Heavy oil is difficult to produce from wells unless it is heated or diluted and
steam is often the agent used to accomplish this.
There are two principal methods used:
- Cyclic Steam Stimulation
Assisted Gravity Drainage (SAGD)
Cyclic Steam Stimulation
High-pressure steam is injected into the formation for several weeks. The heat
softens the oil while the water vapor helps to dilute and separate the oil from
the sand grains. The pressure also creates channels and cracks through which the
oil can flow to the well. > n a portion of the reservoir is thoroughly
saturated, the steam is turned off and the reservoir “soaks” for several weeks.
This is followed by the production phase, when the oil flows, or is pumped, up
the same wells to the surface. he surface.
When production rates decline, another cycle of
steam injection begins. This process is sometimes called “huff-and-puff”
recovery and only involves vertical wells.
Steam Assisted Gravity Drainage(SAGD)
Steam Assisted Gravity Drainage (SAGD)
Until very recently, heavy oil fields were produced either by
primary production techniques, or through “huff’n puff”. These techniques
improve the percentage of reserves recovered but still leave behind significant
quantities of the original oil in place.some wells and producing oil through
others on a continuous basis. The heat reduces the viscosity of the oil thereby
significantly increasing production rates and the percentage of oil in place
that is recoverable.
The benefits of this continuous process have been demonstrated in other oil
fields where actual flow rates and projected total reserve recovery ratios have
shown a considerable improvement.ry
processes, can result in recovery rates of up to 80% of the original oil in
place in a heavy oil field such as the Tapia Canyon field.