Electrical Conductivities in Oil-Bearing Shaly Sands

1968 ◽  
Vol 8 (02) ◽  
pp. 107-122 ◽  
Author(s):  
M.H. Waxman ◽  
L.J.M. Smits
Keyword(s):  
Electrical Resistivity ◽  
Cation Exchange ◽  
Pore Volume ◽  
Cation Exchange Capacity ◽  
Water Saturation ◽  
Exchange Capacity ◽  
Water Conductivity ◽  
Wide Range ◽  
Shaly Sand ◽  
Log Interpretation

ABSTRACT A simple physical model was used to develop an equation that relates the electrical conductivity of a water-saturated shaly sand to the water conductivity and the cation- exchange capacity per unit pore volume of the rock. This equation fits both the experimental data of Hill and Milburn and data obtained recently on selected shaly sands with a wide range of cation-exchange capacities. This model was extended to cases where both oil and water are present in the shaly sand. This results in an additional expression, relating the resistivity ratio to water saturation, water conductivity and cation-exchange capacity per unit pore volume. The effect of shale content on the resistivity index- water saturation function is demonstrated by several numerical examples. INTRODUCTION A principal aim of well logging is to provide quantitative information concerning porosity and oil saturation of the permeable formations penetrated by the borehole. For clean sands, the relationships between measured physical quantities and porosity or saturation are well known. However, the presence of clay minerals greatly complicates log interpretation, particularly the electrical resistivity and SP logs, and considerably affects evaluation of hydrocarbon-bearing formations. The conductance and electrochemical behavior of shaly sands and their relation to log interpretation have been studied by many workers. Wyllie and Lynch reviewed this work in some detail. Virtually all laboratory measurements of electrical resistivity and electrochemical potential of shaly sands published to date are the work of Hill and Milburn.

scholarly journals Exchange Characteristics of Lead, Zinc, and Cadmium in Selected Tropical Soils

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tope O. Bolanle-Ojo ◽  
Abiodun D. Joshua ◽  
Opeyemi A. Agbo-Adediran ◽  
Ademola S. Ogundana ◽  
Kayode A. Aiyeyika ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Tropical Soils ◽  
Exchange Capacity ◽  
Exchange Reactions ◽  
Soil System ◽  
Soil Systems ◽  
Wide Range ◽  
Lead Zinc ◽  
High Base

Conducting binary-exchange experiments is a common way to identify cationic preferences of exchangeable phases in soil. Cation exchange reactions and thermodynamic studies of Pb2+/Ca2+, Cd2+/Ca2+, and Zn2+/Ca2+were carried out on three surface (0–30 cm) soil samples from Adamawa and Niger States in Nigeria using the batch method. The physicochemical properties studies of the soils showed that the soils have neutral pH values, low organic matter contents, low exchangeable bases, and low effective cation exchange capacity (mean: 3.27 cmolc kg−1) but relatively high base saturations (≫50%) with an average of 75.9%. The amount of cations sorbed in all cases did not exceed the soils cation exchange capacity (CEC) values, except for Pb sorption in the entisol-AD2 and alfisol-AD3, where the CEC were exceeded at high Pb loading. Calculated selectivity coefficients were greater than unity across a wide range of exchanger phase composition, indicating a preference for these cations over Ca2+. TheKeqvalues obtained in this work were all positive, indicating that the exchange reactions were favoured and equally feasible. These values indicated that the Ca/soil systems were readily converted to the cation/soil system. The thermodynamic parameters calculated for the exchange of these cations were generally low, but values suggest spontaneous reactions.

scholarly journals ALTERATIONS IN ELECTRICAL RESISTIVITY OF SANDY SOIL IN CONTROLLED EXPERIMENT BY INFLITRATION OF STILLAGE

2019 ◽  
Vol 38 (1) ◽  
pp. 147-156
Author(s):  
Cesar Augusto MOREIRA ◽  
José Ricardo Melges BORTOLIN ◽  
Walter MALAGUTTI FILHO ◽  
João Carlos DOURADO
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Cation Exchange ◽  
Sandy Soil ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Absorption Capacity ◽  
Geophysical Method ◽  
Economic Activities ◽  
Low Resistivity

The sugar and alcohol sector represents one of the most profitable economic activities in Brazil, being ethanol one of the main products. Among the residues related to the production of ethanol, it is highlighted the stillage, a liquid substance generated in the approximate proportion of 13 liters for each liter of ethanol produced. This paper presents the results of a stillage infiltration experiment, in various proportions, through trenches in sandy soil, with the aim to evaluate possible alterations in electrical properties in the geological materials, in individual experiments, with 60L, 300L and 900L of effluent. The initial proportion was defined based on a standard stipulated by the Environmental Agency of the State of São Paulo, which considers the cation exchange capacity of the soil, while the other quantities were defined from ratios of 4 and 15 times higher than those defined by legislation. The experiment was monitored by means of electrical resistivity measurements by indirect means through the geophysical method of Electroresistivity. The data indicate the absence of alterations in electrical properties in the soil below the point of infiltration in the experiment for 60L of stillage. The data for infiltrations with 300L and 900L revealed a zone of low resistivity below the infiltration point, basically limited to the 1m layer of sandy soil and with tendency for lateral flow supported by the soil/rock interface. The results demonstrate that the infiltration of inorganic solutions, in a proportion inferior to the cation exchange capacity of the soil, does not perceptibly alter its electrical properties in studies using the geophysical method of Electro resistivity, whereas proportions that exceed natural absorption capacity are characterized by the geoelectric signature of low resistivity.

scholarly journals Cation-Exchange Capacity Distribution within Hydrothermal Systems and Its Relation to the Alteration Mineralogy and Electrical Resistivity

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5730
Author(s):  
Tobias Björn Weisenberger ◽  
Heimir Ingimarsson ◽  
Gylfi Páll Hersir ◽  
Ólafur G. Flóvenz
Keyword(s):  
Electrical Resistivity ◽  
Cation Exchange ◽  
Clay Mineral ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Pore Fluid ◽  
Alteration Zones ◽  
Resistivity Logs ◽  
Mineral Alteration ◽  
Fluid Conductivity

Cation-exchange capacity (CEC) measurements are widely used to quantify the smectite content in altered rocks. Within this study, we measure the CEC of drill cuttings in four wells from three different high-temperature geothermal areas in Iceland. The CEC measurements in all four wells show similar depth/temperature related pattern, and when comparing the CEC with electrical resistivity logs, we could show that the low resistivity zone coincides with CEC values >5 meq/100 g. The measurements show, in general, an exponential decrease of the CEC with increasing depth. At the facies boundary between the mixed-layer clay and epidote-chlorite zone, the CEC reaches a steady state at about 5 meq/100 g and below that it only decreases slightly within a linear trend with increasing depth. The facies boundary overlaps with the transition where the electrical resistivity logs show an increase in resistivity. It is shown that the measured CEC can be related to the clay mineral alteration within the geothermal system and the CEC reflects the smectite component within the interstratified chlorite/smectite minerals for similar alteration degree. Furthermore, CEC was measured in seven core samples from different alteration zones that had previously been studied in detail with respect to petrophysical and conductivity properties. The results show a clear correlation between CEC and the iso-electrical point, which describes the value of the pore fluid conductivity where transition from surface conductivity to pore fluid conductivity occurs. The presented study shows that the CEC within hydrothermal altered basaltic systems mimics the expandable clay mineral alteration zones and coincides with electrical logs. The presented method can, therefore, be an easy tool to quantify alteration facies within geothermal exploration and drilling projects.

Changes in effective cation exchange capacity and exchangeable aluminum with soil pH in lime-amended field soils

Soil Research ◽  
1992 ◽  
Vol 30 (2) ◽  
pp. 177 ◽  
Author(s):  
Z Hochman ◽  
DC Edmeades ◽  
E White
Keyword(s):  
Cation Exchange ◽  
Linear Relationship ◽  
Soil Ph ◽  
Cation Exchange Capacity ◽  
Ph Value ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Acidic Soils ◽  
Hydrogen Ion Concentration ◽  
Wide Range

Eleven acidic soils from northern N.S.W., having a wide range of values for ECEC, A1 and soil organic carbon (%C), were treated in the field with five rates of lime. The relationships between soil pH and the effective cation exchange capacity (ECEC), and between pH and exchangeable aluminium (Al), were investigated for the top 10 cm of these soils. Increases in the total exchangeable cations (TEC) calculated as ECEC-Al, were shown to be madelup almost entirely by increases in exchangeable calcium. There were no consistent changes in the amount of exchangeable magnesium, potassium or sodium due to liming these acidic soils. Formulae used to predict changes in A1 and ECEC with pH in the 'Lime-it' model were tested and modified on the 11 soils from northern N.S.W. A strong linear relationship was observed in each soil between Al and pH (transformed to hydrogen ion concentration x 103). The slope of this relationship (SALs) can be predicted from the pH and A1 values of unlimed soils. Strong linear relationships were also observed between pH and TEC, for each of the 11 soils. The SL, (the slope of the linear relationship TEC/pH for any soil 's') was shown by multiple regression analysis to be a function of TECi/pHi (where TECi is the sum of exchangeable cations of unlimed soil 's'; and pHi is the pH value of unlimed soil 's'), %C of the unlimed soil, and SALs. By using the measured values of pH, ECEC, Al and %C of unlimed soils, the values of Al, and TEB can be predicted for any pH value that may be measured (or predicted) after liming. The predictive relationships developed on N.S.W. soils were tested against independent data from New Zealand. The results confirmed the Al/pH predictions (R2 = 0.955), while the TEC/pH predictions were less well matched (R2= 0.62) possibly due to unusual clay mineralogy or organic matter fractions of 3 of the 18 soils tested.

Field amelioration of acidic soils in south-east Queensland. I. Effect of amendments on soil properties

1998 ◽  
Vol 49 (4) ◽  
pp. 627 ◽  
Author(s):  
R. L. Aitken ◽  
P. W. Moody ◽  
T. Dickson
Keyword(s):  
Organic Carbon ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Buffer Capacity ◽  
Ph Value ◽  
Field Trials ◽  
Exchange Capacity ◽  
Wide Range ◽  
Initial Ph ◽  
Ph Buffer

Replicated field trials with rates of lime ranging up to 8 t/ha were conducted at each of 27 sites in south-east Queensland. At 16 of these sites, single rates (2 t/ha) of gypsum or phosphogypsum were also applied. Soil samples (0-10 cm) were collected from each plot and analysed for pH in both water (pHw) and 0·01 M CaCl2 (pHCa), for electrical conductivity, exchangeable cations, and extractable Al and Mn. Gypsum application resulted in either a general trend for, or significant (P < 0·05), reductions in pHw but had no significant effect on pHCa. The relationship between rate of applied lime and soil pH at each site permitted the calculation of pH buffer capacity for a wide range of soil types and properties. The pH increase per t applied lime ranged from 0·14 to 0·82 and from 0·16 to 0·63 for pH measured in water and 0·01 M CaCl2, respectively, reflecting the range in pH buffer capacity which was significantly correlated with organic carbon. Multiple regression indicated that organic carbon and clay significantly contributed to the variation in pH buffer capacity but only around 40% of the variation could be accounted for. The pH values at which Al saturation was reduced to 10% ranged from 4·82 to 6·02 (pHw) and from 4·26 to 4·93 (pHCa) and indicated that if neutralising exchangeable Al is the basis for liming, then no single target pH value will be appropriate for all soils. However, the target pH at which Al saturation would be reduced to 10% could be predicted from the initial pH and initial Al saturation. The effective cation exchange capacity (ECEC) was increased by liming at all sites and the additional exchange capacity was occupied by Ca. This increased Ca saturation was not necessarily at the expense of exchangeable K and Mg, which were significantly (P < 0·05) reduced at only a few sites. The increase in ECEC for a unit increase in pH ranged from 0·5 to 9 cmol(+)/kg and at some sites represented a doubling of the soil"s cation exchange capacity.

The Influence of Mineralogy and Cation Exchange Capacity toward Electrical Resistivity Value

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Mohammad Izzat Shaffiq Azmi ◽  
◽  
Ahmad Khairul Abd Malik ◽  
Aziman Madun ◽  
Faizal Pakir ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Degree Of Saturation ◽  
Acetate Solution ◽  
Soil Thickness ◽  
Resistivity Tomography ◽  
Water Resistivity ◽  
Lower Resistivity

Electrical Resistivity Tomography (ERT) is a method used for subsurface profiling in soil to characterize soil thickness, fracture zones, soil saturation, salinity and groundwater based on the electrical resistivity value (ERV). There are multiple factors that influence the electrical resistivity value, such as the porosity, degree of saturation, mineralogy, density, cation exchange capacity (CEC), and water resistivity. For this study, the effect of CEC towards resistivity value is studied via controlling the mineralogy factor, saturation, porosity and water resistivity. Thus, via understanding the CEC factor able to relate the resistivity and mineralogy of soil. This study is using a few common minerals in soil and rock, such as kaolinite, montmorillonite, illite, quartz, mica, and feldspar. The particle sizes of all tested minerals were passing 0.063mm sieve. The basic index properties of minerals such as particle size distribution, specific gravity, and Atterberg limit were tested. The instruments of Terrameter LS2 and resistivity box were used to determine the resistivity value of minerals. The Atomic Absorption Spectroscopy (AAS) machine was used to analyze the CEC of minerals via dilute with the ammonium acetate solution. The porosity and degree of saturation of minerals mixed with distill water were controlled between the range of 0.5 to 0.6 and 20% to 100%. The CEC of each mineral has different value, where the lowest and the highest minerals CEC in this study were Kaolinite and Montmorillonite at 1 and 70, respectively. The electrical resistivity values decrease with the increasing of CEC value and degree of saturation. The mineral that has higher CEC indicates lower resistivity value. Meanwhile, via increasing the degree of saturation of minerals were decrease its resistivity values.

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