Thermal EOR

Thermal recovery techniques principally targets crude oil with very high density  ( < 20 deg API ) which cannot flow on its own. These methods raise the temperature of the reservoir which in turn reduces the viscosity of the crude and breaks the larger crude oil molecules into smaller molecules. The heat also reduces the surface tension and improves the overall mobility of the crude.

Some of the major techniques that are employed in the industry :

• Cyclic Steam Stimulation
• Steam Flood
• In-Situ Combustion

Cyclic Steam Stimulation or more commonly known as the "Huff and Puff" method uses a single well to inject steam into the reservoir over a period of time such as two weeks. This is called the Injection Period. This is followed by the Soak Period where in the well is shut to allow the reservoir to be heated by the steam. The same well is then used to produce from the reservoir.  This entire process is then repeated over a number of cycles.

Cyclic Steam Stimulation

In the Steam Flood, as the name suggests, superheated steam is pumped into the heavy oil reservoir. The steam heats the oil to reduce the viscosity. As the heat content of the steam declines, it condenses into hot water that pushes  the oil towards the producing wells.

An In-Situ Combustion involves lighting the heavy crude in the reservoir on fire. Spontaneous combustion is generated by pumping air into the reservoir. Once the fire is generated, the heat  causes the oil to reduce viscosity improving the flow. The air pumped into the reservoir to sustain the combustion and the large volume of hot gasses generated during combustion pushes the crude to the producing well.

In Situ Combustion