What methods are there for logfacies (electrofacies) determination?
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To characterize and identify electrofacies groups, we perform a multivariate analysis of the well-log data using PCA, MCA, and discriminant analysis.8,9,12-16 Such electrofacies classification does not require any artificial subdivision of the data population: it follows naturally based on the unique characteristics of welllog measurements reflecting minerals and lithofacies within the logged interval.
897139
geology, geography, engineering, hydrology, chemistry, palentology
1109963
Spherically focused logs are used to directly measure resistivity within a borehole. Spherical focus is also sometimes used with induction logs as well. SFL (Schlumberger)  is designed to be  used for investigation of the flushed zone or both the flushed and  invaded zone, which is the zone around a borehole that is filled with drilling mud. Since the resistivity of the drill mud is known, formation porosities and saturations can be estimated. The electrodes are mounted on pads that are pressed against the borehole wall, and the depth of investigation is only a few inches. The electrode pads emit a current and measure the resistivity. Thick mudcake in the borehole or a rough borehole wall will affect the reading.  \n\nHere is a schematic diagram of a SFL:\nhttp://www.spwla.org/library_info/glossary/reference/glosss/glosss.htm\n\nHere is another description of SFL resistivity.\n(I quote from http://www-odp.tamu.edu/publications/201_IR/chap_05/c5_7.htm )\n\n "The SFLU is a shallow-penetration galvanic device that measures the current necessary to maintain a constant voltage drop across a fixed interval of the formation. It is a direct measurement of resistivity, with a higher resolution than the induction devices but more sensitive to borehole conditions. Sand grains and hydrocarbons are electrical insulators, whereas ionic solutions and clays are good conductors. Electrical resistivity can therefore be used to evaluate fluid salinity, water saturation, porosity, and the characteristics of the pore structure."\n\n\nHere is a Halliburton description of a Micro SFL tool:\nhttp://www.halliburton.com/public/lp/contents/Books_and_Catalogs/web/Logging_&_Perforating_Products_&_Services_Catalog/Chapter12.pdf\n\nSome basic definitions of log tools:\nhttp://www.sjgs.com/logs.html
850328
First off sedimentary rock is necessary for oil and gas formation. A known anticline (hill shaped folding),  is necessary for the entrapment of the oil and gas.  The rock needs to be old enough for the oil and gas forming to occur. Your not going to find alot of oil in gas in quaternary or tertiary rock. I live in an area known as the Bradford oil field and the rock age here is mainly Devonian. \n\nMany paleoentologists are being employed these days in this field of oil exploration. A core or test sample is drilled and brought to the surface and from the fossils found a determination can be made if this is a possible site for oil. (2 cent version)
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Take a peice of string, tie a rock on the end.\nUnreel the string down the hole until the string goes slack.\nTie a knot in the string at the top of the hole.\nBring out the string, lay out on the ground, and measure.
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There was a time when all good civil engineers had to know how to operate a slide rule (which used sliding logarithmic scales to add logs (multiply) and subtract logs (divide), etc.  Civil engineers must be familiar with the fundamentals of all engineering disciplines and would know that the pH of acids and alkalies are logarithmic, the dB of sound decibels are logarithmic and the rickter scale used to measure earthquakes (and to design structures to withstand them) is logarithmic.  They must know the significance (and use) of logs to base 10 and natural logs to base e to work with advanced formulas and calculations.
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for starters\n\n0) Digging/going down mines, though that doesn't get very far!!!\n\n1) Seismic waves from earthquakes - they spread through the Earth and are picked up by seismographs all over the world - there are 2 types that travel through, p-waves and s-waves, but the 2 types are not picked up all over; s-waves don't travel through liquids.\n\n2) Lab investigations of the materials that are likely to be within the earth, under appropriately high temperatures and pressures\n\nPutting the results of these together has built up a model of a thin crust, mantle, liquid outer core and solid inner core.\n\nYou may want to search for terms like:\nseismology, body wave, shadow zone, p-wave (promary wave), s-wave (secondary wave)
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Decomposed rock and organic matter.
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Basically it's a complex mathematical process to process the vibration response data obtained from siesmic excitation of an oil field to characterize the field in terms of parameters understandable to the analyst (e.g., porosity and impedance). See the ref.
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1 Deposition\n2 Compaction\n3 Cementation
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Structures resembling remarkably preserved bacterial and cyanobacterial microfossils from ~3,465-million-year-old Apex cherts of the Warrawoona Group in Western Australia currently provide the oldest morphological evidence for life on Earth and have been taken to support an early beginning for oxygen-producing photosynthesis. Eleven species of filamentous prokaryote, distinguished by shape and geometry, have been put forward as meeting the criteria required of authentic Archaean microfossils, and contrast with other microfossils dismissed as either unreliable or unreproducible. These structures are nearly a billion years older than putative cyanobacterial biomarkers, genomic arguments for cyanobacteria, and oxygenic atmosphere and any comparable diverse suite of microfossils. Here we report new research on the type and re-collected material, involving mapping, optical and electron microscopy, digital image analysis, micro-Raman spectroscopy and other geochemical techniques. We reinterpret the purported microfossil-like structure as secondary artefacts formed from amorphous graphite within multiple generations of metalliferous hydrothermal vein chert and volcanic glass. Although there is no support for primary biological morphology, a Fischer-Tropsch-type synthesis of carbon compounds and carbon isotopic fractionation is inferred for one of the oldest known hydrothermal systems on Earth.
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PCBs are normally done by either GC-MS or LC-MS.  I have never heard of an electrochemical method.
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I would recommend the following:\n\n1.  "Applied GeoStatistics" \n        by Edward H. Isaaks and R.M.Srivastava\n2.  "Statistical and Data Analysis in Geology" \n        by J.C.Davis\n\nIf you are asking about use in specific industry then do let me know. I would be able to guide you.\n\nAlso I would suggest you check this website\nhttp://www.statios.com/Training/\n\nyou can download the pdfs which are good source of Information.
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Try Wikipedia.org...Qualitative inorganic analysis. I was just there.
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Firstly a geophysical survey should be undertaken to allow mapping of the sub surface structures and determine if there is a potential for a accumulation of oil or even gas in a reservoir. I have to admit that im not an expert on gravitational or magnetic data but I work with radioactive and electrical resistivity methods whilst drilling. Best thing to do is email me exactly what your require to know about resistivity and radioactive survey methods and I can whip up some easy examples for you and also explain it to you.
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Do a web search for the parameters.  We would need much more information from you on sample types, volumes, etc and you capabilities, instrumentation available, etc.  All of these are factors in deciding a method.
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The Richter scale measuring their intensity is a logarithmic scale.\n\nhttp://en.wikipedia.org/wiki/Richter_scale