﻿STRUCTURE 
  AND 
  CONDITIONS 
  AFFECTING 
  PRESENCE 
  OF 
  OIL. 
  73 
  

  

  near 
  the 
  surface, 
  or 
  at 
  least 
  considerably 
  above 
  the 
  oil-producing 
  

   zones. 
  

  

  It 
  may 
  be 
  questioned 
  whether 
  the 
  presence 
  of 
  water 
  is 
  essential 
  for 
  

   the 
  accumulation 
  of 
  petroleum 
  in 
  the 
  upward 
  folds 
  of 
  the 
  strata 
  under 
  

   the 
  conditions 
  presented 
  by 
  the 
  Santa 
  Maria 
  and 
  Lompoc 
  fields. 
  

   Here 
  the 
  oil 
  tends 
  to 
  rise 
  to 
  the 
  surface 
  and 
  form 
  seepages 
  wherever 
  

   channels 
  of 
  escape 
  are 
  offered. 
  This 
  is 
  probably 
  not 
  due 
  to 
  hydro- 
  

   static 
  pressure, 
  as 
  there 
  is 
  no 
  evidence 
  that 
  the 
  water 
  tended 
  to 
  

   rise 
  in 
  the 
  same 
  way; 
  and 
  it 
  is 
  just 
  the 
  opposite 
  of 
  the 
  tendency 
  

   ascribed 
  to 
  oil 
  by 
  upholders 
  of 
  the 
  anticlinal 
  theory, 
  which 
  would 
  

   result 
  in 
  the 
  oil 
  descending 
  and 
  gathering 
  in 
  the 
  synclinal 
  troughs 
  on 
  

   subsidence 
  or 
  removal 
  of 
  the 
  water. 
  In 
  the 
  fields 
  under 
  discussion 
  

   the 
  oil 
  is 
  always" 
  intimately 
  associated 
  with 
  gas. 
  There 
  do 
  not 
  seem 
  

   to 
  be, 
  as 
  a 
  rule, 
  separated 
  stores 
  of 
  gas 
  and 
  oil, 
  but 
  the 
  two 
  are 
  inter- 
  

   mingled, 
  or 
  at 
  least 
  closely 
  brought 
  together, 
  so 
  that 
  one 
  is 
  not 
  usu- 
  

   ally 
  found 
  without 
  the 
  other, 
  although 
  gas 
  is 
  sometimes 
  found 
  alone. 
  

   The 
  oil 
  exhibits 
  a 
  tendency 
  to 
  migrate, 
  as 
  shown 
  by 
  its 
  original 
  con- 
  

   centration 
  from 
  widely 
  separated 
  points 
  of 
  origin, 
  by 
  its 
  surface 
  seep- 
  

   age, 
  and 
  by 
  the 
  energetic 
  way 
  in 
  which 
  it 
  rises 
  in 
  the 
  drill 
  holes 
  when 
  

   a 
  source 
  of 
  it 
  is 
  tapped. 
  This 
  migratory 
  faculty 
  may 
  be 
  ascribed 
  

   entirely 
  to 
  the 
  presence 
  of 
  the 
  associated 
  gas, 
  which 
  would 
  cause 
  the 
  

   oil 
  to 
  fill 
  every 
  crevice 
  offering 
  a 
  point 
  of 
  escape 
  or 
  a 
  point 
  of 
  lodgment. 
  

   If 
  this 
  is 
  granted, 
  it 
  is 
  evident 
  that 
  the 
  points 
  of 
  accumulation 
  of 
  oil 
  

   will 
  be 
  determined 
  chiefly 
  by 
  the 
  presence 
  of 
  cavities, 
  large 
  or 
  small, 
  

   offering 
  a 
  place 
  for 
  it 
  to 
  gather. 
  Anticlines, 
  being 
  points 
  of 
  fractur- 
  

   ing 
  and 
  in 
  some 
  places 
  opening 
  out 
  of 
  the 
  strata, 
  would 
  afford 
  likely 
  

   places 
  for 
  the 
  oil 
  to 
  lodge 
  in 
  those 
  beds 
  subject 
  to 
  fracture 
  and 
  for 
  it 
  

   to 
  be 
  imprisoned 
  by 
  overarching 
  impervious 
  beds. 
  

  

  Aside 
  from 
  ideas 
  as 
  to 
  accumulation 
  of 
  oil 
  after 
  such 
  a 
  fashion, 
  the 
  

   writers 
  have 
  come 
  to 
  the 
  conclusion 
  that 
  in 
  this 
  region 
  many 
  of 
  the 
  

   "oil 
  sands," 
  so 
  called, 
  are 
  not 
  true 
  sands, 
  but 
  zones 
  of 
  fractured 
  shale 
  

   or 
  flint 
  offering 
  interspaces 
  in 
  which 
  the 
  oil 
  can 
  gather. 
  Beds 
  of 
  sand 
  

   in 
  the 
  Monterey 
  are 
  scarce 
  and 
  thin. 
  Some 
  of 
  the 
  oil-producing 
  zones 
  

   are 
  very 
  thick, 
  amounting 
  to 
  tens 
  or 
  even 
  hundreds 
  of 
  feet. 
  The 
  oil 
  

   occurs 
  chiefly 
  in 
  the 
  lower 
  portion 
  of 
  the 
  formation, 
  where 
  brittle, 
  flinty 
  

   shale 
  is 
  abundant; 
  and 
  as 
  it 
  is 
  a 
  noticeable 
  fact 
  that 
  wherever 
  these 
  

   hard, 
  flinty 
  layers 
  appear 
  at 
  the 
  surface 
  they 
  are 
  usually 
  much 
  more 
  

   contorted 
  and 
  fractured 
  than 
  the 
  associated 
  softer 
  shales, 
  which 
  are, 
  

   in 
  general, 
  only 
  folded 
  and 
  not 
  broken, 
  it 
  seems 
  likely 
  that 
  the 
  same 
  

   fracturing 
  and 
  resultant 
  formation 
  of 
  an 
  ideal 
  reservoir 
  for 
  the 
  oil 
  

   takes 
  place 
  in 
  the 
  depths 
  as 
  at 
  the 
  surface. 
  Where 
  it 
  is 
  so 
  fractured, 
  

   the 
  shale 
  occupies 
  a 
  greater 
  volume 
  than 
  before, 
  showing 
  spaces 
  some 
  

   of 
  which 
  are 
  open 
  and 
  others 
  partially 
  or 
  wholly 
  filled 
  with 
  chalcedonic 
  

   or 
  bituminous 
  material. 
  The 
  unfractured 
  beds 
  are 
  more 
  or 
  less 
  imper- 
  

   vious 
  to 
  the 
  rapid 
  migration 
  of 
  the 
  petroleum, 
  and 
  so 
  act 
  as 
  barriers 
  

   to 
  keep 
  the 
  oil 
  in 
  the 
  porous 
  zones. 
  

  

  