Application of the pole‐dipole resistivity technique to the detection of solution cavities beneath highways

Geophysics ◽  
1986 ◽  
Vol 51 (3) ◽  
pp. 833-837 ◽  
Author(s):  
Douglas L. Smith

Using a multiconductor electrode cable and a 30‐post switching system, pole‐dipole electrical resistivity measurements with a linear electrode array demonstrated a strong correlation between resistivity anomalies and subsurface voids at four sites in Florida. Solution cavities below the water table are filled with a groundwater‐solute mixture which is characterized by a lower electrical resistivity than the enclosing country rock (Eocene and younger limestone). Air‐filled cavities above the water table exhibit markedly high‐resistivity anomalies. Confirmation drilling of postulated cavities and other anomalies suggests the method can be used with confidence for identification and location of highway‐threatening solution cavities with diameters as small as 3 to 5 m to a depth of 25 to 30 m.

Geophysics ◽  
2021 ◽  
Vol 86 (3) ◽  
pp. B209-B221
Author(s):  
Heather Barnes ◽  
Johnny R. Hinojosa ◽  
Glenn A. Spinelli ◽  
Peter S. Mozley ◽  
Daniel Koning ◽  
...  

We have combined electrical resistivity tomography (ERT), geologic information from boreholes and outcrops, and hydrogeologic data to investigate field-scale fault-zone cementation of the Loma Blanca Fault in the Rio Grande Rift. We have collected electrical resistivity data from 16 transects and geologic samples from 29 boreholes (completed as groundwater wells to 30 m depth) across and around the fault. The 2D ERT profiles, whose interpretations are constrained by geologic data, indicate (1) a high resistivity zone in cemented portions of the fault below the water table and (2) in the unsaturated zone, a low-resistivity feature along the cemented portions of the fault. The high-resistivity zone below the water table is consistent with a 10% reduction in porosity due to the fault zone cementation. With the same porosity in the unsaturated zone, the low-resistivity feature in the cemented fault zone is consistent with saturation >0.7, in contrast to saturation 0.2–0.7 for sediment outside of the cemented fault zone. In addition, subsurface samples and ERT profiles delineate a buttress unconformity (i.e., steeply dipping erosional contact) corresponding to a paleovalley margin. This unconformity truncates the cemented fault zone and separates Pliocene axial-fluvial sand (deposited by an ancestral Rio Grande) from late Quaternary sand and gravel (deposited by the Rio Salado, a Rio Grande tributary). The cemented fault zone in the southern portion of the study area is a hydrogeologic barrier; north of the buttress unconformity, where the cemented fault zone has been removed by erosion, the fault is not a hydrogeologic barrier. The integration of geologic, geophysical, and hydrogeologic observations is key to developing our understanding of this complex system, and it allows us to demonstrate the utility of ERT in detecting subsurface fault-zone cementation.


2019 ◽  
Vol 24 (1) ◽  
pp. 145-149
Author(s):  
Pithan Pairojn

This research proposes an investigation of groundwater by using 2D electrical resistivity techniques with the low-cost Chandrakasem Rajabhat University Resistivity Meter (CRU-Resistivity Meter) and processing with the Chandrakasem Rajabhat University Resistivity Images software (CRU-Resistivity Images). The resistivity meter, constructed of parts costing less than $1,000 USD, was tested at Soi Dao in Chantaburi, Thailand with a profile length of 90 m. Using a Wenner electrode array, the results showed that high resistivity zones greater than 100 ohm-m at a depth of 8 m generally considered to be topsoil with sand. Through testing, it was also found that low resistivity zones about 10 ohm-m at a depth of 20 to 50 m depth were generally considered a suitable subsurface range for good quality groundwater. The results of total dissolved solid (TDS) from water samples confirmed that groundwater at the sites of this example survey may be used for agriculture.


2015 ◽  
Vol 54 (4) ◽  
Author(s):  
César Augusto Moreira ◽  
Thais Munhoz ◽  
Fernanda Cavallari ◽  
Lívia Portes Innocenti Helene

Biogas produced in sanitary landfills consists in a potential source, formed by degradation of organic matter, this gas is constituted by CH4, CO2 and water vapor. Sanitary landfills represent important depository of organic matter with great energetic potential in Brazil, although presently with inexpressive use. Estimates for production or maintenance of productive rates of CH4 represent one of the main difficulties of technical order to the planning and continuity of collection systems for rational consumption of this resource. Electrical resistivity measurements are routinuously used in profiling oil wells for the determination of levels with accumulations of oil and gas, facing the contrast among fluids and rocks. This paper aims to evaluate eventual relationship among biogas flow quantified in surface drains of a waste cell in landfill, with characteristic patterns of in depth electrical resistivity. The integration of Electrical Resistivity Tomography (ERT) lines allowed for the generation of 3D blocks and a clear distinction among zones of high biogas production, quantified in surface drains, with areas of high resistivity in depth. The results suggest the possibility of use of the method in studies to place drains in areas promising to the collection of biogas for energetic generation in sanitary landfill.


SPE Journal ◽  
2011 ◽  
Vol 16 (03) ◽  
pp. 608-624 ◽  
Author(s):  
Jesús M. Salazar ◽  
Carlos Torres-Verdín ◽  
Gong Li Wang

Summary We quantify the influence of oil-based mud (OBM)-filtrate invasion and formation-fluid properties on the spatial distribution of fluid saturation and electrical resistivity in the near-wellbore region. The objective is to appraise the sensitivity of borehole resistivity measurements to the spatial distribution of fluid saturation resulting from the compositional mixing of OBM and in-situ hydrocarbons. First, we consider a simple two-component formulation for the oil phase (OBM and reservoir oil) wherein the components are first-contact miscible. A second approach consists of adding water and surfactant to a multicomponent OBM invading a formation saturated with multiple hydrocarbon components. Simulations also include presence of irreducible, capillary-bound, and movable water. The dynamic process of OBM invasion causes component concentrations to vary with space and time. In addition, the relative mobility of the oil phase varies during the process of invasion because oil viscosity and oil density are both dependent on component concentrations. Presence of surfactants in the OBM is simulated with a commercial adaptive implicit compositional formulation that models the flow of three-phase multicomponent fluids in porous media. Simulations of the process of OBM invasion yield 2D spatial distributions of water and oil saturation that are transformed into spatial distributions of electrical resistivity. Subsequently, we simulate the corresponding array-induction measurements assuming axial-symmetric variations of electrical resistivity. We perform sensitivity analyses on field measurements acquired in a well that penetrates a clastic formation and that includes different values of density and viscosity for mud filtrate and formation hydrocarbon. These analyses provide evidence of the presence of a high-resistivity region near the borehole wall followed by a low-resistivity annulus close to the noninvaded resistivity region. Such an abnormal resistivity annulus is predominantly caused by high viscosity contrasts between mud filtrate and formation oil. The combined simulation of invasion and array-induction logs in the presence of OBM invasion provides a more reliable estimate of water saturation, which improves the assessment of in-place hydrocarbon reserves.


Author(s):  
W. E. King

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).


2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Eduardo M.S. Amarante ◽  
Olivar A.L. de Lima ◽  
Susana S. Cavalcanti

ABSTRACT. To investigate the subsurface geological and hydrological conditions around the area of the Alagoinhas county cemetery – Bahia State, Brazil, 38 vertical electrical soundings using Schlumberger electrode array were performed to a maximum AB/2 spacing... RESUMO. Para investigar as condições geológicas e hidrológicas da subsuperfície na área do entorno do Cemitério Municipal de Alagoinhas, Bahia, foram realizadas 38 sondagens elétricas verticais centradas em pontos acessíveis da área. As sondagens foram...


1967 ◽  
Vol 6 (47) ◽  
pp. 599-606 ◽  
Author(s):  
Hans Röthlisberger

A brief description of the resistivity method is given, stressing the points which are of particular importance when working on glaciers. The literature is briefly reviewed.


1991 ◽  
Vol 05 (24n25) ◽  
pp. 1635-1638
Author(s):  
S.M. M.R. NAQVI ◽  
A.A. QIDWAI ◽  
S.M. ZIA-UL-HAQUE ◽  
FIROZ AHMAD ◽  
S.D.H. RIZVI ◽  
...  

Bi1.7-Pb0.3-Sr2-Ca2-Cu3-Ox superconducting samples were prepared at 855°C, 862 C, 870 C, and 882 C sintering temperatures respectively. All samples were sintered for 120 hours. The samples were then quenched in liquid nitrogen. The electrical resistivity measurements showed that the samples sintered at 870° C had the best Tc. For these samples the Tc onset was around 120 K and the zero resistance was obtained at 108 K. X-ray diffraction studies showed that the samples were multiphased.


Sign in / Sign up

Export Citation Format

Share Document