Porosity from sonic log
WebJul 28, 2016 · The sonic log may be used to determine porosity by charting the speed of a compressional sound wave as it travels through the formation. Interval transit time (∆t), measured in microseconds per meter [foot] and often referred to as slowness, is the reciprocal of velocity. Lithology and porosity affect ∆t. WebJun 24, 2015 · The neutron-porosity log first appeared in 1940. It consisted of an isotopic source, most often plutonium-beryllium, and a single detector. Many variations were produced exploiting both thermal and epithermal neutrons. In most of the early tools, neutrons were not detected directly.
Porosity from sonic log
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WebJul 28, 2016 · The sonic log may be used to determine porosity by charting the speed of a compressional sound wave as it travels through the formation. Interval transit time (∆t), … http://petrocenter.com/fe/Acoustic%20%20Properties%20of%20Rock.pdf
WebHowever when sonic porosities of carbonate with vugs or fractures are calculated by W yllie’s formula, porosity values come very low. This happens because sonic logs only record matrix... WebTHIS PAGE Pore Volume Porosity From Sonic Log Porosity From Density Log. The second calculation step in a log analysis is to find shale corrected porosity. Pore volume is the space in a rock filled with oil, gas, or water. Total porosity includes the bound water in the shale and is called PHIt.
WebDensity Log. The density log usually labelled ‘RHOB’ measures the density of the borehole and the rocks penetrated by the drill bit. The unit for density is gram per cubic centimetre. The logs (sonic and density) measurements are usually made every 6 in. down hole, but must be aligned to be ‘on-depth’ with each other. WebJan 1, 1979 · In clean sandstone of 20 percent porosity the sonic log will give a reading of about 80 (msec/ft), in limestone and dolomite about 75 (msec/ft). The simultaneous compensated neutron formation density tool is a combination of three logs, a compensated neutron porosity (%), a bulk density (g/cc) and a gammaray log.
WebThe most critical parameter to calculate sonic porosity is perhaps the matrix compressional travel time Δt matrix . It is not only usually unknown, but in many reservoirs is not a constant parameter, but a curve that depends on the variable column lithology, its matrix fabric, and rock's stiffness.
WebScientists have developed an assortment of porosity logging tools based on various physical principles. Today, although sonic porosity logs are still used, the two predominant porosity measurements are density porosity and neutron porosity. Porosity Measurements Density tools emit medium-energy gamma rays into a borehole wall (above right). top shortageWeb1. n. [Formation Evaluation] An indicator of the porosity that does not contribute to a sonic measurement of interval transit time.The transit time is little affected by vugs, fractures and other irregular events because the sonic wave finds a faster path around them. Spherical pores such as oomolds also have less effect on traveltime than oblate pores. . Thus, when … top shortcutsWebIn this method, it is assumed that the sonic log provides matrix porosity. The difference between neutron (or density or the combination neutron-density) and sonic porosity is … top shorted stocks asxWebThe sonic log will underestimate porosity in uncompacted formations. In general, the sonic log is unsuitable for these formations and should not be used to determine porosities. However, if only the sonic log has been run, then it is possible to correct for this underestimation, an empirical correction factor, C p, is used, as follows: ∅= top shorted stocks 2021WebThis means that a sonic log can be used to calculate the porosity, confining stress, or pore pressure of a formation if the seismic velocity of the rock matrix, , and pore fluid, , are … top shortcuts in excelWebIn this research, two empirical correlations have been introduced to calculate the dynamic Biot coefficients of low-porosity and high-porosity sandstone samples from two open pit mines located in South-West Poland. The experiments were conducted using an acoustic velocity measurement apparatus. Under the undrained condition, firstly, the confining … top shortcut keys used in pcWebMar 13, 2024 · Porosity is the void or space inside the rock, they are very useful to store fluids such as oil, gas, and water, they are also able to transmit those fluids to a place with … top shorted stocks 2022