Talk:Reflection seismology

message: The reflection and transmission coefficients are still wrong - one of them is. Hence the equation relating R to T is not verified. Maybe an expert can decide which is which. My guess is we are talking about pressure indeed, so that R is fine and T is wrong (should be something like T = 2 Z1 / (Z1+Z0) ) and they are related by T=1+R. An expert is required to clarify this. Ferred (talk) 13:19, 29 January 2015 (UTC)
replies: text: I have reverted the edits of Geologos because the equations were correct as they were.  The precise form of the transmission coefficient depends on whether it is for pressure or particle velocity.  The versions quoted are for pressure. Thunderbird2 (talk) 11:26, 26 November 2007 (UTC)

text: I apoligize for altering the content of the page so impolitely, but I believe that the section on reflection and refraction coefficients need altering to avoid misunderstandings of this sort. It is only at the second formula (the transmission coefficient) that it is told which parameter is actually dealt with, and it is put in parenthesis "(the ratio of transmitted to incident pressure)". I therefore suggest that it is clarified to avoid this potential ambiguity. A good name could be pressure reflection and transmission coefficients. A further possibility is to present both pressure and displacement R/T coefficients under separate headers and present their respective relations to the reflected and transmitted energy (To show how surprisingly little energy is actually reflected at real lithological interfaces). Geologos (talk) 20:32, 26 November 2007 (UTC)
replies: text:  Hi Geologos.  There's no need to apologise.  You corrected what you honestly believed to be an error, and I did the same, only in reverse.  That's how Wikipedia works (see wp:bold) :-) Thunderbird2 (talk) 07:09, 27 November 2007 (UTC)

text: That would be a good idea.  As with many resource activities, impact is much less today than in the past.  But finding the specifics may be hard.  I don't know where this would have been documented.  Gwimpey 18:07, 28 December 2005 (UTC)
thread_title:  Wrong reflection and transmission coefficients 

message: 'Seismic technology does not allow the direct detection of hydrocarbons, but it is used by geologists and geophysicists who interpret the data to distinguish the presence of structural traps that could potentially contain hydrocarbons'
This sentence is not strictly true.  Firstly, in seismic data processing we attempt to search for and enhance images artefacts called 'direct hydrocarbon indicators'. usually seen as a 'bright spot' or 'dim spot' on a stcaked seismic section.  Secondly, seismic data processing has long since ceased to be solely about structural interpretation.  Nowadays a significant amount of effort is made to search for various amplitude anomalies to act as lithology and property (egs. porosity, permeability etc) identifiers.
If no-one objects I will consider a re-write over the next few days.
You are absolutely correct that an independent branch of seismic technology has emerged using attributes of seismic data to directly identify presence of hydrocarbons. Go ahead and edit - I will contribute if required. 
My comments (not'draft'): Bright spots, flat-spots, etc have been recognised (and drilled, sometimes successfully) for decades but direct targeting really took off in the late 90's with emergence of relatively inexpensive 3D data and the high quality of deep-water data eg West Africa. The emergence of more powerful computers also made analysis of pre-stack data practical eg Amplitude-Versus-Offset or 'AVO' which shows variation in amplitude with offset in the pre-stack gather (important to note that DHI's are often pre-stack attributes). We should distinguish between structural/stratigraphic attributes (basics), lithology (poro-perm) and DHI (fluids).--Okram999 (talk) 17:26, 4 January 2008 (UTC)
thread_title:  Direct Hydrocarbon Indicators 

message: Made on minor spelling correction while reading this article.
Shanneranner 20:33, 22 September 2006 (UTC)
thread_title:  Spelling correction 

message: “Reflection seismology or seismic reflection is a branch of seismology that uses reflected seismic waves to produce images of the Earth's subsurface.”  When reading this article, it gives more an impression of describing reflection seismology as a method – with applications, to collect subsurface information (data). To interpret the data, scientists make use of seismology  (“the  scientific study of earthquakes and the movement of waves”) and Exploration geophysics among other disciplines. --Roarjo 10:11, 12 November 2006 (UTC)
replies: text: Would it be better to say that "Reflection seismology is an application of seismology that uses..." rather than a branch?  Or maybe "Reflection seismology is a method of exploration geophysics that uses seismology and reflected seismic waves to produce..."?  I will try a variation on one of these and see how it sounds.  GeoGreg 20:49, 31 January 2007 (UTC)

text: After some experimenting, I decided that producing "images" is not correct; reflection seismology estimates properties, a more general statement that is true of all geophysical methods.  But anyone feel free to hack away. GeoGreg 20:57, 31 January 2007 (UTC)
thread_title:   Introduction defining the topic 

message: I'm thinking the application part could be updated to include some of the newer applications of reflection seismic, such as reservoir monitoring through time-lapse and characterisation through inversion. I don't know much about inversion, but I could try to write something about time-lapse. Any thoughts on this?
Asbjørn L. Johansen 14:43, 7 August 2007 (UTC)
thread_title:  Applications 

message: In Googling, I've found innumerable references that use it generically, and haven't been able to find a company by that name or any indication that it is actually a product name. If it's a trademark, what's the company that owns it? TESS shows it as registered to Continental Oil Company, but as "dead;" there are actually two trademark entries:
Registration Number	0737865
Registration Date	September 18, 1962
(CANCELLED) IC 009. US 026. G & S: Electrical and Electronic Apparatus for Seismic Exploration for Oil-Namely, Electrically-Controlled Signal Generating Equipment, Magnetic Tape Recording Equipment, Amplification Equipment, Correlating Equipment, and Other Associated Electrical and Electronic Apparatus for Seismic Exploration. FIRST USE: 19610222. FIRST USE IN COMMERCE: 19610322
and
Registration Number	0735470
Registration Date	July 31, 1962
Goods and Services	(CANCELLED) IC 042. US 100. G & S: Geophysical Prospecting Service. FIRST USE: 19610222. FIRST USE IN COMMERCE: 19610322
I don't know what a "cancelled" trademark is. I wonder why it was cancelled? Dpbsmith (talk) 17:19, 8 August 2008 (UTC)
replies: text: A 'vibroseis survey' is the predominant form of land seismic exploration operations in the world today where survey sizes in data easily run into petabytes. Vibroseis techniques marry perfectly into digital seismic processing, and vibroseis really took off in the 1970s with the introduction of minicomputers. Up to that point signal sources were all the various forms of 'dynamite' (ie explosive) , or weight drop 'Thumper' . I started work in 1974 in seismic processing on onsite systems J R Spigot (talk) 16:12, 8 August 2022 (UTC)
thread_title: Vibroseis is a "cancelled" trademark

message: A diagram is this article purports to show some effect of a landmine. All parts including the axes are unlabelled. There is no telling what names some people are given or choose but the WP name of the loader of the diagram suggests a lack of propriety. Failing validation it should be deleted.--SilasW (talk) 21:41, 15 June 2009 (UTC)
thread_title:  Diagram of dubious provenance 

message: I would like to point out as a former employee of GSI, they are not owned in any way by WesternGeco (whom I also used to work for).  GSI was bought out by Tesla Exploration.
* As far as I know, GSI was bought by Halliburton in the late 1980s and merged with Geosource into Halliburton Geophysical Services (HGS).  A few years later (about 1993), HGS was sold to Western Geophysical, then a division of Western Atlas.  In 1998 or so, Western (as part of Western Atlas) was sold to Baker Hughes.  Baker put Western Geophysical into a JV with Schlumberger's Geco-Prakla in 2000, forming WesternGeco.  As of 2006, I think, WesternGeco is 100% Schlumberger.  Did Tesla buy part of GSI?  If so, I've forgotten it.  But I was on the Western side of the Western-HGS merger, so I might not know all the details. 174.29.145.167 (talk) 05:31, 30 March 2010 (UTC)
thread_title:  GSI 

message: Could someone expand the history section with some information about when 3D seismic became prevalent in the oil industry? Did everyone have 3D seismic for their reservoir modeling by the 60s, for example?  —Preceding unsigned comment added by 134.32.11.71 (talk) 09:23, 12 August 2010 (UTC)
replies: text: 3D surveys only became viable during the 1980s due to economics, computational demands and even more practical things such as the volume of data being recorded vs. the volume of data that a magnetic tape could hold.  I'm going to try and work on some of this article as it is really important. Nwhit (talk) 19:20, 20 February 2012 (UTC)
thread_title:  Questions on History 

message: At the moment, I am hoping to expand the section on applications and work on the current content that is there.  Hopefully this is how the section will end up looking:
2 Applications
:2.1 Near-surface
:2.2 Hydrocarbon exploration
::2.2.1 Land survey acquisition
::2.2.2 Marine survey acquisition (streamer)
::2.2.3 Marine survey acquisition (ocean-bottom incl. 4D)
::2.2.4 Seismic data processing
::2.2.5 Geological interpretation
::2.2.6 Seismic attribute analysis
:2.3 Crustal studies
Once this is done, I can work on the rest of the article.  If anyone has any comments, they're most welcome.Nwhit (talk) 18:08, 29 February 2012 (UTC)
replies: text: I've now managed to remove the vast sections of unreferenced material from this section and replaced it with referenced material.  This will still need adding to, but it's a start.Nwhit (talk) 11:25, 12 March 2012 (UTC)
thread_title:  Moving forward with this article 

message: Think this image might be useful somewhere here? Don't know enough about the subject to know where Mrjohncummings (talk) 15:13, 3 July 2013 (UTC)
thread_title:  A useful image? 

message: We have to remember that most readers do not have degrees in geology, so we should write simply enough to get the point across and leave the details to the grad students and professors. BeenAroundAWhile (talk) 20:28, 25 October 2017 (UTC)
thread_title:  Simplify. 

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thread_title:  External links modified (January 2018) 

message: More inforamtion. I would like to add some information on ways to avoid disturbing marine mammals whilst surveying. See section below.
In 2017, IOGP recommended that, to avoid disturbance whilst surveying:
*Protective measures are employed to address site-specific environmental conditions of each operation to ensure that sound exposure and vessel traffic do not harm marine mammals.* 	
*Surveys planned to avoid known sensitive areas and time periods, such as breeding and feeding areas. * 
*Exclusion zones are typically established around the seismic source to further protect marine fauna from any potentially detrimental effects of sound. The exclusion zone is typically a circle with a radius of at least 500 meters around the sound source. * 
*Trained observers and listening devices are used to visually and acoustically monitor that zone for marine mammals and other protected species before any sound-producing operations begin. These observers help ensure adherence to the protective practices during operations and their detailed reports provide information on the biodiversity of the survey area to the local governments.* 
*Sound production typically begins with a “soft-start” or “ramp-up” that involves a gradual increase of the sound level from the air gun source from a very low level to full operational levels at the beginning of the seismic lines – usually over 20 to 40 minutes. This soft-start procedure is intended to allow time for any animal that may be close to the sound source to move away as the sound grows louder.*
::Seems like a good idea - I know a lot of acquisition outfits already do this stuff. Mikenorton (talk) 15:16, 5 October 2018 (UTC)
thread_title:  Marine section: ways to avoid disturbing marine mammals 

message: I'm not sure that the current content in the marine section is totally relevant at present. There are a few short paragraphs to illustrate that seismic is disruptive and a quote from an IAGC report that's its not, presumably for balance. However, this is a very complex discussion depending upon which perspective you take and simple extracts from research always need to be carefully considered. For example, an extract from an IAGC report (IAGC being a vested interest group for the seismic industry immediately does not sit right as an independent source) and also the claim as quoted that seismic does not injure mammals (I paraphrase here) is not a recommendation either (i.e. does it upset, distress, displace, disrupt migration, disrupt breeding, etc, etc...?). This report is also dated from 2012 and is really old research unlikely to be current thinking.
I propose to remove the text from the Marine section starting from "A study has shown...." through to "...injury to any marine mammal species." and to include a more general discussion on what current thinking is on this issue and how it is managed such as with impact assessments and so on.
Also this is an Earth Science /WikiProject Geology subject and too much detail concerning environmental science is deviating away from its main purpose. Of course, environmental discussions should be had here but at a more general level and we should prompt the reader to look elsewhere for more detailed information on these issues.Blackrock36 (talk) 14:16, 21 February 2021 (UTC)
thread_title:  Marine section: General discussion on impacts on marine mammals