance logging, and is a simple field test that can be carried out without pumping the borehole.

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Section: Introductionmentioning

confidence: 99%

A Tracer Methodology for Identifying Ambient Flows in Boreholes

et al. 2011

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“…Since Tsang et al [1990] introduced the method, it has been widely applied in deep wells down to 1500 m or more [ Kelley et al , 1991; Guyonnet et al , 1993; Doughty et al , 2005], in inclined boreholes drilled in the underground Grimsel Test Laboratory [ Marschall and Vomvoris , 1995], and extensively in shallower wells down to about 100 m [ Evans et al , 1992; Pedler et al , 1992; Bauer and LoCoco , 1996; Paillet and Pedler , 1996; Karasaki et al , 2000]. Continued development of analytical and numerical data analysis techniques [ Löw et al , 1994; Evans , 1995; Tsang and Doughty , 2003; Doughty and Tsang , 2005] have broadened the range of applicability and enhanced the ease of use of the method. Note that FFEC logging requires little or no specialized equipment or expertise, and may be carried out more quickly than most other methods, making it a valuable tool for efficient subsurface characterization.…”

Section: Introductionmentioning

confidence: 99%

Application of direct‐fitting, mass integral, and multirate methods to analysis of flowing fluid electric conductivity logs from Horonobe, Japan

Doughty

Tsang

Hatanaka

et al. 2008

Water Resources Research

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[1] The flowing fluid electric conductivity (FFEC) logging method is an efficient way to provide information on the depths, salinities, and inflow strengths of individual conductive features intercepted by a borehole, without the use of specialized probes. Using it in a multiple-flow rate mode allows, in addition, an estimate of the transmissivities and inherent (far-field) hydraulic heads in each of the conductive features. The multirate method was successfully applied to a 500-m borehole in a granitic formation and reported recently. The present paper describes the application of the method to two zones within a 1000-m borehole in sedimentary rock, which produced, for each zone, three sets of logs at different pumping rates, each set measured over a period of about 1 day. The data sets involve several complications, such as variable well diameter, gradual water level decline in the well during logging, possible fluid flow through the unfractured rock matrix, and effects of drilling mud.Various techniques were applied to analyze the FFEC logs: direct-fitting, mass integral, and the multirate method mentioned above. In spite of complications associated with the tests, analysis was able to identify 44 hydraulically conducting fractures distributed over the depth interval 150-775 m below ground surface. The salinities (in FEC), and transmissivities and hydraulic heads (in dimensionless form) of these 44 features were obtained and found to vary significantly among one another. These results were compared with transmissivity and head values inferred from eight packer tests that were conducted in this borehole over the same depth interval. FFEC results were found to be consistent with packer test results, thus demonstrating the robustness of the FFEC logging method under nonideal conditions. Citation: Doughty, C., C.-F. Tsang, K. Hatanaka, S. Yabuuchi, and H. Kurikami (2008), Application of direct-fitting, mass integral, and multirate methods to analysis of flowing fluid electric conductivity logs from Horonobe, Japan, Water Resour. Res., 44, W08403,

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“…(Colog, Inc., personal communication, 1999). Several integral approaches have been developed Löw et al, 1990;1994) that can provide good initial guesses to BORE, greatly enhancing its ease of use. Additionally, Evans (1995) has formalized the inversion process with an automated search for the feed-point parameters that minimize the misfit between modeled and observed FEC profiles.…”

Section: Introductionmentioning

confidence: 99%