﻿DETAILS 
  OF 
  THE 
  DEVELOPED 
  TERRITORY. 
  107 
  

  

  distance 
  of 
  1,100 
  feet 
  in 
  one 
  well. 
  Either 
  water 
  sand, 
  dry 
  oil 
  sand, 
  or 
  

   limy 
  "shell" 
  usually 
  defines 
  the 
  base 
  of 
  the 
  productive 
  zone. 
  

  

  THE 
  OIL. 
  

  

  Two 
  grades 
  of 
  oil 
  are 
  struck 
  in 
  this 
  field, 
  one 
  a 
  black 
  oil 
  with 
  a 
  

   gravity 
  of 
  18° 
  to 
  24°, 
  the 
  other 
  a 
  brown 
  to 
  greenish 
  oil 
  of 
  about 
  35° 
  

   Baume. 
  The 
  black 
  oil 
  is 
  produced 
  by 
  most 
  of 
  the 
  wells, 
  the 
  

   lighter 
  variety 
  coming 
  only 
  from 
  the 
  Logan 
  well 
  of 
  the 
  Los 
  Alamos 
  

   Oil 
  and 
  Development 
  Company 
  and 
  the 
  No. 
  3 
  Wise 
  & 
  Denigan 
  well 
  

   of 
  the 
  Union 
  Oil 
  Company. 
  The 
  relations 
  of 
  occurrence 
  of 
  the 
  two 
  

   grades 
  are 
  not 
  known. 
  One 
  of 
  the 
  wells 
  yields 
  an 
  emulsion 
  of 
  water 
  

   and 
  20° 
  oil, 
  which 
  is 
  reddish 
  brown 
  in 
  color 
  as 
  it 
  comes 
  from 
  the 
  well. 
  

   This 
  oil 
  turns 
  to 
  the 
  usual 
  black 
  color 
  on 
  separation 
  of 
  the 
  water 
  by 
  

  

  settling. 
  

  

  PRODUCTION. 
  

  

  The 
  production 
  of 
  the 
  individual 
  wells 
  ranges 
  from 
  100 
  to 
  1,000 
  

   barrels 
  per 
  day, 
  the 
  best 
  producers 
  averaging 
  from 
  300 
  to 
  500 
  barrels. 
  

   One 
  of 
  the 
  wells 
  which 
  gave 
  an 
  initial 
  output 
  of 
  200 
  to 
  300 
  barrels 
  at 
  

   first, 
  suddenly 
  began 
  flowing 
  1,000 
  barrels 
  per 
  day. 
  This 
  continued 
  

   for 
  a 
  few 
  days 
  and 
  then 
  gradually 
  fell 
  off 
  to 
  300 
  barrels, 
  which 
  it 
  is 
  

   still 
  yielding. 
  It 
  is 
  said 
  that 
  the 
  wells, 
  as 
  a 
  rule, 
  are 
  exceptionally 
  

   steady 
  producers, 
  falling 
  off 
  but 
  little 
  in 
  the 
  two 
  years 
  since 
  the 
  field 
  

   was 
  first 
  opened. 
  Very 
  few 
  of 
  the 
  wells 
  have 
  been 
  tried 
  to 
  their 
  full 
  

   capacity, 
  so 
  that 
  it 
  is 
  probable 
  that 
  yields 
  greater 
  than 
  those 
  men- 
  

   tioned 
  will 
  be 
  recorded 
  when 
  the 
  field 
  is 
  fully 
  tested. 
  

  

  ARROYO 
  GRANDE 
  FIELD. 
  

   LOCATION. 
  

  

  Drilling 
  has 
  recently 
  shown 
  that 
  at 
  least 
  certain 
  portions 
  of 
  the 
  

   region 
  north 
  and 
  northwest 
  of 
  Arroyo 
  Grande, 
  in 
  the 
  San 
  Luis 
  quad- 
  

   rangle, 
  San 
  Luis 
  Obispo 
  County, 
  a 
  short 
  distance 
  north 
  of 
  the 
  area 
  

   shown 
  on 
  PI. 
  I, 
  are 
  underlain 
  by 
  productive 
  oil 
  formations. 
  The 
  

   successful 
  wells 
  belong 
  to 
  the 
  Tiber 
  Oil 
  Company, 
  and 
  are 
  located 
  on 
  

   the 
  west 
  side 
  of 
  Price 
  Canyon 
  about 
  3 
  miles 
  northeast 
  of 
  Pismo 
  and 
  

   7 
  miles 
  slightly 
  east 
  of 
  south 
  of 
  San 
  Luis 
  Obispo. 
  Although 
  outside 
  

   of 
  the 
  immediate 
  area 
  covered 
  by 
  this 
  report 
  the 
  occurrence 
  is 
  so 
  

   important 
  in 
  showing 
  an 
  extension 
  of 
  the 
  Santa 
  Maria 
  district 
  toward 
  

   the 
  northwest 
  as 
  to 
  merit 
  mention 
  here. 
  

  

  GEOLOGY. 
  

  

  The 
  geology 
  of 
  the 
  San 
  Luis 
  quadrangle 
  has 
  been 
  mapped 
  and 
  

   described 
  by 
  H. 
  W. 
  Fairbanks 
  in 
  the 
  San 
  Luis 
  folio. 
  a 
  According 
  to 
  

  

  a 
  Copies 
  of 
  this 
  folio, 
  which 
  is 
  No. 
  101 
  in 
  the 
  series 
  making 
  up 
  the 
  Geologic 
  Atlas 
  of 
  the 
  United 
  States, 
  

   should 
  be 
  in 
  the 
  hands 
  of 
  every 
  oil 
  man 
  or 
  other 
  person 
  interested 
  in 
  the 
  natural 
  resources 
  of 
  this 
  region; 
  

   it 
  may 
  be 
  obtained 
  for 
  25 
  cents 
  from 
  the 
  Director 
  of 
  the 
  United 
  States 
  Geological 
  Survey, 
  Washington, 
  

   D.C. 
  

  

  