Equipment for start-up of in situ combustion

The two general types of downhole heaters employed in the ignition well to start-up the combustion process in the bed are (a) flame heaters, using either natural gas or liquid fuel and (b) AC-powered electric heaters. Variants of these two main types of heaters have been constructed in Russia and abroad. 

Natural Gas Heaters They can be of three different designs  

Gas heaters of other designs also exist, e.g., diffusor heaters and micro-flares or microtorches. Depending on the design of the gas heater, it can be lowered to the wellbottom by a line, cable, or on the end of a string of tubing. 

The air/oxidizer is injected into the ignition well through the annular space. A pordon of the air is forced into the heater by the injector. The remaining part flows on the outside of the heater along the tail pipe down towards the bottomhole. Here, the air flow insures combustion of the gas fuel and, by entering the formation, it also participates in the in situ oxidation of the crude oil. 

1-gas chamber provided with inlet openings 2-cable 3-nozzle 4-ejector 5-perforated 4.5 m long tail pipe enclosed in a perforated metal sleeve 6-electrical or chemical ignition device affixed on the outside to the upper end of the tail pipe. 

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