CN101333912A

CN101333912A - Flexible drill shaft

Info

Publication number: CN101333912A
Application number: CNA2008100870714A
Authority: CN
Inventors: 究斯·德克塞拉; 多米尼克·塞比纳
Original assignee: Prad Research and Development Ltd
Current assignee: Prad Research and Development Ltd; Prad Research and Development NV
Priority date: 2007-04-20
Filing date: 2008-04-11
Publication date: 2008-12-31
Also published as: DE602007013700D1; EP1983148A1; US20100147045A1; US20080257606A1; ATE504716T1; CA2628981A1; EP1983148B1

Abstract

A flexible drilling column for drilling into a lateral drill hole comprises an outer screw wire helical spring, at least one inner screw wire helical spring which is concentricly arranged in the outer screw wire helical spring, adjacent spring rings have opposite bevel angles, wherein the wire for forming each helical spring has cross section, so as to forming plane contact between adjacent spring rings when the drilling column is aligned.

Description

Flexible drillstem

Technical field

[0001] the present invention relates to flexible drillstem, and relate to the flexible drillstem that can during the lateral drilling probing, transmit high moment of torsion particularly.

Background technology

[0002] in oil and gas well, usually expectation is from main vertical drilling side direction drilling bore hole, to increase and being communicated with of main drilling well and drainage stratum on every side.These side down holes it has been generally acknowledged that the earial drainage well.They provide passes the passage on stratum on every side, and can increase the flow velocity that hydrocarbon enters the casing of main drilling well, and improves the amount of extracting hydrocarbon.

[0003] in order to have the earial drainage well of remarkable length, the equipment or the device that are used to creep into the earial drainage well have flexible column usually, having from the ability of main borehole and flank hole modifier direction, and send revolving force and transmission rate to drill bit.

[0004] US 6,220, and 372 disclose a kind of device that is used to creep into flank hole, comprise the flexible column that is formed by at least two screw winding helical springs.This document discloses spring should be formed by the wire with circular cross section.

[0005] US 4,658, and 916 disclose at least two flexible drillstems that the screw winding helical spring forms that formed by the wire with rectangular cross section.This document description be used to form helical spring wire and have rectangular cross section.Yet if helical spring is formed by the rectangular cross section wire, during winding process, owing to change the pressure of the final shape of cross section wiry that forms spring, wire can be twisted, and no longer is rectangle, as shown in Figure 1.

[0006] a kind of difficulty with flexible column is: though the flexible angle that allows its bending to leave main borehole with employing is pointed to drill bit, to creep into boring, and therefore help drilling apparatus to turn over bending in the boring, so that: it can creep into path with the angle of leaving from main borehole.Need be when linear passages to be crept into when it, this flexibility can reduce the stability of axle, and can reduce to be provided for the moment of torsion of drill bit.

[0007] therefore, target of the present invention is to be provided at the flexible column that has plane contact between the spiral of spring, is used for arriving drill bit along straight path of navigation or along curved guide path stable transmission moment of torsion and axial load.

Summary of the invention

[0008] one aspect of the present invention comprises the flexible drillstem that is used to creep into flank hole, comprising: helical form external metallization silk helical spring; With at least one internal helicoid shape wire helical spring, reside in one heart in the external helical springs, adjacent coils have opposite tiltedly; Wherein: form the helical spring wire of each helical form and have cross section, so that: when drill string adjusting to a line, between the wire of the adjacent turn of spring, there is plane contact.During creeping into, when revolving force and axial load are applied to drill string, between adjacent turn, there is plane contact along straight-through road.Between each helical spring circle of formation, have plane contact and help to prevent buckling of drill string.Cross section wiry so that: even when drill string along Nogata when creeping into, also keep the plane contact between the adjacent turn.

[0009] preferably, cross section wiry is prismatic.More preferably, the cross section wiry of flexible drillstem is square, rectangle or rhombus.These shape of cross sections have been realized the plane contact between the helical spring adjacent turn.

[0010] helical spring circle can have ridge on the contact surface of circle, and/or has groove on the contact surface of circle.Have ridge and/or groove and increased friction ratio between each helical spring circle.

[0011] this helical spring can by parallel spiral around at least two wire form.Make two or the more moment of torsion transmission of the parallel spiral permission of many wire, and reduce spiral angle.

[0012] flexible drillstem can be formed by the helical spring with preload.Have preload and give the spring longitudinal rigidity between conveyor screw, helping provides stability for post during creeping into along straight track.

[0013] this flexible drillstem can also comprise the torque peak strainer.This protects axle to prevent the damage that is caused by torque peak.This strainer can be placed on Anywhere along axle.

[0014] this flexible drillstem can further be included in the drill bit of the lower end of axle.

[0015] another aspect of the present invention comprises the method for making aforesaid flexible drillstem, comprising: Wound wire is to form the helical form helical spring; When it is reeled, wire is applied mechanically deform; And use the helical form helical spring to form flexible drillstem; Wherein: the mechanically deform that applies causes having the wire of cross section behind coiling, so that: when axial load is applied to drill string, between the adjacent turn of spring, there is plane contact.

[0016] preferably, this method comprises when it is just reeled and applies preload to wire.

[0017] this method can comprise use size or thermal expansion, so that two or more helical springs are closely fitted together.This can help to reduce the gap between the helical spring of flexible drillstem.

Description of drawings

[0018] Fig. 1 has shown the schematic diagram of the distortion wiry behind coiling;

Fig. 2 shown before winding process and after schematic diagram wiry;

Fig. 3 has shown the schematic diagram that is used to make a helical spring wire cross section of the present invention;

Fig. 4 has shown and can be used in a helical spring schematic diagram of the present invention; With

Fig. 5 has shown the power that takes place on helical spring.

The specific embodiment

[0019] this flexible column is by the screw winding external helical springs with stay one or more screw winding with one heart and littler inside spin spring forms.Each littler in succession internal helicoid spring has roughly the identical external diameter of internal diameter with the more king bolt spring of adjacency.Each helical spring is along reeling with contiguous helical spring rightabout, and external helical springs is provided with coiling reference direction, and along with drill bit the direction equidirectional of rotation being reeled.This spring keeps rigidity with respect to each other helical spring at the upper and lower end of drill string place.This spring is closely reeled, and each helical spring axial adjacent spiral contacts with each other simultaneously.Between erecting stage, size or thermal expansion can be used in any gap of removing between the contiguous helical spring, so that: helical spring closely is assembled together.

[0020] each spring is formed by Wound wire or wire rod or wire, has geometric cross-section.Yet, when its spiral when forming spring, this winding process can cause initial cross-sectional deformation wiry.Therefore, in case form spring, the wire that forms spring have with its screw winding before the different final cross section that begins at first.

[0021] for example, as shown in Figure 1, owing to when it forms helical spring, place the compressive force on the wire, the wire (wire rod or wire) with initial square cross section is deformed into the wire with trapezoidal cross-section.As shown in Figure 1, the helical spring that is formed by the wire that has trapezoidal cross-section along its length does not have plane contact between the adjacent spiral of spring.

[0022] in order to form the helical spring of plane contact between the adjacent spiral, the initial cross section of wire before coiling must obtain proofreading and correct, with the distortion of considering to occur during winding process.With reference to Fig. 2, wire has initial trapezoidal cross-section when being used to form helical spring, owing to place compressive force wiry during winding process, in case form spring, the final form of cross section wiry is square.This angle beta is the angle that cross section wiry obtains proofreading and correct, and will be out of shape during forming spring at winding process with the compensation wire.This final square cross section allows the plane between the adjacent spiral to connect.Utilize the plane contact between the spiral of spring, when drill string adopted crooked and straight form, flexible drillstem can have moment of torsion and axial load improves the output equipment that is sent to such as drill bit.

[0023] by or during winding process, opposite mechanically deform is applied to wire, or by during the winding process of the final cross section that will cause realizing that the plane connects between the spiral, with since the cross section direct metal silk drawing when changing of the compressive force that applies can carry out being used to form the angle correct initial wiry of spring.

When [0024] between spiral, having plane contact and improved along the drilling well of straight-through road, the performance of flexible drillstem.Plane contact between the adjacent spiral gives post better anti-buckling effect, and when placing axial load, such as during drilling well, guarantees the rigidity of post.

[0025] plane contact between the surface of spiral has increased friction, and this has reduced under moment of torsion, the contraction of the diameter of spring.By having the spring of lozenge shape cross-section, can also help under moment of torsion, to reduce the contraction of spring diameter.When wire has as shown in Figure 3 lozenge shape cross-section, will exist the plane to connect between the adjacent windings.Have lozenge shape cross-section and have angle [alpha] to be used to form helical spring wire, wherein: angle [alpha] equals to proofread and correct angle beta, with the distortion of considering to occur owing to winding process, and additional angle, so that: wire keeps lozenge shape cross-section behind winding process.

[0026] when the spring spiral that forms flexible drillstem is subjected to moment of torsion, this diameter that can or cause having corresponding length and increase reduces, and perhaps having the diameter that the correspondence of length reduces increases.Alternately reel if form the spring of post, when spring is in moment of torsion following time, a spring diameter enlarges, and its adjacent springs diameter reduces, thereby produces strong, stable and flexible column.

[0027] being used to form the spring of flexible column can be by pre-loaded spring.During the winding process of spring, apply pre-loaded.This gives the drill string longitudinal rigidity, when along Nogata when creeping into, make post have stability.

[0028] with reference to Fig. 4, for increasing the friction ratio of contact between the adjacent turn 1, ridge 2 and/or groove 3 are added to the wire that forms spiral.The process that is used on wire forming ridge and groove can comprise the mechanically deform wiry of formation, or the drawing of direct metal silk, yet can use other method.The friction ratio that increases between the adjacent spiral will reduce the slip that meeting occurs between adjacently situated surfaces, and therefore improve the stability of drill string.

[0029] in operation, drilling rig comprises that according to flexible drillstem of the present invention, drill bit invests the lower end of post, and this drilling apparatus is lowered by and enters in the mine.For creeping into boring, this flexible column is directed with rotation, and the sensing drill bit enters in the side of main mine with side direction.The flexibility of this post can be reversed axle with short radius.Electric rotating machine has been realized the rotation of post and drill bit.Rotate by motor, and axial load is sent to flexible drillstem, causes the drill bit rotation, and creep into.By flexible drillstem, rotation torque and axial force are applied to drill bit.

[0030] with reference to Fig. 5, for the flexible drillstem that has plane contact between the adjacent spiral of spring, in drilling process, the moment of torsion and the axial force that apply are more effective.This has improved the moment of torsion that is sent to drill bit.This can transmit the summation that moment of torsion is rotation torque 4 and clutch effect, and the clutch effect is because the combination of the friction ratio between the contact surface of the length axial force 5 of edge axle and adjacent turn.

[0031] in the case of without departing from the present invention, can further change.

Claims

1. flexible drillstem that is used to creep into flank hole comprises:

Helical form external metallization silk helical spring; With

At least one internal helicoid shape wire helical spring resides in the external helical springs with one heart, and the circle of adjacent springs has opposite oblique angle;

Wherein: form each helical spring wire and have cross section, so that: when drill string adjusting to a line, between the adjacent turn of spring, there is plane contact.

2. flexible drillstem according to claim 1, wherein: cross section wiry is square, rectangle or rhombus.

3. according to any one flexible drillstem of claim 1 or 2, wherein: on the contact surface of circle, have ridge.

4. according to any one flexible drillstem of claim 1-3, wherein: on the contact surface of circle, have groove.

5. according to any one flexible drillstem of claim 1-4, wherein: described helical spring is formed by at least two wire of close wind.

6. according to any one flexible drillstem of claim 1-5, wherein: described helical spring has preload.

7. according to any one flexible drillstem of claim 1-6, comprising: the torque peak strainer.

8. a drilling apparatus comprises: according to any one described drill string of claim 1-7; Drill bit with the lower end that invests described drill string.

9. a manufacturing comprises according to the method for any described flexible drillstem of claim 1-8:

Wound wire is to form the helical form helical spring;

When wire is reeled, wire is applied mechanically deform; With

Use the helical form helical spring to form flexible drillstem;

Wherein: the wire after the mechanically deform that applies causes reeling has cross section, makes when axial load puts on drill string, has plane contact between the adjacent turn of spring.

10. a method of making flexible drillstem according to claim 9 comprises: when wire is just reeled, apply preload.

11. one kind according to claim 9 or 10 described methods, comprising: use size to expand or thermal expansion with two or more helical springs of tight assembling.