﻿176 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  material 
  into 
  appreciable 
  quantities 
  of 
  hydrocarbons 
  which 
  would 
  be 
  

   present 
  in 
  the 
  water-saturated 
  sediments 
  either 
  as 
  a 
  solute 
  or 
  in 
  the 
  

   form 
  of 
  globules 
  physically 
  distinct 
  from 
  the 
  water. 
  While 
  the 
  mecha- 
  

   nism 
  of 
  this 
  process 
  is 
  unknown, 
  it 
  appears 
  to 
  be 
  an 
  essential 
  link 
  in 
  

   the 
  chain 
  of 
  the 
  origin 
  of 
  petroleum. 
  

  

  The 
  available 
  evidence 
  indicates 
  that 
  this 
  aggregation 
  occurs 
  within 
  

   the 
  source 
  rock. 
  Older 
  sediments 
  of 
  marine 
  origin, 
  both 
  dense 
  and 
  

   porous, 
  are 
  impregnated 
  with 
  small 
  quantities 
  of 
  petroleum, 
  in 
  con- 
  

   trast 
  with 
  recent 
  sediments 
  in 
  which 
  it 
  is 
  rare 
  or 
  absent. 
  This 
  was 
  

   well 
  known 
  to 
  Orton 
  (1888, 
  p. 
  83) 
  who 
  estimated 
  the 
  quantity 
  of 
  

   petroleum 
  present 
  in 
  this 
  diffused 
  condition 
  in 
  some 
  of 
  the 
  rocks 
  

   of 
  Ohio. 
  Surprisingly 
  little 
  detailed 
  investigation 
  of 
  the 
  quantity 
  

   and 
  distribution 
  of 
  petroleum 
  in 
  older 
  rocks 
  has 
  been 
  carried 
  on. 
  

   Trask 
  has 
  determined 
  the 
  organic 
  content 
  of 
  many 
  samples 
  of 
  older 
  

   rocks 
  from 
  wells, 
  but 
  the 
  analyses 
  do 
  not 
  disclose 
  the 
  amount 
  of 
  organic 
  

   matter 
  present 
  in 
  the 
  form 
  of 
  petroleum. 
  Stout 
  (1936, 
  p. 
  799) 
  studied 
  

   various 
  Ohio 
  limestones 
  and 
  shales 
  and 
  found 
  that 
  the 
  content 
  of 
  hydro- 
  

   carbons 
  was 
  about 
  0.5 
  percent. 
  Most 
  geologists 
  will 
  probably 
  be 
  in 
  

   accord 
  with 
  the 
  statement 
  of 
  Illing 
  (1938b, 
  p. 
  209) 
  that 
  

  

  There 
  can 
  be 
  no 
  doubt 
  that 
  a 
  still 
  larger 
  amount 
  of 
  oil 
  and 
  gas 
  occurs 
  as 
  a 
  more 
  

   widespread 
  but 
  less 
  concentrated 
  impregnation 
  of 
  the 
  denser 
  rocks, 
  the 
  clays, 
  

   marls 
  and 
  limestones 
  surrounding 
  the 
  reservoir 
  rocks. 
  

  

  In 
  concluding 
  this 
  discussion 
  of 
  the 
  genesis 
  of 
  petroleum, 
  the 
  state- 
  

   ment 
  seems 
  justified 
  that 
  the 
  conversion 
  of 
  the 
  complex 
  organic 
  sub- 
  

   stances 
  deposited 
  with 
  the 
  sediments 
  into 
  the 
  petroleum 
  found 
  in 
  older 
  

   rocks 
  takes 
  place 
  within 
  the 
  source 
  bed 
  and 
  results 
  from 
  the 
  various 
  

   chemical 
  and 
  physical 
  forces 
  to 
  which 
  the 
  organic 
  matter 
  has 
  therein 
  

   been 
  subjected. 
  

  

  MIGRATION 
  OF 
  PETROLEUM 
  

   GENERAL 
  STATEMENT 
  

  

  The 
  accumulation 
  of 
  petroleum 
  in 
  immense 
  concentrations 
  in 
  oil 
  

   pools 
  is 
  in 
  contrast 
  with 
  its 
  wide 
  diffusion 
  through 
  the 
  source 
  beds 
  in 
  

   which 
  it 
  had 
  its 
  origin. 
  The 
  movement 
  of 
  petroleum 
  from 
  source 
  to 
  

   reservoir 
  has 
  resulted 
  from 
  the 
  operation 
  of 
  physical 
  forces, 
  and 
  

   geologists 
  are 
  vitally 
  concerned 
  with 
  the 
  character 
  of 
  these 
  forces 
  and 
  

   the 
  extent 
  of 
  their 
  effectiveness. 
  This 
  movement 
  is 
  collectively 
  called 
  

   migration, 
  but 
  the 
  use 
  of 
  such 
  an 
  inclusive 
  term 
  is 
  deceptive, 
  for 
  the 
  

   process 
  is 
  doubtless 
  highly 
  complex. 
  In 
  its 
  simplest 
  form 
  it 
  may 
  

   be 
  resolved 
  into 
  a 
  consideration 
  of 
  (1) 
  movement 
  of 
  oil 
  from 
  source 
  

   bed 
  into 
  carrier 
  bed; 
  and 
  (2) 
  movement 
  through 
  the 
  carrier 
  bed 
  to 
  

   the 
  reservoir. 
  

  

  