The Footage Cost And Bit Optimization Base On Fractal Method In Xushen Stratum

These years the oil and gas exploration gradually extended to deep formation，the depthbegan to increase，the maximum depth has reached to5500m.The workload and the costs ofdrilling became to increase, the drilling speed became to reduce duo to high rock drillability，high rock abrasiveness and mechanical properties change of the rock.A new method apply fractal method to analyze the drilling costs is put forward. Thismethod base on the study on reservoir characteristics and stratigraphic drilling characteristicsin Xushen strata，by studying the grain size distribution of the rock to calculate fractaldimension，analyze the energy of the drilling process to establish the crushing work ratiomodel of rocks in actual drilling situation. Apply the model to determine the relationshipbetween the drilling costs and the crushing work ratio to analyze the drilling costs in Xushenstrata. The drilling parameter calculated in Xushen area indicates that it is feasible to applycrushing work ratio model to analyze the drilling costs. This method provides a new way toreduce the drilling costs in Xushen regions.A new method that applying analytic hierarchy process based on index scale tooptimization the bit is put forward. This method establish comparison matrix base on fullyconsistent theory，the matrix ratings of the degree of importance have the advantage ofconsistency and transitivity，therefore abolish consistency test in the traditional analytichierarchy process, simplify the calculation process. Through the combination of hierarchicaland fractal dimension to select the adjacent ratio of Importance, reduce the impact of the ratioof the adjacent important degree disturbance on the optimization results. Through thecombination of hierarchical and fractal dimension to select the adjacent ratio of Importance,reduce the impact of the ratio of the adjacent important degree disturbance on theoptimization results, effectively ensure the accuracy of the bit optimization model result,enhance the stability and flexibility of the model. This model can apply to different regionsaccording to actual requirements to solve different types of drill bits problem. The bitoptimization results in Xushen regions show that the new bit optimization model can preciseoptimize the bit. This method provides a new way to optimize the bit in Xushen regions.