CN104314465A - Method for reducing frictional resistance between drill column and well wall and partitioning joint - Google Patents

Abstract

The invention discloses a method for reducing frictional resistance between a drill column and a well wall and a partitioning joint. The partitioning joint is used for partitioning the drill column into an upper drill column section and a lower drill column section which are respectively connected with the partitioning joint; a piece of wellhead equipment is used for driving the upper drill column section to axially slide or circumferentially twist or axially slide and circumferentially twist against the lower drill column section according to a selected friction resistance mode. By virtue of the method, the upper drill column section moves against the lower drill section; static friction between the upper drill column section and the well wall is changed into dynamical friction, so that the frictional resistance between the upper drill column section and the well wall is reduced; the contact state between the upper drill column section and well wall rock is improved; the drill pressure and the torque can be smoothly and effectively transmitted to a drill bit; the mechanical drilling speed and the extreme extension distance of the wellhead are increased; the well drilling period is shortened; the well drilling cost is lowered.

Description

A kind of reduce drill string and borehole wall frictional resistance method and a kind ofly split joint

Technical field

The present invention relates to oil and gas well drilling technical field, particularly relate to a kind of frictional resistance for reducing in dark straight well and complex structural well drilling process between drill string and the borehole wall, the one of the method passing to shaft bottom drill bit level and smooth for the pressure of the drill and strengthening the method is split joint.

Background technology

Develop dark straight well and complex structural well technology, Efficient Development complex hydrocarbon layer, deep oil-gas reservoir and Marine oil and gas resource, meet the great demand of China to the energy, the important leverage of Ye Shi China energy reserves safety.

In the drilling process of dark straight well, the formation hardness that brill is met is large, variation of lithological is various, non-homogeneity is strong, causes hole deviation and orientation to control difficulty and increases.General gently pressure by employing pendulum assembly hangs up and beats or uses the mud motor combination left-hand thread with bent angle to control wellbore quality in this case; The mode that light pressure is hung up and beaten ensure that wellbore quality to a certain extent, and rate of penetration is sharply declined, although use mud motor combination left-hand thread can effectively control hole deviation and orientation, but but exacerbates the formation of well " dog-leg ".Therefore, can say that straight well is only present in the design stage, and the true well got out is all the helical buckling wells with some " dog-leg " under existing drilling technology condition.In drilling process, spend senior general when local dog-leg and inevitably cause the generation of " dragging pressure " and " stick-slip " phenomenon, reduce rate of penetration, will cause time serious being hampered and bit freezing, make the pressure of the drill be added to drill bit, creep into operation and have to stop.On the other hand, the Open-Hole Section of large section is there is in dark straight well, ultra-deep straight well drilling process, the leakage of easy generation leakage and high permeability formation, drill string is pressed to the borehole wall by the drilling fluid in annular space and the pressure differential of formation fluid pressure, produce " dragging pressure " and " stick-slip " phenomenon, rate of penetration is reduced, also will occur " differential sticking " time serious, serious threat downhole safety.

In the drilling process of complex structural well, along with the extension of well and the increase of hole deviation, most of drill string lies in rock of borehole, and the pressure of the drill major part that drill collar is applied consumes and overcoming the borehole wall on the frictional resistance of drill string, the pressure of the drill effectively cannot pass to drill bit, and rate of penetration significantly reduces; Especially in slip directional drilling process, drill string non rotating more than downhole motor makes the coefficient of friction resistance between drill string and the borehole wall increase, and produces " dragging pressure " phenomenon, and when the frictional resistance between drill string and rock of borehole equals the pressure of the drill, well cannot continue to extend.

Summary of the invention

First technical problem to be solved by this invention: cause " dragging pressure " and " stick-slip " for the high frictional resistance phenomenon existed in dark straight well and complex structural well drilling process, a kind of method reducing frictional resistance between drill string and the borehole wall is proposed, enable the pressure of the drill and moment of torsion smoothly effectively pass to drill bit, improve the ultimate extension distance of rate of penetration and well.

Second technical problem to be solved by this invention is: provide a kind of segmentation joint for strengthening reduction drill string of the present invention and borehole wall frictional resistance method.

For solving above-mentioned first technical problem, technical scheme of the present invention is: a kind of method reducing drill string and borehole wall frictional resistance, and the method is as follows:

S10, in drill string, determine a position, a segmentation joint is installed in this position, drill string is divided into upper drilling string section and lower drilling string section by described segmentation joint, the upper end of described segmentation joint is connected with described upper drilling string section, the lower end of described segmentation joint is connected with described lower drilling string section, and described upper drilling string section can slide axially relative to described lower drilling string section under wellhead equipment drives or circumference is reversed or slide axially and circumference is reversed;

S20, selection antifriction resistance pattern, described antifriction resistance pattern comprises axially-movable antifriction resistance pattern, circumferential movement antifriction resistance pattern and compound motion antifriction and hinders pattern, selects one wherein;

S30, according to selected antifriction resistance pattern, by wellhead equipment drive described upper drilling string section produce relative to described lower drilling string section slide axially or circumference is reversed or to slide axially and circumferential twist motion.

As preferably, in described S10 step, also comprise step S11: the installation site determining described segmentation joint.

As preferably, when selecting described axially-movable antifriction resistance pattern, the installation site of described segmentation joint is determined according to following formula according to the pressure of the drill of required applying

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{q}_i{l}_i=W---\left(1\right)$

$L=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{l}_i---\left(2\right)$

In formula, W is required the pressure of the drill, N; N is segmentation joint and the many drilling tool quantity be connected in series between drill bit; q _ibe the line buoyant weight of i-th drilling tool, N/m; l _ibe the length of i-th drilling tool, m; L is the distance of segmentation jiont treatment position apart from drill bit, m.

As preferably, when selecting described circumferential movement antifriction resistance pattern or compound motion antifriction resistance pattern, the installation site of described segmentation joint, determines according to following formula

$\frac{{\mathrm{dM}}_t}{\mathrm{dl}}=f_1{R}_{o}N+m_0---\left(3\right)$

$\frac{d{F}_t}{\mathrm{dl}}={\mathrm{EIk}}_b\frac{{\mathrm{dk}}_b}{\mathrm{dl}}-f_{2}N-\mathrm{Cv}-B+q\stackrel{\→}{k}\·{\stackrel{\→}{e}}_t=0---\left(4\right)$

$-{\mathrm{EIk}}_b\frac{d^2{k}_b}{{\mathrm{dl}}^2}+k_b{F}_t+{\mathrm{EIk}}_n^2{k}_b+k_n{k}_b{M}_t+N_n+f_1{N}_b+q\stackrel{\→}{k}\·{\stackrel{\→}{e}}_n=0---\left(5\right)$

$-\frac{d({\mathrm{EIk}}_n{k}_b+k_b{M}_t)}{\mathrm{dl}}-{\mathrm{EIk}}_n\frac{{\mathrm{dk}}_b}{\mathrm{dl}}+N_b-f_1{N}_n+q\stackrel{\→}{k}\·{\stackrel{\→}{e}}_b=0---\left(6\right)$

$m_0=2\mathrm{\π}{R}_o^2\mathrm{\ω}[\frac{\mathrm{\τ}}{\sqrt{v^2+{\left(R_o\mathrm{\ω}\right)}^2}}+\frac{2\mathrm{\ξ}}{D_w-2R_o}]---\left(7\right)$

$B=\frac{2\mathrm{\π}{R}_o\mathrm{\τv}}{\sqrt{v^2+{\left(R_o\mathrm{\ω}\right)}^2}}---\left(8\right)$

$C=\frac{2\mathrm{\π\ξ}}{\ln \frac{D_w}{2R_o}}---\left(9\right)$

$f_1=\frac{R_0\mathrm{\ωf}}{\sqrt{v^2+{\left(R_0\mathrm{\ω}\right)}^2}}---\left(10\right)$

$f_2=\frac{\mathrm{vf}}{\sqrt{v^2+{\left(R_0\mathrm{\ω}\right)}^2}}---\left(11\right)$

$F_t\left(0\right)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{q}_i{l}_i-W_b---\left(12\right)$

M _t(0)＝0 (13)

F _t(L)＝-W (14)

M _t(L)＝T _b (15)

In formula, M _tfor the moment of torsion of drill string, Nm; L is the arc length of borehole axis, m; R _ofor drill string outer radius, m; N is the contact force of the unit length of drill string and the borehole wall, N/m; N _nfor contact force exists component on direction, N/m; N _bfor contact force exists component on direction, N/m; F _tfor the axial tension of drill string, N; E is modulus of elasticity, Pa; I is drill string second moment of area, m ⁴; k _bfor hole curvature, °/30m; k _nfor borehole torsion, °/30m; f ₁and f ₂be respectively tangential component and the circumferential component of friction factor f; V is drill string axial velocity, m/s; Q is drill string line buoyant weight, N/m; K is the unit vector of rectangular Cartesian earth coordinates, vertically downward; be respectively the unit vector in borehole track tangent line, principal normal and binormal direction; ω is drill string rotating angular velocity, rad/s; τ is the structural capacity of drilling fluid, Pa; ξ is the dynamic viscosity of drilling fluid, Pas; D _wfor hole diameter, m; W _bfor drill bit place the pressure of the drill, N; T _bfor drill bit place moment of torsion, Nm.

As preferably, in described step S30, the tensile force f that described wellhead equipment applies drill string _tand moment of torsion M (0) _t(0) determine according to formula (3)-(11) and formula (16), (17):

F _t(L′)＝0 (16)

M _t(L′)＝0 (17)

In formula, L ' for well head is according to the distance of described segmentation joint, m.

Owing to have employed technique scheme, the method of reduction drill string of the present invention and borehole wall frictional resistance, by a segmentation joint, whole drill string is divided into upper drilling string section and lower drilling string section, lower drilling string section is used for applying the reaction torque that the pressure of the drill and mud motor creep into drill bit, after selecting antifriction resistance pattern according to on-site actual situations, under the prerequisite not affecting the stressed and motion state of lower drilling string section, by wellhead equipment to upper drilling string section apply axially reciprocating or circumferential twist motion or slide axially and circumference reverse compound motion, upper drilling string section is allowed " to move up ", the static friction between upper drilling string section and the borehole wall is made to become dynamic friction, thus the frictional resistance reduced between upper drilling string section and the borehole wall, improve the contact condition between upper drilling string section and rock of borehole, the pressure of the drill and moment of torsion is enable effectively to pass to drill bit, improve the drilling efficiency in dark straight well and complex structural well slipping drilling process and ultimate extension distance.

For solving above-mentioned second technical problem, technical scheme of the present invention is: a kind of segmentation joint, and described segmentation joint comprises:

Sleeve, the upper end of described sleeve is fixedly installed upper limit dish, and described upper limit dish is provided with upper limit dish through hole, and the cross section of described upper limit dish through hole is polygon or internal spline shape; The lower end of described sleeve is provided with shrouding, and described shrouding is provided with shrouding through hole;

Sliding bar, through sliding bar runner is axially arranged with along it in described sliding bar, the vertical section of described sliding bar is the T-shaped of hollow, described upper limit dish through hole passes and the bottom extended in described sleeve in the bar portion of described sliding bar, the head of described sliding bar is positioned at the top of described upper limit dish for connecting upper drilling string, and the bar portion outer peripheral face of described sliding bar is in the polygon suitable with the cross section of described upper limit dish through hole or external splines shape;

Piston, described piston fixed cover is located on the periphery of described sliding bar bar subordinate end, and described piston coordinates with the inwall slipper seal of described sleeve;

Anti-lost pipe nipple, through anti-lost pipe nipple runner is axially arranged with along it in described anti-lost pipe nipple, the vertical section of described anti-lost pipe nipple is the T-shaped of hollow, and the head of described anti-lost pipe nipple is positioned at described sleeve, and the bar portion of described anti-lost pipe nipple to stretch out outside described shrouding through hole and is fixedly connected with lower contact; The upper end of described lower contact and the lower end spline joint of described sleeve, leave the running clearance rotated for described sleeve between the keyway of described spline joint and key tooth.

As preferably, described running clearance is 2 °-15 ° along the angle of described sleeve radial direction.

As preferably, the top of described piston is provided with top resilient snubber, and the below of described piston is provided with lower elastic bolster.

As preferably, described top resilient snubber is be sheathed on the upper spring in described sliding bar bar portion, and described lower elastic bolster is be arranged at the lower spring between described piston lower surface and described anti-lost pipe nipple head.

Owing to have employed technique scheme, when using segmentation joint of the present invention, the head of sliding bar is connected with upper drilling string section, and lower contact is connected with lower drilling string section, during selected axially-movable antifriction resistance pattern, by lifting drill string at well head hook up and down with certain displacement amplitude and frequency, upper drilling string section and sliding bar produce sliding axially relative to sleeve and lower drilling string section, upper drilling string section " moves up ", makes the static friction between upper drilling string section and the borehole wall become dynamic friction, during selected circumferential movement antifriction resistance pattern, by at well head rotating disk, top driving device reverses drill string with certain moment of torsion and frequency, allow upper drilling string section, sliding bar and sleeve produce the reciprocal twist motion along well circumference, upper drilling string section " moves up ", the static friction between upper drilling string section and the borehole wall is made to become dynamic friction, due to the upper end of lower contact and the lower end spline joint of sleeve, and between the keyway of spline joint and key tooth, leave the running clearance rotated for sleeve, the reciprocal torsional amplitude of sleeve is no more than this running clearance, therefore, upper drilling string section, the stressed of lower drilling string section and motion state can not be affected when sliding bar and the reciprocal twist motion of sleeve, during selected compound motion antifriction resistance pattern, by applying the effect of the power of certain amplitude and frequency to drill string at well head hook and top driving device, upper drilling string section is made to produce the compound motion of " axially+torsion ", make the static friction between upper drilling string section and the borehole wall become dynamic friction, thus reduce frictional resistance.

Accompanying drawing explanation

Fig. 1 is the structure cross-sectional schematic splitting joint in the embodiment of the present invention;

Fig. 2 is A-A sectional drawing in Fig. 1;

Fig. 3 is B-B sectional drawing in Fig. 1;

In figure: 1-sliding bar; The head of 101-sliding bar; The bar portion of 102-sliding bar; 103-sliding bar runner; 2-upper limit dish; 3-sleeve; 301-sleeve key tooth; 4-upper spring; 5-piston; 6-sealing ring; The anti-lost pipe nipple of 7-; The anti-lost pipe nipple runner of 701-; 8-lower contact; 801-lower contact key tooth; 9-lower spring; 10-locking nut; 11-sealing ring.

Detailed description of the invention

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

The method of frictional resistance between the reduction drill string of the embodiment of the present invention and the borehole wall is as follows:

S10, requirement according to drilling assembly and required applying the pressure of the drill, a position is determined in drill string, a segmentation joint is installed in this position, drill string is divided into upper drilling string section and lower drilling string section by this segmentation joint, the upper end wherein splitting joint is connected with upper drilling string section, the lower end of segmentation joint is connected with lower drilling string section, upper drilling string section can slide axially relative to lower drilling string section under wellhead equipment drives or circumference is reversed or slide axially and circumference is reversed, and the stressed and motion state of lower drilling string section is unaffected;

S20, selection antifriction resistance pattern, antifriction resistance pattern comprises axially-movable antifriction resistance pattern, circumferential movement antifriction resistance pattern and compound motion antifriction and hinders pattern, according to on-site actual situations and drag reduction demand, selects one wherein from above Three models;

S30, according to selected antifriction resistance pattern, driven by hook, rotating disk, top or the wellhead equipment such as device with identity function drive upper drilling string section produce relative to lower drilling string section slide axially or circumference is reversed or slides axially and circumferential twist motion; Upper drilling string section is allowed " to move up ", the static friction between upper drilling string section and the borehole wall is made to become dynamic friction, thus the frictional resistance reduced between upper drilling string section and the borehole wall, improve the contact condition between upper drilling string section and rock of borehole, enable the pressure of the drill and moment of torsion effectively pass to drill bit, improve the drilling efficiency in dark straight well and complex structural well slipping drilling process and ultimate extension distance.

Wherein, also step S11 is comprised in S10 step: the installation site determining to split joint.

Wherein, when selecting axially-movable antifriction resistance pattern, the installation site of segmentation joint is determined according to following formula according to the pressure of the drill of required applying

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{q}_i{l}_i=W---\left(1\right)$

$L=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{l}_i---\left(2\right)$

In formula, W is required the pressure of the drill, N; N is segmentation joint and the many drilling tool quantity be connected in series between drill bit; q _ibe the line buoyant weight of i-th drilling tool, N/m; l _ibe the length of i-th drilling tool, m; L is the distance of segmentation jiont treatment position apart from drill bit, m.

Wherein, when selecting circumferential movement antifriction resistance pattern or compound motion antifriction resistance pattern, the installation site of segmentation joint is determined according to the reaction torque of the mud motor of required applying, and the pulling force-torque model namely passing through formula (3)-(15) below calculates L

$\frac{{\mathrm{dM}}_t}{\mathrm{dl}}=f_1{R}_{o}N+m_0---\left(3\right)$

$\frac{d{F}_t}{\mathrm{dl}}={\mathrm{EIk}}_b\frac{{\mathrm{dk}}_b}{\mathrm{dl}}-f_{2}N-\mathrm{Cv}-B+q\stackrel{\→}{k}\·{\stackrel{\→}{e}}_t=0---\left(4\right)$

$-{\mathrm{EIk}}_b\frac{d^2{k}_b}{{\mathrm{dl}}^2}+k_b{F}_t+{\mathrm{EIk}}_n^2{k}_b+k_n{k}_b{M}_t+N_n+f_1{N}_b+q\stackrel{\→}{k}\·{\stackrel{\→}{e}}_n=0---\left(5\right)$

$-\frac{d({\mathrm{EIk}}_n{k}_b+k_b{M}_t)}{\mathrm{dl}}-{\mathrm{EIk}}_n\frac{{\mathrm{dk}}_b}{\mathrm{dl}}+N_b-f_1{N}_n+q\stackrel{\→}{k}\·{\stackrel{\→}{e}}_b=0---\left(6\right)$

$m_0=2\mathrm{\π}{R}_o^2\mathrm{\ω}[\frac{\mathrm{\τ}}{\sqrt{v^2+{\left(R_o\mathrm{\ω}\right)}^2}}+\frac{2\mathrm{\ξ}}{D_w-2R_o}]---\left(7\right)$

$B=\frac{2\mathrm{\π}{R}_o\mathrm{\τv}}{\sqrt{v^2+{\left(R_o\mathrm{\ω}\right)}^2}}---\left(8\right)$

$C=\frac{2\mathrm{\π\ξ}}{\ln \frac{D_w}{2R_o}}---\left(9\right)$

$f_1=\frac{R_0\mathrm{\ωf}}{\sqrt{v^2+{\left(R_0\mathrm{\ω}\right)}^2}}---\left(10\right)$

$f_2=\frac{\mathrm{vf}}{\sqrt{v^2+{\left(R_0\mathrm{\ω}\right)}^2}}---\left(11\right)$

$F_t\left(0\right)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{q}_i{l}_i-W_b---\left(12\right)$

M _t(0)＝0 (13)

F _t(L)＝-W (14)

M _t(L)＝T _b (15)

In formula, M _tfor the moment of torsion of drill string, Nm; L is the arc length of borehole axis, m; R _ofor drill string outer radius, m; N is the contact force of the unit length of drill string and the borehole wall, N/m; N _nfor contact force exists component on direction, N/m; N _bfor contact force exists component on direction, N/m; F _tfor the axial tension of drill string, N; E is modulus of elasticity, Pa; I is drill string second moment of area, m ⁴; k _bfor hole curvature, °/30m; k _nfor borehole torsion, °/30m; f ₁and f ₂be respectively tangential component and the circumferential component of friction factor f; V is drill string axial velocity, m/s; Q is drill string line buoyant weight, N/m; K is the unit vector of rectangular Cartesian earth coordinates, vertically downward; be respectively the unit vector in borehole track tangent line, principal normal and binormal direction; ω is drill string rotating angular velocity, rad/s; τ is the structural capacity of drilling fluid, Pa; ξ is the dynamic viscosity of drilling fluid, Pas; D _wfor hole diameter, m; W _bfor drill bit place the pressure of the drill, N; T _bfor drill bit place moment of torsion, Nm.

Wherein, in step S30, the tensile force f that the wellhead equipment such as hook, top driving device applies drill string _tand moment of torsion M (0) _t(0) determine according to formula (3)-(11) and formula (16), (17):

F _t(L′)＝0 (16)

M _t(L′)＝0 (17)

In formula, L ' for well head according to segmentation joint distance, m.

As shown in Figure 1, be the structure cross-sectional schematic of segmentation joint used in frictional resistance method between the reduction drill string of the embodiment of the present invention and the borehole wall, for convenience of explanation, this figure only provides the structure division relevant with the present invention.

This segmentation joint comprises:

Sleeve 3, upper limit dish 2 is connected with at the threaded upper ends of sleeve 3, upper limit dish 2 is provided with upper limit dish through hole, as shown in Figure 2, in the present embodiment, the cross section of upper limit dish through hole is hexagon, can also be polygon or the internal spline shapes such as triangle, quadrangle, pentagon, octagon, in order to transmitting torque; Be provided with shrouding in the lower end of sleeve 3, shrouding is provided with shrouding through hole;

Sliding bar 1, through sliding bar runner 103 is axially arranged with along it in sliding bar 1, the vertical section of sliding bar 1 is the T-shaped of hollow, the head 101 of sliding bar is positioned at the top of upper limit dish 2 for connecting upper drilling string, upper limit dish through hole passes and the bottom extended in sleeve 3 in the bar portion 102 of sliding bar, be slidably matched between the bar portion 102 of sliding bar and upper limit dish through hole, bar portion 102 outer peripheral face of sliding bar and the shape of cross section of upper limit dish through hole suitable, be hexagon, triangle, quadrangle, pentagon, the polygons such as octagon or external splines shape, in order to transmitting torque,

Piston 5, this piston 5 fixed cover is located on the periphery of lower end, bar portion 102 of sliding bar, and is locked by locking nut 10, and between piston 5 and the inwall of sleeve 3, slipper seal coordinates;

Anti-lost pipe nipple 7, through anti-lost pipe nipple runner 701 is axially arranged with along it in this anti-lost pipe nipple 7, the vertical section of anti-lost pipe nipple 7 is the T-shaped of hollow, the head of anti-lost pipe nipple 7 be positioned at sleeve 3 and support in the upper surface of shrouding, the bar portion of anti-lost pipe nipple 7 to stretch out outside shrouding through hole and is fixedly connected with lower contact 8; As shown in Figure 3, wherein, the upper end of lower contact 8 and the lower end of sleeve 3 adopt spline joint, and leave the running clearance rotated for sleeve 3 between sleeve key tooth 301 and the keyway of lower contact 8, this running clearance is that the span of α, α is preferably at 2 °-15 ° along the angle of sleeve 3 radial direction; This spline joint form can also be, leaves the running clearance rotated for sleeve 3 between lower contact key tooth 801 and the keyway of sleeve 3.

As shown in Figure 1, sealing ring 11 is provided with between the inwall of piston 5 and sleeve 3, sealing ring 6 is provided with between the head of anti-lost pipe nipple 7 and the inwall of sleeve 3, drilling fluid aerial to the drilling fluid and external rings of splitting joint inside is divided into two pressure systems by sealing ring 6 and arranging of sealing ring 11, prevents the drilling liquid pressure loss splitting joint inside.

As shown in Figure 1, also resilient snubber is provided with further respectively above and below piston 5, when preventing piston 5 from sliding axially into range with sliding bar 1, the lower surface of upper limit dish 2 or the upper surface of anti-lost pipe nipple 7 are impacted, wherein, top resilient snubber is the upper spring 4 be sheathed in the bar portion 102 of sliding bar, and lower elastic bolster is be arranged at the lower spring 9 between the lower surface of piston 5 and anti-lost pipe nipple 7 head.

When applying segmentation joint of the present invention, be connected with upper drilling string section by the head 101 of sliding bar, lower contact 8 is connected with lower drilling string section, elected determine axially-movable antifriction when hindering pattern, by lifting drill string at well head hook up and down with certain displacement amplitude and frequency, upper drilling string section and sliding bar 1 produce sliding axially relative to sleeve 3 and lower drilling string section, slide axially distance preferably at 100-200mm, upper drilling string section " moves up ", the static friction between upper drilling string section and the borehole wall is made to become dynamic friction, and the stressed and motion state of lower drilling string section unaffected, when selected circumferential movement antifriction resistance pattern, by at well head rotating disk, top driving device reverses drill string with certain moment of torsion and frequency, allow upper drilling string section, sliding bar 1 and sleeve 3 produce the reciprocal twist motion along well circumference, upper drilling string section " moves up ", the static friction between upper drilling string section and the borehole wall is made to become dynamic friction, due to the upper end of lower contact 8 and the lower end spline joint of sleeve 3, and between the keyway of spline joint and key tooth, leave the running clearance rotated for sleeve 3, the reciprocal torsional amplitude of sleeve 3 is no more than this running clearance, therefore, upper drilling string section, sliding bar 1 and sleeve 3 back and forth twist motion time can not affect the stressed of lower drilling string section and motion state, when selected compound motion antifriction resistance pattern, by applying the effect of the power of certain amplitude and frequency to drill string at well head hook, rotating disk and top driving device, make the generation of upper drilling string section relative to " axially+torsion " compound motion of lower drilling string section, make the static friction between upper drilling string section and the borehole wall become dynamic friction, thus reduce frictional resistance.

To the present invention is directed in dark straight well and complex structural well drilling process the high frictional resistance phenomenon existed in especially slipping drilling process to cause " dragging pressure " and " stick-slip ", propose a kind of reduce frictional resistance between drill string and the borehole wall method and one segmentation joint for strengthening the method, the method makes upper drilling string section " move up " relative to lower drilling string section, static friction between upper drilling string section and the borehole wall becomes dynamic friction, reduce the frictional resistance between upper drilling string section and the borehole wall, improve the contact condition between upper drilling string section and rock of borehole, the pressure of the drill and moment of torsion is enable smoothly effectively to pass to drill bit, improve the ultimate extension distance of rate of penetration and well, shorten drilling period and decrease drilling cost.

Claims (9)

1. reduce a method for drill string and borehole wall frictional resistance, it is characterized in that, the method for described reduction drill string and borehole wall frictional resistance is as follows:

S10, in drill string, determine a position, a segmentation joint is installed in this position, drill string is divided into upper drilling string section and lower drilling string section by described segmentation joint, the upper end of described segmentation joint is connected with described upper drilling string section, the lower end of described segmentation joint is connected with described lower drilling string section, and described upper drilling string section can slide axially relative to described lower drilling string section under wellhead equipment drives or circumference is reversed or slide axially and circumference is reversed;

S20, selection antifriction resistance pattern, described antifriction resistance pattern comprises axially-movable antifriction resistance pattern, circumferential movement antifriction resistance pattern and compound motion antifriction and hinders pattern, selects one wherein;

S30, according to selected antifriction resistance pattern, by wellhead equipment drive described upper drilling string section produce relative to described lower drilling string section slide axially or circumference is reversed or to slide axially and circumferential twist motion.

2. a kind of method reducing drill string and borehole wall frictional resistance as claimed in claim 1, is characterized in that, in described S10 step, also comprises step S11: the installation site determining described segmentation joint.

3. a kind of method reducing drill string and borehole wall frictional resistance as claimed in claim 2, is characterized in that, when selecting described axially-movable antifriction resistance pattern, the installation site of described segmentation joint is determined according to following formula according to the pressure of the drill of required applying

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{q}_i{l}_i=W---\left(1\right)$

$L=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{l}_i---\left(2\right)$

In formula, W is required the pressure of the drill, N; N is segmentation joint and the many drilling tool quantity be connected in series between drill bit; q _ibe the line buoyant weight of i-th drilling tool, N/m; l _ibe the length of i-th drilling tool, m; L is the distance of segmentation jiont treatment position apart from drill bit, m.

4. a kind of method reducing drill string and borehole wall frictional resistance as claimed in claim 2, is characterized in that, when selecting described circumferential movement antifriction resistance pattern or compound motion antifriction resistance pattern, the installation site of described segmentation joint, determines according to following formula

$\frac{{\mathrm{dM}}_t}{\mathrm{dl}}=f_1{R}_{o}N+m_0---\left(3\right)$

$m_0=2\mathrm{\π}{R}_O^2\mathrm{\ω}[\frac{\mathrm{\τ}}{\sqrt{v^2+{\left(R_o\mathrm{\ω}\right)}^2}}+\frac{2\mathrm{\ξ}}{D_w-2R_o}]---\left(7\right)$

$B=\frac{2\mathrm{\π}{R}_o\mathrm{\τv}}{\sqrt{v^2+{\left(R_o\mathrm{\ω}\right)}^2}}---\left(8\right)$

$C=\frac{2\mathrm{\π\ξ}}{\ln \frac{D_w}{2R_o}}---\left(9\right)$

$f_1=\frac{R_0\mathrm{\ωf}}{\sqrt{v^2+{\left(R_0\mathrm{\ω}\right)}^2}}---\left(10\right)$

$f_2=\frac{\mathrm{vf}}{\sqrt{v^2+{\left(R_0\mathrm{\ω}\right)}^2}}---\left(11\right)$

$F_t\left(0\right)=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{q}_i{l}_i-W_b---\left(12\right)$

M _t(0)＝0 (13)

F _t(L)＝-W (14)

M _t(L)＝T _b (15)

In formula, M _tfor the moment of torsion of drill string, Nm; L is the arc length of borehole axis, m; R _ofor drill string outer radius, m; N is the contact force of the unit length of drill string and the borehole wall, N/m; N _nfor contact force exists component on direction, N/m; N _bfor contact force exists component on direction, N/m; F _tfor the axial tension of drill string, N; E is modulus of elasticity, Pa; I is drill string second moment of area, m ⁴; k _bfor hole curvature, °/30m; k _nfor borehole torsion, °/30m; f ₁and f ₂be respectively tangential component and the circumferential component of friction factor f; V is drill string axial velocity, m/s; Q is drill string line buoyant weight, N/m; K is the unit vector of rectangular Cartesian earth coordinates, vertically downward; be respectively the unit vector in borehole track tangent line, principal normal and binormal direction; ω is drill string rotating angular velocity, rad/s; τ is the structural capacity of drilling fluid, Pa; ξ is the dynamic viscosity of drilling fluid, Pas; D _wfor hole diameter, m; W _bfor drill bit place the pressure of the drill, N; T _bfor drill bit place moment of torsion, Nm.

5. a kind of method reducing drill string and borehole wall frictional resistance as claimed in claim 4, is characterized in that, in described step S30, and the tensile force f that described wellhead equipment applies drill string _tand moment of torsion M (0) _t(0) determine according to formula (3)-(11) and formula (16), (17):

F _t(L′)＝0 (16)

M _t(L′)＝0 (17)

In formula, L ' for well head is according to the distance of described segmentation joint, m.

6. a segmentation joint, is characterized in that, described segmentation joint comprises:

Sleeve, the upper end of described sleeve is fixedly installed upper limit dish, and described upper limit dish is provided with upper limit dish through hole, and the cross section of described upper limit dish through hole is polygon or internal spline shape; The lower end of described sleeve is provided with shrouding, and described shrouding is provided with shrouding through hole;

Sliding bar, through sliding bar runner is axially arranged with along it in described sliding bar, the vertical section of described sliding bar is the T-shaped of hollow, described upper limit dish through hole passes and the bottom extended in described sleeve in the bar portion of described sliding bar, the head of described sliding bar is positioned at the top of described upper limit dish for connecting upper drilling string, and the bar portion outer peripheral face of described sliding bar is in the polygon suitable with the cross section of described upper limit dish through hole or external splines shape;

Piston, described piston fixed cover is located on the periphery of described sliding bar bar subordinate end, and described piston coordinates with the inwall slipper seal of described sleeve;

Anti-lost pipe nipple, through anti-lost pipe nipple runner is axially arranged with along it in described anti-lost pipe nipple, the vertical section of described anti-lost pipe nipple is the T-shaped of hollow, and the head of described anti-lost pipe nipple is positioned at described sleeve, and the bar portion of described anti-lost pipe nipple to stretch out outside described shrouding through hole and is fixedly connected with lower contact; The upper end of described lower contact and the lower end spline joint of described sleeve, leave the running clearance rotated for described sleeve between the keyway of described spline joint and key tooth.

7. a kind of segmentation joint as claimed in claim 6, it is characterized in that, described running clearance is 2 °-15 ° along the angle of described sleeve radial direction.

8. as claimed in claims 6 or 7 one segmentation joint, it is characterized in that, the top of described piston is provided with top resilient snubber, and the below of described piston is provided with lower elastic bolster.

9. a kind of segmentation joint as claimed in claim 8, it is characterized in that, described top resilient snubber is be sheathed on the upper spring in described sliding bar bar portion, and described lower elastic bolster is be arranged at the lower spring between described piston lower surface and described anti-lost pipe nipple head.