Assets

Thermal Oil Recovery

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:
  1. Cyclic Steam Stimulation
  2. Steam Assisted Gravity Drainage (SAGD)

Cyclic Steacyclic 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. >

When 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.

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)

SCHEMATIC (7)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.

This technique, particularly when used together with other steam recovery 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.