EP0211925A1 - Drilling pipe for making a drill string - Google Patents

Drilling pipe for making a drill string

Info

Publication number
EP0211925A1
EP0211925A1 EP19860901528 EP86901528A EP0211925A1 EP 0211925 A1 EP0211925 A1 EP 0211925A1 EP 19860901528 EP19860901528 EP 19860901528 EP 86901528 A EP86901528 A EP 86901528A EP 0211925 A1 EP0211925 A1 EP 0211925A1
Authority
EP
European Patent Office
Prior art keywords
drilling
tubes
drilling pipe
drill string
ribs
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19860901528
Other languages
German (de)
French (fr)
Inventor
Henning Narum
Sigbjorn Sangesland
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Raufoss Ammunisjonsfabrikker AS
Original Assignee
Raufoss Ammunisjonsfabrikker AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Raufoss Ammunisjonsfabrikker AS filed Critical Raufoss Ammunisjonsfabrikker AS
Publication of EP0211925A1 publication Critical patent/EP0211925A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B7/00—Special methods or apparatus for drilling
    • E21B7/04—Directional drilling
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings

Definitions

  • Drilling pipe for making a drill string Drilling pipe for making a drill string.
  • the present invention relates to drilling pipes for making a drill string, in particular adapted to deviation drilling, i.e. drilling performed in such a manner that the drilling direction at the beginning is substantially vertical, while the direction is later changed towards one side, so that the direction of drilling finally is under a larger or smaller angle with the vertical direction, up to 90°.
  • Such drilling allows drilling into several mutually separate sources from one point , and is used for offshore drilling.
  • Deviation drilling causes, however, and in particular when the deviation angle from the vertical direction is large, problems with respect to transporting of the cuttings. Moreover, the friction against the bore hole becomes large, and the weight on the drill bit may be insufficient. Generally the weight of a conventional drill string will be a problem when the more or less horizontal portion of the bore hole has a large length.
  • a large deviation angle means that the cuttings have a short way to "fall” until they reach the "bottom” of the hole.
  • the weight of the drill string will generally be proportional to the frictional forces and frictional torques which occur between the drill string and the wall of the hole. In long holes having a large deviation angle said forces and torques will be of importance, and they will determine the possible length of drilling until the friction becomes too large.
  • the object of the present invention is to provide a drilling pipe which makes it possible to reduce the frictional forces and the frictional torques and which simultaneously keeps the pressure losses and the operational and handling conditions within acceptable limits.
  • the above has been achieved with a drilling pipe as specified in the accompanying claims.
  • a buoyancy which causes that the pressure of the drill string against the under side of a more or less horizontal portion of a hole is reduced.
  • the drilling pipe is made of an inner and an outer tube, and the inner tube has ribs which maintain the distance from the outer tube and contribute to prevent that the outer tube is squeezed together by the outer pressure.
  • At least the outer tube is helical.This brings about a reduction of the contact surface of the drill pipe against the wall of the hole and reduced problems related to friction between the drill string and the wall of the hole.
  • drilling pipes according to the invention does not have to comprise drilling pipes according to the invention,because these may be combined with drilling pipes without cavities for buoyancy.
  • Conventional drilling pipes may for instance be used during the first phase of the drilling, when the transporting of cuttings and the frictional forces are small problems, and drilling pipes according to the invention may be used in the area where the major deviation takes place.
  • the buoyance chamber or channels may be permanemtly closed, and the cross section of the chamber or the channels is of course adapted to the desired buoyancy, taking into account the weight of the drilling mud which determines the buoyancy per unit of volume.
  • Fig. 1 shows a longitudinal section through an originally straight drilling pipe according to the invention.
  • Fig.2 shows a cross section through a drilling pipe according to the invention.
  • Fig. 3 shows a longitudinal section through a drilling pipe according to the invention, in which the outer tube is of helical shape, while the inner tube primarily is straight.
  • the shown drilling pipes are sections which are adapted to form a drill string by being joined, and they may, as mentioned, provide a combination together with sections which have no cavities for buoyancy.
  • the drilling pipe shown in Fig.1 consists of an outer tube 1 and an inner tube 2, and said tubes are concentrical and are spaced radially by means of ribs 3.
  • a head 4,5 On each end of the drilling pipe is a head 4,5, which may have outer and inner threads, respectively, for screwing together of drilling pipes to form a string.
  • the tubes 1 and 2 may have cross sections as shown in Fig. 2, where the tube 1 has smooth walls while the tube 2 has outer ribs 3.
  • Fig.3 shows an embodiment where the outer tube 1 is of helical shape, while the inner tube 2 is straight.
  • the drilling pipe shown in Fig.3 has heads 4 and 3, in the same manner as the drilling pipe shown in Fig.1, and ribs 3 maintain the distance between the tubes 1 and 2. In this case, however, the ribs 3 have a height which varies with the distance between the tubes 1 and 2.
  • a not shown modification is a drilling pipe of which both the outer tube 1 and the inner tube 2 have helical shape.
  • the heads 4 and 5 may be of conventional type, and are not closer described.
  • the tubes 1 and 2 may be made of aluminium. It is theoretically possible to extrude the tubes 1 and 2 and the ribs 3 together, but because of the compression loading to which the tubes are subjected it is considered necessary to use heavily extrudable alloys , which makes it necessary to manufacture the tubes 1 and 2 separately, whereupon the tubes are joined. The joining may be performed in different ways, of which are mentioned:
  • Explosive technology for instance placing of a detonating fuse around the tube 1, whereby the detonation will press the ribs 3 into the wall of the tube 1.
  • the above processes may also be used when the outer tube is of helical shape, as shown in Fig.2. If both the tubes are of helical shape the inner tube must be screwed into the outer one after giving both the tubes their shape. Thereupon one of the above mentioned processes may be used. Alternatively the two tubes may be moved together in straight condition, whereupon they are given a helical shape.
  • a drilling pipe according to the invention contains a closed chamber or a plurality of channels which are closed against the exterior. There is no hindrance of providing mutually communicating channels, but grounds of manufacture make it most appropriate that the channels are separate.
  • the cavity or the channels for buoyanca may as mentioned contain air, but also other media can be used, such as a liquid or a more or less solid mass. Also another gas than air may be used.
  • the invention makes it possible , in particular when the mud weight is relatively high, to achieve a "positive" buoyancy. Compared with conventional drilling pipes o f aluminium the invention makes it possible to achieve a substantial weight reduction, for instance by a factor in the range of 3, and relatively to conventional drilling pipes of steel there may be achieved a weight reduction by a factor in the range o f 7 ( I . e . approximately 1 /3 and 1 /7 , respectively, of the weight of conventional drilling pipes ) .
  • the joining of the tubes 1 and 2 and the heads 4 and 3 may be performed in any suitable manner. As examples are mentioned threaded connections and welding.
  • the inner tube which is adapted to convey mud, of course communicates with apertures in the heads 4 and 5, in such a manner that a plurality of joined drilling pipes constitute a string having a continuous inner channel.
  • the tubes 1 and 2 must be designed for the prevailing pressures, they must also be designed to withstand the bending which necessarily occurs during deviated drilling, and the tubes must furthermore be designed to withstand the axial forces and the torque to which they are subjected.

Abstract

Une tige de forage pour réaliser un train de tiges de forage, en particulier un forage dévié, comprend un tube extérieur et un tube intérieur (2) connectés à des têtes (4, 5) à chaque extrémité de telle manière que le tube intérieur communique avec des ouvertures aménagées au travers de chaque tête, et de telle manière qu'une cavité fermée est formée entre les tubes (1, 2), ladite cavité contribuant à donner à la tige de forage et au train de tiges de forage une flottabilité dans le trou de forage.A drill pipe for making a drill pipe string, in particular a deviated drilling, comprises an outer tube and an inner tube (2) connected to heads (4, 5) at each end so that the inner tube communicates with openings arranged through each head, and such that a closed cavity is formed between the tubes (1, 2), said cavity helping to give the drill pipe and the drill pipe string a buoyancy in the drill hole.

Description

Drilling pipe for making a drill string.
The present invention relates to drilling pipes for making a drill string, in particular adapted to deviation drilling, i.e. drilling performed in such a manner that the drilling direction at the beginning is substantially vertical, while the direction is later changed towards one side, so that the direction of drilling finally is under a larger or smaller angle with the vertical direction, up to 90°.
Such drilling allows drilling into several mutually separate sources from one point , and is used for offshore drilling.
Deviation drilling causes, however, and in particular when the deviation angle from the vertical direction is large, problems with respect to transporting of the cuttings. Moreover, the friction against the bore hole becomes large, and the weight on the drill bit may be insufficient. Generally the weight of a conventional drill string will be a problem when the more or less horizontal portion of the bore hole has a large length.
The problem of transporting the cuttings will increase with the deviation angle and the length of the hole. A large deviation angle means that the cuttings have a short way to "fall" until they reach the "bottom" of the hole.
The weight of the drill string will generally be proportional to the frictional forces and frictional torques which occur between the drill string and the wall of the hole. In long holes having a large deviation angle said forces and torques will be of importance, and they will determine the possible length of drilling until the friction becomes too large.
The object of the present invention is to provide a drilling pipe which makes it possible to reduce the frictional forces and the frictional torques and which simultaneously keeps the pressure losses and the operational and handling conditions within acceptable limits. In accordance with the invention the above has been achieved with a drilling pipe as specified in the accompanying claims.
With a drilling pipe according to the invention is achieved a buoyancy, which causes that the pressure of the drill string against the under side of a more or less horizontal portion of a hole is reduced.
According to an embodiment the drilling pipe is made of an inner and an outer tube, and the inner tube has ribs which maintain the distance from the outer tube and contribute to prevent that the outer tube is squeezed together by the outer pressure.
According to another embodiment at least the outer tube is helical.This brings about a reduction of the contact surface of the drill pipe against the wall of the hole and reduced problems related to friction between the drill string and the wall of the hole.
It is to be noted that the entire drill string does not have to comprise drilling pipes according to the invention,because these may be combined with drilling pipes without cavities for buoyancy. Conventional drilling pipes may for instance be used during the first phase of the drilling, when the transporting of cuttings and the frictional forces are small problems, and drilling pipes according to the invention may be used in the area where the major deviation takes place.
The buoyance chamber or channels may be permanemtly closed, and the cross section of the chamber or the channels is of course adapted to the desired buoyancy, taking into account the weight of the drilling mud which determines the buoyancy per unit of volume.
In the following the invention will be explained closer, with reference to the accompanying drawings.
Fig. 1 shows a longitudinal section through an originally straight drilling pipe according to the invention. Fig.2 shows a cross section through a drilling pipe according to the invention.
Fig. 3 shows a longitudinal section through a drilling pipe according to the invention, in which the outer tube is of helical shape, while the inner tube primarily is straight.
The shown drilling pipes are sections which are adapted to form a drill string by being joined, and they may, as mentioned, provide a combination together with sections which have no cavities for buoyancy.
The drilling pipe shown in Fig.1 consists of an outer tube 1 and an inner tube 2, and said tubes are concentrical and are spaced radially by means of ribs 3. On each end of the drilling pipe is a head 4,5, which may have outer and inner threads, respectively, for screwing together of drilling pipes to form a string.
The tubes 1 and 2 may have cross sections as shown in Fig. 2, where the tube 1 has smooth walls while the tube 2 has outer ribs 3.
Fig.3 shows an embodiment where the outer tube 1 is of helical shape, while the inner tube 2 is straight. The drilling pipe shown in Fig.3 has heads 4 and 3, in the same manner as the drilling pipe shown in Fig.1, and ribs 3 maintain the distance between the tubes 1 and 2. In this case, however, the ribs 3 have a height which varies with the distance between the tubes 1 and 2.
A not shown modification is a drilling pipe of which both the outer tube 1 and the inner tube 2 have helical shape.
The heads 4 and 5 may be of conventional type, and are not closer described.
The tubes 1 and 2 may be made of aluminium. It is theoretically possible to extrude the tubes 1 and 2 and the ribs 3 together, but because of the compression loading to which the tubes are subjected it is considered necessary to use heavily extrudable alloys , which makes it necessary to manufacture the tubes 1 and 2 separately, whereupon the tubes are joined.The joining may be performed in different ways, of which are mentioned:
Stretching of the tube 1 until it comes into pressure contact with the ribs 3.
Pulling of a plunger through the tube 2, in order to bring the ribs 3 into pressure contact with the tube 1.
The use of a temperature difference between the tubes 1 and 2 and moving the tubes 1 and 2 together, followed by the above mentioned stretching or pulling of a plunger.
Explosive technology, for instance placing of a detonating fuse around the tube 1, whereby the detonation will press the ribs 3 into the wall of the tube 1.
The manufacture, however, does not constitute any limitation with respect to the scope of the invention, and is merely mentioned as examples of possibilities.
The above processes may also be used when the outer tube is of helical shape, as shown in Fig.2. If both the tubes are of helical shape the inner tube must be screwed into the outer one after giving both the tubes their shape. Thereupon one of the above mentioned processes may be used. Alternatively the two tubes may be moved together in straight condition, whereupon they are given a helical shape.
A drilling pipe according to the invention contains a closed chamber or a plurality of channels which are closed against the exterior. There is no hindrance of providing mutually communicating channels, but grounds of manufacture make it most appropriate that the channels are separate.
The cavity or the channels for buoyanca may as mentioned contain air, but also other media can be used, such as a liquid or a more or less solid mass. Also another gas than air may be used. The invention makes it possible , in particular when the mud weight is relatively high, to achieve a "positive" buoyancy. Compared with conventional drilling pipes o f aluminium the invention makes it possible to achieve a substantial weight reduction, for instance by a factor in the range of 3, and relatively to conventional drilling pipes of steel there may be achieved a weight reduction by a factor in the range o f 7 ( I . e . approximately 1 /3 and 1 /7 , respectively, of the weight of conventional drilling pipes ) .
It will be appreciated that the joining of the tubes 1 and 2 and the heads 4 and 3 may be performed in any suitable manner. As examples are mentioned threaded connections and welding. The inner tube , which is adapted to convey mud, of course communicates with apertures in the heads 4 and 5, in such a manner that a plurality of joined drilling pipes constitute a string having a continuous inner channel.
In addition to the fact that the tubes 1 and 2 must be designed for the prevailing pressures, they must also be designed to withstand the bending which necessarily occurs during deviated drilling, and the tubes must furthermore be designed to withstand the axial forces and the torque to which they are subjected.

Claims

Claims.
1. Drilling pipe for making a drill string, in particular for deviation drilling, characterized in that it comprises an outer tube (1) and an inner tube (2) which are connected to heads (4,5) on each end, in such a manner that the inner tube (2) communicates with apertures through each head, and such that a closed cavity is constituted between the tubes (1,2).
2. Drilling pipe according to claim 1 , characterized in that ribs (3) are provided in said cavity, in order to maintain the radial distance between the tubes.
3. Drilling pipe according to claim 2, characterized in that the ribs (3) are made integrally with one of the tubes (1,2).
4. Drilling pipe according to claim 3, characterized in that the ribs (3) are exterior ribs on the inner tube (2).
5. Drilling pipe according to claims 1 to 4, characterized in in that at least the outer tube (1) is of helical shape.
EP19860901528 1985-02-21 1986-02-21 Drilling pipe for making a drill string Withdrawn EP0211925A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO850689 1985-02-21
NO850689 1985-02-21

Publications (1)

Publication Number Publication Date
EP0211925A1 true EP0211925A1 (en) 1987-03-04

Family

ID=19888133

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860901528 Withdrawn EP0211925A1 (en) 1985-02-21 1986-02-21 Drilling pipe for making a drill string

Country Status (2)

Country Link
EP (1) EP0211925A1 (en)
WO (1) WO1986004950A1 (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2226583A (en) * 1988-12-30 1990-07-04 Shell Int Research Method of placing a pipe string in a borehole and pipe section for use in the method
US5174395A (en) * 1991-09-13 1992-12-29 Inco Limited In-the-hole drill inner tube rod
CA2097366A1 (en) * 1992-07-24 1994-01-25 J. Scott Martin Drill pipe
US5713423A (en) * 1992-07-24 1998-02-03 The Charles Machine Works, Inc. Drill pipe
DE19702983C1 (en) 1997-01-28 1998-06-04 Wirth Co Kg Masch Bohr Drilling head adapting efficiently to both soft and hard going
GB0019502D0 (en) * 2000-08-08 2000-09-27 Oil States Ind Uk Ltd Pipe assembly
EP3510233B1 (en) * 2016-09-12 2022-03-16 Perforator GmbH Extended directional drilling
US10407996B2 (en) * 2017-05-03 2019-09-10 Hunting Energy Services, Inc. One piece forged fluidic displacement drill pipe and method of manufacture thereof

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1024310A (en) * 1911-10-14 1912-04-23 Roger H Canfield Apparatus for boring wells.
DE816464C (en) * 1942-11-08 1951-10-11 Wieland Werke Ag Metallic hollow tube
US3552779A (en) * 1968-05-31 1971-01-05 Homer I Henderson Dual-conduit drill pipe for earth boring
CA926377A (en) * 1970-08-25 1973-05-15 Can-Tex Drilling And Exploration Ltd. Dual concentric drillpipe
US3871486A (en) * 1973-08-29 1975-03-18 Bakerdrill Inc Continuous coring system and apparatus
DE3239342A1 (en) * 1982-10-23 1984-04-26 Schmidt, Kranz & Co GmbH Zweigniederlassung Zorge, 3421 Zorge Drill column
CA1191454A (en) * 1983-01-19 1985-08-06 Harold F. Jarvis Insulated tubular structure

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8604950A1 *

Also Published As

Publication number Publication date
WO1986004950A1 (en) 1986-08-28

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Inventor name: SANGESLAND, SIGBJORN

Inventor name: NARUM, HENNING