DE102016223883A1 - Axial thrust bearing with measuring bolt for drilling rigs - Google Patents

Abstract

Kraftdrehkopfaxiallager 200 for a drilling rig with a first bearing ring 232, a second bearing ring 234 and a plurality of rolling elements 236 between the first bearing ring 232 and the second bearing ring 234. According to the invention, the first bearing ring 232 or the second bearing ring 234 at least one material recess 240-244 whose end face, and at least one measuring element with at least one sensor for measuring the bearing load is pressed with oversize into the at least one material recess 240-244.

Description

Field of the invention

The present invention relates to a Kraftdrehkopfaxiallager for a drilling rig, the Kraftdrehkopfiaxager having a material recess with a pressed-measuring element with a sensor. More particularly, the invention relates to a Kraftdrehkopfaxiallager, which is designed as axial tapered roller bearings.

Background of the invention

The creation of wells, particularly in the oil and gas industry, requires careful handling of the drilling tool to drill along a desired path. The construction of such a drilling tool generally comprises a drill string having a drill bit disposed at the lower end of the drill string, the drill string extending downwardly from a derrick into the earth formation or wellbore. In the derrick is usually a so-called power turret (English "Top Drive") mounted to drive the drill string via a rope in a crane hook on a crane bottle. The rope is in turn anchored with a dead rope anchor with the soil. The control of the drilling can be influenced inter alia by feeding or returning the rope. The drill bit includes a so-called downhole engine and a drill bit for actual drilling.

For the drilling process, it is important to know the forces acting on the drill bit in order to avoid damage to the drilling tool, in particular to the drill bit. The knowledge of the forces acting on the drill bit is also helpful in order to carry out the drilling process economically.

It is known that the axial load and torque acting on a drill bit (hereinafter also referred to as drill bit) during the drilling operation are important parameters that influence the direction and inclination of the borehole as well as the efficiency of the drilling work. The axial load on the drill bit is also known as weight-on-bit (WOB). A load acts on the drill bit over the drill string, which is biased on the derrick with the other surface mounted components, such as the "top drive", so that the size of the WOB can be adjusted by varying the superior hook load. WOB affects penetration rate, drill bit wear and drilling direction. Torque-on-bit (TOB) torque is also important in terms of drill bit wear and drilling direction, especially when combined with WOB. Thus, excessive TOB is indicative of serious bit damage, such as failure of a camp under jammed skittles.

Methods and apparatus for measuring WOB and / or TOB are known over days or underground. Over-day measurements are taken by comparing the hook load weight to the "over-the-sole weight": if the hook load with lifted drill string is, for example, 100 tons and after lowering to the bottom of the hole, then the drill bit must now be five tons Load on the bottom of the hole. A drill guide can now lift the drill string from the drill floor again and adjust its control. On continuation of the boron process, he then receives the "missing" hook load as a bit load.

In order to record the hook load over days, pressure cells on the dead rope anchor or the so-called pulley in the derrick ("Crown Block") are known. Measuring sensors, such as strain gauges, are also known on the (dead) cable itself.

Underground measurements are often taken via force sensors arranged, for example, on additional cylinders or pockets in the downhole tool. However, these measurements are subject to significant inaccuracies due to the effects of borehole pressure and temperature gradients. Nor can they generally distinguish between tension caused by the weight and axial tension caused by the pressure difference. They are also adversely affected by the pressure exerted by drilling fluids.

Summary of the invention

It is the object of the invention to improve the detection of the bit load, in particular to make it more robust against measurement errors and to capture further parameters for the control of the drilling tool.

This object is achieved by a Kraftdrehkopfiaxager for a drilling rig according to claim 1. The axial swivel bearing can be used in a "top drive". The bearing comprises two bearing rings with rolling elements arranged therebetween. According to the invention, one of the bearing rings has at least one material recess on its end face. In the at least one material recess a measuring element is pressed with at least one sensor for measuring the bearing load with excess.

The detection of the forces transmitted by the rolling elements upon rolling of the measuring element in the material recess makes it possible to derive the load of the bit in the borehole. The Thrust bearing thrust bearing is not affected by the above-described problems of underground force measurements. Even with respect to the known over-the-day force measurements, the detection of the forces at the top-mounted power turret bearing has considerable advantages with regard to measuring errors.

In one embodiment, the at least one material recess is arranged on the bearing ring which is in relation to the rotation. This has the advantage that no telemetry is required to detect the forces of the rotating drill string. In particular, no data from the borehole must be transmitted.

In one embodiment, the first bearing ring is a wave washer and the second bearing ring is a housing washer. Thus, the wave washer can rotate and the housing disc is stationary in relation to the rotation.

In a further embodiment, the at least one measuring element is designed as a bolt and / or the at least one sensor as a strain-sensitive sensor, in particular as a direct coating. A direct coating has, in contrast to film strain gauges, inter alia an individually adaptable measuring structure, a higher precision and long-term stability as well as increased resistance to environmental conditions such as strong temperature fluctuations. Such a direct coating technology or thin-film technology is known to the applicant under the name Sensotect®. A measuring bolt with different arrangements of a strain-sensitive sensor is, for example, in DE 10 2014 204 025 A1 described.

The external load of the Kraftdrehkopfaxiallagers has strains and compressions of the individual bearing components result. These expansions and compressions can be detected metrologically with the at least one measuring element, for example a measuring pin with Sensotect® coating, ie a Sensotect® pin.

This Sensotect® pin can be made small in size. Since not the large-scale bearing ring, so for example, the wave washer, but only small-sized Sensotect® pins are coated directly, costs can be saved.

In addition, with the measuring element pressed into the material recess, it is achieved that the strain-sensitive sensors are introduced into the material of the bearing ring and there detect compressions and expansions in the interior of the bearing ring, which are introduced into the bearing ring by the rolling elements. The strain sensors are positioned with the help of a measuring element, such as the bolt, at locations where much larger strains and compressions occur than is the case on the surface of a bearing ring. On the surface of a bearing ring similar large expansions and compressions could only be achieved if the bearing ring is weakened for example by a groove. However, this has the disadvantage that the life of the bearing decreases. However, a measuring element is pressed in excess so that it can also detect strains, and so that it acts in one piece with the bearing ring. The bearing ring is thus not significantly weakened. Overall, the bearing is not weakened in its structure and rigidity.

Since the bearing load is introduced via the rolling elements in the bearing ring, a measuring element detects the maximum bearing load when a rolling element is exactly above the measuring element. Therefore, the maxima of the sensor signals can be used for a calculation of the bearing load. It is thus possible to determine the load variations which are smaller in their frequency than the rolling body rollover frequency.

In order to be able to meet this limitation, in one embodiment one of the bearing rings has at least two adjacent material recesses each having a measuring element, wherein the distance between the at least two material recesses is smaller than the distance between two adjacent rolling elements. The distance is preferably smaller by a factor of 10. Thus, one of the measuring elements is always rolled over in succession at short intervals by a rolling body.

In a further embodiment, one of the bearing rings has at least two further adjacent material recesses each having a measuring element. Here, the distance between the adjacent material recesses and the other adjacent material recesses is a multiple, in particular an integer multiple, of the distance between two adjacent rolling elements. In other words, one of the bearing rings at least two groups of closely spaced sensing elements, wherein the at least two groups are spaced by a multiple of the Wälzkörperabstands spaced apart in material recesses.

In a further embodiment, one of the bearing rings has at least one group of at least three material recesses each having at least one measuring element. In this case, the at least one group is arranged such that the three measuring elements can be rolled over by a rolling body at the same time. This has the advantage that also different directions of force can be determined. Within such a group can namely magnitude and direction of the force are determined by the measured values are considered as vertices of a virtual level. The force vector is perpendicular to this virtual plane and has the length of the average of the readings of all sensors within the group.

In a further development of the above-described embodiment of a group of at least three material recesses with measuring elements, at least three such groups are arranged on the circumference of the bearing ring. Preferably, the groups are arranged at approximately equal angular intervals. The arrangement with such staggered groups has the advantage that a higher temporal resolution of the measurement can be achieved. Furthermore, the results of the groups can be averaged together to increase the accuracy.

However, in order to achieve this higher temporal resolution, the rolling elements must not stand simultaneously above the material recesses with measuring elements. This is then fulfilled if the number of rolling elements causes the rolling elements not to be simultaneously above the material recesses with equally spaced material recesses.

In a further embodiment, therefore, the distances of the Materialausnehmungen with measuring elements can also be selectively varied with each other, so are not kept exactly the same so that the rolling elements are not all at the same time on the Materialausnehmungen.

For example, a first measuring element can be located just below a first rolling element, a second measuring element in 1/10 pitch below a second rolling element, a third measuring element in 2/10 pitch below the third rolling element, etc. This has the advantage that also 10 measuring elements next to each other can be introduced into the distance between two rolling elements.

Alternatively, for example, the odd measuring elements can be positioned under a first rolling element and the straight measuring elements offset according to a second rolling element.

In one embodiment, the Kraftdrehkopfiaxager is designed as axial tapered roller bearings. Axial tapered roller bearings allow for very high load capacity, shock-resistant and rigid bearings with only a small axial space requirement.

Further advantages, features and details of the invention will become apparent from the embodiments described below and with reference to the figures.

list of figures

• 1 eine Überblicksdarstellung einer Bohranlage mit Bohrwerkzeug in Anwendung,
• 2 ein Kraftdrehkopfaxiallager mit Messbolzen in einem Lagerring,
• 3 einen vergrößerten Querschnitt eines Teils eines Kraftdrehkopfaxiallagers mit einem Messbolzen in einer Ausnehmung auf einer Stirnseite eines Lagerrings, und
• 4 eine Anordnung mehrere Messbolzen in Ausnehmungen auf einer Stirnseite eines Lagerrings.

Hereinafter, embodiments of the invention will be illustrated with reference to figures. The figures show unscaled drawings. Show it:

• 1 an overview of a drilling rig with drilling tool in use,
• 2 a thrust bearing thrust bearing with measuring pin in a bearing ring,
• 3 an enlarged cross section of a portion of a Kraftdrehkopfiaxager with a measuring pin in a recess on an end face of a bearing ring, and
• 4 an arrangement of a plurality of measuring bolts in recesses on an end face of a bearing ring.

Detailed description of the drawings

1 shows an overview of a drilling rig 100 with drilling tool in application. The drilling rig 100 includes the derrick 120 , which is arranged on the ground over days. From the derrick 120 extends a drill string 110 in the soil 105 , The drill string includes at its end a downhole motor 112 the one in a drill bit 114 ends. On the drill bit 114 the force F 116 acts during operation. Underground motor 112 , Drill bits 114 and partly the drill string 110 are underground, so in the ground 105 in a borehole. At the derrick 120 is on a crane bottle and crane hook 124 a power turret and components 122 hooked. The power turret and components 122 that the drill string 110 are driving, with the (dead) rope 126 at a dead rope anchor 128 secured. The dead rope anchor is typically firmly connected to the ground. In 1 is separated over days and underground by means of the horizontal line.

2 shows a Kraftdrehkopfiaxager 200 with measuring pin in the bearing ring 234 , For example, a housing plate. The measuring pins are in the material recesses 240-244 on the front side of the bearing ring 234 pressed in with oversize. The measuring bolts, or measuring elements, each comprise a sensor for measuring the bearing load (not in 2 illustrated). Between the bearing rings 232 . 234 are rolling elements 236 arranged. rolling elements 236 The material recesses 240-244 roll over with the measuring bolts. When overrolling, the sensors can detect the force applied to the measuring pin. This is done, for example, with a sensor layer at the end of the force measuring bolt, which on the pressure angle of action of a rolling element 236 comes to rest. See also the description to 3 ,

3 shows an enlarged cross section of a part of a power rotary bearing thrust 300 with a measuring pin in a recess 340 on a front side of a bearing ring 334 , in particular a housing plate. The Kraftdrehkopfaxiallager 300 has another bearing ring 332 with between the bearing rings 332 . 334 lying rolling elements 336 on. At the end of the measuring bolt is a strain-sensitive sensor layer 350 arranged. The material recess 340 is so in the bearing ring 334 introduced that the end of the force measuring pin, and thus the strain-sensitive sensor layer 350 , on the pressure angle line of action 352 of the rolling element 336 lies.

4 shows an arrangement of a plurality of measuring bolts in recesses 440 . 441 . 442 on a front side of a bearing ring 400 , The recesses 440 . 441 . 442 form a group 447 Materialausnehmungen, which are rolled over by rolling elements at short intervals. Further corresponding groups 445 . 446 Materialausnehmungen with measuring bolts are at approximately equal angular intervals over the circumference of the bearing ring 400 distributed.

LIST OF REFERENCE NUMBERS

100

drilling rig

105

soil

110

drill string

112

Downhole motor

114

drill bit

116

Force F on drill bit

120

derrick

122

Power turret and components

124

Crane hook and crane bottle

126

(Tot) rope

128

Totseilanker

200, 300

Kraftdrehkopfaxiallager

232, 332

first bearing ring

234, 334

second bearing ring

236, 336

rolling elements

240-244

Material recess with bolts

340

Material recess with bolts

350

Strain-sensitive sensor layer

352

Contact angle line of action

400

Bearing ring of a Kraftdrehkopfaxiallagers

440, 441, 442

Material recess with bolts

445, 446, 447

Groups of material recesses with bolts

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014204025 A1 [0013]

Claims (10)

A power rotary bearing (200, 300) for a drilling rig (100) comprising - a first bearing ring (232, 332), - a second bearing ring (234, 334), - and a plurality of rolling elements (236, 336), wherein the plurality of Rolling body (236, 336) between the first bearing ring (232, 332) and the second bearing ring (234, 334) is arranged, characterized in that the first bearing ring (232, 332) or the second bearing ring (234, 334) at least one Material recess (240-244, 340, 440, 441, 442) on the end face, and that at least one measuring element with at least one sensor (350) for measuring the bearing load with excess in the at least one material recess (240-244, 340, 440 , 441, 442) is pressed. Axial thrust bearing (200, 300) after Claim 1 wherein the at least one material recess (240-244, 340, 440, 441, 442) is arranged on the rotatable bearing ring (234, 334). Axial thrust bearing (200, 300) after Claim 1 or 2 wherein the first bearing ring (232, 332) is a wave washer, and the second bearing ring (234, 334) is a housing washer. Kraftdrehkopfaxiallager (200, 300) one of Claims 1 to 3 , wherein the at least one measuring element is designed as a bolt and / or the at least one sensor (350) as a strain-sensitive sensor, in particular as a direct coating, is formed. Kraftdrehkopfaxiallager (200, 300) one of Claims 1 to 4 wherein the first bearing ring (232, 332) or the second bearing ring (234, 334) has at least two adjacent material recesses (240-244, 440, 441, 442), each with a measuring element, and wherein the distance between the at least two material recesses ( 440, 441, 442) is smaller than the distance between two adjacent rolling elements. Axial thrust bearing (200, 300) after Claim 5 , wherein the distance is smaller by a factor of 10. Axial thrust bearing (200, 300) after Claim 5 or 6 wherein the first bearing ring (232, 332) or the second bearing ring (234, 334) has at least two further adjacent Materialausnehmungen, each with a measuring element, and wherein the distance between the adjacent material recesses and the other adjacent material recesses a multiple, in particular an integer multiple , is the distance between two adjacent rolling elements. Kraftdrehkopfaxiallager (200, 300), after one of Claims 1 to 7 wherein the first bearing ring (232, 332) or the second bearing ring (234, 334) at least one group (445, 446, 447) of at least three material recesses (440, 441, 442) each having at least one measuring element, and wherein the at least one group (445, 446, 447) is arranged such that the three measuring elements can be rolled over by a rolling body at the same time. Axial thrust bearing (200, 300) after Claim 8 , wherein at least three such groups (445, 446, 447) on the circumference of the first bearing ring (232, 332) or the second bearing ring (234, 334), preferably at approximately equal angular intervals, are arranged. Axial thrust bearing (200, 300) according to one of the Claims 1 to 9 , wherein the Kraftdrehkopfaxiallager is designed as axial tapered roller bearings.

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