RU2708743C1 - Method of drilling offshoots from an openhole well horizontal part - Google Patents

Abstract

FIELD: soil or rocks drilling.

SUBSTANCE: invention relates to the field of oil and gas wells offshoots drilling. Prior to drilling of offshoots at the mouth of horizontal well with open bore, assembly is assembled from below upwards: telesystem, one weighted drill pipe, whipstock with inclination angle of working surface 4°, assembly is lowered on the tubing string to the main horizontal uncased hole so that the whipstock is in the interval of offshoot cutting, the whipstock is oriented. Then, at the well head, assemblage is assembled from below upwards: milling cutter, downhole drilling motor (DDM), hydraulic emergency disconnector, assembly is lowered to the tubing string on the flexible pipe string. Offshoot is drilled and drilled with load at cutter to 1.0 t. Drilling process is stopped, and assembly is performed on horizontal string on flexible pipe string. Geophysical instrument is lowered to tubing string to borehole of drilled offshoot on flexible pipe string to define minimum distance from drilled offshoot to oil-water contact (OWC). At minimum distance from drilled offshoot to OWC from 5 to 10 m, tubing string is lowered into tubing string, equipped with rotary spherical head fitted on end, to the bottomhole of the drilled offshoot and acid treatment of the bottomhole zone of the drilled offshoot. At a minimum distance from the drilled offshoot to OWC of more than 10 m, a string of flexible pipes with DDM is lowered into the tubing string, oscillator-turbulence promoter and bit at the end, and drilling of the offshoot is continued with the bit load up to 1.5 t to the specified face. After the offshoot bottom is reached, the drilling process is stopped and the assembly is lifted to the flexible pipes from the tubing string, string of flexible pipes with rotating spherical nozzle at the end to the depth of the drilled bottom of the offshoot is lowered into the tubing string and acid treatment of the bottomhole zone of the drilled offshoot is performed. Pressure of treatment of bottomhole area of offshoot may vary for each offshoot.

EFFECT: enabling accuracy of orientation direction of sidetracking to the right relative to the main horizontal uncased wellbore, exclusion of deviation of trajectory of offshoot during drilling, exclusion of opening of water-bearing formation, higher efficiency of treatment of side wells with hydrochloric acid solution using flexible tube with spherical nozzle, improving treatment quality of bottomhole zone of well, reducing duration of drilling of offshoot.

1 cl, 7 dwg

Description

The invention relates to the construction of multilateral wells, and in particular to a technology for drilling additional (side) shafts from the horizontal part of an open hole.

A known method of drilling a lateral oil wellbore (patent RU No. 2626103, IPC E21 B 7/04, publ. 07/21/2017 in bull. No. 21), including continuous cutting of the interval of production casing and cement stone of cylindrical shape from above and a truncated cone from below, isolation the expansion interval by installing an easily drilled insert of soft metal of a cylindrical shape longer than the length of the cutting interval, in the upper part of which a channel is made, pumping into the expansion interval of a hardening sealing compound. Drilling after polymerization of an easily drilled insert. Installation in the main trunk of a temporary cement bridge below the cut-off point of the side trunk and diverter wedge. Drilling of the sidetrack through the hardened hermetic composition. Sidetracking from the main trunk. Opening the main wellbore by drilling a deflecting wedge and a temporary cement bridge, while continuously cutting out the interval of the production string and cement stone, is performed in the vertical part of the wellbore. An easily drilled insert has a central channel, which is covered by an easily destructible membrane on top, and an easily drilled insert is drilled with a milling cutter, the lower end of which is provided with a cylindrical guide with a diametric size that allows moving inside the central channel according to the class of wide-pass landing. The upper part of the cutter is equipped with centralizers.

The disadvantages of this method are:

- firstly, a high probability of opening the aquifer and flooding of the main horizontal wellbore due to the lack of geophysical studies during sidetracking and, as a result, the sidetrack deviation from the given trajectory;

- secondly, low oil recovery from the sidetrack due to the lack of acid treatment of the bottomhole zone of the sidetrack;

- thirdly, significant material and financial costs associated with the fact that after drilling the main horizontal well, it is necessary to cushion it. In addition, the high complexity of the method, due to the fact that for sidetracking, continuous cutting of the interval of production string and cement stone of a cylindrical shape from above and a truncated cone from below, isolation of the expansion interval by installing an easily drilled insert made of soft metal of a cylindrical shape with a length longer than the cutting interval and etc .;

- fourthly, the high duration of the drilling process due to the low speed of penetration by a bit when drilling a sidetrack.

The closest in technical essence and the achieved result is a method of drilling sidetracks from the horizontal part of an uncased borehole (patent RU No. 2376438, IPC ЕВВ 7/04, publ. 12/20/2009 in bull. No. 35), including drilling the main horizontal and sidetracks, acid treatment of the sidetracks. Filling the entrance to the sidetrack after drilling with insulating material. Flushing insulating material from the shafts after drilling the last wellbore and developing the well. Sidetracks are drilled in different lengths, and a natural aqueous suspension is used as the drilling fluid. After drilling, the bottom of each trunk, except the last, is filled with a Ringo-EM emulsifier solution. After drilling the last wellbore during well development, all the wellbores are filled with oil. A tubing string (tubing) with a packer is lowered into the well. The well space is packaged in the interval of the vertical wellbore and the under-packer space is swabbed. Additionally, the bottom-hole zone of one or several trunks is treated with hydrochloric acid solution with swabbing.

The disadvantages of the method:

- firstly, the difficulty of accurately orienting the sidetracks before cutting them out of the main horizontal trunk due to the lack of a geophysical telesystem, which leads to sidetracking in an arbitrary direction with an uncontrolled trajectory;

- secondly, the high probability of the opening of the aquifer and flooding of the main horizontal wellbore due to the lack of geophysical studies during the drilling of the sidetrack and, as a result, the sidetrack deviation from the given trajectory downward;

- thirdly, inefficient treatment of the bottomhole zone of the lateral trunks with a solution of hydrochloric acid, and for this additional tripping operations are necessary, which complicates the method;

- fourthly, the low quality of the treatment of the bottomhole zone of the sidetracks, since all the sidetracks are treated with a solution of hydrochloric acid "common filter" under one pressure, i.e. it is impossible to individually treat the bottom-hole zone of each side wellbore;

- fifthly, a low speed of penetration by a bit when drilling a sidetrack, which increases the duration of the drilling process;

- sixth, significant material and financial costs associated with the fact that after drilling the main horizontal well, it is necessary to cushion it.

The technical tasks of the invention are to achieve accuracy in orienting the direction of sidetracking to the right relative to the main horizontal wellbore of an open hole, eliminating deviation of the sidetrack path during drilling, eliminating the opening of an aquifer, increasing the efficiency and quality of acid treatment of sidetracks, and reducing the duration of drilling of the sidetrack and reduction of financial and material costs for the implementation of the method.

Technical problems are solved by the method of drilling sidetracks from the horizontal part of an open hole, including drilling the main horizontal and sidetracks, acidizing the sidetracks.

The new one is that before drilling the sidetracks at the mouth of a horizontal well with an open hole from bottom to top, the assembly is assembled: a telesystem, one weighted drill pipe, a deflector wedge with an angle of inclination of the working surface of 4 °, the assembly is lowered on the tubing string - tubing in the main horizontal open hole so that the deflector wedge is in the interval of sidetracking, the deflecting wedge is oriented relative to the main horizontal open hole important, then at the wellhead the assembly is assembled from bottom to top: milling cutter, screw downhole motor - VZD, hydraulic emergency disconnector, lower the assembly into the tubing string on the flexible pipe string - GT, then make a cut in the direction oriented by the deflecting wedge, and drill the side trunk 40 m long at an angle of 4 ° relative to the main horizontal open-hole wellbore with a cutter load of up to 1.0 t, after which the drilling process is stopped and the layout on the GT string is removed from the horizontal well, for the geophysical instrument is lowered into the tubing string to the bottom of the drilled sidetrack on the GT string and the minimum distance from the drilled sidetrack to the oil-water contact — VOC — is determined from the drilled sidetrack path, and at a minimum distance of 5 to 10 m from the drilled sidetrack to the VOC, in the tubing string, a GT string equipped at the end with a rotating spherical nozzle to the bottom of the drilled side trunk and acidizing the bottomhole zone of the drilled side stem At a minimum distance of more than 10 m from the drilled sidetrack to the OWC, a GT column with a VZD, an oscillator-turbulator and a chisel at the end is lowered into the tubing string and sidetracking is continued with a bit load of up to 1.5 t to the specified bottom, after reaching the bottom hole bottom stop the drilling process and raise the assembly to the GT from the tubing string, lower the GT string with a rotating spherical nozzle at the end to the depth of the drilled bottom hole bottom and make an acid treatment of the bottomhole zone drilled sidetrack, and the processing pressure of the bottomhole zone of the sidetracks can be different for each sidetrack.

In figures 1-7 schematically and sequentially shows the implementation of the proposed method.

A method of drilling sidetracks from the horizontal part of an open hole is as follows.

Drill the main horizontal open hole 1 well. Before drilling the sidetracks at the mouth of a horizontal well with an open hole 1 (Fig. 1), the assembly is assembled from bottom to top: telesystem 2, one spiral weighted drill pipe (hereinafter UBT) 3, for example, with a diameter of 127 mm, a wedge-deflector 4.

The assembly is lowered on the tubing string 5, for example, with a diameter of 89 mm, into the main horizontal open hole 1 so that the deflecting wedge 4 is in the interval of sidetracking, for example, in the interval of 1096 m (the installation intervals of the deflecting wedge 4 are determined according to the plan works).

As the deflecting wedge 4, any known deflecting wedge is used, which allows deflecting the tubing string with a layout at an angle of 4.0 ° with respect to the main horizontal open hole 1 of the well.

Using the telesystem and using the geophysical lot, the deflector 4 is oriented in the required direction relative to the main horizontal open hole 1 of the well, for example, to the right by 130 ° (Fig. 2).

Orientation of the deflecting wedge 4 must be carried out in such a way that the lateral trunk being created does not cross the main horizontal open hole 1, i.e. when the azimuth of the main horizontal open hole 1 decreases, sidetracking must be performed to the right, and the deflecting wedge 4 should be oriented to the right (0 ° -180 °).

With an increase in azimuth, sidetracking should be planned to the left and the deflecting wedge 4 should be oriented to the left, sidetracking should be done in the interval of the largest set of curvature of the main horizontal open hole 1, for example 6 °, in order to more intensively remove the created sidetrack from the main horizontal open hole 1.

According to the experience of the work carried out, the greatest removal of drilled sidetracks from the main horizontal open hole 1 was achieved when the layout was oriented to the right at an angle from 0 ° to 180 °. In the process of orienting the layout, the telesystem 2 (Fig. 2) sends a signal to the wellhead (not shown in Fig. 1-6), which the station (in Fig. 1-6 not shown) receives the geophysical batch, simultaneously turn the tubing string 5 with a diameter of 89 mm with the layout from the wellhead to the right with pacing and stopping for 4-5 minutes.

When receiving a signal from the telesystem 2 at the station of the geophysical lot, they reach the planned left direction of 130 ° (Fig. 2) relative to the main horizontal open hole 1 of the well. Next, at the wellhead, the layout is assembled from bottom to top (Fig. 3): milling cutters 6, VZD 7, hydraulic emergency disconnector (GAR) 8. For example, D-55 brand VZD is used, and the milling cutter is 68 mm in diameter.

GAR 8 (shown in FIGS. 4 and 6 conventionally) is made in the form of a hollow body (not shown in FIGS. 1-7), equipped inside with a landing seat fixed with a shear pin to the hollow body. The GAR 8 seating saddle is made under the ball that is discharged from the mouth into the GT 9 column and allows the GT 9 column to be disconnected from the VZD 7 in the event that the assembly is stuck in the drilled sidetrack 10 '.

The assembly is lowered into a tubing string 5 with a diameter of 89 mm on a GT 9 string at a speed of 15 m / min without fluid circulation at the wellhead with pacing every 500 m of descent, 10 m before the estimated interval of sidetracking, reduce the descent rate to 5 m / min

The process fluid is pumped into the GT 9 column (Fig. 3) and the VZD 7 is launched, then 130 ° to the right are cut to the right (Figs. 2 and 3) and a sidetrack 10 'is drilled with a length of 1, equal to 40 m, at an angle of 4 ° with respect to to the main horizontal open hole 1 of the well (for example, in the interval 1096-1136 m, i.e. until the bottom 11 'is reached) with a load on the cutter up to 1.0 t. Process water with a density of 1100 kg / m ³ is used as a process fluid .

Then they stop the drilling process and raise the layout on the GT 9 column, dismantle the layout.

Then a geophysical instrument 12, for example, an autonomous inclinometer AIK-52, is lowered into a well through a tubing string 5 (Fig. 4) with a diameter of 89 mm, a wedge diverter 4 on a GT 9 string, into a drilled sidetrack 10 'before the bottom 11, and the drilled trajectory is recorded the sidetrack 10 ', after which the GT column with the geophysical instrument 12 is removed from the well.

That is, the descent of the autonomous inclinometer AIK-52 mm on the GT 9 investigates the aforementioned drilled sidetrack 10 'with a length of l = 40 m in the interval 1096-1136 m.

According to the results of geophysical studies (in the interval of the drilled sidetrack), the minimum distance - N from the drilled sidetrack 10 'to the level of the oil-and-gas complex is determined (Fig. 4)

The distance from the drilled sidetrack 10 'to the VNK level of less than 5 m is highly likely to lead to a breakthrough of the VNK level.

At a minimum distance from the drilled sidetrack 10 'to the OWC from 5 to 10 m, (for example, the distance from the bottom of 1136 m to the level of the OWC (Fig. 4) is 8 m), a GT 9 with a rotating column is lowered into the tubing string 5 with a diameter of 89 mm spherical nozzle 13 (Fig. 5) at the end to a depth of 1136 m of the drilled face 11 'of the sidetrack 10' and the bottomhole zone of the sidetrack 10 'is treated with hydrochloric acid being injected into the GT 9 column while the GT 9 column is moved up to the side cutoff interval barrel 10 'at a speed of 0.5 m / s, i.e. produce hydrochloric acid treatment of the drilled sidetrack 10 'in the range of 1136-1096 m.

Then remove the GT 9 column with a rotating spherical nozzle 13 at the end of the tubing string 5 with a diameter of 89 mm.

Further, depending on the number of sidetracks 10 ', 10 ⁿ (Fig. 7), the above technological operations are repeated, starting with the assembly assembly: telesystem 2, one UBT 3, wedge deflector 4 - and ending with the extraction of the GT 9 column with a spherical nozzle 13 on the end.

With a minimum distance from the drilled sidetrack 10 'to the OWC of more than 10 m (for example, the distance from the interval of 1107 m to the level of the OWC (Fig. 4) is 15 m), the assembly is assembled from the bottom to the top of the well (Fig. 6): bit 14, Oscillator-Turbulator (OT) 15, VZD 7, GAR 8. For example, use DZ-55 brand VZD, and a bit with a diameter of 68 mm.

Next, the above arrangement is lowered into the well through the tubing string 5, and the deflecting wedge 4 until the bit 14 rests in the bottom 11 '(Fig. 6) of the drilled side trunk 10' and the process fluid is pumped through the GT 9 column, the side stem 10 'is drilled with a load on a bit up to 1.5 tons to a given bottom 11 '' in the work plan indicated, for example, L = 100 m, i.e. in the range of 1096-1196 m.

In the process of drilling a sidetrack 10 ', the use of OT 15 leads to oscillation of low-frequency vibrations of the process fluid pumped through the GT 9 column and to the creation of low-amplitude longitudinal vibrations that contribute to the formation of a dynamic load on the bit 14, which leads to more efficient destruction of the rock and, as a result, an increase in speed penetration of the bit 14. In addition, the bit 14, in contrast to the cutter 6, has the ability to destroy the drilled rock with a radial surface.

Next, a GT 9 column with a rotating spherical nozzle 13 (Fig. 5) is lowered into the tubing string 5 with a diameter of 89 mm, with a rotating spherical nozzle 13 (Fig. 5) at the end to a depth of 1196 m of the drilled face 11 'of the side trunk 10' and the bottom hole is processed along the entire length L of the side trunk 10 ' those. in the range of 1196-1096 m, the injection of a hydrochloric acid solution into the GT 9 column with simultaneous movement of the GT 9 column up to the sidetracking interval 10 'at a speed of 0.5 m / s.

Then remove the GT 9 column with a rotating spherical nozzle 13 at the end of the tubing string 5 with a diameter of 89 mm.

Then, depending on the number of sidetracks 10 ', 10 ⁿ (Fig. 6), the above-described technological operations are repeated starting from the assembly assembly, including the telesystem 2, one spiral-shaped drill collar 3, the wedge-deflector 4, and ending with the extraction of the GT 9 column with a spherical nozzle 13 at the end.

The processing pressure of the bottomhole zone of the sidetracks 10 ', 10 ⁿ may be different for each sidetrack 10', 10 ⁿ depending on the permeability of the rocks. For example, the bottomhole zone of the sidetrack 10 'is treated under a pressure of 8.0 MPa, and the bottomhole zone of the sidetrack 10 ⁿ is treated under a pressure of 10.0 MPa.

During drilling (l = 40 m) or drilling (L = 100 m) of the sidetrack 10 ', it is possible to seize the assembly with GT 9, for example, as a result of shedding of weakly cemented drilled rocks. In order to exclude damage (breakage, extension), the GT 9 string drives the GAR 8. For this, a ball is dropped from the wellhead into the GT 9 string.

The ball along the GT 9 column reaches GAR 8, made in the form of a hollow body, and sits on its landing saddle. Hydraulic pressure is created in the column GT 9, sufficient for the destruction of the pins. For example, create a hydraulic pressure of 8.0 MPa, at which the destruction of the pins. The GT column 9 is removed from the well, and the remaining arrangement remains in the drilled sidetrack 10 '.

Implementation of the proposed method allows the orientation of the lateral wellbores before they are cut from the main horizontal open hole 1 of the well in any direction from 0 to 360 ° (Fig. 2) by 4.0 ° relative to the main horizontal open hole 1 of the well.

Carrying out a geophysical study using an autonomous inclinometer after drilling a part of the lateral wellbore allows us to determine the well’s path relative to the main horizontal open hole 1 of the well and the level of the oil hole (Fig. 4), as well as determine the distance - H from any interval of drilled sidetracks 10 ', 10 ⁿ to VNK level. This is guaranteed to exclude the opening of the aquifer and flooding of the main horizontal open hole.

The efficiency of processing the bottom-hole zone of the sidetracks 10 ', 10 ^{n is} increased by injecting a solution of hydrochloric acid under pressure through a rotating spherical nozzle while moving the GT string at a speed of 0.5 m / s from the bottom to the cutting interval of the drilled sidetracks 10', ... 10 ⁿ , which allows you to remove the clogging of the radial surface of the side shafts 10 ', ... 10 ⁿ after drilling and to expand respectively drilled side shafts 10', ... 10 ⁿ .

The quality of processing of the sidetracks is increased, since the bottom-hole zone of each sidetrack is processed under an individual pressure value.

The material and financial costs associated with the fact that after drilling the main horizontal wellbore there is no need to casing it are reduced. When performing the side boreholes, the cutter is first used sequentially, and then in combination with the bit with the oscillator-turbulator, and then the acid treatment of the bottom-hole zone of the sidetracks 10 ', ... 10 ⁿ , with a rotating spherical nozzle, is performed.

A rotating spherical nozzle allows to increase the efficiency of acid treatment due to radial and uniform action (along the entire perimeter of the sidetracks 10 ', ... 10 ⁿ ) with axial displacement at a speed of 0, 5 m / s by the pressure of the jet of acid on the treated bottom-hole zones of the sidetracks 10', ... 10 ⁿ .

In addition, when a bit sticking occurs in drilled sidetracks, complex emergency operations are eliminated due to the use of GAR 8, which allows the GT string to be removed without breaking, leaving the layout in the stuck sidetrack. All this reduces the duration of sidetracking 10 ', ... 10 ⁿ , which means it saves material and financial costs.

It has been experimentally established that the use of OT increases the mechanical penetration rate when drilling a sidetrack from the horizontal part of an open hole by 40-50%.

The proposed method of drilling sidetracks from the horizontal part of an open hole allows you to:

- to achieve accuracy in orienting the direction of sidetracking to the right relative to the main horizontal uncased wellbore;

- eliminate deviation of the sidetrack during drilling;

- exclude the opening of the aquifer;

- to increase the efficiency of processing the sidetracks of the well with a hydrochloric acid solution using a flexible pipe with a spherical nozzle;

- to improve the quality of processing the bottom-hole zone of the well due to the possibility of separately processing the bottom-hole zone of each side wellbore;

- reduce financial and material costs for the implementation of the method;

- reduce the duration of sidetracking.

Claims (1)

A method of drilling sidetracks from the horizontal part of an uncased borehole, including drilling the main horizontal and sidetracks, acidizing the sidetracks, characterized in that before drilling the sidetracks at the mouth of a horizontal well with an uncased borehole, an assembly is assembled: a telesystem, one weighted drill pipe, a deflecting wedge with an inclination angle of the working surface of 4 °, lowering the layout on the tubing string into the main horizontal open hole so so that the deflecting wedge is in the interval of sidetracking, the deflecting wedge is oriented relative to the main horizontal open-hole wellbore, then the assembly is assembled from the bottom of the wellhead: milling cutter, helical downhole motor (VZD), hydraulic emergency disconnector, lower the assembly into the tubing string on a string of flexible pipes (GT), then make a cut in the direction oriented by the deflecting wedge, and drill a sidetrack 40 m long at an angle of 4 ° relative to the main mountains a horizontal open hole with a cutter load of up to 1.0 t, after which the drilling process is stopped and the layout on the GT string is removed from the horizontal well, then the geophysical instrument is lowered into the tubing string to the bottom of the drilled side trunk on the GT string and determined by the path of the drilled lateral the minimum distance from the drilled lateral trunk to the oil-water contact (OWC), and with a minimum distance from the drilled lateral hole to the OWC from 5 to 10 m, the column G is lowered into the tubing string equipped at the end with a rotating spherical nozzle to the bottom of the drilled side trunk and acidizing the bottomhole zone of the drilled side trunk, they are acidified, with a minimum distance from the drilled side trunk to the drill hole of more than 10 m, a GT column with a high pressure drop, an oscillator-turbulator and a bit are lowered into the tubing string at the end, and continue to drill the sidetrack with a bit load of up to 1.5 tons to the specified bottom, after reaching the bottom of the sidetrack, the drilling process is stopped and the layout is put on the GT from the column The tubing, the GT string is lowered into the tubing string with a rotating spherical nozzle at the end to the depth of the drilled bottom of the side wellbore and the bottom-hole zone of the drilled side-hole is acid treated, and the pressure of the bottom-hole treatment of the side boreholes may be different for each sidebore.

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