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Swell Filter
The term swell filter in high resolution seismics (reflection seismology) or sub bottom profiling refers to the static correction that restores the coherence of a high resolution seismic profile. The coherence of the image got lost because of the relative movement (a function of the wavelength of the signal and the Swell (wavelength), swell) of the source and receiver during the recording. In normal seismic recordings, the term swell filter refers to filtering the acoustic noise, created by waves, out of the seismic recording. High resolution seismics and subbottom profiling Very high resolution seismics (reflection seismology) is applied to make detailed acoustic profiles of a sea floor or lake floor. Acoustic sources used include: air gun, water gun, sleeve gun, sparker and boomer. The frequency used in this field ranges from 100 Hz to 10.000 Hz. Subbottom profiling is a technique used in acoustical oceanography. Sonars or echo sounder are typical sources for very high resol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection Seismology
Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite or Tovex blast, a specialized air gun or a seismic vibrator. Reflection seismology is similar to sonar and echolocation. This article is about surface seismic surveys; for vertical seismic profiles, see VSP. History Reflections and refractions of seismic waves at geologic interfaces within the Earth were first observed on recordings of earthquake-generated seismic waves. The basic model of the Earth's deep interior is based on observations of earthquake-generated seismic waves transmitted through the Earth's interior (e.g., Mohorovičić, 1910). The use of human-generated seismic waves to map in detail the geology of the upper few kilometers of the Earth's crust followed shortly thereafter and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Depth Conversion
Depth conversion is an important step of the seismic reflection method, which converts the acoustic wave travel time to actual depth, based on the acoustic velocity of subsurface medium (sediments, rocks, water). Depth conversion integrates several sources of information about the subsurface velocity to derive a three-dimensional velocity model: * "Well tops", i.e., depth of geological layers encountered in oil and gas wells * Velocity measurements made in oil and gas wells * Empirical knowledge about the velocities of the rocks in the area investigated * Root Mean Square (RMS) stacking velocities which are derived from the processing of the seismic reflection data The conversion permits the production of depth and thickness maps that depict subsurface layers that are based on reflection data. These maps are crucial in hydrocarbon exploration because they permit the volumetric evaluation of gas or oil in place. In the example subsurface map presented below, depth increases from red ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petroleum Geology
Petroleum geology is the study of origin, occurrence, movement, accumulation, and exploration of hydrocarbon fuels. It refers to the specific set of geological disciplines that are applied to the search for hydrocarbons (oil exploration). Sedimentary basin analysis Petroleum geology is principally concerned with the evaluation of seven key elements in sedimentary basins: * Source * Reservoir * Seal * Trap * Timing * Maturation * Migration In general, all these elements must be assessed via a limited 'window' into the subsurface world, provided by one (or possibly more) exploration wells. These wells present only a 1-dimensional segment through the Earth, and the skill of inferring 3-dimensional characteristics from them is one of the most fundamental in petroleum geology. Recently, the availability of inexpensive, high quality 3D seismic data (from reflection seismology) and data from various electromagnetic geophysical techniques (such as magnetotellurics) has greatly aid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismology Measurement
Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. It also includes studies of earthquake environmental effects such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, glacial, fluvial, oceanic, atmospheric, and artificial processes such as explosions. A related field that uses geology to infer information regarding past earthquakes is paleoseismology. A recording of Earth motion as a function of time is called a seismogram. A seismologist is a scientist who does research in seismology. History Scholarly interest in earthquakes can be traced back to antiquity. Early speculations on the natural causes of earthquakes were included in the writings of Thales of Miletus (c. 585 BCE), Anaximenes of Miletus (c. 550 BCE), Aristotle (c. 340 BCE), and Zha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swell (ocean)
A swell, also sometimes referred to as ground swell, in the context of an ocean, sea or lake, is a series of mechanical waves that propagate along the interface between water and air under the predominating influence of gravity, and thus are often referred to as surface gravity waves. These surface gravity waves have their origin as wind waves, but are the consequence of dispersion of wind waves from distant weather systems, where wind blows for a duration of time over a fetch of water, and these waves move out from the source area at speeds that are a function of wave period and length. More generally, a swell consists of wind-generated waves that are not greatly affected by the local wind at that time. Swell waves often have a relatively long wavelength, as short wavelength waves carry less energy and dissipate faster, but this varies due to the size, strength, and duration of the weather system responsible for the swell and the size of the water body, and varies from event ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Refraction
Seismic refraction is a geophysical principle governed by Snell's Law of refraction. The seismic refraction method utilizes the refraction of seismic waves by rock or soil layers to characterize the subsurface geologic conditions and geologic structure. Seismic refraction is exploited in engineering geology, geotechnical engineering and exploration geophysics. Seismic refraction traverses (seismic lines) are performed using an array of seismographs or geophones and an energy source. The methods depend on the fact that seismic waves have differing velocities in different types of soil or rock. The waves are refracted when they cross the boundary between different types (or conditions) of soil or rock. The methods enable the general soil types and the approximate depth to strata boundaries, or to bedrock, to be determined. P-wave refraction P-wave refraction evaluates the compression wave generated by the seismic source located at a known distance from the array. The wave is gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seismic Waves
A seismic wave is a wave of acoustic energy that travels through the Earth. It can result from an earthquake, volcanic eruption, magma movement, a large landslide, and a large man-made explosion that produces low-frequency acoustic energy. Seismic waves are studied by seismologists, who record the waves using seismometers, hydrophones (in water), or accelerometers. Seismic waves are distinguished from seismic noise (ambient vibration), which is persistent low-amplitude vibration arising from a variety of natural and anthropogenic sources. The propagation velocity of a seismic wave depends on density and elasticity of the medium as well as the type of wave. Velocity tends to increase with depth through Earth's crust and mantle, but drops sharply going from the mantle to Earth's outer core. Earthquakes create distinct types of waves with different velocities. When recorded by a seismic observatory, their different travel times help scientists locate the quake's hypocen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SEG Y
SEG or seg may refer to: Organisations * Society of Economic Geologists * Society of Exploration Geophysicists * Semaphore Entertainment Group, co-founder of the Ultimate Fighting Championship * Southern Examining Group, a former English examining body * Special Escort Group (Metropolitan Police), England * Special Escort Group (Ministry of Defence Police) (SEG (MDP)), UK Other uses * Smart Export Guarantee, a scheme which rewards export of electricity by small-scale low-carbon generators in the United Kingdom * ''Supplementum Epigraphicum Graecum'', new studies of ancient Greek inscriptions * Penn Valley Airport IATA code * ''Ség.'', taxonomic author abbreviation of Jean-François Séguier (1703–1784), French botanist See also * Segment (other) Segment or segmentation may refer to: Biology * Segmentation (biology), the division of body plans into a series of repetitive segments ** Segmentation in the human nervous system * Internodal segment, the portion of a n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swell (wavelength)
Swell may refer to: In nature *Swell, another name for a geographic hillock * Swell (ocean), a formation of long wavelength ocean surface waves *Swell (geology), a large domed area Places * Swell, Somerset, a hamlet in the Somerset parish of Fivehead *Swell, Gloucestershire, England Music * Expression pedal, a control found on many organs and synthesizers, also called a swell box or swell pedal *Swell (band), an indie rock band from San Francisco *''Swell'', album by Psyched Up Janis *''Swell'', album by Tiny Moving Parts * Swell Maps, an experimental English rock group of the 1970s People *George Gilbert Swell (1923–1999), Indian academic and politician * Steve Swell (born 1954), American musician, composer and educator * Steven Wells (1960–2009), punk poet and journalist known as Swells Other uses *Swell (bookbinding), a term in bookbinding *Swell (gum), a brand of chewing gum produced by Philadelphia Gum *Swell (exhibit), an art exhibition *Swell, another word for a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deconvolution
In mathematics, deconvolution is the operation inverse to convolution. Both operations are used in signal processing and image processing. For example, it may be possible to recover the original signal after a filter (convolution) by using a deconvolution method with a certain degree of accuracy. Due to the measurement error of the recorded signal or image, it can be demonstrated that the worse the SNR, the worse the reversing of a filter will be; hence, inverting a filter is not always a good solution as the error amplifies. Deconvolution offers a solution to this problem. The foundations for deconvolution and time-series analysis were largely laid by Norbert Wiener of the Massachusetts Institute of Technology in his book ''Extrapolation, Interpolation, and Smoothing of Stationary Time Series'' (1949). The book was based on work Wiener had done during World War II but that had been classified at the time. Some of the early attempts to apply these theories were in the field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
