The LF7-2 Oilfield is a small-scale oilfield located in the LF block of the Pearl River Mouth Basin in the South China Sea. According to previous exploration wells， the upper stratum is dominated by thick mudstone which is easily hydrated and dispersed， leading to poor performance of the drilling fluid， frequent drilling string sticking and resistance during tripping， and bit balling due to improper bit selection. The lower stratum is dominated by alternate sand and mudstone which is dense， and of poor drillability. As a result， the drilling torque/drag increased with difficulty in slide drilling and control of the well trajectory during directional drilling， which brough many difficulties to the drilling speed and efficiency. According to the geological conditions and rock mechanics profiles from exploratory wells， drilling software was used to optimise the platform location and simulate development well drilling in terms of the wellbore structure， wellbore trajectory， drill string mechanics， drilling fluid， cementing and other aspects， so as to formulate proper drilling design. For the vertical well section， the “rock bit+mudmotor+MWD” drill assembly was used for vertical drilling； for build-up sections， the “PDC bit+mudmotor+MWD/LWD” was used for compound drilling； and for horizontal sections， the “PDC bit+PowerDriver+MWD/LWD” was used for rotary steering drilling to achieve precision drilling. In such a way， 6 development wells were successfully completed. Field use indicated the average ROP was 29.43m/h with the total drilling period per well of 191.59 days， 28.41 days ahead of the design， which improved drilling efficiency， and reduced development costs. Near-bit inclination and gamma real-time measurement and transmission of PowerDriver reduced geological misdiagnosis， and can provide real-time detection of the roof of the reservoir with the reservoir intersection rate reaching 100%， resulting in good economic benefits and investment return to achieve profitable development of small oilfields.