﻿PETKOLEUM 
  GEOLOGY 
  

  

  By 
  Wtt.tjam 
  B. 
  Heeoy 
  

   Director 
  of 
  Foreign 
  Production, 
  Petroleum 
  Administration 
  for 
  War 
  

  

  INTRODUCTION 
  

  

  Among 
  the 
  various 
  substances 
  which 
  are 
  found 
  in 
  the 
  earth's 
  crust, 
  

   petroleum 
  and 
  natural 
  gas 
  occupy 
  a 
  unique 
  position 
  in 
  that 
  they 
  are 
  

   combustible 
  fluids. 
  The 
  highly 
  distinctive 
  and 
  interesting 
  properties 
  

   of 
  petroleum 
  would 
  alone 
  have 
  led 
  to 
  close 
  investigation 
  of 
  its 
  origin 
  

   and 
  occurrence, 
  but 
  its 
  widespread 
  distribution 
  and 
  great 
  usefulness 
  

   to 
  mankind 
  have 
  made 
  it 
  the 
  objective 
  of 
  many 
  lines 
  of 
  scientific 
  

   research 
  and 
  have 
  gained 
  for 
  petroleum 
  geology 
  a 
  leading 
  position 
  in 
  

   geologic 
  science. 
  

  

  The 
  geology 
  of 
  petroleum 
  may 
  be 
  considered 
  from 
  either 
  of 
  two 
  

   standpoints. 
  In 
  the 
  field 
  of 
  economic 
  geology 
  it 
  has 
  become 
  one 
  of 
  

   the 
  most 
  important 
  branches 
  and 
  has 
  attracted 
  to 
  it 
  the 
  largest 
  group 
  

   of 
  specialists 
  concerned 
  with 
  any 
  mineral 
  resource. 
  Apart 
  from 
  its 
  

   economic 
  importance 
  and 
  in 
  its 
  proper 
  relation 
  to 
  other 
  divisions 
  of 
  

   geologic 
  science, 
  petroleum 
  geology 
  may 
  be 
  regarded 
  as 
  a 
  branch 
  of 
  

   sedimentary 
  petrology, 
  coordinate 
  with 
  hydrology 
  or 
  the 
  geology 
  

   of 
  coal 
  deposits. 
  

  

  A 
  distinction 
  may 
  be 
  made 
  between 
  the 
  science 
  of 
  petroleum 
  geology 
  

   and 
  the 
  art 
  of 
  oil 
  finding 
  and 
  development. 
  The 
  latter 
  lies 
  in 
  the 
  

   field 
  of 
  applied 
  science 
  or 
  engineering. 
  The 
  line 
  between 
  the 
  two 
  is 
  

   not 
  sharply 
  drawn, 
  and 
  the 
  association 
  between 
  the 
  science 
  and 
  the 
  

   art 
  is 
  so 
  intimate 
  that 
  the 
  advance 
  of 
  both 
  has 
  been 
  hand 
  in 
  hand. 
  

   The 
  need 
  for 
  advancing 
  the 
  art 
  has 
  stimulated 
  the 
  progress 
  of 
  the 
  

   science. 
  New 
  scientific 
  concepts 
  have 
  soon 
  been 
  tried 
  out 
  in 
  practice. 
  

   As 
  a 
  part 
  of 
  a 
  survey 
  of 
  the 
  advances 
  made 
  in 
  geologic 
  science 
  during 
  

   the 
  last 
  half 
  century 
  it 
  is 
  fitting 
  that 
  this 
  account 
  of 
  the 
  progress 
  in 
  

   petroleum 
  geology 
  should 
  emphasize 
  the 
  scientific 
  rather 
  than 
  the 
  

   engineering 
  aspects, 
  and 
  the 
  writer 
  has 
  approached 
  the 
  subject 
  from 
  

   that 
  direction. 
  Geographic 
  distribution 
  of 
  petroleum 
  deposits 
  and 
  

   other 
  matters 
  which 
  are 
  primarily 
  economic 
  in 
  character 
  will 
  not 
  be 
  

   considered 
  in 
  this 
  paper. 
  

  

  * 
  Reprinted 
  by 
  permission 
  from 
  Fiftieth 
  Anniversary 
  Volume, 
  Geological 
  Society 
  of 
  

   America, 
  June 
  1941. 
  

  

  161 
  

  

  