Research On Bit Selection System Based On The Database

Bits are to crush the rock and stretch the well. The appropriate bit matching formation characteristics can enhance drilling speed and footage, and lower the drilling cost. So the standard of evaluating the formation drilling resistance and the method of selecting bit are both critical. According to the summary of the methods to evaluate the formation drilling resistance, the rock drillability and abrasiveness were selected to be the standards. Indoor experiments of acoustic time , micro-bit drillability, density and shale content were done. The emphasis was laid on the effects of lithology, density and shale content on the rock drillability, and these factors were introduced to found new compositive models to predict rock drillability, using acoustic logging, density logging and gamma logging. Then the formation lithology, drillability and abrasiveness were analyzed and evaluated, a profile of formation drilling resistance was erected.The Access data base was used to deal with the data of used bit, to calculate the formation drilling resistance, in order to found the corresponding relationship between the bit type and the formation. The primary selection of bits was done according to the formation drilling resistance of the planned well,using the method of iteration. Then the optimized bit was recommended according to the benefit index. A software was developed with VB6.0, which can predict the formation drilling resistance and select optimized bit according to the well logging data.