Abstract: Slim hole drilling technology can be used to recover the low permeability poor reservoirs efficiently, as the conventional development method costs too much and produces little profits. Study and tests of this technology have been conducted in such oilfields as Daqing, Jiling and Changqing in China, and its applications in different types of low permeability reservoirs have been investigated and evaluated. It concludes that the slim drilling technology can largely reduce drilling costs, and extensive specialized slim hole drilling equipment and technologies are essential for effective development of low permeability reservoirs.