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The method of rock drillability classification-Yikuang Science and Technology.
Release time:
2019-11-04
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1. Mechanical property index method
A single mechanical property is used to classify the drillability level of rock. According to the press-in hardness valueRockIt is divided into 6 categories and 12 levels. According to the rebound times of the pendulum ball, the rock is divided into 12 levels. If the drillability levels determined by the two methods are inconsistent, the drillability K value can be determined according to the regression equation (1-17) including the indentation hardness value Hy and the pendulum ball hardness value Hn.
K = 3.198 8.854 × 10-4Hy 2.578 × 10-2Hn
2. Actual drilling speed method
The actual drilling is carried out under the conditions of the specified equipment, tools and technical specifications, and the penetration rate is used as the drillability level of the rock. As technology advances, it must be corrected in real time. The former Ministry of Geology and Mines has developed a rock drillability suitable for diamond drilling.
3. Micro-drilling method
The simulated micro-impregnated diamond bits are used to carry out drilling tests on the cores according to certain procedures.
The specification of the former Ministry of Geology and Mineral Resources: the average drilling speed of micro-drill is taken as the drillability index of rock, which is divided into 12 levels.
The specification of the original Ministry of Petroleum: drill three holes with a depth of 2.4mm on the rock sample with a micro-drill, take the average of the drilling time of the three holes as the drilling time t, and take it as the drillability grade of the rock sample after rounding. The drillability of the oilfield formation can be divided into 10 grades. The higher the grade, the more difficult it is to drill.
Kd=log2t（1-18）
4. Crushing ratio method
When the cylindrical indenter is used for the indentation test, the crushing work can be calculated from the pressure and depth curve, and then the crushing specific work per unit contact area AS can be calculated, and the rock drillability can be divided into 10 grades according to the crushing specific work method.
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