Editing Well logging (section)

==Mudlogging==
{{See also|Mud logging}}
''[[Mud log]]s'' are well logs prepared by describing rock or soil cuttings brought to the surface by mud circulating in the borehole. In the oil industry they are usually prepared by a [[mud logging]] company contracted by the operating company. One parameter a typical mud log displays is the formation gas (gas units or ppm).  "The gas recorder usually is scaled in terms of arbitrary gas units, which are defined differently by the various gas-detector manufactures. In practice, significance is placed only on relative changes in the gas concentrations detected."<ref>{{cite book
  | last1 = Bourgoyne
  | first1 = Adam
  | first2 = Keith
  | last2 = Millheim
  | first3 = Martin
  | last3 = Chenevert
  | first4 = F.S. 
  | last4 = Young Jr.
  | title = Applied Drilling Engineering
  | url = https://archive.org/details/applieddrillinge00bour
  | url-access = limited
  | publisher = Society of Petroleum Engineers
  | year = 1986
  | location = Richardson, TX
  | isbn = 1-55563-001-4
  | page = [https://archive.org/details/applieddrillinge00bour/page/n279 274]}}</ref> The current [[oil industry]] standard [[mud log]] normally includes real-time drilling parameters such as [[rate of penetration]] (ROP), [[lithology]], gas [[hydrocarbons]], flow line temperature (temperature of the [[drilling fluid]]) and [[chloride]]s but may also include [[mud weight]], [[estimated pore pressure]] and [[corrected d-exponent]] (corrected drilling exponent) for a pressure pack log. Other information that is normally notated on a [[mud log]] include directional data ([[deviation surveys]]), [[weight on bit]], [[rotary table (drilling rig)|rotary speed]], [[pump pressure]], [[pump rate]], [[viscosity]], drill bit info, casing shoe depths, formation tops, mud pump info, to name just a few.