OPTIMIZING BIT TECHNOLOGY THROUGH WELL LOGGING AND ITS APPLICATION IN THE NORTHERN WORK AREA OF ORDOS BASIN

The formation strength characteristics in the work area are evaluated with the logging data and geological data after drilling to establish the quantitative relation between formation sonic differential time and rock drillability, then to estimate the level value of rock drillability of each interval. The formation drillability is graded and compared. According to the rock mechanics parameters as the grade value of drillability, hardness of formation and compressive strength, etc. and drilling condition, type of the bit is chosen to adapt the research work area using bit optimization method. Feasibility analysis and evaluation are made to the bit types of different horizons. The experimental study and application of the bit type selection in several wells demonstrate that drilling rate and bit footage have been improved. The drilling cycle has been shorten, and the cost of drilling reduced.