Talk:Well logging

The Logging Measurement Types section seems too specialized and leaves out the basic logging measurements of resistivity, gamma-ray, density, neutron, etc. Should we clean this up and sub-divide the current section into perhaps specialty measurements? --Claygate 04:05, 19 December 2005 (UTC)

Definition of well log
The authors of this article have forgotten the fundamentals. For one thing, they assume that geophysical well logs are the only kind that exist. Well logging did not start with Conrad Schlumberger. In fact, well loggingis nothing more than making a record (a log) of the formations being drilled through. Drillers were making geological well logs since the early days of the Pennsylvania oil industry, and even today it is standard practice to make a geological log (in the oil business called a mud log. Plazak 13:33, 29 June 2007 (UTC)
 * Then please add a history section and expand this. --Claygate 15:41, 29 June 2007 (UTC)

That's my point. Geological well logs are not just history: they are current practice.Plazak 18:25, 29 June 2007 (UTC)
 * Thanks for your edits, point well taken. --Claygate 04:20, 30 June 2007 (UTC)

Wireline and "While Drilling" well logging
I was reading through this, and the phrasing in this section seems to be rather clunky. I edited it minorly (to get rid of a passive statement in the first sentence that did not make sense), but I don't want to go through and rephrase things too much without permisssion. "However, because there is no high bandwidth telemetry path available — no wires to the surface — data are recorded downhole and retrieved when the drill string is removed from the hole. In addition, a small subset of the the measured data is usually transmitted to the surface in real time via pressure pulses in the well's mud fluid column. This mud telemetry method provides a bandwidth of much less than 100 bits per second. Fortunately, drilling through rock is a fairly slow process and data compression techniques mean that this is an ample bandwidth for real-time delivery of critical information."

IMO, I think it would sound better as follows:

However, because there are to wires to the surface, data are recorded downhole and retrieved when the drill string is removed from the hole. A small subset of the measured data can also be transmitted to the surface in real time via pressure pulses in the well's mud fluid colum. This mud telemetry method provides a bandwidth of much less than 100 bits per second, although, as drilling through rock is a fairly slow process, data compression techniques mean that this is an ample bandwidth for real-time delivery of information.Alison Troup (talk) 01:46, 11 December 2007 (UTC) Alison Troup
 * sounds fine to me... TastyCakes (talk) 15:07, 14 November 2008 (UTC)

Merger proposal
12:57, 10 May 2008 (UTC) It looks to me like mud logging and mudlogger should both be merged into this article. So far as I can make out, it is simply an industry-specific term for the same thing, and both articles contain a variety of disorganised information about the technique which could equally apply (where not already repeated) in this article. Could someone with more knowledge on the subject confirm this?

If there is sufficient difference that mud logging should get its own article, mudlogger should be merged into mud logging, per others like miner&mdash;it is the job done, not the nature of the job position, which is notable. BigBlueFish (talk) 15:07, 5 May 2008 (UTC)

I agree. I am a new Wikipedian and will try to make this my area of specialization for a while. Please watch (and edit) my efforts as I learn the mechanics. Thanks! Caveman1949 (talk) 13:43, 6 May 2008 (UTC)

I agree that mud logging and mudlogger should be merged into one article. However, the term Mudlogger or Mudlogging (One Word) is the Norm. Mudlogging is a Separate and Distinct form of data gathering from that of Wireline, MWD, & LWD. Although MWD, LWD, & Mudlogging are done "While "Drilling (Where the "WD" part originates from in the MWD & LWD terms), Mudlogging is the gathering of the Drilled cuttings samples for geological analysis which is plotted on a chart (Mudlog) versus the depth that was drilled. A comprehensive hydrocarbon analysis is also done by extracting the gases contained in the drilling fluid (Mud) that has been liberated from the formation that was bored through. This information, along with physical measurements (the weight of the bit, the rate of penetration into the earth by the drill bit, the mud temperature out, torque, flow, pit volume, rotational speed of the drillstring, equivalent circulating density, pressure of the mud pumps, the density of the drilling fluid going into the hole versus the density of the drilling fluid coming out of the hole, estimated formation pore pressure of the drilled rock, etc, are also plotted versus the depth on the mudlog, depending on the operator's (Oil Company) requirements. LWD, MWD, & Wireline data are used to take specific measurements of the borehole, whether in real time or after the well has been drilled.  These generally include the Gamma Ray (Natural radiation emitted from the surrounding rock), Resistivity (The electrical resistance properties of the rock and the fluid(native water or fresh)/gas/oil contained in the pore spaces of the rock, Spontaneous Potential (I believe a simple form of this is what Conrad & Marcel Schlumberger first used), Neutron Density, Sonic (Acoustic), Core samples, Directional Information for deviated wells (Inclination, Azimuth, and Gravity or Magnetic Toolface), and many other sensors that may be used to help evaluate whether a reservoir containing hydrocarbons will be financially viable to produce. Madro (talk) 13:01, 10 May 2008 (UTC)
 * Merge Mudlogger into Mud logging, but keep Mud logging separate from this article. Mudlogging is enough of its own specialty to merit an article separate from Well logging. Plazak (talk) 22:24, 10 May 2008 (UTC)

Well logging is a general term that includes several specialized fields, including; mud logging, coring, wireline logging and MWD/LWD. Well logging should be a jumping-off point to the more specialized fields, with brief descriptions of each, and possibly explaining their differences since well logging is such a general term. Each field is significantly broad enough to warrant their own pages and if each is correctly detailed, will be more than a brief stub. It should be done this way so that the uninitiated does not become confused into thinking that a mud logger may also do wireline logging. Each is a completely separate job and should have it's own separate page. I agree though that mud logger should be merged into, or more correctly, be redirected to mud logging. Mudgineer (talk) 23:59, 1 June 2008 (UTC)
 * I agree. "Well logging" is something of an umbrella term, and I  believe each type of well logging is notable to have its own article, as is the case now.  Some of the articles could stand to be fleshed out though.  TastyCakes (talk) 19:36, 9 July 2008 (UTC)

Add coring, differences of each, advantages/disadvantages
Someone should add core-barrel coring as a type of logging, for historical purposes, even if it is a dying and seldom used technique these days. As well as shotgun cores taken from wireline logging. I think detailing the differences and advantages/disadvantages of each should be done also, such as: Electric logs do not actually identify formation types, rather they make assumptions to what the formations are based on parameters of what the average readings would be for sand and shale. Whereas mud logging, because samples are actually obtained and visually/chemically analyzed, can identify the actual formations. This can be of use when correlating to offset wells for formations such as lime. As well as formations such as anhydrite which can cause problems with the mud system. Mudgineer (talk) 23:55, 2 June 2008 (UTC)

merging with wireline logging, electric line and formation evaluation
I'm all for merging with the first two, not sure about formation evaluation. So I'm going to go ahead and vote:  Strong Support for the first two and weak support for the third. TastyCakes (talk) 15:14, 14 November 2008 (UTC)

Strong Support for the first two being merged. --claygate (talk) 18:12, 14 November 2008 (UTC)

I am totally against merging Wireline and Well Logging, only those with a narrow view of both topics would consider them the same. —Preceding unsigned comment added by 195.173.105.62 (talk) 11:39, 12 December 2008 (UTC)
 * From reading the introduction to each of them, I find them rather similar and thus mergeable. Do you mean that one or both of the articles don't reflect your perception of what the articles should contain? If so, it would be appreciated if you could elaborate. --Berland (talk) 17:16, 12 December 2008 (UTC)


 * I would definitely merge all together, then split off articles on different tools (SP, gamma, neutron, density, mud logging, etc.), with summaries and links in the main article. Plazak (talk) 19:37, 12 December 2008 (UTC)
 * A lot of them already have articles of their own... TastyCakes (talk) 21:00, 12 December 2008 (UTC)

Ok, well I'm going to start putting stuff from electric line and wireline into this article. How does merging go about? Can I just put a redirect in when I think all the information is duplicated or does an admin have to do something so the merged article shows up in people's watch lists etc? TastyCakes (talk) 21:26, 12 December 2008 (UTC)


 * See WP:MERGE --claygate (talk) 00:05, 13 December 2008 (UTC)

Negative Support for merger. Well logging covers many many more disciplines than electric line. Well logging covers mudlogging, LWD, DST, etc., surely you don't plan on merging those into well logging? Ideally well logging should look something like Well intervention where it gives brief snippets of different well logging methods and links over to them. I think the data in well logging should be merged into the other wikipedia entries. Finally, electric line does not always produce a log. Perforating services and mechanical services, like those used to set plugs, packers, and cement, do not necessarily produce any well logs at all, yet they are very important aspects of wireline operations. Entire wireline companies never produce electric line logs (namely, plug and abandonment companies) Jax8248 (talk) 03:59, 23 April 2009 (UTC)


 * Negative support Formation evaluation is something going far from the the "simple" well logging and wireline is just an aspect of well logging. The actual perception is due to the fact that, at present, these articles are still  covering a small portion of the subjects.--Bramfab 07:54, 23 April 2009 (UTC)  —Preceding unsigned comment added by Bramfab (talk • contribs)


 * Negative support Electric WIreline is only 1 aspect of the techniques used for formation evaluation. Generally the techniques used for FE are spead across many technology and conveyance systems. These conveyance systems and Physics of the measurements are changing and improving all the time. Wireline is gradually being replaced by other conveyance techniques. —Preceding unsigned comment added by 86.141.212.211 (talk) 07:49, 12 September 2010 (UTC)

Reorganising this article
I'm going to try and reorganise this article to make it more readable and complement formation evaluation. There's a lot of good information here but I think it needs some re-organising and I am very open for discussion on how to do this. Reading the previous comments, I am currently proposing that this article summarises the tools used in formation evaluation, with links to the appropriate pages, as follows:


 * 1.Introduction
 * 2.Wireline Logging
 * Introduction
 * History (??)
 * Electrical Logs
 * Resistivity
 * Image Log
 * Porosity Logs
 * Density
 * Neutron Porosity
 * Sonic
 * Lithology Logs
 * Gamma Ray
 * Self/Spontaneous Potential
 * Miscellaneous
 * Caliper
 * NMR - Maybe put in porosity log section
 * Logging-while-drilling? (Or Perhaps a new section for this?)


 * 3.Coring


 * 4.Mud Logging

There are a whole load of other wireline logs to include, but we have to start somewhere! Nwhit (talk) 17:18, 14 October 2012 (UTC)

companies involved
Please add links to articles about companies who do this activity — Preceding unsigned comment added by Skysong263 (talk • contribs) 16:26, 23 June 2014 (UTC)

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