Abstract: Through testing three microorganism adsorption rules on pipe walls and changes of wall′s wettability and alteration of the paraffin crystal structure，results indicate that paraffin control mechanism of microorganism is same as the waterfilm theory. That is, the microorganism adsorbs on the pipe wall, grows and produces the metabolite which forms biowaterfilm that changes the wettability of the pipe wall. It prevents the paraffin crystal adsorbing and depositing on the pipe wall or each other. The new mechanism has well explained the illogical phenomena that the paraffin control function has been existed when microorganism concentration reduced rapidly in the oilfield operation.

Key words: microorganism, mechanism of paraffin control, adsorption, wettability, adhere work