Study And Application Of Bit Selection For Zhongyuan Oil Field

Correct bit selection is one of the key techniques that can improve both the drilling rate and footage largely increased. A method that built with advanced models which can evaluate the formation characters and select drill bit properly is what the drilling industry desired. On the basis of theoretical analysis, lab experiments and application in Zhongyuan oil field, this dissertation presents a new formation evaluation and bit selection method. Visual Basic and Delphi were selected to programme the formation evaluation and bit selection softwares, and the developed softwares have been applied in real drilling management to validate the developed model. The comparision of the neighbor wells drilling data proves the feasibility and trustbility of the model and software. The main content includes:Based on the evaluate the formation characters by logging data, the formation classification method was set up , which can apply in oil field easily and lay a foundation of bit selection, integrating the discussion of the classification criterion, classification method and questions in the formation classification at the same time. Bit integration index R and selection method was advanced, which integrate the actual well drilling date, bit parameters, footage and cost per meter. This method makes bit selection measurable.Through the lab rock experiments, acoustic tests and cutting tests, the experimental relationship was built between the rock drillability and sonic interval transit time. By the relationship, the Zhongyuan oil field rock drillability can be calculated easily. And, the cutting test technique was put forward, which can evaluate the formation lack of core data. Based on the theory analyses of rock breaking, we evaluate formation drilling character with the triaxial compression strength, get the empirical relationship between PDC bit cutting structure and the triaxial compression strength, and establish the selection method of PDC bit with the triaxial compression strength.The Formation Evaluation and Bit Selection in Zhongyuan Oil Field software was developed by Visual Basic and Delphi language, with fault tolerance strong, accurate calculation, simple, interactive nature, and better portability.Through the application in PuCheng and WeiCheng in Zhongyuan oil field, formation evaluation and bit selection were performed. Compared with similar well, an average increase of 18.6% in the footage of single bit, the average penetration rate increase of 13.8%, an average of 7.1% to shorten the drilling cycle.