Abstract: Hanjiang reservoir formation is shallowly buried with un-cemented and unconsolidated oil sands in oilfield located at the east of the South China Sea. The coring recovery in this formation is only 30%~50% with conventional tools due to the serious washout during operation. Loss of centering and stability, together with high torque of the drill pipe in high inclination directional well will exacerbate the coring difficulties. We analyze the factors affecting the coring recovery in un-cemented and unconsolidated oil sands. Through selecting the coring tools, optimizing the drilling tools combination, starting from the mudstone caprock above oil sand, adjusting the drilling parameters and improving technical measures, coring operation is achieved with high recovery of 78.7% which exceeds the coring recovery of 50% stipulated in industry standard of China.