Study on rock mechanics parameters and drill bit selections for Liuhua oilfield in South China Sea

Rational selection of the bit type is of major importance in achieving high penetration rates and reducing drilling comprehensive cost. Drill bit using effects were evaluated by use of improved benefit exponential model.Combined with evaluation results of rock mechanics parameters,bit type for Liuhua oilfield was optimized.Because of considering bit wear,improved benefit exponential model was more reasonable.According to rock mechanics parameters,Formation was classified for lack of formation classification data.It is very important for selecting bit type,optimizing drilling parameters and programming drilling measures.According to the method for formation classification,many rock mechanics parameters were clustered.Then formation was classified on the least square which was least in interior formation and was greatest in interbedded formation.The field test results indicate that bit selection result and formation classification method are feasible.