CN206530287U - Constant pressure type rotates vibration screw motor - Google Patents

Abstract

Vibration screw motor is rotated the utility model discloses a kind of constant pressure type, it includes shell body and the rotating mechanism installed in it, wherein：Positive displacement power assembly that rotating mechanism includes being sequentially connected from top to bottom, power transmission shaft and determine valve, determine in the middle part of valve outer wall between shell body to be provided with formation annular space B and its annular space can be around determining the dynamic valve that valve is rotated against；Constant pressure type rotation vibration motor is arranged between BHA and drill bit; both meet routine " PDC+ motors " combined drilling process specifications, axial vibration can be eliminated again, and keep the pressure of the drill of drill bit constant; be conducive to protecting PDC drill bit, extend drilling life of bit；And rotation vibration energy can also be provided for PDC drill bit broken rock, overcome damage of the axial vibration to PDC drill bit during deep-well, ultra-deep well drilling, and the problems such as broken rock energy deficiency, on the basis of deviation control with drilling straight well technical requirements are met, further increase bit speed.

Description

Constant pressure type rotates vibration screw motor

Technical field

The utility model belongs to the industry undergrounds such as oil and gas well drilling, CBM Drilling, geological prospecting, mine probing and made Industry apparatus field, and in particular to a kind of constant pressure type rotates vibration motor.

Background technology

With superficial part oil-gas reservoir exploitation totally, deep-well, the quantity of ultradeep well increase year by year, but with the increase of well depth, Rock stratum is harder to be difficult to crush, and has had a strong impact on the raising of rate of penetration, and the reduction of drilling speed has become restriction China deep layer The technical bottleneck of oil-gas reservoir Efficient Development, and existing conventional rock-breaking and well-drilling technology can not meet the technological requirement for putting forward effect, state It is outer to be monopolized for advanced speed-raising technical know-how, limit the development of domestic technique." PDC+ motors " combined drilling technology was both The advantage of PDC drill bit high-efficient cutting can be played, compound drilling can be carried out again, deviation control with drilling straight well effect is preferable, moreover it is possible to reduce ground machine The energy consumption of pump, therefore be widely applied in deep-well, the drilling process of ultradeep well, but in order to which inclining prevention can only use small The drilling mode of the pressure of the drill, and the pressure of the drill is to influence the key factor of drilling speed, for routine " PDC+ motors " technique, although the pressure of the drill is smaller It is advantageously ensured that wellbore quality, is conducive to deviation control with drilling straight well, but it is the field practice to sacrifice drilling speed as cost to a certain extent Prove, appropriate increase the pressure of the drill can greatly improve bit speed, but it is excessive to easily cause hole angle, influences wellbore quality, and Cause shaft bottom drill bit to occur axial vibration so that the pressure of the drill being applied on drill bit is unstable, damage Cutter, reduce drill bit Service life, reduces rate of penetration, and domestic and international correlative study result shows that axial vibration damping instrument is closer to drill bit, effectiveness in vibration suppression It is better, and existing screw motor does not possess vibration-damping function, if existing conventional vibration dampening tool to be arranged on to the top of screw motor, Vibration dampening tool is just extended to the distance of drill bit, so as to reduce effectiveness in vibration suppression, and has not seen that vibration dampening tool is arranged at present Application example between motor and drill bit；Field practice proves that rotation vibration effect can effectively improve the cutting energy of PDC drill bit Amount, prevents the influence of stick slip vibration, protects drill bit, has positive role for improving drilling speed, related torsion is it is also proposed both at home and abroad The patent of power percussion tool（CN201520767504.6、CN201410514618.X、CN201310726252.8、 CN201410306930.X、CN201310586179.9、CN201010511421.2、CN200910058083.9、 CN201310698227.3、CN201420040141.1）, but existing torsion impact tool construction is complicated, parts are more, body Product it is larger, and torsion impact instrument need under the conditions of larger the pressure of the drill competence exertion effect, and the pressure of the drill it is big when, not only result in well Eye is glanced off, and is influenceed wellbore quality, can also be produced axial vibration, if reducing the pressure of the drill, it is ensured that wellbore quality, but can not Effect of torsion impact instrument is played, also has not seen that torsion impact instrument and the application that motor is used cooperatively are real both at home and abroad at present Example, it can be seen that, if conventional torsion percussion tool simply connected with motor, not only influence " PDC+ motors " technique Speed-increasing effect, it is also possible to cause the damage of motor internal structure；And domestic and international existing motor, which only has, utilizes drilling well liquid energy The simple functions of amount driving bit, axial vibration damping is not provided simultaneously with or the function of vibration is rotated, therefore is badly in need of design research and development It is a kind of that both there is vibration-damping function, and shock absorber is as close to drill bit, additionally it is possible to rotation vibration effect is produced, is bored playing PDC Drill bit can also be protected while head technical advantage, also simple in construction, dependable performance, the convenient constant pressure type rotation of attended operation is shaken Screw motor is hit, this further improves the efficiency of well drilling and rock crushing, lifting for playing " PDC+ motors " drilling technology advantage The drilling technology level of China's deep-seated oil gas reservoir Efficient Development, enhances our international competitiveness with important economic value and society It can be worth.

Utility model content

In order to further improve the bit speed of deep-well, ultradeep well, on the basis of prior art equipment, should fully it send out The speed-raising advantage of " PDC+ motors " combined drilling technique is waved, deviation control with drilling straight well effect is taken into account again, the control energy of hole quality is improved Power, will also reduce drilling well integrated cost, shorten the construction operation cycle, and the technique for meeting deep-seated oil gas reservoir Efficient Development drilling well will Ask, break the external technical monopoly in terms of deep-well, ultradeep well improve drilling speed.It is that oil is natural that the purpose of this utility model, which is exactly, The scene of pneumatic drill well, CBM Drilling, geological prospecting, mine probing etc. provides a kind of perseverance with vibration damping or rotation vibration function Pressure type rotates vibration motor.

The utility model solves the technical scheme that its technical problem used：

A kind of constant pressure type rotates vibration screw motor, including shell body and its interior rotating mechanism installed, wherein：

The rotating mechanism is including the positive displacement power assembly being sequentially connected from top to bottom, power transmission shaft and determines valve；It is described Power transmission shaft is hollow tubular and it forms annular space A between shell body, described determine valve upper end and the drive connection of power transmission shaft lower end, and Determine to form sealing cooperation between valve outer wall upper and lower ends and shell body, the transmission axial wall, which is provided with, connects annular space A and its inner chamber Logical by-pass prot；

It is described to determine in the middle part of valve outer wall to be formed that be provided with annular space B, and annular space B be relative around valve is determined between shell body The dynamic valve of rotation；The guide pad for determining to be arranged with two axial directions in the middle part of valve outer wall and by annular space B at intervals of being arranged symmetrically Two and half chambers, form sealing and coordinate between the guide pad and shell body；The dynamic valve includes being located in the two halves chamber respectively Sliding block, corresponding half chamber is divided into the central slot and and shell of chamber A and cavity C and each sliding block by each sliding block respectively Body, determine valve and surround to constitute chamber B；The inner chamber center for determining valve by safety valve be divided into above and below two chambers, and epicoele side wall sets There are multiple pressure holes, cavity of resorption side wall to be provided with multiple low pressure holes, pressure hole connection corresponding with chamber B, the low pressure hole and chamber Room A is connected with cavity C correspondence；

It is described to determine to offer two groove-type channels on valve outer wall, for being respectively communicated with chamber A and chamber B, chamber B and chamber C；When the dynamic valve around determine valve and rotate when, the sliding block top can alternately open groove-type channel and by chamber A and chamber B, chamber Room B is respectively communicated with cavity C, while the sliding block bottom can be by chamber A and cavity C alternate communication low pressure hole.

Further, shaft coupling is installed between the positive displacement power assembly and power transmission shaft.

Further, the power transmission shaft and determine spring is installed between valve, power transmission shaft and determine valve composition spline fitted.

Further, the power transmission shaft bottom is provided with spline, and power transmission shaft is by spline and determines valve inwall composition spline fitted.

Further, it is described to determine first sealing device, the second sealing device are installed between valve outer wall and shell body inwall.

Further, alignment bearing is installed between power transmission shaft and the shell body top；It is described to determine valve bottom and shell Lower alignment bearing is installed between body bottom.

Further, constant pressure type rotation vibration motor also includes thrust bearing, the thrust bearing be arranged on power transmission shaft with Between spring, and installed in upper alignment bearing bottom.

Principle of the present utility model is：Determine valve, it is dynamic formed respectively between valve, shell body inwall chamber A, chamber B, cavity C, Chamber D, chamber E, chamber F（Chamber A, chamber B, cavity C are located at one and half chambers, and chamber D, chamber E, chamber F members are located at another Half chamber, structure and action principle are identical）, under drilling fluid effect, positive displacement power assembly produces rotation torque, passes through shaft coupling Device is transferred to power transmission shaft, due to power transmission shaft and determines between valve to be spline fitted mode, therefore determines valve also concomitant rotation, due to drill bit Directly it is connected with determining valve lower end, and then drives drill bit to rotate broken rock；Drilling fluid enters after positive displacement power assembly through by-pass prot Enter power transmission shaft, then reach and determine inside valve, during original state, chamber A is connected with chamber B, and chamber D is connected with chamber E, cavity C Connected with chamber F by low pressure hole with drill bit, now drilling fluid is introduced into chamber B and chamber D by pressure hole, subsequently into chamber Room A and chamber E, now chamber A and chamber E is high pressure chest, and cavity C and chamber F are low pressure chambers, in the effect of cleaner for high-pressure drilling fluid Under, dynamic valve starts quick rotation clockwise, in this process, and chamber A and chamber E spaces gradually increase, cavity C and chamber F Space is gradually reduced, and the drilling fluid in chamber flows to drill bit by low pressure hole, and rotation will be produced when dynamic valve is with determining valve jacket Rotational oscillation hits power, and is transferred to drill bit by determining valve, at the same time, and the runner between chamber A and chamber B is closed, between chamber D and chamber E Runner close, cleaner for high-pressure drilling fluid can not be again introduced into, and chamber A is connected with chamber E by low pressure hole with drill bit, chamber A Low pressure chamber is converted into chamber E, and chamber B is connected with cavity C, chamber D is connected with chamber F, and cavity C is converted into height with chamber F Chamber is pressed, with the entrance of drilling fluid, dynamic valve will be rotated counterclockwise, with the rotation of dynamic valve, chamber A and chamber E spaces are gradually Reduce, the drilling fluid in chamber flows to drill bit through low pressure hole, until with determining valve jacket, when valve is determined in dynamic valve shock counterclockwise, chamber A Connected again with chamber B, chamber D is connected again with chamber E, cavity C is connected with chamber F by low pressure hole with drill bit, high pressure is bored Well liquid can drive dynamic valve, and valve is determined in shock clockwise, so as to complete once to rotate the process of vibration, connection cavity C is with chamber F's The design attitude of low pressure hole has carried out special optimization design according to calculating, it is ensured that dynamic valve turning anticlockwise, which hits, determines shaking for valve generation Hit power smaller, because shaft bottom drill bit is the rock cutting that turns clockwise, therefore anticlockwise vibration power is for improving drill bit Cutting energy effect is little, and only needs to clockwise vibration power.Said process reciprocation cycle, just forms rotation to drill bit Rotational oscillation hits effect, and then improves the energy of bit cutting rock.When axial vibration occurs for shaft bottom drill bit, because drill bit is with determining Valve is connected, therefore the axial vibration at drill bit is transferred to spring through determining valve, and compression deformation of the spring shakes with regard to that can absorb the axial direction of drill bit Dynamic impulsive force, when axial vibration weakens, spring recovers to extend, the axial impact force due to spring buffer at drill bit, therefore It ensure that the steady of drill bit and stratum is contacted, maintain the stabilization of the pressure of the drill on drill bit, it is to avoid impulsive force is to Cutter Damage, reached the purpose that protection drill bit increases the service life；Determine because dynamic valve is arranged on outside valve, determine valve and make in axial vibration During with lower generation axial displacement, dynamic valve also can be with being moved together, and during moving axially, dynamic valve still can bored with determining valve Rotation vibration effect, i.e. constant pressure type rotation vibration motor are produced in the presence of well liquid while vibration damping keeps drill bit the pressure of the drill stable Drill bit broken rock energy can be increased again, this is that routine techniques is difficult to.If rotation vibration can not be produced by moving valve or determining defective valve Effect, then drilling fluid, which cannot pass through dynamic valve and determine valve, reaches shaft bottom drill bit, with the continuous rise of drilling liquid pressure, when pressure is super When crossing the setting value of safety valve, safety valve will be opened, and drilling fluid is flowed directly to drill bit, the circulation without influenceing drilling fluid. Constant pressure type rotation vibration motor can will surge and can be converted into mechanical energy, produce rotation vibration effect, improve bit broken rock Cutting force, the axial vibration of cushioned drill bit can be absorbed again, damage of the axial impact force to drill bit is prevented, and keep drill bit broken rock The pressure of the drill it is steady, this under domestic prior art equipment condition further improve deep-well, ultradeep well drilling efficiency have weight Want meaning.Site test results show that drilling efficiency 38.2%- can averagely be improved by rotating vibration motor using constant pressure type 67.9%, drilling period 8-15 days are saved, and drilling quality meets design standard, realizes low energy consumption, efficient drilling well mesh 's.

Meanwhile, constant pressure type rotation vibration motor also have simple structure design, dependable performance, it is easy to operate the features such as.

Brief description of the drawings

Fig. 1 is the constant pressure type rotation vibration motor configuration schematic diagram proposed according to the utility model.

Fig. 2 is the constant pressure type rotation vibration motor Section A-A schematic diagram proposed according to the utility model.

Fig. 3 is the constant pressure type rotation vibration motor section B-B schematic diagram proposed according to the utility model.

Reference：1- shell bodies, 2- positive displacement power assemblies, 3- shaft couplings, 4- by-pass prots, the upper alignment bearings of 5-, 6- Power transmission shaft, 7- thrust bearings, 8- springs, 9- splines, 10- first sealing devices, 11- determines valve, and 12- safety valves, 13- moves valve, 14- Alignment bearing under second sealing device, 15-, 16- pressure holes, 17- low pressure holes, 18- cavitys A, 19- cavity B, 20- cavity C, 21- Cavity D, 22- cavity E, 23- cavity F.

Embodiment

It is described in detail the utility model below in conjunction with the accompanying drawings.

Such as Fig. 1, constant pressure type rotation vibration motor major capsid body 1, positive displacement power assembly 2, shaft coupling 3, by-pass prot 4, Upper alignment bearing 5, power transmission shaft 6, thrust bearing 7, spring 8, spline 9, first sealing device 10, determine valve 11, safety valve 12, dynamic valve 13rd, the second sealing device 14, lower alignment bearing 15, pressure hole 16, low pressure hole 17 are constituted.Positive displacement power assembly 2 and power transmission shaft 6 Between install shaft coupling 3, the top of power transmission shaft 6 processing by-pass prot 4, install alignment bearing between power transmission shaft 6 and the inwall of shell body 1 5, thrust bearing 7 is arranged on the upper bottom of alignment bearing 5, thrust bearing 7 and determine to install spring 8 between valve 11, and the bottom of power transmission shaft 6 is spent Key 9, and constitute spline fitted with determining the inwall spline of valve 11.Determine the first sealing is installed between the outer wall of valve 11 and the inwall of shell body 1 Device 10, the second sealing device 14, dynamic valve 13, which is arranged on, to be determined outside valve 11, is determined the inside of valve 11 and is installed safety valve 12, determines under valve 11 Lower alignment bearing 15 is installed between portion and the bottom of shell body 1, the top of valve 11 processing pressure hole 16, bottom processing low pressure hole 17 is determined.

Referring to the drawings 2 and Fig. 3, determine valve 11, move formed respectively between valve 13, the inwall of shell body 1 chamber A18, chamber B19, Cavity C 20, chamber D21, chamber E22, chamber F23.Determine to offer a plurality of groove-type channel on the outer wall of valve 11, for intermittence connection Chamber A18 and chamber B19, chamber B19 and cavity C 20, i.e., when chamber A18 is connected with chamber B19, chamber B19 and cavity C 20 are not Connection, but now cavity C 20 is connected by low pressure hole 17 with bit port.Similarly, chamber D21, chamber E22, chamber F23 are also same Sample passes through groove-type channel alternate communication.

Under drilling fluid effect, positive displacement power assembly produces rotation torque, and power transmission shaft 6 is transferred to by shaft coupling 3, by In power transmission shaft 6 and determine between valve 11 to be spline fitted mode, therefore determine the also concomitant rotation of valve 11, because drill bit is directly with determining valve 11 Lower end is connected, and then drives drill bit to rotate broken rock.Drilling fluid enters power transmission shaft after positive displacement power assembly through by-pass prot 4 6, then reach and determine inside valve 11.During original state, determine the groove-type channel on the outer wall of valve 11 and chamber A18 and chamber B19 is connected Logical, chamber D21 is connected with chamber E22, and cavity C 20 is connected with chamber F23 by low pressure hole 17 with drill bit.Now drilling fluid Chamber B19 and chamber D21 are introduced into by pressure hole 16, subsequently into chamber A18 and chamber E22, now chamber A18 and chamber E22 is high pressure chest, and cavity C 20 and chamber F23 is low pressure chamber.In the presence of cleaner for high-pressure drilling fluid, dynamic valve 13 starts clockwise Quick rotation, in this process, chamber A18 and chamber E22 spaces gradually increase, and cavity C 20 and chamber F23 spaces gradually subtract It is small, and drilling fluid in chamber flows to drill bit by low pressure hole 17.Rotation will be produced when dynamic valve 13 is with determining the shock of valve 11 to shake Power is hit, and drill bit is transferred to by determining valve 11, at the same time, the runner between chamber A18 and chamber B19 is closed, chamber D21 and chamber Runner between E22 is closed, and cleaner for high-pressure drilling fluid can not be again introduced into, and chamber A18 and chamber E22 passes through low pressure hole 17 and drill bit Connection, chamber A18 and chamber E22 are converted into low pressure chamber, depending on groove-type channel on the outer wall of valve 11 cause chamber B19 and chamber C20 is connected, and chamber D21 is connected with chamber F23, and cavity C 20 and chamber F23 is converted into high pressure chest.With the entrance of drilling fluid, move Valve 13 will be rotated counterclockwise, with the rotation of dynamic valve 13, and chamber A18 and chamber E22 spaces are gradually reduced, the drilling well in chamber Liquid flows to drill bit through low pressure hole 17, until dynamic valve 13 hits with determining valve 11, when valve 11 is determined in the dynamic shock counterclockwise of valve 13, chamber A18 Connected again with chamber B19, chamber D21 is connected again with chamber E22, cavity C 20 and chamber F23 connects by low pressure hole with drill bit Logical, cleaner for high-pressure drilling fluid can drive dynamic valve, and valve is determined in shock clockwise, so as to complete once to rotate the process of vibration.Connect chamber The design attitude of C20 and chamber F23 low pressure hole has carried out special optimization design according to calculating, it is ensured that the dynamic turning anticlockwise of valve 13 The vibration power that the generation of valve 11 is determined in shock is smaller, because shaft bottom drill bit is the rock cutting that turns clockwise, it is anticlockwise Vibration power is little for improving the effect of bit cutting energy, and only needs to clockwise vibration power.Said process is back and forth followed Ring, just forms rotation vibration effect, and then improve the energy of bit cutting rock to drill bit.

When axial vibration occurs for shaft bottom drill bit, because drill bit is connected with determining valve 11, therefore the axial vibration warp at drill bit Determine valve and be transferred to spring 8, the compression of spring 8 is with regard to that can absorb the axial vibration impulsive force of drill bit, when axial vibration weakens, bullet Spring 8 recovers elongation, because spring 8 has buffered the axial impact force at drill bit, it is ensured that drill bit is contacted with the steady of stratum, Maintain the stabilization of the pressure of the drill on drill bit, it is to avoid damage of the impulsive force to Cutter, reached that the extension of protection drill bit is used The purpose in life-span；Determine because dynamic valve 13 is arranged on outside valve 11, determine valve 11 and during generation axial displacement, moved under axial vibration effect Valve 13 also can be with being moved together, and during moving axially, dynamic valve 13 still can be produced with determining valve 11 in the presence of drilling fluid Raw rotation vibration effect, i.e. constant pressure type rotation vibration motor can increase drill bit while vibration damping keeps drill bit the pressure of the drill stabilization and break again Rock energy, this is that routine techniques is difficult to.

If rotation vibration effect can not be produced by moving valve 13 or determining the failure of valve 11, drilling fluid cannot pass through dynamic valve 13 and determine valve 11 reach shaft bottom drill bit, with the continuous rise of drilling liquid pressure, when pressure exceedes the setting value of safety valve 12, safety valve 12 It will open, drilling fluid is flowed directly to drill bit, the circulation without influenceing drilling fluid.Constant pressure type rotation vibration motor can be by liquid Kinetic energy is converted into mechanical energy, produces rotation vibration effect, improves the cutting force of bit broken rock, cushioned drill bit can be absorbed again Axial vibration, prevents damage of the axial impact force to drill bit, and keeps the steady of drill bit broken rock the pressure of the drill, and this is conducive to existing Deep-well, the drilling efficiency of ultradeep well are further improved under the conditions of the pump of face.

Claims (7)

1. a kind of constant pressure type rotates vibration screw motor, it is characterised in that：Including shell body（1）And the whirler installed in it Structure, wherein：

The rotating mechanism includes the positive displacement power assembly being sequentially connected from top to bottom（2）, power transmission shaft（6）And determine valve （11）；The power transmission shaft（6）For hollow tubular and itself and shell body（1）Between form annular space A, it is described to determine valve（11）Upper end with Power transmission shaft（6）Lower end is connected, and determines valve（11）Outer wall upper and lower ends and shell body（1）Between formed sealing coordinate, it is described Power transmission shaft（6）Wall is provided with the by-pass prot for connecting annular space A with its inner chamber（4）；

It is described to determine valve（11）Outer wall middle part and shell body（1）Between form that be provided with annular space B and annular space B can be around determining valve （11）The dynamic valve rotated against（13）；It is described to determine valve（11）The guide pad of two axial directions is arranged with the middle part of outer wall and by annular space B At intervals of two and half chambers being arranged symmetrically, the guide pad and shell body（1）Between formed sealing coordinate；The dynamic valve（13）Bag The sliding block being located at respectively in the two halves chamber is included, corresponding half chamber is divided into chamber A by each sliding block respectively（18）And cavity C （20）, and the central slot and and shell body of each sliding block（1）, determine valve（11）Surround and constitute chamber B（19）；It is described to determine valve（11） Inner chamber center pass through safety valve（12）Two chamber above and below being divided into, and epicoele side wall is provided with multiple pressure holes（16）, cavity of resorption side wall Provided with multiple low pressure holes（17）, the pressure hole（16）With chamber B（19）Correspondence connection, the low pressure hole（17）With chamber A （18）And cavity C（20）Correspondence connection；

It is described to determine valve（11）Two groove-type channels are offered on outer wall, for being respectively communicated with chamber A（18）With chamber B（19）, chamber Room B（19）With cavity C（20）；When the dynamic valve（13）Around determining valve（11）During rotation, the sliding block top can alternately open groove Type passage and by chamber A（18）With chamber B（19）, chamber B（19）With cavity C（20）It is respectively communicated with, while the sliding block bottom Can be by chamber A（18）With cavity C（20）Alternate communication low pressure hole（17）.

2. constant pressure type according to claim 1 rotates vibration screw motor, it is characterized in that：The positive displacement power assembly （2）With power transmission shaft（6）Between shaft coupling is installed（3）.

3. constant pressure type according to claim 1 rotates vibration screw motor, it is characterized in that：The power transmission shaft（6）With determining valve （11）Between spring is installed（8）, power transmission shaft（6）With determining valve（11）Constitute spline fitted.

4. constant pressure type according to claim 3 rotates vibration screw motor, it is characterized in that：The power transmission shaft（6）Bottom is set There is spline（9）, power transmission shaft（6）Pass through spline（9）With determining valve（11）Inwall constitutes spline fitted.

5. constant pressure type according to claim 1 rotates vibration screw motor, it is characterized in that：It is described to determine valve（11）Outer wall with it is outer Housing（1）First sealing device is installed between inwall（10）, the second sealing device（14）Sealing is constituted to coordinate.

6. vibration screw motor is rotated according to any described constant pressure types of claim 1-5, it is characterized in that：The power transmission shaft（6） And shell body（1）Alignment bearing is installed between top（5）；It is described to determine valve（11）Bottom and shell body（1）Installed between bottom Lower alignment bearing（15）.

7. constant pressure type according to claim 6 rotates vibration screw motor, it is characterized in that：Also include thrust bearing（7）, institute State thrust bearing（7）Installed in power transmission shaft（6）With spring（8）Between, and installed in upper alignment bearing（5）Bottom.