Abstract: By applying fractal theory to study Ordovician fault and reservoir fracture in Lunnan area in northern Tarim basin, it is shown that the distribution of fault and reservoir fracture in study area is of fractal structure and strong autocorrelation (correlation coefficient more than 0.99).Further study showed that the fault distribution trend in plane corresponds to fracture developed belt of reservoir.Reservoir is the key to explore oil in carbonate rock.In order to clarify hydrocarbon potential of Ordovician in Lunnan area, we should start to operate in the district with best-reservoir quality. Fractal study showed that the west platform has the best-reservoir quality in Lunnan area, and therefore is the first block of oil and gas exploration.

Key words: Tarim basin, Lunnan oilfield, Ordovician, Fault, Reservoir, Fracture, Fractal