Where can we find
oil and natural gas?
Oil and natural gas are found in the small
spaces between the grains in a sedimentary
rock.
Mathematically, porosity is the pore space in a rock divided
by the total rock volume.
In good reservoirs the porosity is 10-30%.
Porosity and Permeability
= Open space in rock
Flow
Direction
Microscopic Thin- Section of
a sandstone
Porosity
30% Porosity
No Permeability
Flow
Direction
Flow
Direction
30% Porosity
Good Permeability
Permeability
Sand Grains
How do we find Oil and Natural Gas?
Geologists and Engineers use
reflection seismology to see
if a rock has oil in it
Seismology trucks (thumper
trucks) send sound waves
through the earth and computers
record how long it takes the
waves to reflect back to receivers
The tires on a thumper truck
are approximately 5 feet tall!
Seismic Lines
What are we looking for
during seismic testing?
Geologic Structures
Syncline
Anticline
Anticlines are folds in which the oldest rock lies in the center or core and synclines have the
youngest rock in its center or core.
Geologic Structures
Anticlines and Synclines form when rock layers are compressed, (pushed together)
similar to carpet folds when its sides are pushed together. When rocks are
compressed they can either bend, creating folds, or they can fracture, creating faults.
Anticlines are sought out by geologists who explore for oil and gas because the
arches form natural traps these hydrocarbons.
Structural Trap - Anticline
Upwarping of rocks (anticlinal folds) are particularly
good at trapping crude oil and natural gas.
Structural Trap - Anticline
OIL
Oil formed in the source rock migrates upward through the
reservoir rock until it is stopped by the cap rock.
How do we get it out of the
ground once we’ve found it?
Drilling Rig
Drilling for Oil
Sometimes the oil reservoir is under a city, lake or
other sensitive area.
Drilling for Oil
To reach oil reserves
underneath the Oklahoma
State Capitol Building, one
oil well was directionally
drilled from across the street.
Directional Drilling
To drill a directional well, the first part of the hole is
drilled vertically. The hole kicks off, or deflects, so that
the bottom of the well is hundreds of meters away from
its starting point on the surface.
After drilling, sometimes a pumping unit is installed
Oil and Gas Production
A Christmas Tree is used to control the flow of oil and natural either to a
storage tank or pipeline.
After the oil is pumped it is
taken to an oil refinery
Refining Process
Oklahoma has five oil refineries.
The refinery is where oil is
heated until it separates into
many different parts. These
parts are then used to make
products like gasoline, jet fuel
heating fuel, tar and plastic
Uses of Crude Oil and Natural Gas
Natural Gas
Crude Oil