Borehole Resistivity | US EPA
Electrical properties can vary with variations in factors such as temperature, saturation, water content, porosity, clay minerals, and/or fluid conductivity. Thus, resistivity logs can aid the interpretation of resistivity-related material properties and are most commonly used to estimate salinity and delineate lithology for hydrogeological ...
Well log analysis for reservoir characterization
Well log is one of the most fundamental methods for reservoir characterization, in oil and gas industry, it is an essential method for geoscientist to acquire more knowledge about the condition below the surface by using physical properties of …
Improving the Total Organic Carbon Estimation of the
the Eagle Ford Shale with Density Logs by Considering the Effect of Pyrite ... porosity log with resistivity log data and ... large amounts of heavy minerals, ...
Lithology and rock type determination
Various electrically conductive minerals impact the resistivity logs, like: Clay minerals; Pyrite; Clay-mineral properties. Clay minerals are, in general, composed of layered alumina and silicate molecules, and the properties of the various clay minerals vary widely. Some swell when wet, are plastic, and can easily deform, while others are hard ...
Analysis of Shaly Sands Using Neutron and Density Logs
Ma's model used neutron and density logs to analyze shaly sand formations and generated a simulated resistivity curve to be compared to the actual resistivity recorded in a well. The model removes the shale effect from the resisti vity logs and gives a more representative water saturation index in oil bearing zones.
Resistivity log
Resistivity logs are electrical well logs that record the resistivity of a formation. Resistivity is usually recorded in ohm meters (Ωm) and is displayed on track 4 of a well log. Three depths of resistivity can be logged (shallow, medium, and deep) that record the resistivity of the formation with increasing distance away from the borehole.
Resistivity
Even in small quantities, they can significantly affect the bulk resistivity of geologic materials. Most metallic ore minerals are electronic semiconductors. Their resistivities are lower than those of metals and highly variable because the inclusion of impurity ions into a particular metallic mineral has a big effect on the resistivity.
Dakota--Petrophysics 6--Resistivity Logs
In a sandstone-shale sequence, resistivity variation is controlled by a variety of phenomena, including cation-exchange mechanisms by clay minerals within the shalier zones, conduction by metallic minerals, and the dissolved ions within the pore water of …
Toward the Scientific Interpretation of Geophysical Well Logs…
Geophysical well log data are widely used in the field of structural geology, sedimentary geology and petroleum geology. Gaps and misunderstandings are still existing in the scientific interpretation of geophysical well logs. Logging environments and log curves need correction and standardization before interpretation, additionally, there are …
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From the results of research that has been conducted on the effect of shale minerals on sandstone resistivity, several conclusions can be obtained. among others: 1. The presence of shale in the rock will cause the resistivity to be low. The shale content has an effect on the decline in resistivity prices. 2.
Minerals | Free Full-Text | Improving the Total Organic Carbon
Pyrite is a common mineral with a higher density than most other minerals in the Eagle Ford Shale formation. Hence, if pyrite is not considered in the total organic carbon (TOC) estimation, based on density logs, it may lead to errors. In order to improve the accuracy of the TOC estimation, we propose an updated TOC estimation method …
Modeling The Effects Of Glauconite On Some Openhole Logs …
The effect of glauconites on resistivity can be appreciable since they can have significant cation exchange capacity (CEC). This work evaluated potential problems associated with interpreting logs from glauconite-rich formations and proposes log interpretation procedures to determine porosity and water saturation in these lithologies.
Water saturation determination
Resistivity logs are run in all wells, ... more-complicated electrical models were developed to account for the effects of the geometries of conductive clay minerals and shale on rock resistivity.
CO2-Containing Reservoir Evaluation Based on the Joint …
In this study, a joint inversion evaluation method was used to evaluate CO 2-containing reservoirs, and the joint inversion of neutron, density, GR, and resistivity logs was performed to evaluate the CO 2 content and other parameters of the reservoirs in the Yinggehai Basin. We modified the joint inversion model based on the characteristics of …
Effects of Bentonite Content on Electrical Resistivity of Soils
Clay minerals were artificially mixed with fine sands at an increment of 20% to determine the effect of mineral contents on resistivity. A total of 10 artificial soils with different bentonite ...
Effects of Clay Minerals and Pore-Water Conductivity on
The calculation of water saturation from resistivity logs relies on the saturation exponent of Archie's equation. The accurate determinations of the water saturation in clay-bearing sand reservoirs have been found to be very complicated due to the additional conductivity of the clay minerals, which tend to increase with the increase …
Geophysical Well Logging | SpringerLink
The resistivity log is used to determine the fraction of pore space that is occupied by water, called the water saturation, S w (the fraction that is hydrocarbons S hc = 1 – S w). Because the rock's matrix or grains are commonly nonconductive, the ability of the rock to transmit a current is almost entirely a function of water in pores.
Effect of Mineralogy on NMR, Sonic, and Resistivity: A …
Effect of Mineralogy on NMR, Sonic, and Resistivity: A Case Study of ... High detrital clay content identified by high Thorium content in spectral gamma ray logs masks the resistivity response due to an increase in neutron porosity (NPHI) and decrease in resistivity. ... siliceous shale, and diatomites. Some of the primary minerals that make …
Resistivity Logs | Basic well log analysis
By far the most important use of resistivity logs is the determination of hydrocarbon-bearing versus water-bearing zones. Because the rock's matrix or grains are …
(PDF) THE INFLUENCE OF PYRITE ON ROCK ELECTRICAL
Pyrite is conductive, suppressing the true resistivity measurements of the logging tools. If not properly corrected, this leads to overestimation of the water saturation in the reservoir.
Chapter 20.PDF
THE EFFECT OF CLAY ON POROSITY AND RESISTIVITY LOGS. 20.1 Introduction. The presence of clay minerals or shale in porous formations presents problems from the …
Microsoft Word
HOW COMMON MINERALS CAN MISLEADINGLY INFLUENCE LOG RESPONSES ... 2011 Stolper Geologic, Inc.
Resistivity log
One of the most useful applications of resistivity logs is identifying hydrocarbon saturation vs. water saturation in a formation. Also, by distinguishing …
(PDF) Relationship between Electrical Resistivity and Physical
Recently, the use of electrical prospecting with high spatial density of electrodes has increased and is being applied to underground investigations for mineral exploration and other civil ...
Evaluation of Rock Properties from Logs Affected by …
In this paper, we discuss how we corrected the logs for invasion effects through an iterative workflow between petrophysics and rock physics modeling. This resulted in a set of high quality reservoir and
Application of geophysical well logs in solving
Geophysical well logs are widely used in geological fields, however, there are considerable incompatibilities existing in solving geological issues us…
Electrical resistivity and chemical properties of kerogen
Our outcomes can potentially improve interpretation of electrical resistivity logs in organic-rich mudrocks, such as enhancing well-log-based assessment of in situ hydrocarbon saturation. ... H. Chen, and Z. Heidari, 2014, Quantifying the effect of kerogen on resistivity measurement in organic-rich mudrocks: Petrophysics ... Effects of minerals ...
Well log interpretation
All water saturation determinations from resistivity logs in clean (nonshaly) formations with homogeneous intergranular porosity are based on Archie's water saturation equation, or variations thereof. ... (Points 2, 9, and 10) are probably the result of either deep invasion or adjacent-bed effect in which deep resistivity is greater than R t.
Methods for estimating petrophysical parameters from well logs …
Abstract. Estimating petrophysical parameters from well logs plays a significant role in the exploration and development of tight oil resources, but faces
Basic Relationships of Well Log Interpretation
resistivity logs. This is due in part to their recent ... effects on the logs were observed in shaly or clay-con-taining sandstones. With the advent of multiple poros- ... of more detailed interpretive methods, it has become possible to estimate the primary solid constituents, normally as a mineral pair or triad. total volumeof rock volumeof ...