WO2002072994A1

WO2002072994A1 - Reamer

Info

Publication number: WO2002072994A1
Application number: PCT/BE2002/000031
Authority: WO
Inventors: Leif Åkesson; Antonio Carosielli; Philippe Fanuel; Jean-Pierre Lassoie
Original assignee: Halliburton Energy Services, Inc.
Priority date: 2001-03-12
Filing date: 2002-03-12
Publication date: 2002-09-19
Also published as: BE1014047A3; CA2440273A1; US20040084224A1

Abstract

The invention relates to a borehole underreamer, in particular for a hole below a well casing in the field of oil exploration, comprising a longitudinal body, a drilling fluid conduit, which is disposed longitudinally in the body and which is provided with a fluid flow section having an internal radius i, and at least two underreaming arms (5) which are supported by the body and which are provided with an active part (7) that is equipped with cutting means (8). The underreaming arms are arranged so as to slide between a rest position inside the body and partially outside the body in an active position (10). Said arms are guided and supported for this purpose in the body over a distance g and, when in the active position (10), project from the body by a length o, wherein values i, g and o are selected to satisfy conditions i + g + o = s simultaneously; 0.30 < i/s < 0.45, 0.40 < g/s < 0.60, 0.07 < o/s < 0.20.

Description

To hope

The present invention relates to a borehole enlarger, in particular of this hole below a casing in the field of oil exploration, the enlarger comprising a body with a longitudinal axis, a drilling fluid conduit arranged longitudinally in the body, and having a fluid passage section of an interior radius i, and at least two widening arms which have an active part provided with cutting means, which are arranged to be able to slide between a rest position in the body and an active position partially outside the body, which are guided and supported for this purpose in the body over a distance g and which, in the active position, protrude from the body by a length o.

This kind of enlargement tool has for example a body diameter of, for example, between 119 and 427 millimeters. This leaves little space to build a simple mechanism, provide the elements mentioned above and give them proportions ensuring them, as well as the enlarger as a whole, a balanced relative strength.

The object of the present invention is to provide a solution to this problem and proposes to respect a determined proportionality between, on the one hand, the above respective values of internal radius i, of distance g, of length o and, of on the other hand, the sum s of these three values.

To this end, according to the invention, the values of i, g and o are chosen to simultaneously satisfy the following conditions: i + g + o = s; 0.30 <i / s <0.45, 0.40 <g / s <0.60, 0.07 <o / s <0.20.

Surprisingly, it turned out that these conditions are advantageously successfully applicable to different sizes of expanders, as explained below.

According to one embodiment of the invention, for its sliding guide in the body, each arm can comprise a cylindrical portion of diameter d whose value is at least equal to the value of g above.

According to a particular embodiment of the invention, for its displacement from the rest position to the active position, each expander arm has a face, internal to the body, arranged to be subjected directly, in the manner of a face active piston, at the pressure of the drilling fluid circulating in the body.

Other details and particularities of the invention will emerge from the appended claims and from the description of the schematic drawings annexed to this specification and which illustrate by way of nonlimiting example, a preferred embodiment of the enlarger of the invention.

Figure 1 shows in axial section a widener, an arm visible in the figure being in the rest position.

Figure 2 shows a partial axial section in which the visible arm is in the active position.

Figures 3 and 4 each show a cross section in which are shown three widening arms in the rest position and respectively in the active position.

Figure 5 shows on a larger scale, in longitudinal section, an assembly comprising an arm and an intermediate support, for mounting and rapid exchange of arms.

In the different figures, the same references designate similar or analogous elements.

The widener 1, as shown by way of example in FIGS. 1 to 4, comprises a body 2 with a longitudinal axis 3, a conduit 4 of drilling fluid, formed longitudinally in the body 2, and at at least two widening arms 5 which are distributed symmetrically in the body 2, around the longitudinal axis 3, to ensure a substantially balanced operation of the widener 1. Figures 3 and 4 show that one can easily arrange in the body 2 three arms 5 at angles of 120 ° between two successive arms 5.

The arms 5 each have an active part 7 provided with cutting means 8 (Figures 3 to 5), known and explained below. The arms 5 are arranged in the body 2 so that they can be moved between a rest position 9 in this body 2 and an active position 10 partially outside this same body 2.

Each arm 5 may include, for its displacement from the rest position 9 to the active position 10, a face 12, internal to the body 2, arranged to be subjected directly, in the manner of an active piston face, to the pressure drilling fluid circulating in the body 2. By this arrangement, mechanical parts are avoided between the fluid which must actuate the arm 5 and the latter, and the problems known to those skilled in the art and which may result therefrom.

By internal face 12 of arm 5, it is necessary to understand any face / surface in contact, at any moment of drilling and / or widening operation, with the pressurized fluid circulating in the conduit 4. It appears that some of these faces / surfaces subjected to the same pressure compensate each other but, overall, there remains a sufficient positive surface so that with, for example, a positive pressure differential of the order of 2 MPa (approximately 300 psi) between the pressure of the fluid in the duct 4 and that of the fluid outside of the body 2, at the level of the arm (s) 5, a thrust force of the order of 2,000 kg is obtained to remove the arm 5 from the body 2.

The arm 5 is mounted so that it can slide parallel to itself in the body 2, in order to pass from the rest position 9 to the active position 10 and vice versa. The choice of such a movement is most favorable for operation in the manner of a piston.

The movement of the arm 5 can be oriented radially and / or in any other favorable direction, whether it is upwards, downwards with respect to a working direction of the expander eVou forwards, rearwards by relative to a direction of rotation of the expander, possibly along any combination of these directions of movement.

A pivoting movement around an axis (not shown) perpendicular to the longitudinal axis 3 and to the direction of travel of the arm 5, and arranged somewhat away from the arm 5, is however also possible but its setting implemented would require specific machining operations that are significantly more expensive than those of the previous embodiment.

To perform the above-mentioned piston function, sealing means 11 are provided at the locations known to those skilled in the art.

For its displacement from the active position 10 to the rest position 9 when the pressure in the duct 4 is reduced, the or each arm 5 advantageously comprises elastic return means 13, for example helical compression springs 14 as shown in the drawings. This arrangement allows the expander 1 to be easily removed from the borehole.

The arm 5 may have, in the active position 10 outside the body 2, a posterior face 16 (relative to a direction F of advance of enlargement in the hole) at an angle, adapted to help, for example in the event of deficiency of the springs 14, the arm 5 to enter the body 2 during a withdrawal of the expander 1 out of the borehole.

The arm 5 can be mounted in the body 2 by means of an intermediate support 15 which serves to house and guide the arm 5 in the body 2 and which is fixed to the latter, for example by screws 17. sealing 18 can then be provided between the body 2 and said intermediate support 15. The fluid conduit 4 has (FIGS. 2 and 4) a section for the passage of an internal radius i. The term radius must be understood in a broad sense, for example of an average linear half-dimension of this passage section. The arms 5 are guided, at least in the active position, in the body 2 or, where appropriate, in their respective intermediate support 15 over a distance g. The same arms 5, in the active position, protrude from the body 2 with a length o.

As shown in Figures 2 and 4, - the sum s of the three values i, g and o corresponds to the radius or half of the opening diameter of the arms 5,

- the outside diameter of the body 2 is equal to (i + g) x 2 or to (s - o) x 2,

- therefore the projection length o is equal to s - g - i.

The invention proposes to maintain between respective determined values the three values i, g and o related to their sum s. This follows from various experiments which surprisingly gave fairly tight ranges for the following three proportions:

0.30 <i / s <0.45, 0.40 <g / s <0.60, 0.07 <o / s <0.20. The value of o considered is the maximum possible value for the movement of the arm 5 in the expander.

Table 1 attached gives for seven expanders of different sizes, increasing from size 1 to size 7, characteristic dimensions and corresponding proportions. It appears that the following respective ranges may be preferred for said proportions:

0.34 <i / s <0.39, 0.45 <g / s <0.53, 0.10 <o / s <0.16.

For any other identical construction condition, proportions outside of these ranges have not given rise to wideners as efficient as those whose proportions are in the above ranges, whether it is operating reliability, of service life, quality of work, performance, etc.

For its sliding guide in the body 2 or in the intermediate support 15, each arm 5 may comprise a preferably cylindrical portion of diameter d whose value is advantageously at least equal to the value of g above. We are looking for an embodiment of a massive and solid arm 5.

This advantageously cylindrical portion of the arm 5, in the shape of a piston, can be made of a steel, for example surface hardened on the guide surface so as to reach a hardness of the order of at least 120 or even 140 or up to at 240 kg / mm ² . The guide cavity of the body 2 or of the intermediate support 15, having the function of a cylinder for said piston, can be formed from a steel, treated for example by quenching in the mass of the guide surface to obtain a hardness of at least 120 or preferably 140 kg / mm ² . We are of course looking for the most favorable economic and technical combination for the choice of these hardnesses.

Preferably, before a widening operation, each arm 5 is held in the rest position 9 in the body 2 by at least one pin 19 arranged to rupture when the pressure of the drilling fluid circulating in the body 2 exceeds a value determined greater than a usual maximum drilling value.

To this end, the pin 19 may include a weakened zone 19A, in a calibrated manner, at the place or at each transition point 20 where the pin 19 passes, as the case may be, either from the body 2 or from the intermediate support 15 in the arm 5. It is clear that, contrary to what is shown in FIGS. 3 and 4, the pin 19 does not necessarily have to come out on both sides of the arm 5.

This pin 19 can fix the arm 5 only to the intermediate support 15 (Figures 3 and 4). We see in Figure 4 the pin 19 broken in part

19B in the arm and two parts 19C in the intermediate support 15. The intermediate support 15, the arm 5, the above-mentioned elastic means 14 and the spindle 19 can then constitute an assembly 21 (FIG. 5) arranged to be assembled beforehand outside the body 2 and to be installed thereafter. Thus we can facilitate not only the mounting of the expander 1 but also its maintenance, repair in the event of damage, etc.

It should be understood that the present invention is in no way limited to the embodiments described above and that many modifications can be made thereto without departing from the scope of the claims given below.

The body 2 may have on its external face, between two successive arms 5, a longitudinal channel 22, for a return of drilling fluid towards the surface, and a boss 23 arranged in this channel 22 so as to deflect and / or project onto the wall part of the hole that the arms 5 attack the drilling fluid which rises towards the surface. The channel 22 and the boss 23 are produced so as not to form a restriction that is too sensitive to the passage of the return fluid.

In the preferred embodiment of the expander 1, the stroke of an arm 5 between the rest position 9 and the active position 10 is limited in the two directions of movement by stops. In the rest position 9, the arm 5 is usually completely retracted into the body 2 and is retained there by reciprocal abutment surfaces 25 (FIG. 3) or, where appropriate, by the spindle 19. In the active position 10, the arm 5, retained by reciprocal abutment surfaces 26 (Figures 2 and 4), scans a space whose largest diameter is equal to between 1.05 and 1.3 times, preferably 1.2 times, the nominal diameter d 'a drilling head associated with the expander 1 for a combined drilling and widening operation.

The cutting means 8 on the arms 5 are arranged by the skilled person so as for example to obtain a cutting efficiency similar to that of the cutting means of the drilling head associated.

The reciprocal abutment surfaces 26 can be arranged on exchangeable or adjustable elements so as to allow a user of the expander 1 to choose the degree of output of the arms 5 from the body 2 during service.

Table 1

I

Legend of figures

1 widener

2 bodies

3 longitudinal axis duct widening arm active part cutting means rest position 0 active position 1 sealing means 2 internal face 3 elastic return means 4 helical springs 5 intermediate support 6 rear face 7 screws 8 sealing means 9 spindle 9A weakened area (s) 9B spindle part 9C spindle part 0 transition location 1 assembly 2 longitudinal channel 3 boss 5 reciprocal abutment surfaces 6 reciprocal abutment surfaces direction of advance of enlargement process / drilling

Claims

1. Drill hole enlarger, in particular of this hole below a casing in the field of oil exploration, comprising: - a body (2) with longitudinal axis (3),

a conduit (4) for drilling fluid, formed longitudinally in the body (2) and having a fluid passage section with an internal radius i, and

- at least two widening arms (5), carried by the body (2), - which have an active part (7) provided with cutting means (8), which are arranged therein so as to be able to slide between a rest position (9) in the body (2) and an active position (10) partially outside the body (2), and - which are guided and supported for this purpose in the body (2) over a distance g and which, in the active position (10), protrude from the body of a length o, characterized in that the values of i, g and o are chosen to simultaneously satisfy the following conditions: î + g + o = s;

0.30 <i / s <0.45, 0.40 <g / s <0.60, 0.07 <o / s <0.20.

1. Expander according to claim 1, characterized in that the values of i, g and o are chosen to simultaneously satisfy the following conditions: i + g + o = s,

0.34 <i / s <0.39, 0.45 <g / s <0.53, 0.10 <o / s <0.16.

2. Expander according to either of claims 1 and 2, characterized in that, for its sliding guide in the body (2), each arm (5) comprises a cylindrical portion of diameter d whose value is , preferably at least equal to the value of g.

3. Expander according to any one of claims 1 to 3, characterized in that, for its displacement from the rest position (9) to the active position (10), each arm (5) has a face (12), internal to the body (2), arranged to be subjected directly, like an active piston face, to the pressure of the drilling fluid circulating in the body (2).

4. Expander according to any one of claims 1 to 4, characterized in that the arm (5) is mounted so as to be able to slide parallel to itself in the body (2), to pass from the rest position ( 9) in the active position (10) and vice versa.

5. Expander according to any one of claims 1 to 5, characterized in that, for the displacement of the arms from the active position (10) to the rest position (9), the expander (1) comprises elastic return means of the arm (5).

6. Expander according to any one of claims 1 to 6, characterized in that each arm (5) is held in the rest position (9), before an enlargement operation, by at least one spindle (19) arranged to rupture when the pressure of the drilling fluid circulating in the conduit (4) exceeds a determined value greater than a usual maximum drilling value.

7. Expander according to any one of claims 1 to 7, characterized in that the arm (5) is mounted in the body (2) by means of an intermediate support (15) which serves as a housing for the arm (5) in the body (2) and which is fixed to the latter.

8. Expander according to claim 8, characterized in that the aforementioned pin (19) fixes the arm to the intermediate support (15).

9. Expander according to either of claims 8 and 9, characterized in that the intermediate support (15), the arm (5), the elastic return means (13) mentioned above and the spindle (19) constitute an assembly (21) arranged to be assembled beforehand outside of the body (2) and to then be installed there.

10. Widener according to any one of claims 7 to 10, characterized in that the spindle (19) has a weakened zone (19A), in a calibrated manner, at the place or at each transition place (20) where the pin (19) passes, as appropriate, either from the body (2) or from the intermediate support (15) in the arm (5).

11. Expander according to any one of claims 1 to 11, characterized in that

the body (2) has on its external face, between two successive arms (5), a longitudinal channel (22) for a return of drilling fluid, and

- A boss (23) arranged in this channel (22) so as to project the drilling fluid onto the wall part of the hole that the arms (5) attack.

12. Expander according to any one of claims 1 to 12, characterized in that the stroke of an arm (5) between the rest position (9) and that active (10) is limited by stops, if necessary also by the spindle (19), so that in the rest position (9) the arm (5) is fully retracted into the body (2) and that in the active position (10) the arm (5) scans a space whose the largest diameter is equal to between 1.05 and 1.3 times, preferably 1.15 times, the nominal diameter of a drilling head associated with the expander (1) for a combined drilling and d 'enlargement.