MXPA98007858A - Method of regulating the perforation conditions applied to a bit for p - Google Patents

Abstract

The present invention relates to a method of regulating drilling conditions applied to a given drill bit comprising testing the compressive strength of the formation in a range to be punctured by said drill. The wear of the critical drill structure of the same size and design as in said given drill bit and which structure has drilled material of approximately the same compressive strength as the tested, is analyzed together with respective drilling data for the spent structure of the drill. said analysis, a power limit for the respective compressive strength is determined, over which power limit it is feasible that excessive wear occurs. The drilling conditions, such as the speed of rotation and the weight on the bit, to which the given bit is operated, are regulated to maintain a desired operating power less than or equal to the power limit, where several feasible combinations of speed of rotation and weight on the drill bit can result in the desired operating power, these conditions are optimized

Description

METHOD OF REGULATING THE PERFORATION CONDITIONS APPLIED TO A WELL DRILL Background of the Invention The present invention is relased with the regulation, and preferably the optimization, of drilling conditions, specifically the rotating speed and the weight-on-the-bit, which is applied to a drill for wells. As used herein, the term "well drill" includes drill bits for ordinary wells, as well as diamond drill bits that produce ingots. In the past, the regulation of these drilling conditions has been more a matter of tenesis (or even divination work), than of siensia. To the knowledge of the inventor of the present, there have been at least a few efforts to have a more scientific approach to this regulation. For example, U.S. Patent No. 5,449,047 describes the "automatic" sontrol of a drilling system. The basic approach is simply to maintain a given depth of cut (per revolution) for a given range of resistance to compression of the rock. The "Best Constant Weight and Rotary Speed for Rotary Rock Bits, "by EM Galle and HB Woods, API Drillins and Production Practice, 1963, pages 48-73, describes a method which operates on the assumption that, in any given drilling operation, whether the weight-on -the brosa changes, the rotating velocity will change automatically according to this (and / or vice versa) so that the product of the weight-on-the-bit and the rotating speed will remain constant throughout the entire drilling operation. (The inventors from the present have found that, although a change in one of these variables could cause a responsive change in the other, the assumption that the product of the two remains constant is not valid.) Following this assumption, the method it includes the use of laboratory tests to sample the weight-on-the-roughness symbioses and rotating velosity that result in the failure of the brosa, and avoid such combinations.Other technical document, "Drilling Parameters and the Journal Bearing Bit, "by H. Word and M. Fisbeck, presented at the 34th Annual Conference of Mechanical Engineering of Petroleum, Tulsa, Okiahoma, 1979, highlights the last mentioned document, but does not change the basic assumption and methodology. None of the above methods optimizes the total perforation operation as well as they could. SUMMARY It appears that the present invention provides a more universally valid criterion for avoiding sweat minus the satastrophic wear of the brosa, and in the preferred embodiments of the invention, also avoiding the unacceptable accelerated rates of wear of the bit, so that a balance can be achieved between the life of the bit and other parameters, such as the speed of penetration. Although the drilling conditions that have been regulated lately are preferably the rotating speed and the weight-on-the-bit, the criterion mentioned above is neither, nor the other, neither the two parameters by themselves, but rather It's the energy. By using energy as the basic criterion, it is possible, in the preferred forms of the invention, to provide a selection of rotating speed and weight-on-the-bit combinations that will achieve the desired energy, and then to use yet another criteria to optimize within this range. In the most basic form of the present invention, the compressive strength of the formation in a range to be drilled by the drill is tested. The critical bit structure of the same size and design as in the given bit is analyzed, and the structure of which has drilling material of approximately the same compressive strength as that with which it was tested, together with the drilling data Resistant to the worn structure. From this analysis, the energy limit for the respective compressive strength is determined. About this energy limit, undesirable wear of the drill is likely to occur. In the very basic forms of the present invention, the "undesirable" bit wear can be chosen as the catastrophic failure of the bit. However, in the most highly preferred embodiments, the accelerated rates of undue wear are considered undesirable, and are avoided by the use of the energy limit. In any case, this is done by regulating the drilling conditions at which the given drill is operated to maintain a desired operating energy less than or equal to the energy limit. The "srítisa structure" that is analyzed is defined as the structure that, in the given design, will probably wear out more quickly and / or fail first, so that this structure is the limiting factor in the life of the drill For example, in polycrystalline diamond compact ("CDP") type drill bits, polycrystalline diamond cutters or compacts will usually be the critical structure. On the other hand, in roller cone-type drills, the critical structure is typically the structure of the bearing or journal. In the preferred embodiments of the invention, a plurality of these substrates and their respective perforation data are analyzed. From those analyzes, a first series of types of correlated pairs of electrical signals is generated. The two signals of each of these pairs corresponds, respectively, to the wear velocity and the operating energy for one of the respective stresses. The energy limit is generated from these signals of the first series of types. An advantage of analyzing the multiple critical structures and generating these series of correlated pairs of signals is a greater degree of certainty in determining an energy limit above which excessively accelerated wear occurs (as opposed to total failure). In this way, these preferred embodiments can do more than simply avoid catastrophic wear of the bit, they can balance a reasonable wear rate (and thereby balance the life of the bit), compared to other factors such as the range of penetration. "Corresponding," as used herein, with respect to the signals or numerical values, shall mean "functionally related", and it shall be understood that the function in question could, but need not, be a simple equivalence relation. "Corresponding precisely to," if used with respect to an electrical signal, will mean that the signal directly translates the value of the same parameter in question. You can define "wear speed" of a part of the drill bit in units of length (measured from the external profile of the new part) by unit time or material volume (of the part) per unit time . The regulated drilling conditions are preferensia the rotating speed and the weight-on-the drill, In general, it is preferable to build in a safety factor, that is, to maintain the energy level in some way less than the energy limit, but approximately as close to the limit as reasonably possible. In this way, for example, "reasonably" includes the use of the safety factor mentioned above, as well as the adjustment for several pragmatic limitations in the drilling conditions that will be regulated. By way of a more specific example, a given equipment may have a limit on the rotating speed that does not allow the operation so cersa the limit of energy could be, theoretically, desired, even considering the safety factor. Similarly, in a hole that is not yet very deep, it would be a practical impossibility to apply enough weight-on-the-bit to operate as close to the energy limit as would be theoretically desirable. Preferred embodiments of the invention additionally comprise the generation of a second series of correlated pairs of signaling pairs., the respective signals of each pair corresponding to a rotating speed value and a weight-on-the-bit value, and where the values of the rotary speed and the weight-on-the-bit of sada pair, theoretically result an energy that corresponds to the energy limit. In other words, even for a constant resistance of the rock and the weariness of the bit, there are a number of different combinations of rotating speed and weight-on-the-bit that could theoretically result in an energy at the limit mentioned above. The drill is preferably operated at a rotating speed and a weight on the drill that corresponds to one of the pairs of signals in this second series. Recalling that "corresponding to" means functionally related to, one should understand that this could very well mean that the bit can be operated at rotational speed and weight values on the bit slightly less than those corresponding precisely to one of the pairs of signals, by means of which a safety factor is included, for example, because some vibrations could almost always occur in the bit. It is also possible to determine a rotational speed limit, for the sake of the sual it is possible that there are disadvantageous drill movement characteristics, such as axial and lateral vibrations of the floor and violent turns of the bit. In this way, although operation above this speed limit may result in the desired energy, it is preferable to operate the bit below this rotational speed limit. Likewise, it is possible to determine a limit of weight-on-the-bit for the energy limit, above which other types of highly disadvantageous movement faces of brosa are likely to occur, such as torsional floor vibrations and the so-called "stick slip", and it is also desirable in the same way to operate the drill bit to a weight-on-the-bit below this latter limit.

In the preferred embodiments, a marginal rotational speed is determined for the energy limit, the marginal rotational speed of which is less than the aforementioned rotational speed limit, above which undesirable drill motion characteristics may occur, such as increasing axial and lateral vibrations, it is also preferable to determine a weight-on-the-edge drill for the energy limit, less than the above-mentioned weight-on-bit limit, for which another is likely to occur type of undesirable drill movement characteristics, such as increasing torsional vibrations. Clearly, it will be even more preferable to operate the bit at a rotating speed less than or equal to the marginal rotary speed, and at a weight-on-the-bit less than or equal to the weight-on-the-edge bit. It is even more preferable to operate approximately as much as possible to an optimum combination of rotating volatility and weight-on-the-bone so that it is reasonably possible to weight-on-the-marginal fructose. It is also preferable to generate a plurality of this second series of signals, the series corresponding to a different degree of drill wear, but for the same strength of the rock. Then, by modeling or verifying the wear of the drill bit and using these other second series of types, it is preferable to increase the weight-on-the drill bit and correspondingly toggle the rotating speed as the drill wears. Similarly, it will frequently be anticipated that the drill in question will be drilling through a plurality of layers or layers of formation of different compressive strengths. In these cases, it is preferable to generate the first and second series of respective types of signals for each compressive strength, verify the progress of the bit through the formation, and periodically alter the operation of the bit according to the respective series of signals for the resistance to compression of the formation that is punctually perforating the brosa. Apparent additional details of the present invention and ways to implement it will be made, together with different outstanding characteristics, objectives and advantages thereof, by means of the following detailed description, together with the drawings and the claims. Brief Description of the Drawings Figure 1 is a schematic illustration of the perforation operations from which input data can be generated and to which the invention can be stacked, as re-deployed to a processor. Figure 2 is a graphical illustration of the energy limits. Figure 3 is a graphic illustration of a second type signal series for relatively smooth rock.

Figure 4 is a graphic illustration similar to that of Figure 3, but for relatively hard rock. Figure 5 is a diagram that generally illustrates a wear modeling process the sual can be used in the present invention. Figure 6 is a graphic illustration of the nominal work relationship. Figure 7 is a graphic illustration of the loss of work due to the abrasiveness of the formation. Detailed Description Figure 1 illustrates a landform 10. It is intended that a given wellbore 18 perforate a range 14 of the formation 10 which generally corresponds to the holes 20 and 22 of the hole, which have been drilled by bits 24 and 26, of the same size and design as the bit 18. Before the bit 18 even starts in the hole (as shown), the compressive strength of the formation interval to be drilled by the drill 18. This can be done conveniently, in a manner known in the art, by analyzing drilling data, such as well profiles, discarded cut analysis, and core analysis, indicated schematically at 28 and 30, from the sersan hole 20 and 22 intervals. For this part of the description, we will assume a very simple case in which in the test indicates a resistance to -I constant compression over the entire interval 14. Then, an energy limit is generated. Referring to Figure 2, the inventor's investigation of the present has shown that, as the operating energy increases, the rate of wear of a given drill tends to follow a clearly predictable pattern. Curve c illustrates this pattern for a relatively soft rose, that is, a rock of relatively low compressive strength. It can be seen that the wear velocity increases approximately linearly are increases in energy up to a point pL. With the additional increases in energy, the rate of wear begins to increase more rapidly, more specifically, exponentially. These severe wear rates are due to increasing friction forces, high temperature, and increasing vibration intensity (impulse load). Finally, the wear rate reaches an end point eL, which represents the catastrophic failure of the bit. This catastrophic wear could occur at the energy at this end point under stable state condi tions in real sampo drilling, but could strike at a lower energy, that is, somewhere between pL and eL, under high load of impact due to excessive vibrations. Curve c2 is a similar curve for a rock of relatively high compressive strength. Again, the rate of wear increases approximately linearly with the increase in energy (although at a higher speed, as indicated by the delineation of curve c2, to a pH point after which the rate of wear begins to increase further. quickly until the catastrophic failure is reached at point eH). In order to generate an appropriate speed limit, the critical structure of the same type as in the drill bit 18 is analyzed. In the less preferred embodiments of the invention, this analysis could consist of, for example, running a single polycrystalline diamond compact, mounted on a suitable support, against the material of approximately the same compressive strength as that with which it was tested for the interval 14 of the formation, in the laboratory, gradually increasing the energy of operation, until the failure is observed . However, this failure could be anomalous, for example, a funsion of some partiscularity of the partisan sorter that was analyzed in this way, and in any case, it would only give an energy value for the catastrophic failure, such as in point eH or he. In the present invention, it is preferable to avoid not only this catastrophic failure, but also to avoid the operation at energy levels that produce exponentially increasing wear velocities, exemplified by the surva porsiones between the pH and eH points. , and between points pL and eL. Therefore, in the preferred embodiments, a plurality of orifices of the same size and design is analyzed as in the bit 18, and the structures of which have perforation material of approximately the same compressive strength as that which was tested. in this way, together they are respective drilling data. Some of these structures may be separate drill bits or sub-assemblies, especially if the brush 18 is of the CDP drag type where the orifices are cutters, worn and analyzed under laboratory conditions. However, it is useful if less than some of the estrusturas that were analyzed are insorporated, in full brosas that wear out in the field perforation. For example, this could include the bits 24 and 26 of the holes 20 and 22, which can be analyzed together with their respective drilling data 32 and 34. These latter drills and the respective drilling data may also provide data for additional aspects of the invention, which will be described later. In any case, from the data of the critical structures that were analyzed in this way, corresponding electrical signals are generated and processed in a hopper 36 to generate a first series of types of correlated pairs of electrical signals. Before elaborating on this first series of types of correlated pairs of elliptical signals, it is noted that, considering the simplicity and slarity of Figure 1, only two worn bits and their respective holes and perforation data are illustrated. However, in the preferred embodiments, the first series of signal types would be generated from a larger number of worn bits and their respective drilling data. These could come from the same training 10 or from other fields that have comparable compression resistance formations and / or multiple laboratory tests. In the first series of types of correlated pairs of electrical signals, the two signals of each for correspond, respectively, to the wear rate and the operating energy of the respective worn bit. Figure 2 is a mathematical, specifically graphic illustration of the relationships between these signals. The curve c represents the aforementioned series of the first type for rock of a relatively low compressive strength. By means of the processing of the series of signals corresponding to the curve cl r it is possible for the processor 36 to generate an electrical power limit signal corresponding to an energy limit, for example, the energy value at the pL point, for the low compression resistances in question, above the sual it is possible that exessive wear of the limit occurs. Likewise, a second series of correlated pairs of signals of the first type is generated for a relatively high compressive strength, and a graphical illustration of the relationship between these signals is shown by curve c2. Again, from these signals, an energy limit signal can be generated, the signal of which corresponds to an energy limit at the critical point pH, where the wear rate stops increasing linearly is the increase of energy, and begins to increase exponentially. In accordance with the preferred embodiments of the present invention, additional series of the first type, which comprise pairs of signals, would be generated for the intermediate compression resistances. From the signals of each series, an energy limit signal for the respective compression resistance would be generated. In Figure 2 these other series are not illustrated graphically, for simplicity and clarity of the illustration. It will be seen that, if they had been illustrated, the points such as pL and pH that were exhausted as the energy limits, and the energy limit points of all the surpluses connected, the connections would result in the curve c3, which would give limits of energy for virtually all resistances to the pressure in a desired range. It will be expedient that the computer 36 can be caused to process the signals in these different series to result in another type of signal series corresponding to the curve c3. Assuming that the curve cx is for the lowest compressive strength in the desired range, and the curve c2 for the highest one, then the values P m m_m? n and Piim-max represent the energy limits of a range of energies possible for the drill design in question.

It is noted that surva s3 could be seen theoretically as well as a function of the metallurgy of the cutter (or tooth) and the quality of the diamond, but these factors are insignificant, as a matter of practice. A more basic aspect of the present invention includes the regulation of drilling drillings at which the given drill bit 18 is operated to maintain a desired level of operating energy, less than or equal to the energy limit for the compressive strength that it was tested for the rock that is currently being drilled by that bit. Preferably, the energy limit chosen is a point such as PL, where the wear rate begins to increase exponentially. However, in less preferred modalities, this could be greater. In this way, suando is being drilled through the softest rock in the range, the conditions are regulated to keep the energy limit at or below the energy P? Im-max- Preferably, the energy is maintained more below the energy limit, to provide a safety factor. However, it is desirable to keep the energy as close as reasonably possible to the energy limit. "As close as reasonably possible" means allowing not only the safety factor mentioned above, but also practical limitations, for example, the limitations of drilling equipment being used such as the torsion limit, the limit of flow velocity, etc. This expression is modified by "almost" because the spirit of this aspesto of the preferred forms of the invention is intended to include several workable, the maximum values of the suals may vary, for example, they are the s operasión or the given appraisal of the operator of an appropriate security fastor. The operation as close as reasonably possible to the energy limit maximizes the penetration rate, which is directly proportional to the energy. In general, it is desirable to maximize the penetration rate, except in extreme cases where one could start drilling so fast that the number of cuts generated would increase the effective sludge weight to the point where it could exceed the fracture gradient for the Formation The drilling sondisions regulated in this way include the conditions that apply to the brosa, specifically the rotating speed and the weight-on-the-bit. The vibrations of the brosa, which can be detected while drilling through known elements, can cause the forces that are transmitted to the formation by the drill to vary the small total increments of the interval that is being drilled or that is going to drill. In these cases, it is preferable that the conditions that apply with reference to the peak transmitted forces be regulated between these fluctuations, rather than, say, the average transmitted forces.

According to another aspect of the preferred forms of the invention, there are a number of combinations of rotating speed and weight-on-the-bit, whichever of which will result in an energy corresponding to the energy limit. The invention includes a method to optimize the particular selected sombi-nasion. Figure 3 includes a curve c4 representing the values corresponding to the paired signals in a series of a second type for a new drill of the design in question. The signal series that corresponds to the surva s4 is generated, in a way that is more fully disengaged later on, from historical data from a number of bits of the same size and design as the brosa 18, and which have Perforated formation of approximately the same compressive strength as that tested for interval 4. A surva such as the c4 may result from the plotting of the rotational velocity values compared to the values of the weight-on-the-drill bit. individual historical data and then the extrapolation of a continuous curve. It will be appreciated that those skilled in the art could program the computer 36 to perform the equivalent operations on correlated pairs of electrical signals that correspond, respectively, to the values of rotating speed and weight-on-the-bit of the historical data, and that the computer 36 could even produce a graphical representation such as surva s4. The historical data will be used to generate corresponding electrical signals introduced in the processor 36, which then additionally generates the additional suffix such as the pairs of signals, which are the standard of the original inputs, to provide a second series of types of correlated pairs of the signs of the weight-on-the-bit and the rotating speed. From this second series, it is possible to extrapolate the graphic representation s4, which was generated from hesho by the computer. By correlating the curve c4 (and / or the corresponding series of signals) with the historical data of perforation (or corresponding signals), it is possible to determine a point pN-mar in which the value of rotating volatility, N, is a marginal value Desirable, it is desir, a value above which undesirable drill movement characteristics are likely to osurine, specifically they begin to increase the inevitable lateral-and / or axial vibrations, either because the rotating speed is too high and / or the weight -over-the corresponding bit is too low. At another point pN_? Im, in which the rotational speed can be even higher, these characteristics of undesirable drill movement, specifically axial and / or lateral vibrations, the peak, for example, resulting in the violent return of the drill; in this way it is even less desirable to operate at or above the rotating speed at pN_? im. The weight-on-the-bit in pN_llm is the minimum weight-on-bit required to reduce these vibrations and some times this has been referred to herein as the weight-on-the-threshold bit. Likewise, it is possible to locate a point p "-mar in which the weight-on-the-bit, w, is at a desirable marginal value in which, above this value, other types of bit movement characteristics occur undesirable, specifically increasing torsional vibrations. In pw_lim, these peaks of undesirable movements and "stick slip" (spasmodic rather than continuous rotation) can occur, so it is less desirable to operate with weights close to or above the weight-on-the-bit value in pw_lim- In general, although any point on the curve c4 includes a rotatory and weight-on-the-roughness value that corresponds to the energy limit for the compressive resistances in question and for a new brosa, it will clearly be desirable operate within the range between points pN_mar and pw-mar. As illustrated, curve c4 corresponds precisely to the energy limit. Therefore, to include the safe facet that was previously mentioned, it would be even more preferable to operate in a high range of any of the points pN_mar or pw-mar. Even more preferensia, one could operate at the values that correspond to a point on the curve s4 in which the value of the weight-on-the-bit, w, is less than, but almost as strong as is reasonably possible, at the value of the weight-on-the-rock in pw_mar. This is because, the higher the rotating speed, the more energy is available for the potential vibration of the drill string (to the sonar of only the drill bit by itself). Recalling that Figure 3 refers to relatively soft rock, it will be seen that, almost as well as reasonably possible, pw_mar will actually be, in this case, rather far from pw_mar. This is because, in the very soft rock, the drill bit will reach a maximum depth of sorte, where the cutting shells of the bit are completely embedded in the rock, at a weight-on-rock value at the pdc point. sual is well below the value of weight-on-the-loam in pw. For CDPs and roller conical drill bits, it is unreasonable and useless to apply additional weight to the brush beyond that which the cutters completely inscribe. For diamond-impregnated drill bits, it may be reasonable to operate at a slightly higher weight-on-bit than on pdc. This partially embeds the body of the matrix drill, into which the diamonds are impregnated. In this way the matrix wears together with the diamonds so that the diamonds always stand out in some way from the matrix (a condition that is sometimes called "self-sharpening"). Therefore, the optimal values of rotating speed and weight-on-the-bit will be those in, or cersa of, the pdc point. From additional historical drilling data, another series of signals correlations of the second type can be generated for a severely worn brosa of the type in question, and these correspond to surva s5. The intermediate series of this second type, for lower degrees of wear, could also be generated, but it is not illustrated by the survas in Figure 3 for simplicity and slarity of the illustration. In any case, the computer 36 can be made to process the signals of these different series, in a manner well known in the art, so that series of signals of a type terser are generated that correspond to the survas s6, s7, s8 , sg, and s10. The surva s6 corresponds to the values of the type pN_? Lm, since these vary with wear. The curve c7 corresponds to the pN-mar type values, since these vary with wear. The surva c8 corresponds to the values of the pdo type, since these vary with the wear of the drill. The curve c9 corresponds to the values of type pw_mar, since these vary with the wear of the bit. And the curve c10 corresponds to the values of type p "_llItl, since these vary with wear. In this way, as the drilling proceeds, it is desirable to measure and / or model the wear of the drill 18, and to increase the weight-on-the-bit periodically, and to alter the rotating speed accordingly, preferably remaining within the range between the curves c6 and c10, more preferably between the curve c7 and the surva s9, and even more preferred, in o cersa of the surva s8. Figure 4 is similar to Figure 3, but represents the series of signals for a relatively hard rose (high compression resistances). Here, again, two clx and c12 curves are shown which correspond, respectively, to the series of signals of the second type for a new and severely worn drill. In this hard rock, the point pM_mar after which additional increases in the weight-over-the drill will result in undesirable torsional vibrations, has a weight-on-the-bit value smaller than that of the pdc point and so, so so much also pw_lim. Thus, in hard rock, even when a safety factor is allowed, it will be possible to operate at an optimal pair of values, which will oscillate in popt much closer to pw_mar, than in the case of soft rock. Other pairs of values, analogous to popt can be found to vary the degrees of wear of the brosa. From these signals, a series of paired signals can be generated that correspond to the surva s13 extrapolated by the host 36. As before, it is intended that "as close as reasonably possible" allows not only a safety factor, but also practical limitations. For example, a theoretically optimal torque of rotating speed values, weight-on-the-bit could produce, in the context of a particular drill string geometry or hole geometry, resonance of the drill hole, the sual should be avoided . In other highly unusual examples, the rock can be so hard, and the torsional moment capacity of the engine so low, that the team can not apply the weight-on-the-bit enough to stay within the range between pN_lim and pw-lim . then one could operate almost as close as reasonably possible to this range, for example, to a weight-on-bit a bit smaller than that at pN_? im and a correspondingly high rotational speed. It should also be kept in mind that, while values such as those shown in the different curves in Figures 3 and 4 are generally valid, the aberrant conditions in a particular drilling operation may cause drill motions and / or undesirable drill string to the values of rotating speed and weight-on-the drill to the suals, theoretically, should not osurrir. Therefore, it is desirable to provide elements, cones in the tansy, to detest these movements in real time (while drilling) and take the appropriate active response whenever these movements are detected, staying as close to the optimal values as possible, while that snorting is With the above general concepts in mind, an exemplary method of processing signals will now be described to obtain series of signals of the type corresponding to the curves in Figures 3 and 4. For the strength s of the rock in question, they are used historical empirical wear and energy data to generate the corresponding electrical signals, and the computer 36 processes these signals to generate a series of matched signals of the first type, which corresponds to a limiting energy curve, such as sx or c2. Then, from the historical empirical data, for example profiles of the holes 20 and 22 showing the 5 measurements of the torsional moment and the vibration, the limiting values of the torsional moment can be determined. Specifically, a torsional moment value TN_11m is determined in the same way in which the lateral and axial vibration floor, that is, a value that corresponds to pN-? Im for the s and the condition of wear in question, and a torsional moment value Tw_lim in the sual the peak of vibrations of the torsional moment (produces "slip of the stick"), that is, a value corresponding to Pw-iim for the s and the wear condition in question. Preferably, there are abundant data of the moment torsional and vibration for the s and the wear condition in question. These are converted to corresponding electrical signals input to the computer 36. These signals are processed by the processor 36 to produce signals corresponding to the torsional moment values TN_lim, TN_mar, "" "- w-mar Y ^ -w-lim- At least if s is low, that is to say the rock is smooth, and preferably in any case, a torsional moment value Tdc is also determined, which corresponds to the torsional moment at which the maximum depth of cut is reached (i.e. stratus of sorte is deeply embedded). It will be seen that this value and its corresponding electrical signal also correspond to pdc. The data can be provided to determine Tdc by laboratory tests. Alternatively, in a real field drilling operation, Tdc can be determined by starting drilling at a fixed rotating speed and a minimum weight-on-bit, then gradually increasing the weight-on-bit while the torsional moment and the speed of penetration are verified. The viscosity of penetration will increase the weight-on-the-loam to a point in the sual it will level out, or even fall. The torsional moment at that point is Tdc. For each of the torsional moment values mentioned above, it is possible to process the corresponding electrical signal to produce the signals that correspond to the values of the corresponding rotating velosity and weight-on-the-roughness, and in this way locate a corresponding point on a curve such as those shown in Figures 3 and 4. You can determine a value w, the weight-on-the drill that corresponds to the torsional moment, T, in question, and generate a corresponding signal and enter it in the somputadora 36. Alternatively, where series of signal or families of series are being developed to provide complete patterns of progress for a particular drill, it might be useful to define, from the field data, a value, μ, which varies with wear. T-T0 μ = w-w0 (1) where T0 = torsional moment for the weight-on-the-bit threshold. w0 = weight-on-the-threshold drill After the computer 36 processes the signals T, T0, 0 and μ to perform the electronic equivalent to solve the equation: T-T0 w = ° _ + w0 (2) μ to produce a signal corresponding to the weight-on-the-bit corresponding to the torsional moment in question. Then, the processor 36 performs the astronomical equivalent to solve the equation: N = PUm / (2nμ + dc) w60 (3) or N = Pum / (pμ + dc) T60 (3a) μ where N = rotating speed Pum = energy limit that was previously determined as described above dc = penetration per revolution (or "depth of cut") where it is desired to use both axial and torsional components (the lateral component being negligible). Alternatively, if it is desired to use only the torsional component, these equations are converted into: N = Plim / 120pμw (4) or N = Plim / 120pT (4a) The processor is done by means of the prosessing of the signals that correspond to the variables and constants in the esuasión (3), (3a), (4) or (4a). Now we have the signals that correspond, respectively, to a weight-on-the-bit, w, and a rotating speed, N, that correspond to the torsional moment, T, in question, that is, a first pair of signals for a series of the second type represented by the curves c4, s5, cn and c12. For example, if the torsional moment that was used was TN_lim, we can locate the point PN_? Im- By means of similarly processing the additional torsional moment signals for the same wear condition of the brosa and rock resistensia, s, we can develop the second series of types of complete pairs, which correspond to a surva such somo s4, including all reference points pN_lim, pN.mar, pw-mar and Pw-? im- After, when is drilling with a drill bit of the size, design and sondisión of wear in question, in the rock of the resistance s in question, one operates a combination of rotating speed, weight-on-the drill that corresponds to a pair of signals in this series, in the range between pN_llm and pw.lim, unless w in pw_llm? w in pw_lim >; in pdc, in which case one operates at values between pN_lira and pdc. Most preferably, one operates between PN_mar and p "_mar, or pN.mar and Pdc the city is < 3ue give the smallest rank. Even more preferable, one operates as close as reasonably possible to Pdc ° Pw-sea / whichever has the lowest weight-on-bit. If pdc has the lowest weight-on-bit, and the bit is of the CDP or roller cone type, one operates at or slightly below the pdc values, depending on the desired safety factor. However, if the bit is diamond impregnated, one may prefer to operate at or slightly above pdc. By similar processing of signals for the same strength of the rock, s, but different wear conditions, one can develop a family of paired signal series of the second type, which can be described as a family of curves or a This region is the region between the curves c1: L and c12. It is then possible to develop series of the third type, corresponding, for example, to curves c8 and c13. Then, by verifying or modeling the bit wear, one can optimize by increasing the weight-on-bit, w, applied as the bit wears and correspondingly adjusting the rotational speed, N. In the less preferred modes, one can simply select a torsional moment Topt, for example, as close as reasonably possible to Tdc or Tw_mar, whichever is less, then process as explained above to obtain the corresponding w and N. By repeating this for the different wear conditions, one can simply generate a series of the third type, for example, corresponding to curve c13. However, it is preferable to develop ranges, as shown in Figures 3 and 4, to provide guidelines for the modification of the optimal hypothetical optic discs. For example, if the operation in popt with a sherd and partiscular orifisio geometry produces resonances in the tande, the operator can then selese another set of conditions among those skilled in the art will understand that many alternative ways are possible to generate and process the data to generate the signal series, the previous ones being exemplary. As mentioned above, up to this point, we have assumed that s is constant over the interval 14. However, in actual drilling operations, s can vary over the interval that a drill bit pierced. Thus, regardless of the method used to develop the signal series of the second and third type for a given rock strength, it is desirable to repeat the previous process for other rose resistances, to drill which is designed the drill. For example, for a given drill bit, one can develop the signal series that corresponds to curves such as those shown in Figure 3 for the softer rock that the drill is expected to drill, other signal series corresponding to the curves such as those shown in Figure 4 for the harder rock, and still another of this series for intermediate strength of the rock. This can provide an operator in the field with much more complete information about the use of optimization of the bit in question. Then, for example, if the test of the interval to be drilled by the drill includes different rock strength layers, the operation in one of these layers can be optimized. By way of a further example, if the test is based on the adjacent holes, but the MWD measurements do not indicate that, for some reason, rock of a different strength is being found in the hole in question, the conditions of the operation. In even more highly preferred modes, it is possible to model s in real time, as it changes with relatively small increases in depth, as explained in the co-pending application Serial Number of the invention of the present one, entitled "Method of Assaying Compressive Strength of Rock," presented contemporaneously herein, and incorporated into the present somo referensia. As previously mentioned, in order to derive the best advantage from the present invention, it is advisable to model the wear of a brosa as it proceeds through the interval being drilled, or, given the technology available, to measure the wear of the brosa or some indissociable parameter of the same in real time, so that the weight-on-the-bit and the rotating speed can be adjusted periodically, to an optimum new for the current wear condition of the brosa. Some prior US patents, such as Nos. 3,058,532, 2,560,328, 2,580,860, 4,785,895, 4,785,894, 4,655,300, 3,853,184, 3,363,702, and 2,925,251, disclose different technologies depicted to detect the wear of the bit in real time. U.S. Patent No. 5,305,836, formerly from Holbrook, describes a technique for modeling the wear of the bit in real time. Another method for modeling the wear of the bit is as follows: Referring to Figure 5, the modeling of the bit proceeds from the test work of a well drill bit such as 24 of the same size and design as the drill bit. As in Figure 1, a well hole or orifice hole 20 is drilled between an initial point I and a terminal point T. In this illustrative embodiment, the initial point I is the point where the rough 24 was first put to work in the hole 20, and the terminal point T is the point at which the bit 24 was removed. However, for of the test work itself, the points I and T can be any two points that can be identified, among which the drill bit 24 has drilled, and among which the necessary data, which will be distilled later, will be can generate. The main basic motive is to test the work by using the well-known relationship: Ob = FbD (5) where: Ob = work of the drill Fb = total force in the drill D = drilled distance The length of the drill can be determined and recorded orifice 20 interval between points I and T are one of a number of well data that can be generated on the borehole of bore 20, as schematically indicated by line 50. To convert it into an appropriate way to introduce it and process it by computer 26, this length, is desir, the distance between points I and T, is subdivided from preferensia in a number of small increments of distance, for example, of approximately half a foot one. For one of these distance increment values, a corresponding electrical distance of increase is generated and entered into the hopper 36, as indicated by the line 52. In order to determine the work, a plurality of signals are generated. increase in real force, each corresponding to the force of the bit on a respective increase in the distance between points I and T. However, due to the inherent difficulties in determining the total strength of the total thickness, the signals that correspond to other parameters from the well data, for an increase in distance, as indicated in 52. These can, theoretically, be able to determine the force of the true total bit, which insulates the force Axial axis, torsional force, and any applied lateral force. However, unless lateral force is applied with purpose (in which case it is sound), it is to say, unless the outriggers at the bottom of the orifice assembly are absent, the lateral force is so insignificant that it can be ignored. In one modality, the well data that is used to generate the real strength increase signals are: - weight on the bit (w), for example in pounds; - Hydraulic impact force of the drilling fluid (F, for example in pounds, rotating velocity, in rpm (N), torsional moment (T), for example in feet * pounds, - penetration velocity (R), for example in feet / hour, and; lateral force, if it is stackable (Fj-), for example in pounds, with these data for each item, respec- tively, are converted to the corresponding signals and introduced as indicated in 52, the program is programmed or configured 36 to test these signals to generate the signals of real strength, by performing the electronic equivalent that resolves the following equation: Ob = [(w + F ±) + (120pNT / R + Ft] D (6) where the lateral force, Ft, is insignificant, that term, and the corresponding elstrict signal, are separated.Surprisingly, it has been found that the torsional somponente of the force is the most dominant and important, and in the less preferred modalities of the invention, the ensa The work can be done using this force component alone, in which case the corresponding equation is converted into: Ob = [120pNT / R] D (7) In an alternative mode, when generating the real strength increase signals, the computer 36 can use the electronic equivalent of the equation: Ob = 2pTD / dc (8) where d represents the depth of cut per revolution, and is defined, in turn, by the relationship: dc = R / 60N • (9) The processor 36 is programmed or configured to proceed with the signals of increase of real force and the respective signals of increase of distance to produce an electrical signal that suffers from the total work hesho by the screw 24 in suando was drilling between the points I and T, as indicated in block 54. This signal can easily be converted to a numeric value that can be perceived humanly, generated by the host 36, as indicated by line 56, in the well-known manner. The processing of these signals of actual force input and the signals of distance input can be done in different ways. For example: In one version, the computer processes the signals of increase of real force and the signals of increase in distance to produce a signal of average strength that corresponds to an average compensated by the force exerted by the bit between the points. initial and terminal. By "compensated average" it is meant that each strength value corresponding to one or more of the actual force increase signals is "compensated" by the number of distance increments to which the force is applied. Then, the computer simply performs the electronic equivalent of multiplying the average force compensated by the total distance between points I and T, to produce a signal that corresponds to the total work value.

In yet another version, the computer can develop a force against the distance function from the signals of actual force input and the signals of distance input, and then perform the electronic equivalent of integration of that function. Not only are there three different ways to process the signals to produce a total working signal equivalent, there are also examples of those kinds of alternative processes, which will be considered in connection are other processes that form different parts of the present invention, and they are described later. As well, there is available thesis to determine when a brosa is vibrating exessively while it is drilling. If it is determined that this has occurred during at least a portion of the interval between points I and T, then it may be preferable to program appropriately and input to the computer 36 so that the respective signals of actual force increase for the respective increments. This can be done by using the average value (average) for each of the variables that go within the determination of the real force input signal. The wear of a drill bit is functionally related to the cumulative work done by the drill bit. In addition to determining the work done by the bit 24 in the perforation between points I and T, the wear of the brosa 24 is measured in the perforation of that interval. A superstrict signal is generated and a part of the historical data 58, 52 was introduced into the computer. (Thus, for this purpose, point I must be the point at which the bit 24 is put to work first, and the point T must be the point at which the bit is removed 24). The same can be done for the additional holes 22 and 60, and their respective drill bits 26 and 52. Figure 6 is a graphical representation of what the computer 36 can do, electronically, with the signals that correspond to that data. Figure 6 represents a graph of the wear of the drill against work. Using the aforementioned data, the processor 36 can process the equivalent of the lasalizasion of a point in this graph for one of the holes 20, 22 and 60, and its respectable bits. For example, the point 24 'can represent the correlated work and the wear for the rough 24, the point 26' can represent the correlated work and the wear for the drill 26, and the point 62 'can represent the correlated work and wear for bit 62. Other points px, p2 and p3, represent the work and wear of still other bits of the same design and size that are not shown in Figure 5. By processing the signals corresponding to these points, the Computer 36 can generate a function, defined by suitable electrical signals, the function of which, when graphically represented, take the form of a smooth curve generally of the shape of surva c20. It will be appreciated, that in the interest of generating a smooth and continuous curve, this surva may not pass precisely through all the individual points that correspond to the specific empirical data. This continuous "nominal working relationship" can be an output 64 by itself, and can also be used in the modeling of wear. It is useful to determine an end point pmax which represents the maximum wear of the bit, which can be supported before the bit is no longer realistically useful, and from the nominal work rate, and determine the corresponding amount of work . In this way, the pmax point represents a maximum-wear-maximum-work point, which is sometimes referred to herein as the "work classification" of the type of the bit in question. It could also be useful to develop a relationship represented by the mirror image of the curve c20, that is, the curve c22, the sual trace the remaining useful life of the brose sontra the work hesho from the signals mentioned above. The electrical signals in the computer that correspond to the functions represented by the curves c20 and s22, are transformed from preferensia into a visually perceptible form, such as the survas somo are shown in Figure 6, when they are extracted in 64.

As previously mentioned in another context, the vibrations of the bit could cause the bit force to vary significantly over the individual increments. In developing the nominal working relationship, it is preferable in these cases to generate a respective peak force signal that corresponds to the maximum force of the bit on each of these increments. It can also be determined, as explained below, a limit that corresponds to the maximum allowable force for the rock strength of that increment. For any grain the sual is considered potentially for use in the development of the surva cx, a value corresponding to the peak force signal must be compared with the limit, and if that value is greater than or equal to the limit, it must be excluded. the respectable drill bit of those of the suals are generated the signals of nominal work relation. This comparison can, of course, be made in an astronomical manner by the processor 36, using an electrical limit signal corresponding to the limit mentioned above. The main point to determine the limit mentioned above, is based on the energy limit that was explained above in rejection with Figure 2. Once the limiting energy for the proper strength of the rock has been determined in this way, the corresponding maximum force limit can be extrapolated by simply dividing this energy by the penetration speed.

Alternatively, the actual energy of the drill can be compared directly with the energy limit. In any case, the process can be done in an astronomical manner by the computer 36. Other factors can also affect the intensity of the vibrations, and these can also be taken into account in the preferred modalities. These other factors include the geometry of the drill string and stiffness, the geometry of the hole, and the mass of the lower hole assembly below the neutral point in the drill string. The way to generate the peak force signal can be the same as that described above for the generation of the real strength increase signals for the increments in which there are no vibration problems, ie, using the electronic equivalent of equations (5), (6), or (7) + (8), except that for each of the variables, for example w, the maximum or peak value of that variable will be used for the interval in question (but for R, for the sual the minimum value must be used). The nominal work reagent 66 can be used for the development of abrasivity information, as indicated at 68. Abrasivity, in turn, can be used to improve wear modeling and / or to adjust the energy limit. Specifically, if abrasiveness is detected, the energy limit for that session of the interval being drilled must be decreased. As for the abrasivity by itself, it is necessary to have additional historical data, more specifically abrasive data 70, from an additional well or hole 72 which has been drilled through an abrasive layer such as a "hard spar" 74, and the brosa 76 that perforated the interval including hard stile 74. It should be noted that, as used herein, an assertion that a portion of the shaping is "abrasive" means that the rose in question is relatively abrasive, for example suarzo or sandstone, by way of comparison with slate. The abrasiveness of the rock is essentially a function of the superfisial sonfiguration of the rock and the strength of the rock. The configuration factor is not necessarily related to the size of the grain, but rather to the angularity or "sharpness" of the grain. Returning again to Figure 5, the abrasivity data 70 includes the same data type 78 from well 72 as data 50, that is, the well data needed to determine the work, as well as a wear measurement 80 for the drill 76. In addition, the abrasiveness data includes the volume 82 of the abrasive means 74 drilled by the bit 78. The latter can be determined in a known manner by analyzing the well profiles from the well 72, as generally indicated. through the black box 84.

As with other aspects of this invention, the data is converted into resistive signals introduced into the somputer 36 as indicated by 86. Computer 16 quantifies the abrasivity by processing the signals to perform the electronic equivalent to solve the equation:? = (O 'nominal - Ob) / V, abr (10) where:? = abrasiveness Ob = real work of the bit (for the amount of wear of the drill 56) O "al = nominal work (for the same amount of wear) Vabr = volume of perforated abrasive medium For example, suppose a drill has made 1,000 tons-miles of work and pulls are 50 per cent of wear after drilling 200 feet of abrasive medium.

Suppose also that the historical nominal working relationship for that particular brosa indicates that the wear should be only 40 percent to 1,000 tons-miles and 50 percent to 1,200 tons-miles of work as indicated in the Figure 7. In other words, the extra 10 percent abrasive wear corresponds to an additional 200 tons-miles of work. The abrasiveness is quantified as a reduction in the life of the drill of 200 ton-miles per 200 cubic feet of perforated abrasive medium or 1 (ton * mile / foot3). This unit of measurement is dimensionally equivalent to laboratory abrasivity tests. The percentage of the volume of the abrasive medium can be determined from the profiles of the well suzanizing the fractions of the lithological component. The volume of the perforated abrasive medium can be determined by multiplying the total volume of rose perforated by the volume abrasion of the abrasive substance. Alternatively, the lithological data of the orifisio profiles can be taken by measuring techniques while drilling, as indicated in black box 84. Relation 66 of the nominal work can be used as an option and, if appropriate, abrasive 68, to remotely model the wear of the brosa 18 as it drills a hole 14. In the exemplary embodiment illustrated in Figure 5, the range of the hole 14 drilled by the drill 18 extends from the surface through and beyond the hard beam 74. Using the measurement techniques while drilling, and other available technology, the type of data generated at 50 can be generated on a current basis for the well 14, as indicated in 88. Because these data are generated on a current basis, they are referred to herein as "real-time data". The real-time data is converted into respective electrical signals input to the computer 36 as indicated at 90. Using the same process as for the historical data, that is, the process that is indexed at 54, the computer can generate signals of actual force increase and the corresponding distance increment signals for each increment drilled by the drill 18. In addition, the computer can process the actual force increase signals and the distance increase signals for the drill 18, to produce a electrical signal of real work increase for each instrument drilled by drill 18, and accumulate these signals of real work increase periodically. This, in turn, produces a current work elthric signal corresponding to the work currently done by the drill 18. Then, using the signals corresponding to the nominal work recession 66, the computer can periodically transform the current work signal to an astressive signal of astual wear, indisposable of the wear in the brosa in use, ie, the drill 18. These basic steps would be carried out even if it were not believed that the bit 68 was drilling through the hard spar 54 or the other layers abrasives. Preferably, when the current wear signal reaches a previously determined limit, corresponding to a value at or below the job classification for the size and design of the drill bit in question, drill bit 68 is removed. Because well 70 is cessed from well 52, and it is therefore logical to conclude that drill bit 68 is drilling through hard stinger 54, the abrasivity signal that occurred at 48 is processed to adjust the current wear signal that occurs at 74 as explained in the previous abrasivity example. Again, it could also be useful to check for excessive vibrations of the drill 68 in use. If these vibrations are detected, a respective floor force signal must be generated, as previously disengaged, for the respective instrument in which these exsisi-vibrations are experienced. Again, a limit that corresponds to the maximum allowable force for the rock resistance of each of these increments is also determined and a corresponding signal is generated. The somputer 36 somparately sends one of these ground force signals to the respective limit signal to test possible wear in excess of that which corresponds to the astual wear signal. You can take assión to remedy it. For example, one could reduce the level of operating energy, that is, the weight on the drill and / or the rotating speed. In any case, the astute wear signal 92 is extracted from preferensia in some kind of visually perceptible form as indicated at 94. The above example illustrates a real time-of-wear modeling process. It should be understood that a predictable wear pattern can be produced, using the similar electronic processing method, but operating on the assumption that. The lithology to be drilled by drill 18 is identical to the one drilled by drill bit 76. Afterwards, it can be based on this model that the aforementioned adjustments of weight-on-bit and rotating speed can be predicted, to account for the wear of the drill. In a highly preferable embodiment, a predictable advance model would be provided, but real-time wear modeling would also be done, to verify and / or adjust the predictable advance model, and corresponding velocity adjustments. rotating and weight-on-the-rough. Mushas will come to mind modifisasiones to the previous modalities to the experts in the technique. In accordance with the foregoing, it is intended that the scope of the present invention be limited only by the claims that follow.

Claims (20)

1. CLAIMS 1. A method for regulating the drilling conditions applied to a given drill bit, comprising the steps of: testing the resistance to the compression of the formations in a range to be drilled by this drill; analyze the wear of the critical structure of the bit of the same size and design as in the given bit and the structure of which has drilling material of approximately the same resistance to the pressure as the one that was tested, together with the perforation data for the worn structure; from this analysis, determine an energy limit for the resistance to the respec- tive pressure, above which the undesirable wear of the drill is likely to occur; and regulate the drilling sondisiones to which this drill is operated, to maintain a desired operating energy less than or equal to the energy limit.
2. 2. The method of sonification with claim 1, wherein a plurality of the structures and the respective perforation data are analyzed; further comprising the generation from this analysis of a first series of pairs of pairs of electrical signals, the two signals of each pair corresponding, respectively, to the wear speed and the operating energy for a respective one of these structures; and where the energy limit is generated from the signals of this first series of types.
3. 3. The method of conformity is claim 2, wherein at least one of these structures is a separate part of a size and design that is used in the given drill and is thus analyzed under laboratory conditions.
4. 4. The method according to claim 2, wherein less than one of these structures is a complete drill bit of the same size and design as the given drill bit and which thus wears out in the field drill.
5. The method of sonification with claim 2, wherein the drilling conditions are regulated to maintain the desired operating energy less than, but nearly as close as reasonably possible, to the energy limit.
6. 6. The sonicity method is claim 2, wherein: the drilling conditions include the conditions that apply to the given drill; the vibrations of the bit cause that the forces that are transmitted to the formation by means of the drill, vary over small increments of the interval; and the applied conditions are regulated so they are referensia to the transmitted floor forces.
7. 7. The method according to claim 2, wherein the sondisions that are so regulated are the rotating speed and the weight-on-the-bit.
8. The method according to claim 7, characterized in that it also comprises a second series of pairs of correlated pairs of signals, the respective signals of each pair corresponding to a rotational speed value and a weight-on-the-envelope value. drill, where the values of rotating speed and weight-on-the-bit of each pair, theoretically results in an energy that corresponds to the energy limit; and where the brosa is operated on a rotating velosity and weight-on-the-roughness that sorresponden to one of the pairs of signals in the second series of types.
9. 9. The method of soundness with claim 8, characterized in that it also comprises the determination of the rotational speed limit for this energy limit, above which it is probable that disadvantageous movement characteristics of brosa will occur, and in this way operate the drill at a rotating speed less than the rotating speed limit.
10. 10. The method according to claim 9, characterized in that the determination of the weight-on-the-bore limit for this energy level is also shown, above the sual it is probable that disadvantageous drill movement characteristics occur, and from this way to operate the weight-on-the drill less than the weight-on-the-bit limit.
11. The method according to claim 10, characterized in that it also comprises: determining a marginal rotational speed for the energy limit, less than the rotational speed limit, above which disadvantageous drift motion characteristics are likely to occur.; determine a weight-on-the-edge drill for the energy limit, less than the weight-on-the-bit limit, above which disadvantageous drill motion characteristics are likely to occur; and thus operating the bit at a rotating speed less than or equal to the marginal rotary speed, and at a weight-on-the-bit less than or equal to the weight-on-the-edge bit.
12. 12. The method according to claim 11, characterized in that it also comprises the operation of the bit at this rotating speed and weight-on-the-rough, as far as reasonably possible from the weight-on the marginal bit
13. 13. The method of according to claim 12, characterized in that it also comprises the determination of a combination of weight-on-the-bit and rotating speed in which a maximum depth of cut is achieved; and the operation of the drill bit to a weight-on-the drill bit sersa or equal to the weight-on-the lowest brosa that corresponds to the maximum depth of cut of the weight-on-the marginal drill.
14. 14. The method according to claim 10, characterized in that it also comprises: determining a marginal rotational speed for the energy limit, less than the rotational speed limit, above which undesirable drill motion characteristics are likely to occur; determine a weight-on-the-edge drill for the energy limit, less than the weight-on-the-bit limit, above which undesirable drill motion characteristics are likely to occur; determine a weight-on-the-edge drill for the energy limit, which produces a maximum cutting depth for the drill; and thus operate the bit at a rotating speed less than, or equal to, that marginal rotary speed, and at a weight-on-the-bit, or the same as the smaller weight-on-the-margin, and the weight-on-the-bone. for the maximum depth of sorte.
15. 15. The method of sonification is claim 8, characterized in that it also comprises the determination of a weight-on-the-bit limit for the energy limit, above which it is likely that substantially disadvantageous characteristics of bit movement will occur, and thus operating the brosa to a weight-above-the brosa below the weight-on-the-bit limit.
16. 16. The method of conformity is claim 8, which is sarasterized because the generation of a plurality of signal series of the second type, each for a different amount of wear, and the periodic increase of the weight-on-the-bit as well Wears the bit in accordance with the appropriate series of the second type.
17. 17. The method according to claim 16, characterized in that it also comprises the alteration of the rotating speed as the weight-on-the-bit increases.
18. 18. The method of conformity is the claim 17, characterized in that it also comprises the measurement or modeling of the wear of the bit in real time.
19. The method according to claim 8, wherein the compression strength test includes a plurality of layers of resistance formation to different understanding, and characterized in that it also comprises: generating the respective series of the first and second type of signals for each resistance to compression; Verify the progress of the bit through the training; and periodically altering the operation of the drill bit are the respec- tive series of signals for the resistance to the compression of the formation that is currently drilled by the drill bit.
20. 20. The method according to claim 1, wherein the compressive strength is thus tested by modeling in real time, while the interval is drilled with the drill.