J Formation in Oilfield A of Syria is a rare low resistance limestone reservoir in the world,with high porosity,low permeable matrix reservoir and with resistance of 0.5~5.0 Ω·m lower than water layer. Because few studies have been made on the causes for this low resistance reservoir before,to correctly evaluate the reservoir,this paper analyzes the forming mechanism and dominating factors of low resistance carbon ate oil formation. We found that the special geological background is the basic of petrophysic...