A Study On The Forecast And Application Of Rock Drillability

Rock drillability is a mechanical parameter which characterizes weather rock is easy breaking or not, which contains abundant messages. It not only synthesis manifests the formation properties, but also can reflect the current craft and the technical factors. In predicting and calculating the rock drillability, the active method to estimate the rock drillability needs to bore with sampling, do laboratory experiments and tests. Due to the downhole lithology is complex and the core changes very largely, it is unable to bore with sampling to the whole formation and hard to establish the series section. In application of the rock drillability, the domain research results use in most in optimizing the bit type and designing the bit parameters in different formations. Therefore, it is extremely important to enhance drilling speed and reduce drilling cost which by more accurate, continual, real-time forecasting rock drillability and expanding the drillability application scope to optimize drilling mechanical parameters and the water power parameters in different formations.Aiming at the above questions, the article deeply studies on synthesis prediction and application of the rock drillability. Firstly, through analyzing the earthquake information, the logging information and the returns rock debris information, and combining the data of the rock mechanics parameters which is based on the experiments, the integration forecasting rock drillability mathematical model with earthquake information, the loggng information and the upward information is established. The method can evaluate the rock drillability in drilled area and exploration areas, establish series section in real time. Simultaneously, the article also puts forward the method of formation separation compute on rock drillability by fuzzy clustering analysis. Secondly, the paper elaborates on the drill bit optimal process and the mechanism with the rock mechanics parameters method and the combined benefit exponential method. Finally,through massive field test and the laboratory experiments,using statistical analysis methods (multiple regression analysis and principal components analysis), the drilling rate model on the basis of the drillability, bit wear model and the mathematical model of optimization for the drilling parameters are established. The model is versatile and parameters are conveniently gained. Related techniques and conditions are provided for drilling parameters optimization to particular oil fields.