crude oil extraction ( lec 3a )
TRANSCRIPT
Crude Oil Extraction
Crude Oil Extraction
Various steps in Extraction of Petroleum
are:-
Identification or locating of the Oil Field
Drilling
Oil Extraction and Recovery
• Primary Recovery
• Secondary Recovery
• Tertiary Recovery
Crude Oil Extraction
• Locating Oil fields
Before starting the extraction of crude oils, the crude oil fields has been identified.
There are number of methods available for this
1. Magnetometer
2. Gravimeter
3. Satellite imagery
4. Seismic surveys
5. Sniffers
Locating Oil fields
1. Magnetometer
An instrument used to measure the strength, direction of magnetic fields
Measure the change in earth’s magnetic field caused by oil flow
Locating Oil fields ( Cont. )
2. Gravimeter
An instrument used for measuring earth’s gravitational field
Typically designed to measure very tiny fractional changes in earth’s gravitational field
Tiny changes in gravitational field can give idea about oil flowing in earth
Locating Oil fields ( Cont. )
3. Satellite Imagery
Imagery is vital to exploration, geophysical surveying and in determining suitable drill sites based on surface conditions. A high-resolution image acquired prior to exploration and drilling activity serves as a baseline for other activities including site modeling, facilities monitoring, environmental assessments, and vegetation reclamation
4. Seismic surveys
creating shock waves that pass through hidden rock layers and interpreting the waves that are reflected back to the surfaceIn seismic surveys, a shock wave is created by the following:
• Compressed-air gun - shoots pulses of air into the water (for exploration over water)
• Thumper truck - slams heavy plates into the ground (for exploration over land)
• Explosives - detonated after being drilled into the ground (for exploration over land) or thrown overboard (for exploration over water)
Locating Oil fields ( Cont. )
Locating Oil fields ( Cont. )
4. Seismic surveys
Locating Oil fields ( Cont. )
5. Sniffers
They can detect the smell of hydrocarbons using sensitive electronic noses called sniffers.
High-tech devices that act like a "nose" are also used to detect traces of hydrocarbon gases that escape from below-surface oil deposits.
Drilling
• The oil well is created by drilling a hole into the earth
• A steel pipe (casing) is placed in the hole, to provide structural integrity to the newly drilled wellbore.
• Holes are then made in the base of the well to enable oil to pass into the bore
• Finally a collection of valves is fitted to the top, the valves regulating pressures and controlling flows.
Drilling Machine
Drilling
Primary Recovery
• During the primary recovery stage, reservoir drive comes from the natural mechanisms.
• Natural water displaces oil downward into the well.
• Recovery factor during the primary recovery stage is typically 5-15%
DrillingPrimary Recovery
Drilling
Secondary Recovery
• They rely on the supply of external energy into the reservoir in the form of injecting fluids to increase reservoir pressure, hence replacing or increasing the natural reservoir dry
• Other secondary recovery techniques increase the reservoir's pressure by water injection, natural gas reinjection and gas lift, which injects air, carbon dioxide or some other gas into the bottom of an active well, reducing the overall density of fluid in the wellbore with an artificial drive.
Drilling
Secondary Recovery
the recovery factor after primary and secondary oil recovery operations is between 35 and 45%.
Drilling (Secondary Recovery )
Drilling
Tertiary Recovery
• This type of method is used where oil is thicker and heavier than normal crude oil.
• Steam is injected into the oil reservoir to increase its mobility and thus reducing viscosity
• This method is also called Thermally Enhanced Oil Recovery method (TEOR).
Drilling (Tertiary Recovery )
• Some of the oil is burned to heat the surrounding oil
• In some cases, surfactants are added to alter the surface tension between oil and water
• Another method to reduce viscosity is carbon dioxide flooding
• Recovery rate is 5-15%
Tertiary Recovery
Recovery Rates
The amount of oil that is recoverable is determined by 3 major factors:
• Permeability of the Rocks
• The Strength of Natural Drives
• Viscosity of the Oil