Research About The Fractal Tepresentation Of Rock Drillability

The active way to fix on the rock drillability needs to test mechanics of the rock sample withlaboratory experiment, or simulate the actual condition and use the micro bit method to researchthe drillability index. Although the test result with the micro bit method has a high coincidence,the laboratory experiment lags to the actual drilling, has the more expenses and the longer cycle.So it disturbs the improvement of the drilling speed.In order to solve these problems, the article propounds a kind of test method to fix on the rockdrillability classification number with the fractal geometry principle;the abbreviated name of themethod is the rock drillability fractal graduation. Objecting to the drilling cuttings returned frombottom hole, the method can test and catch sample simultaneously. In this way, it can not onlycomplete test while drilling, but also can radically solve the flaws of coring posterity and highcost. Through dealing with the upward debris standardly, the method can commendably removethe influence that different break rock implements and drilling fluid conditions have effects onthe upward debris' grain grade distribution. The experimentation indicates that the debris' massdistribution has a good linearity. The regress correlating modulus is above 0.85 and the debriswith standard broken has the higher pertinent (above 0.96).Based on these data, we can concludethat the upward debris' grain grade distribution is fractal.Through doing the micro bit experiment in the laboratory, we ascertain the measurementstandard of the rock drillability. If we establish the relationship between fractal dimension andthe microbit drillability grade, we will establish the relationship between fractal dimensionand rock drillability. The test result indicates that the regress correlating modulus between fractaldimension and microbit drillability grade is above 0.7227. According to the result, we constitutethe predicting index of the rock drillability which based on the fractal dimension of the debrisgrade distribution. After sample examination, the error fluctuates between 2%-11%, and theoverall mean value is 6.5%. It is obvious that it has very high precision with the fractal methodto describe the rock drillability grade.