EP0353309B1 - Method of constructing a well - Google Patents

Abstract

A method of constructing a well consisting in drilling the rock, casing the latter with a guiding column (1) of pipes, with a guide (2) and with an exploitation column (6) of pipes, and in isolating drilling zones (3) which present complications with profiled pipes (4) of which the diameter is enlarged at the time of installation. The enlargement of the profiled pipes (4) is effected by creating a pressure gradient inside them, with their subsequent expanding by rolling. The drilling of the rock after the casing of the well with the guiding column (1) of pipes and with the guide (2) is effected by means of a drill-bit of one and the same diameter whereas the complicated drilling zones (3) are enlarged to a diameter equal to the external diameter of the expanded profiled pipes (4) which are consecutively mounted in all the complicated drilling zones (3) as they are entered.

Description

The invention relates to a method for building a multi-tube tour bore of the type specified in the preamble of the claim.

The invention can be effectively applied when drilling through rock layers that are critical in terms of drilling technology, i. H. of layers with abnormally high rock pressure and loose mountains, in which rock, liquid or gas are pressed into the drilling chamber.

In conventional deep drilling methods, a drilling fluid is pressed into the cased borehole in order to flush out the cuttings and to balance the rock pressure by the pressure of the flushing column, which is regulated by adjusting the specific weight of the flush. With strongly changing rock pressures in different layers or formations, this balance can no longer be compensated for by changing the specific weight of the flushing. In these cases, the digested layer is covered with a casing pipe tour before the subsequent layer is digested, which is then cemented. After setting a suitable specific weight of the rinse, bringing down the Drilling continued with a smaller diameter drill bit. As a result, the borehole is drilled down to the productive layer with a gradually decreasing diameter, with casing pipes having to be used to support the borehole walls. Special guide pipes, intermediate pipes and delivery pipes are installed concentrically in these casing pipes. Such a drilling process requires a lot of time, cement and casing pipes.

From SU-A-907 220 a method for producing a deep borehole is known, in which the borehole wall in the area of critical mountain layers is covered by specially designed casing sections in order to prevent the penetration of liquids and solids into the borehole. These casing pipe sections have cylindrical end pieces with a thread and a central part profiled by longitudinal recesses. Several casing pipes screwed together at their end pieces and closed off at the lower end by a shoe are lowered into the borehole to the depth of the critical mountain layers and hydraulically expanded in their middle longitudinally profiled sections to the borehole diameter. After the expansion, the drill pipe used for lowering is unscrewed and pulled. The diameter of the cylindrical end pieces of the casing pipes is then increased. In this method, after the casing pipe sections have been introduced, drilling can only be carried out with a drill head of smaller diameter, which leads to a gradual reduction in the borehole width when drilling through several critical rock layers.

Another method for producing cased deep boreholes is known from US Pat. No. 4,501,327, in which the borehole walls are sealed in certain rock-technically critical sections by a hollow cylindrical insert or cassette which is expanded and cemented after being introduced into the borehole .

Finally, in the specialist journal "Neftjanoe chozjajstvo", No. 4, 1982, pp. 26, 27, a generic deep drilling method with sealing of the borehole wall in the area of critical mountain strata is described, in which the borehole in the area of the critical mountain strata is expanded and a continuous casing pipe section is lowered into this enlarged borehole area by means of the drill pipe. The middle longitudinally profiled part of the casing section is expanded hydraulically and then mechanically by means of a suitable tool until it touches the wall of the borehole. After the narrow end pieces have been drilled out, drilling can continue with a drill head of the same diameter.

The invention has for its object to provide a method for producing a multi-pipe tour bore with a constant inner diameter, which ensures a secure seal even of layers with particularly high rock pressure.

This object is achieved by the measures specified in the claim.

By drilling the hole with chisels of the same diameter after installing the standpipe tour and The predefined borehole diameter can be maintained up to the projected depth in the casing, which means that the use of intermediate pipe tours is unnecessary and the material expenditure is reduced and the construction of the boreholes is accelerated. The profile tube tour is securely fixed in the borehole by the hydraulic expansion of the upper and lower profile tubes. The expansion of the middle section tubes by rolling their inside diameter onto the inside diameter of the other section pipes causes the section pipes to solidify by changing the metal structure, which increases the resistance to very high rock pressures. This means that profile tubes can be used as coverings of layers with an abnormally high deposit pressure and can be converted using cheaper means. Depending on the type of metal and wall thickness, a maximum increase in hardness of the tubular metal of 130 to 260 % can be achieved with a diameter increase of 3 to 5% achieved by rolling.

Fig. 1

eine fertige Tiefbohrung von gleichbleibendem Durchmesser, bei der mehrere bohrtechnisch kritische Gebirgsschichten gegen das Bohrlochinnere abgedichtet sind;

Fig. 2

einen Bohrlochabschnitt mit einer gemäß der Erfindung eingebauten Profilrohrtour, deren mittlerer Teil einen kleineren Außendurchmesser als der erweiterte Bohrlochdurchmesser aufweist;

Fig. 3

einen Bohrlochabschnitt mit einer im kritischen Bereich eingebauten Profilrohrtour;

Fig. 4

einen Schnitt IV-IV in Fig. 2;

Fig. 5

einen Schnitt V-V in Fig. 2.

Further special features and advantages of the invention are explained in more detail below with reference to an embodiment shown in the drawing. Show it:

Fig. 1

a finished deep drilling of constant diameter, in which several rock layers that are critical in terms of drilling technology are sealed against the interior of the borehole;

Fig. 2

a borehole section with a built in profile tube tour according to the invention, the central part has a smaller outside diameter than the enlarged borehole diameter;

Fig. 3

a borehole section with a profile pipe tour installed in the critical area;

Fig. 4

a section IV-IV in Fig. 2;

Fig. 5

a section VV in Fig. 2nd

To produce a cased deep borehole, an upper borehole section with a chisel of large diameter was drilled down according to FIG. 1 and lined with a guide tube tour 1. Thereupon, drilling continued with a chisel of smaller diameter and a casing was fixed in the borehole. Subsequently, drilling continued with a chisel with a constant diameter to the projected depth. In the case of disruption of rock layers that are critical in terms of drilling technology, a reamer was arranged above the chisel, with which the borehole diameter was expanded by an amount that corresponded to the outer diameter of a widened profile tube. A profile pipe tour was then lowered into the borehole section of the critical mountain layer using the drill pipe and widened by the pressure of a pressed-in liquid. The passage cross section of this pipe section was then calibrated to a diameter by means of a rolling device, which enables the bit to pass freely for further drilling. Similarly, all other critical ones Mountain strata and complication zones were lined and solidified to the projected depth when the well was brought down, whereupon a conveyor pipe tour was finally installed and cemented.

If a layer that is critical in terms of drilling technology is opened up, the rock pressure of which exceeds the compressive strength of one of the profiled tubes installed in the above-mentioned manner, then additional profiled tubes are arranged between these profiled tubes in a profiled tube tour, the outer diameter of which before the profiling is smaller than the borehole diameter and the length of which is greater than that Thickness of the rock layer with abnormally high reservoir pressure. According to the invention, these profiled tubes are rolled up to a diameter which exceeds their initial diameter by 3 to 5%.

In the following, a concrete example for producing a cased deep borehole is described.

1, an exit bore for a guide tube tour 1 with a chisel of 394 mm in diameter was drilled to a depth of 6 m and solidified with conventional guide tubes with an outside diameter of 324 mm. Thereafter, drilling continued with a chisel with a diameter of 295 mm to a depth of 300 m while rinsing with a rinsing liquid of 1.1 g / cm ³ density. This bore was consolidated with a casing pipe 2 with a diameter of 245 mm. Subsequently, drilling continued with chisels with a diameter of 215.9 mm to the projected depth of 1800 m. In a water-bearing layer 3 at 460 to 470 m, profile tubes 4 were introduced, which were in an interval of 380 to 480 m by an internal liquid pressure of 10 to 12 MPa expanded and then pressed against the walls of the borehole by rolling. The drill hole had previously been broadened to a diameter of 335 mm using a reamer. The oil and water-bearing zone 3 'was sealed at a depth of 600 to 640 m using a similar method, a profile tube tour 4' being installed at an interval of 534 to 650 m. Zone 3 "carrying pressurized water was sealed at a depth of 820 to 840 m with the help of a 4" profile tube tour in an interval of 800 to 900 m. Furthermore, drilling continued with a chisel of 215.9 mm in diameter using a drilling fluid with a density of 1.43 g / cm ³ , which corresponded to the geological conditions of the layer 5 to be digested. Finally, a conveyor tube tour 6 with a diameter of 146 mm was installed. Drilling was carried out in the depths of 380 to 800 m using a rinsing liquid with a density of 1.29 g / cm ³ and in the depths of 800 to 900 m with a rinsing liquid density of 1.6 g / cm ³ .

In this way, the critical zones 3, 3 ', 3 "were sealed after their respective digestion by installing the profile tube tours 4, 4' and 4".

In the method according to the invention shown in FIGS. 2 to 4, when a mountain layer is opened with an abnormally high reservoir pressure, the ends of a central profile tube 4b in the drilling-critical section of this mountain layer 7 are provided with packer elements 8 and with a lower profile tube closed off by a shoe 9 4c and an upper profile tube 4a, which has a left-handed connection thread 10 at its upper end. This profile tube tour 4 is lowered on a drill pipe 11 into the critical borehole section 7a, so that the central profile tubes 4b to be consolidated are located in the area of the critical rock layer 7.

After installing the profiled tube tour 4 in the critical borehole section 7a, an excess pressure is created in the interior of this profiled tube tour 4 by injecting a liquid with the aid of e.g. B. a irrigation pump or a cementing unit. Under the effect of this internal pressure, the upper and lower profile tubes 4a and 4c are dressed and fixed. The middle, also dressed, profile tube 4b is given a diameter that is 3 to 5% smaller than the diameter of the widened borehole section 7. After pressure relief, the drill pipe 11 is unscrewed from the upper profile tube 4a and removed. A rolling device 12 according to FIG. 3 is then moved in on the drill pipe 11, with which the profile tube tour 4 is rolled on. As a result, the upper and lower profile tubes 4a, 4c are calibrated, while the middle profile tube 4b is rolled up to a diameter increased by 3 to 5%. The middle profile tube 4b is expanded and pressed tightly against the borehole wall, the packer elements 8 separating the borehole section 7a to be sealed from the rest of the borehole. After completion of the calibration process, the shoe 9 is released from the lower profile tube 4c.

When the inner surface of the middle profile tube 4b of the profile tube tour 4 is rolled out, a material deformation occurs in FIG radial direction, which leads to metal hardening, which is expressed in an increase in metal hardness. The increase in hardness is 130 to 260% depending on the type of steel and the wall thickness.

Claims (1)

1. Method of producing a cased deep bore, in which

   - a section of the bore hole is widened by means of a reamer in the region of a zone which is critical from the boring technology viewpoint,

   - a profile tube turn (4) which is formed from profile tubes is positioned in this widened section of the bore hole,

   - the positioned profile tube turn is enlarged by means of a hydraulic internal pressure,

   - the hydraulically enlarged profile tube turn is further enlarged and grooved by means of an expanding device (12) until it abuts against the wall of the bore hole, and

   - boring is thereupon continued with a boring bit of the same diameter,

   characterised in that

   - the profile tube turn consisting of upper, middle and lower profile tubes (4a, 4b, 4c) is positioned in the widened section (7a) of the bore hole in such a way that the middle profile tubes (4b) cover the stratum (7) which is critical from the boring technology viewpoint and the upper profile tubes (4a) are located above, and the lower profile tubes (4c) below, this critical stratum (7), the upper and lower profile tubes (4a, 4c) are trimmed until they abut, with pressure, against the widened wall of the bore hole, and also the middle profile tubes (4b) are trimmed until they reach a diameter which is 3 to 5% smaller than the diameter of the enlarged section (7a) of the bore hole, and

   - the upper and lower profile tubes (4a, 4c) are then grooved by means of the expanding device, and also the middle profile tubes (4b) are expanded until they abut, in a pressure-resistant manner, against the wall of the widened section (7a) of the bore hole, with metal reinforcement.

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