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Publication numberUS3578092 A
Publication typeGrant
Publication dateMay 11, 1971
Filing dateFeb 11, 1966
Priority dateFeb 16, 1965
Also published asDE1220357B
Publication numberUS 3578092 A, US 3578092A, US-A-3578092, US3578092 A, US3578092A
InventorsBecker Herbert, Gotte Hans, Haverkamp Gunther, Tesch Hans-Jurgen, Wacker Alexander
Original AssigneeHoechst Ag
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Drilling tools
US 3578092 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent [7 2] Inventors Hans-Jurgen Tesch Hannover; Gunther l-laverkamp, Hamburg; Herbert Becker; Alexander Wacker, Frankfurt, Main; Hans Gotte, Kelkheim, Taunus, Germany [21] Appl. No. 526,740 [22] Filed Feb. 11, 1966 [45] Patented May 11, 1971 [73] Assignee Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius & Bruning Frankfurt, Main, Germany [32] Priority Feb. 16, 1965 [33] Germany [31] F45,256

[54] DRILLING TOOLS 10 Claims, 2 Drawing Figs.

[52] US. Cl 175/39 [51] Int. Cl E21b 13/00 [50] Field ofSearch 175/39,42; 166/4 [56] References Cited UNITED STATES PATENTS 2,457,960 1/1949 Walker 175/42X Warren 2,658,724 11/1953 Arps 175/39X 2,659,046 1 H1953 Arps 175/42X 2,868,506 1/1959 Nestle 175/42X 3,011,566 12/1961 Graham 175/39 OTHER REFERENCES Oil & Gas Journal" Publication of August 29, 1955 Pages 77 79 relied on. Copy in 166/4 Primary Examiner-Nile C. Byers, Jr. Att0rneyCurtis, Morris and Safford ABSTRACT: A drilling tool has been provided which has a method of marking the tools as well as the tools thus marked I are within the scope of the invention. Further, the improvement in the method of drilling deep bore holes with a tool possessing these indicating means is similarly within the scope of the disclosed invention.

DRILLING TOOLS The present invention relates to the marking of tools and instruments used for deep drilling with radioactive tracer substances which serve to indicate the occurrence of the critical wear.

When using the drilling instruments which are generally applied for geological and industrial deep drilling, for example, roller bits, diamond bits, drilling turbines, reamers and smoothing instruments, it is necessary to know with a high degree of certainty when a predetermined, namely the highest permissible, amount of wear has occurred upon the tools and instruments, which are exposed to a high stress. In roller bits, for example, an excessive wear on the roller bearings which are exposed to a very high degree of abrasion causes the rolls to be out of a true alignment and this may result in the destruction of the cutter head of the drill bit. Extensive and expensive locating and catching operations are then necessary as a result. When the reamers and smoothing instruments have undergone excessive wear the well bores obtained are badly sized and this requires a time-consuming additional treatment.

Up to now it has to be judged by experience and feeling whether or not the highest tolerable service life of such tools and instruments has been reached. When the tools or instruments are brought to the surface for visual inspection it turns out in most cases that they could have been used for a much longer period or that they should have been replaced already a long time ago because a dangerous amount of wear has occurred. The removal of the tools or instruments requires much time and expenditure, especially when the well is very deep.

lt has previously been proposed to indicate to the driller that his bit has worn away the highest admissible amount by providing the instruments for drilling deep wells with recesses into which a radioactive tracer substance is embedded, the recesses being closed in such a manner that the tracer substance is released as soon as the highest tolerable amount of wear has occurred whereupon the radioactive tracer substance becomes suspended or dissolved in the circulating drilling fluid and is brought in it to the earth s surface where it is detected by a measuring and indicating instrument. It has also been proposed to embed in the recesses provided for this purpose in addition to the tracer substance, a propellent which when coming into contact with the drilling fluid decomposes with the evolution of gas and expels the tracer substance from the recess. It has further been proposed to mark the propellent itself by a radioactive substance for example, to use as the propellent sodium amide containing nitrogen or tritium. an alanate or boranate containing tritium, carbon dioxide containing carbon" or a carbide containing carbon. lt has also been proposed to use water-soluble radioactive tracer substances, for example, a chloride containing chlorine or a radioactive cation such as potassium, sodium or cesium The hitherto known processes have not been used for practical drilling. Soluble tracer substances cannot be used because they contaminate the drilling fluid and this has to be avoided at all costs. lonogenic tracer substances are not reliable as indicators in the processes concerned since they may be retained in the well bore by ion exchange or other interferring effects. Besides, many of the tracer substances which have been proposed for marking purposes emit gamma particles which must be prevented from penetrating into the well bore for they would very much complicate the measurement of natural radioactivity which has to be carried out during the drilling operation.

The substances emitting beta particles which have hitherto been proposed are either not suitable for the marking of drilling instruments for one of the aforesaid reasons as is for example, the case with the ionogenic chlorine, or they are difficulty accessible substances such as, for example, carbon,

which are too expensive for use in practice or they are substances having too short a hair life, as is the case with nitrogen, or they are substances emitting very soft betaparticles, for example, tritium, which can only be detected by means of sensitive measuring instruments which are expensive and not able to withstand the hard usage at drilling sites.

The present invention provides a process for indicating the occurrence of the critical amount of wear upon instruments and tools by means of a radioactive tracer substance in which the radioactive tracer substance is krypton? The tracer substance is advantageously used in the form of an inclusion compound. It is particularly advantageous to use krypton in the form of its clathrate with hydroquinone.

The tracer substance is introduced in known manner into the bore holes with which the instrument is provided and which are cut open and release the tracer substance as soon as the critical amount of wear has occurred.

In cases in which the well bores are deeper than about 300 meters the proper pressure of the gas released from the inclusion compound is in general too small as compared with the pressure of the supernatant liquid column so that the gas cannot leave the bore hole in which it is embedded. Even in cases in which the gas is embedded as such in the bore hole the pressure cannot be increased to any desired degree since the increase of the pressure is limited by increasing tightening difflculties.

In such a case it is preferred to introduce into the tracer bore hole not only the tracer substance but also a propellent which when coming into contact with the drilling fluid decomposes with the evolution of gas. For this purpose there may be used, for example, mixtures of water-soluble acids and carbonates. There may also be used alkali metals, for example, sodium or potassium. It is particularly advantageous to use hydrides, in particular lithium hydride or calcium hydride, since these compounds enable a particularly high yield of gas to be obtained in comparison with the volume of solid substances introduced.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawing in which FIG. 1 is a sectional view of a smoothing instrument which has been marked in accordance with the invention,

FIG. 2 illustrates a roller bit marked in accordance with the invention.

Referring to FIGS. 1 and 2 the tracer bore hole 1 contains the tracer substance 2 and, if desired or required, the propellent 3. The hole is closed by an appropriate closure 5, for example, a riveted screw or a shrinking closure, so as to be impermeable to gas. Numerals 4 designate the surfaces of the marked tool which are exposed to abrasion. The thickness of the material between the bore hole 1 and the surface 4 is so designed as to correspond to the highest tolerable amount of wear. As soon as such an amount of material has been abraded from the surface 4 that the bore hole 1 is cut open the drilling fluid penetrates into the bore hole 1 and the tracer substance 2 leaves the hole, is carried to the earths surface by the drilling fluid and can there be determined by means of a known counter which by way of known devices can actuate an indicator, a warning signal or a stopping device.

When the external pressure is high, as is always the case when the drilling is carried out in a great depth, the discharge of the tracer substance 2 is supported by the propellent 3 which upon reacting with the drilling fluid that has entered develops a gas which expels the tracer substance 2 out of the bore hole 1.

ln instruments and tools in which much material is available where the bore hole for the marking can be made, for example, in smoothing instruments, the tracer substance may be embedded in the bore hole in a relatively large, closed capsule which may also contain the propellent. In such a case the marking need not be carried out by the manufacturer. It is sufficient to provide the part to be marked with the bore hole and to introduce the capsule immediately before use.

The following example serves to illustrate the invention but it is not intended to limit it thereto.

EXAMPLE The process according to the invention was tested in practice on a drilling site in a series of experiments. The results of a typical test will now be described.

Data of the Drilling Core boring with a diamond bit;

depth: between 2345.3 and 2363.3 meters tubing of the well to a depth of 2250 meters diameter of the well bore in the depth according to the experiment: 216 mm;

geological formation: transition from Zechstein to carboniferous formation (layers of sandstone and argillaccous slate);

circulating fluid: fluid of clay and brine; total quantity 80 cubic meters;

speed of circulation of the fluid: 82 minutes per circulation; throughput of fluid: approximately 1 cubic meter/min. drilling load at the bottom of the well: 5 to 7 tons;

number of revolutions of the drill poles: 120 revolutions per minute;

arrangement of the drill poles from bottom to top: diamond head, core barrel, smoothing instrument, l2 heavy bars, the rest being normal drill bars.

Test Proceeding lnto appropriate pocket holes disposed in the three ribs of the smoothing instrument brass capsules were introduced in such a manner that their points were 1. millimeter below the surface of the ribs. The upper parts of the capsules were embedded in screws which had been hollowed by boring, the capsules being thus secured in the pocket holes. The parts of the screws projecting over the surface of the ribs were filed off so that the said surface was smooth. The brass capsules had walls 1 millimeter thick and a total length of 30 millimeters. In their front part which had a length of 20 millimeters they had a diameter of 5.6 millimeters and in their back part which was designed as a lock they had a diameter of 9 millimeters. In their front parts, which were next to the surface of the ribs, the capsules contained a mixture of about 100 millicuries of krypton in the form of hydroquinone clathrate 40 milligrams) and 150 milligrams of Lil-l which latter when reacting completely with water sufficed to produce at 100 C. pressure of l 100 atmospheres in the capsule which had a volume of 0.5 cubic centimeter. At its end the capsule was closed with a conical lead plug which had been pressed into it by means of a threaded pin. The place into which the screw was introduced had been filled with a cold-setting plastic so that no gas could escape through the threads after the screw had been in troduced.

After the smoothing ribs had undergone an abrasion of 1.5 to 2 millimeters during the drilling operation the point of the capsule was opened, drilling fluid entered the capsule, dissolved the clathrate and by reacting with the propellent produced hydrogen which expelled the krypton from the capsule, so that it entered the ascending fluid. The krypton distributed in the fluid, one-third of the total quantity of krypton being contained in the first, uppermost cubic meter of fluid and the rest being contained in diminishing concentration in the remaining 9 of the 10 cubic meters. Immediately behind the fluid funnel a large area counter tube was arranged which had a surface of 260 sq. centimeters and was mounted on a float. The measuring arrangement comprising counter tube, cathode follower, cable and ratemeter had a blind counting rate of 600 impulses per minute.

Result After the first capsule had been perforated by abrasion in the earth's fonnation 3.4Xl0 impulses per minute'were first indicated. After the first circulation (82 minutes) only 4X10 impulses per minute were indicated had further dropped to 1 2X10", no considerable increase of the degree of mixing with the fluid taking place. The experiment shows that 10 millicuries of krypton which corresponds to five times the blind counting rate are sufficient to produce an alarm. Also, after another three or four circulations the activity drops to l percent of the value first indicated, so that further indications will not be disturbed.

We claim:

1. A drilling tool containing in a closed cavity therein krypton?" or a compound thereof, as a gaseous nonionogenic the cavity being so positioned in the too that the krypton or the compound thereof is liberated when the tool has been subjected to the highest permissible amount of wear.

2. A tool as claimed in claim 1, wherein the krypton is present in the form of an inclusion compound.

3. A tool as claimed in claim 1, wherein the krypton is present in the form of a hydroquinone clathrate.

4. A process for marking a drilling tool to indicate when the highest permissible amount of wear has taken place, the improvement of which comprises inserting in a cavity in the tool krypton" or a compound thereof as a gaseous nonionogenic indicator.

5. A process as claimed in claim 11, wherein the krypton is present in the form of an inclusion compound.

6. A process as claimed in claim 11, wherein the krypton is present in the form of a hydroquinone clathrate.

7. In a process for marking tools and instruments for drilling deep wells with the aid of a circulating drilling fluid using radioactive tracer substances which serve to indicate the occurrence of the highest permissible amount of wear and which are embedded in bore holes in the tools or instruments in such a manner that upon the occurrence of the highest permissible amount of wear, these tracer substances occur in the circulating fluid and with it are carried to the earth's surface, the improvement which comprises using krypton as a gaseous nonionogenic radioactive tracer substance in conjunction with a propellant expelling the same from the tool into the fluid.

8. A process as claimed in claim 7, wherein the krypton is present in the form of an inclusion compound.

9. A process as claimed in claim 7, wherein the krypton is present in the form of a hydroquinone clathrate.

l0. ln a process for drilling deep bore holes by means of a drilling tool containing indicating means said drilling being aided by a fluid, the improvement which comprises:

a. placing in the tool in a gastight cavity krypton and an agent to expel from the tool krypton if needed, said cavity being placed at a distance away from a wear surface with a filling opening away from said wear surface for filling said cavity in the tool, said distance corresponding to the permissible amount of wear of said surface,

b. indicating a permissible amount of wear of the drilling tool by puncturing said compartment by abrasive wear of said tool, and

c. recording a wear indicating occurrence of said krypton aided by the drilling fluid acting as a carrier for krypton.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2457960 *Jun 15, 1944Jan 4, 1949Walker William EDrill bit
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US2868506 *Jun 1, 1954Jan 13, 1959Texas CoDetermination of fluid movement in bore holes
US3011566 *Nov 16, 1959Dec 5, 1961Jersey Prod Res CoBearing wear indication for a roller bit
Non-Patent Citations
1 * Oil & Gas Journal , Publication of August 29, 1955 Pages 77 79 relied on. Copy in 166/4
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3865736 *Aug 9, 1973Feb 11, 1975Chevron ResRadioactive grease containing krypton 85
US4346591 *Aug 21, 1981Aug 31, 1982Evans Robert FSensing impending sealed bearing and gage failure
US6308787Sep 24, 1999Oct 30, 2001Vermeer Manufacturing CompanyReal-time control system and method for controlling an underground boring machine
US6470976Sep 19, 2001Oct 29, 2002Vermeer Manufacturing CompanyExcavation system and method employing adjustable down-hole steering and above-ground tracking
US6631772Aug 21, 2001Oct 14, 2003Halliburton Energy Services, Inc.Roller bit rearing wear detection system and method
US6634441Aug 21, 2001Oct 21, 2003Halliburton Energy Services, Inc.System and method for detecting roller bit bearing wear through cessation of roller element rotation
US6648082Oct 26, 2001Nov 18, 2003Halliburton Energy Services, Inc.Differential sensor measurement method and apparatus to detect a drill bit failure and signal surface operator
US6691802Oct 26, 2001Feb 17, 2004Halliburton Energy Services, Inc.Internal power source for downhole detection system
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US6755263Oct 29, 2002Jun 29, 2004Vermeer Manufacturing CompanyUnderground drilling device and method employing down-hole radar
US6817425Oct 26, 2001Nov 16, 2004Halliburton Energy Serv IncMean strain ratio analysis method and system for detecting drill bit failure and signaling surface operator
US7044242Apr 26, 2002May 16, 2006Halliburton Energy Services, Inc.Roller cone bits with reduced packing
US7357197Oct 17, 2001Apr 15, 2008Halliburton Energy Services, Inc.Method and apparatus for monitoring the condition of a downhole drill bit, and communicating the condition to the surface
US7404457 *Jun 30, 2006Jul 29, 2008Baker Huges IncorporatedDownhole abrading tools having fusible material and methods of detecting tool wear
US7424910Jun 30, 2006Sep 16, 2008Baker Hughes IncorporatedDownhole abrading tools having a hydrostatic chamber and uses therefor
US7464771Jun 30, 2006Dec 16, 2008Baker Hughes IncorporatedDownhole abrading tool having taggants for indicating excessive wear
US7484571 *Jun 30, 2006Feb 3, 2009Baker Hughes IncorporatedDownhole abrading tools having excessive wear indicator
US7575070 *Dec 5, 2008Aug 18, 2009Baker Hughes IncorporatedDownhole abrading tools having excessive wear indicator
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DE102005016346B3 *Apr 9, 2005Jan 4, 2007Hochtief Construction AgDevice for measuring wear in disc cutters, especially on tunnel drilling machines, has a magnet in the wearing layer at the circumference of the disc and a sensor for measuring the magnetic field strength
WO1999028590A1 *Nov 27, 1998Jun 10, 1999Austoil Technology LimitedDrilling tools and wear detection methods
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U.S. Classification175/39
International ClassificationE21B12/00, E21B12/02, B23Q17/09
Cooperative ClassificationE21B12/02, B23Q17/09
European ClassificationB23Q17/09, E21B12/02