The Ordovician carbonate reef-bank complex reservoirs in the Lungudong area of the Tarim Basin are the important exploration targets in the recent development scheme of Tarim Oilfield Company.The reservoir rocks mainly include sparry grainstone

fine-granular grainstone

mieritic grainstone

and micrite

among which the sparry grainstone has much better poroperm characteristics.Matrix porosity of these reservoirs are low with dissolution vugs and fractures as the main pore space.The reservoirs can be divided into the following four types :cavity

vug

fracture

and fracture-vugg

whose development was dominated by sedimentary facies

solution

and fracturing.The Ordovieian carbonate reef-bank reservoirs in the Lungudong area are characterized by extensive

superimposed and continuous distribution.