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%.
Flow Direction
30% Porosity No Permeability
30% PorosityGood Permeability
Flow Direction
Porosity
Sand Grains
Microscopic Thin- Section of a sandstone
Porosity and Permeability
Flow Direction
= Open space in rock
Permeability
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?
Anticline
Syncline
Geologic Structures
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 formed in the source rock migrates upward through the reservoir rock until it is stopped by the cap rock.
OIL
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
Crude OilNatural Gas
Uses of Crude Oil and Natural Gas