Cutting structure for roller cone drill bits

Abstract

New cutting structures for roller cone drill bits are disclosed. In one aspect, a drill bit includes a bit body, roller cones attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on each of the roller cones, such that axial force on the bit during drilling is substantially balanced between the cones. In another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that the amount of work performed by each cone during drilling is substantially the same as the amount of work performed by each of the other cones. In yet another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that distribution of axial force on the bit is optimized. Additional aspects of the invention are also disclosed.

What is claimed is:  
     
         1 . A roller cone drill bit for drilling an earth formation, comprising: 
 a bit body;    three roller cones attached to the bit body and able to rotate with respect to the bit body; and    a plurality of cutting elements arranged on each of the roller cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that axial force exerted on the bit during drilling is substantially balanced between the cones, wherein the axial force on the cones is determined by 
 selecting bit design parameters, comprising at least a geometry of a cutting element on said bit;  
 selecting drilling parameters, comprising at least an axial force on said bit;  
 selecting an earth formation to be represented as drilled;  
 calculating from said selected drilling parameters, said selected bit design parameters and said earth formation, parameters for a crater formed when one of a plurality of said cutting elements contacts said earth formation;  
 calculating a bottomhole geometry, wherein said crater is removed from a bottomhole surface;  
 simulating incrementally rotating said bit, and repeating said calculating of said crater parameters and said bottomhole geometry, based on calculated roller cone rotation speed and geometrical location with respect to rotation of said roller cone drill bit about its axis; and  
 summing axial force developed by each of said cutting elements in creating said craters.  
   
     
     
         2 . The drill bit according to  claim 1 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         3 . The drill bit according to  claim 1 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         4 . The drill bit according to  claim 1 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         5 . The drill bit according to  claim 1 , wherein said cutting elements are disposed on each cone, such that an amount of work performed by each cone during drilling is substantially the same as the amount of work performed by each of the other cones.  
     
     
         6 . The drill bit according to  claim 5 , wherein said amount of work performed by each cone differs by less than about 30% from the amount of work performed by each of the other cones.  
     
     
         7 . The drill bit according to  claim 5 , wherein said amount of work performed by each cone differs by less than about 20% from the amount of work performed by each of the other cones.  
     
     
         8 . The drill bit according to  claim 5 , wherein said amount of work performed by each cone differs by less than about 10% from the amount of work performed by each of the other cones.  
     
     
         9 . The drill bit according to  claim 5 , wherein the cones have volume cutting ratios of about 1.02, 1, and 1.08.  
     
     
         10 . The drill bit according to  claim 1 , wherein a distribution of time that each of a number of cutting elements contacts the formation during drilling thereof is substantially the same for each of the cones.  
     
     
         11 . The drill bit according to  claim 10 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of each of the other cones.  
     
     
         12 . The drill bit according to  claim 1 , wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.  
     
     
         13 . The drill bit according to  claim 1 , wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.  
     
     
         14 . The drill bit according to  claim 1 , wherein a distribution of axial force on the bit is optimized.  
     
     
         15 . The drill bit according to  claim 14 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         16 . The drill bit according to  claim 14 , wherein the cutting elements are disposed in rows on each of the cones so that axial forces on corresponding rows on each cone are substantially the same.  
     
     
         17 . The drill bit according to  claim 16 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         18 . The drill bit according to  claim 16 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         19 . The drill bit according to  claim 14 , wherein axial force on each cutting element on one cone is substantially the same as axial force on each corresponding cutting element on each of the other cones.  
     
     
         20 . The drill bit according to  claim 19 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         21 . The drill bit according to  claim 19 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         22 . The drill bit according to  claim 1 , wherein said cutting elements comprise superhard inserts.  
     
     
         23 . The drill bit according to  claim 22 , wherein said superhard inserts comprise boron nitride.  
     
     
         24 . The drill bit according to  claim 22 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         25 . The drill bit according to  claim 1 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         26 . The drill bit according to  claim 25 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         27 . The drill bit according to  claim 1 , wherein said cutting elements comprise milled steel teeth.  
     
     
         28 . The drill bit according to  claim 27 , wherein said cutting elements further comprise hardface coating.  
     
     
         29 . A roller cone drill bit, comprising: 
 a bit body;    three roller cones attached to said bit body and able to rotate with respect to said bit body; and    a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that an amount of work performed by each cone during drilling is substantially the same as the work performed by each of the other cones.    
     
     
         30 . The drill bit according to  claim 29 , wherein the work performed by each cone differs by less than about 30% from the work performed by each of the other cones.  
     
     
         31 . The drill bit according to  claim 29 , wherein the work performed by each cone differs by less than about 20% from the work performed by each of the other cones.  
     
     
         32 . The drill bit according to  claim 29 , wherein the work performed by each cone differs by less than about 10% from the work performed by each of the other cones.  
     
     
         33 . The drill bit according to  claim 29 , wherein said plurality of cones has normalized volume of formation cutting ratios of about 1.02, 1, and 1.08.  
     
     
         34 . The drill bit according to  claim 29 , wherein axial force exerted on the bit during drilling is substantially balanced between the cones.  
     
     
         35 . The drill bit according to  claim 34 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         36 . The drill bit according to  claim 34 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         37 . The drill bit according to  claim 34 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         38 . The drill bit according to  claim 29 , wherein a distribution of time that each of a number of cutting elements contacts the formation during drilling thereof is substantially the same for each of the cones.  
     
     
         39 . The drill bit according to  claim 38 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of the other cones.  
     
     
         40 . The drill bit according to  claim 29 , wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.  
     
     
         41 . The drill bit according to  claim 29 , wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.  
     
     
         42 . The drill bit according to  claim 29 , wherein a distribution of axial force on the bit is optimized.  
     
     
         43 . The drill bit according to  claim 42 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         44 . The drill bit according to  claim 42 , wherein the cutting elements are disposed in rows on each of the cones so that axial forces on corresponding rows on each cone are substantially the same.  
     
     
         45 . The drill bit according to  claim 44 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         46 . The drill bit according to  claim 44 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         47 . The drill bit according to  claim 42 , wherein axial force on each cutting element on one cone is substantially the same as axial force on each corresponding cutting element on each of the other cones.  
     
     
         48 . The drill bit according to  claim 47 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         49 . The drill bit according to  claim 47 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         50 . The drill bit according to  claim 29 , wherein said cutting elements comprise superhard inserts.  
     
     
         51 . The drill bit according to  claim 50 , wherein said superhard inserts comprise boron nitride.  
     
     
         52 . The drill bit according to  claim 50 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         53 . The drill bit according to  claim 29 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         54 . The drill bit according to  claim 53 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         55 . The drill bit according to  claim 29 , wherein said cutting elements comprise milled steel teeth.  
     
     
         56 . The drill bit according to  claim 55 , wherein said cutting elements further comprise hardface coating.  
     
     
         57 . A roller cone drill bit for drilling a formation, comprising: 
 a bit body;    three roller cones attached to said bit body and able to rotate with respect to said bit body; and    a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that a distribution of time that each of a number of cutting elements contacts a formation during drilling thereof is substantially the same for each of the cones.    
     
     
         58 . The drill bit according to  claim 57 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of the other cones.  
     
     
         59 . The drill bit according to  claim 57 , wherein axial force exerted on the bit during drilling is substantially balanced between the cones.  
     
     
         60 . The drill bit according to  claim 59 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         61 . The drill bit according to  claim 59 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         62 . The drill bit according to  claim 59 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         63 . The drill bit according to  claim 57 , wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed by each of the other cones.  
     
     
         64 . The drill bit according to  claim 63 , wherein the work performed by each cone differs by less than about 30% from the work performed by each of the other cones.  
     
     
         65 . The drill bit according to  claim 63 , wherein the work performed by each cone differs by less than about 20% from the work performed by each of the other cones.  
     
     
         66 . The drill bit according to  claim 63 , wherein the work performed by each cone differs by less than about 10% from the work performed by each of the other cones.  
     
     
         67 . The drill bit according to  claim 63 , wherein the cones have volume of formation cutting ratios of about 1.02, 1, and 1.08.  
     
     
         68 . The drill bit according to  claim 57 , wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.  
     
     
         69 . The drill bit according to  claim 57 , wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.  
     
     
         70 . The drill bit according to  claim 57 , wherein a distribution of axial force on the bit is optimized.  
     
     
         71 . The drill bit according to  claim 70 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         72 . The drill bit according to  claim 70 , wherein the cutting elements are disposed in rows on each of the cones so that axial forces on corresponding rows on each cone are substantially the same.  
     
     
         73 . The drill bit according to  claim 72 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         74 . The drill bit according to  claim 72 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         75 . The drill bit according to  claim 70 , wherein axial force on each cutting element on one cone is substantially the same as axial force on each corresponding cutting element on each of the other cones.  
     
     
         76 . The drill bit according to  claim 75 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         77 . The drill bit according to  claim 75 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         78 . The drill bit according to  claim 57 , wherein said cutting elements comprise superhard inserts.  
     
     
         79 . The drill bit according to  claim 78 , wherein said superhard inserts comprise boron nitride.  
     
     
         80 . The drill bit according to  claim 78 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         81 . The drill bit according to  claim 57 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         82 . The drill bit according to  claim 81 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         83 . The drill bit according to  claim 57 , wherein said cutting elements comprise milled steel teeth.  
     
     
         84 . The drill bit according to  claim 83 , wherein said cutting elements further comprise hardface coating.  
     
     
         85 . A roller cone drill bit, comprising: 
 a bit body;    three roller cones attached to said bit body and able to rotate with respect to said bit body;    a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.    
     
     
         86 . The drill bit according to  claim 85 , wherein axial force exerted on the bit during drilling is substantially balanced between the cones.  
     
     
         87 . The drill bit according to  claim 86 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         88 . The drill bit according to  claim 86 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         89 . The drill bit according to  claim 86 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         90 . The drill bit according to  claim 85 , wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed each of the other cones.  
     
     
         91 . The drill bit according to  claim 90 , wherein the work performed by each cone differs by less than about 30% from the work performed by each of the other cones.  
     
     
         92 . The drill bit according to  claim 90 , wherein the work performed by each cone differs by less than about 20% from the work performed by each of the other cones.  
     
     
         93 . The drill bit according to  claim 90 , wherein the work performed by each cone differs by less than about 10% from the work performed by each of the other cones.  
     
     
         94 . The drill bit according to  claim 90 , wherein the cones have volume of formation cutting ratios of about 1.02, 1, and 1.08.  
     
     
         95 . The drill bit according to  claim 85 , wherein a distribution of time that each of a number of cutting elements contacts the formation during drilling thereof is substantially the same for each of the cones.  
     
     
         96 . The drill bit according to  claim 95 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of the other cones.  
     
     
         97 . The drill bit according to  claim 85 , wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.  
     
     
         98 . The drill bit according to  claim 85 , wherein a distribution of axial force on the bit is optimized.  
     
     
         99 . The drill bit according to  claim 98 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         100 . The drill bit according to  claim 98 , wherein the cutting elements are disposed in rows on each of the cones so that axial forces on corresponding rows on each cone are substantially the same.  
     
     
         101 . The drill bit according to  claim 100 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         102 . The drill bit according to  claim 100 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         103 . The drill bit according to  claim 98 , wherein axial force on each cutting element on one cone is substantially the same as axial force on each corresponding cutting element on each of the other cones.  
     
     
         104 . The drill bit according to  claim 103 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         105 . The drill bit according to  claim 103 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         106 . The drill bit according to  claim 85 , wherein said cutting elements comprise superhard inserts.  
     
     
         107 . The drill bit according to  claim 106 , wherein said superhard inserts comprise boron nitride.  
     
     
         108 . The drill bit according to  claim 106 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         109 . The drill bit according to  claim 85 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         110 . The drill bit according to  claim 109 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         111 . The drill bit according to  claim 85 , wherein said cutting elements comprise milled steel teeth.  
     
     
         112 . The drill bit according to  claim 111 , wherein said cutting elements further comprise hardface coating.  
     
     
         113 . A roller cone drill bit, comprising: 
 a bit body;    three roller cones attached to said bit body and able to rotate with respect to said bit body;    a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that a depth of penetration for the cutting element into a formation during drilling is substantially the same for each of the cones.    
     
     
         114 . The drill bit according to  claim 113 , wherein axial force exerted on the bit during drilling is substantially balanced between the cones.  
     
     
         115 . The drill bit according to  claim 114 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         116 . The drill bit according to  claim 114 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         117 . The drill bit according to  claim 114 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         118 . The drill bit according to  claim 113 , wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed by each of the other cones.  
     
     
         119 . The drill bit according to  claim 118 , wherein the work performed by each cone differs by less than about 30% from the work performed by each of the other cones.  
     
     
         120 . The drill bit according to  claim 118 , wherein the work performed by each cone differs by less than about 20% from the work performed by each of the other cones.  
     
     
         121 . The drill bit according to  claim 118 , wherein the work performed by each cone differs by less than about 10% from the work performed by each of the other cones.  
     
     
         122 . The drill bit according to  claim 118 , wherein the cones have volume of formation cutting ratios of about 1.02, 1, and 1.08.  
     
     
         123 . The drill bit according to  claim 113 , wherein a distribution of time that each of a number of cutting elements contacts the formation during drilling thereof is substantially the same for each of the cones.  
     
     
         124 . The drill bit according to  claim 123 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of the other cones.  
     
     
         125 . The drill bit according to  claim 113 , wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.  
     
     
         126 . The drill bit according to  claim 113 , wherein a distribution of axial force on the bit is optimized.  
     
     
         127 . The drill bit according to  claim 126 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         128 . The drill bit according to  claim 126 , wherein the cutting elements are disposed in rows on each of the cones so that axial forces on corresponding rows on each cone are substantially the same.  
     
     
         129 . The drill bit according to  claim 128 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         130 . The drill bit according to  claim 128 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         131 . The drill bit according to  claim 124 , wherein axial force on each cutting element on one cone is substantially the same as axial force on each corresponding cutting element on each of the other cones.  
     
     
         132 . The drill bit according to  claim 131 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         133 . The drill bit according to  claim 131 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         134 . The drill bit according to  claim 113 , wherein said cutting elements comprise superhard inserts.  
     
     
         135 . The drill bit according to  claim 134 , wherein said superhard inserts comprise boron nitride.  
     
     
         136 . The drill bit according to  claim 134 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         137 . The drill bit according to  claim 113 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         138 . The drill bit according to  claim 137 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         139 . The drill bit according to  claim 113 , wherein said cutting elements comprise milled steel teeth.  
     
     
         140 . The drill bit according to  claim 139 , wherein said cutting elements further comprise hardface coating.  
     
     
         141 . A roller cone drill bit, comprising: 
 a bit body;    three roller cones attached to said bit body and able to rotate with respect to said bit body;    a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged such that a distribution of axial force on the bit is optimized.    
     
     
         142 . The drill bit according to  claim 141 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         143 . The drill bit according to  claim 141 , wherein the cutting elements are disposed in rows on each of the cones so that axial forces on corresponding rows on each cone are substantially the same.  
     
     
         144 . The drill bit according to  claim 143 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         145 . The drill bit according to  claim 143 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         146 . The drill bit according to  claim 141 , wherein axial force on each cutting element on one cone is substantially the same as axial force on each corresponding cutting element on each of the other cones.  
     
     
         147 . The drill bit according to  claim 146 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         148 . The drill bit according to  claim 146 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         149 . The drill bit according to  claim 141 , wherein axial force exerted on the bit during drilling is substantially balanced between the cones.  
     
     
         150 . The drill bit according to  claim 149 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         151 . The drill bit according to  claim 149 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         152 . The drill bit according to  claim 149 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         153 . The drill bit according to  claim 141 , wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed by each of the other cones.  
     
     
         154 . The drill bit according to  claim 153 , wherein the work performed by each cone differs by less than about 30% from the work performed by each of the other cones.  
     
     
         155 . The drill bit according to  claim 153 , wherein the work performed by each cone differs by less than about 20% from the work performed by each of the other cones.  
     
     
         156 . The drill bit according to  claim 153 , wherein the work performed by each cone differs by less than about 10% from the work performed by each of the other cones.  
     
     
         157 . The drill bit according to  claim 153 , wherein the cones have volume of formation cutting ratios of about 1.02, 1, and 1.08.  
     
     
         158 . The drill bit according to  claim 141 , wherein a distribution of time that each of a number of cutting elements contacts the formation during drilling thereof is substantially the same for each of the cones.  
     
     
         159 . The drill bit according to  claim 158 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of the other cones.  
     
     
         160 . The drill bit according to  claim 141 , wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.  
     
     
         161 . The drill bit according to  claim 141 , wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.  
     
     
         162 . The drill bit according to  claim 141 , wherein said cutting elements comprise superhard inserts.  
     
     
         163 . The drill bit according to  claim 162 , wherein said superhard inserts comprise boron nitride.  
     
     
         164 . The drill bit according to  claim 162 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         165 . The drill bit according to  claim 141 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         166 . The drill bit according to  claim 165 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         167 . The drill bit according to  claim 141 , wherein said cutting elements comprise milled steel teeth.  
     
     
         168 . The drill bit according to  claim 167 , wherein said cutting elements further comprise hardface coating.  
     
     
         169 . A roller cone drill bit, comprising: 
 a bit body;    three roller cones attached to said bit body and able to rotate with respect to said bit body;    a plurality of cutting elements arranged on each of the roller cones so that cutting elements on adjacent cones intermesh between the cones, the cutting elements being generally arranged in rows on each cone so that axial forces on corresponding rows on each cone are substantially the same.    
     
     
         170 . The drill bit according to  claim 169 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         171 . The drill bit according to  claim 169 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         172 . The drill bit according to  claim 169 , wherein a distribution of axial force on the bit is optimized.  
     
     
         173 . The drill bit according to  claim 172 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         174 . The drill bit according to  claim 172 , wherein axial force on each cutting element on one cone is substantially the same as axial force on each corresponding cutting element on each of the other cones.  
     
     
         175 . The drill bit according to  claim 174 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         176 . The drill bit according to  claim 174 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         177 . The drill bit according to  claim 169 , wherein axial force exerted on the bit during drilling is substantially balanced between the cones.  
     
     
         178 . The drill bit according to  claim 177 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         179 . The drill bit according to  claim 177 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         180 . The drill bit according to  claim 177 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         181 . The drill bit according to  claim 169 , wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed by each of the other cones.  
     
     
         182 . The drill bit according to  claim 181 , wherein the work performed by each cone differs by less than about 30% from the work performed by each of the other cones.  
     
     
         183 . The drill bit according to  claim 181 , wherein the work performed by each cone differs by less than about 20% from the work performed by each of the other cones.  
     
     
         184 . The drill bit according to  claim 181 , wherein the work performed by each cone differs by less than about 10% from the work performed by each of the other cones.  
     
     
         185 . The drill bit according to  claim 181 , wherein the cones have volume of formation cutting ratios of about 1.02, 1, and 1.08.  
     
     
         186 . The drill bit according to  claim 169 , wherein a distribution of time that each of a number of cutting elements contacts the formation during drilling thereof is substantially the same for each of the cones.  
     
     
         187 . The drill bit according to  claim 186 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of the other cones.  
     
     
         188 . The drill bit according to  claim 169 , wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.  
     
     
         189 . The drill bit according to  claim 169 , wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.  
     
     
         190 . The drill bit according to  claim 169 , wherein said cutting elements comprise superhard inserts.  
     
     
         191 . The drill bit according to  claim 190 , wherein said superhard inserts comprise boron nitride.  
     
     
         192 . The drill bit according to  claim 190 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         193 . The drill bit according to  claim 169 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         194 . The drill bit according to  claim 193 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         195 . The drill bit according to  claim 169 , wherein said cutting elements comprise milled steel teeth.  
     
     
         196 . The drill bit according to  claim 175 , wherein said cutting elements further comprise hardface coating.  
     
     
         197 . A roller cone drill bit, comprising: 
 a bit body;    three roller cones attached to said bit body and able to rotate with respect to said bit body;    a plurality of cutting elements arranged on each of the cones so that cutting elements on adjacent cones intermesh between the adjacent cones, the cutting elements being arranged so that axial forces on cutting elements on one cone are substantially the same as axial forces on corresponding cutting elements on each of the other cones.    
     
     
         198 . The drill bit according to  claim 197 , wherein axial force on cutting elements on each cone is within about 50% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         199 . The drill bit according to  claim 197 , wherein axial force on cutting elements on each cone is within about 25% of the axial force on the corresponding cutting elements on each of the other cones.  
     
     
         200 . The drill bit according to  claim 197 , wherein a distribution of axial force on the bit is optimized.  
     
     
         201 . The drill bit according to  claim 200 , wherein the cutting elements are disposed in rows on each of the cones so that the distribution of axial force on the bit is substantially unimodal.  
     
     
         202 . The drill bit according to  claim 200 , wherein the cutting elements are disposed in rows on each of the cones so that axial forces on corresponding rows on each cone are substantially the same.  
     
     
         203 . The drill bit according to  claim 202 , wherein axial forces on corresponding rows balance to within about 50%.  
     
     
         204 . The drill bit according to  claim 202 , wherein axial forces on corresponding rows balance to within about 25%.  
     
     
         205 . The drill bit according to  claim 197 , wherein axial force exerted on the bit during drilling is substantially balanced between the cones.  
     
     
         206 . The drill bit according to  claim 205 , wherein said axial force on the bit is balanced within about 25% between cones.  
     
     
         207 . The drill bit according to  claim 205 , wherein said axial force on the bit is balanced within about 10% between cones.  
     
     
         208 . The drill bit according to  claim 205 , where said axial force on the bit is balanced between the cones in a ratio of about 1.09, 1, and 1.03.  
     
     
         209 . The drill bit according to  claim 197 , wherein said cutting elements are disposed on each cone, such that work performed by each cone during drilling is substantially the same as the work performed by each of the other cones.  
     
     
         210 . The drill bit according to  claim 209 , wherein the work performed by each cone differs by less than about 30% from the work performed by each of the other cones.  
     
     
         211 . The drill bit according to  claim 209 , wherein the work performed by each cone differs by less than about 20% from the work performed by each of the other cones.  
     
     
         212 . The drill bit according to  claim 209 , wherein the work performed by each cone differs by less than about 10% from the work performed by each of the other cones.  
     
     
         213 . The drill bit according to  claim 209 , wherein the cones have volume of formation cutting ratios of about 1.02, 1, and 1.08.  
     
     
         214 . The drill bit according to  claim 197 , wherein a distribution of time that each of a number of cutting elements contacts the formation during drilling thereof is substantially the same for each of the cones.  
     
     
         215 . The drill bit according to  claim 214 , wherein a fraction of a total time any number of cutting elements on each cone contacts the formation differs by less than about 20% from the fraction of the other cones.  
     
     
         216 . The drill bit according to  claim 197 , wherein a projected area of said cutting elements in contact with a formation during drilling is substantially the same for each of the cones.  
     
     
         217 . The drill bit according to  claim 197 , wherein a depth of penetration for each cutting element into a formation during drilling is substantially the same for each of the cones.  
     
     
         218 . The drill bit according to  claim 197 , wherein said cutting elements comprise superhard inserts.  
     
     
         219 . The drill bit according to  claim 218 , wherein said superhard inserts comprise boron nitride.  
     
     
         220 . The drill bit according to  claim 218 , wherein said superhard inserts comprise polycrystalline diamond compacts.  
     
     
         221 . The drill bit according to  claim 197 , wherein said cutting elements comprise tungsten carbide inserts.  
     
     
         222 . The drill bit according to  claim 221 , wherein said cutting elements further comprise a superhard material coating.  
     
     
         223 . The drill bit according to  claim 197 , wherein said cutting elements comprise milled steel teeth.  
     
     
         224 . The drill bit according to  claim 223 , wherein said cutting elements further comprise hardface coating.  
     
     
         225 . The drill bit according to  claim 29 , wherein the work performed by the cones is determined by: 
 calculating an amount of axial and lateral movement of said cutting elements through said formation;    calculating an amount of said axial force on bit sustained by each of said cutting elements through said formation and an amount of lateral force from said lateral movement; and    calculating from said axial force, said axial movement, said lateral force and said lateral movement the work performed by each of the cutting elements, the work performed by each said cone determined as a sum of the work of cutting elements disposed on each of the cones.    
     
     
         226 . The drill bit according to  claim 1 , wherein the axial force on the cones is determined by measuring strain in the bit body proximal to each cone during a drilling test operation of the bit.  
     
     
         227 . The drill bit according to  claim 1 , wherein the axial force on the cones is determined by measuring strain at distributed positions in a formation sample as the sample is drilled by the drill bit; measuring rotary orientation of the bit corresponding to each measurement of strain; and correlating the orientation to the strain measurements.