The method of forming and fixing the casing branch wellbore
(57) Abstract:The invention relates to the fastening of the wellbore in the formation of branched stem during operation of oil or gas wells. It is aimed at solving the problem of insufficient support at the upper end of the downhole diverter. The method includes the following stages: placement support in the main wellbore at a point below the location of the formed branched stem, installation on a support downhole diverter, cutting a window in the casing of the main wellbore and the beginning of the development of branched stem with the use of a milling cutter, guided by the downhole steering tool; removing the downhole diverter, installation on a support baffle having a main body, the diameter of which is less than the internal diameter of the casing string in the main wellbore, drilling the branch wellbore to the desired depth, the introduction of the casing in the bifurcated wellbore by deflection of the casing from the main wellbore, using the deflector up until the casing will not occupy a position in which the first part of the casing is a branched stem and the second in globalnej columns and cement at the junction of trunks, remove baffle from the main trunk, to reopen the main trunk passage for branched trunk. The invention provides a more effective fastening of the casing. 5 C.p. f-crystals, 13 ill. The present invention relates to a method of forming and securing the casing branch wellbore.It is known that in the operation of oil or gas wells to form one or more branched trunks wells, which are typically known as an "offshoot" of the existing main wellbore. Basically, the main wellbore is vertical, branched stem and each leaf stem departs from the vertical wellbore. However, in some cases, the initial main wellbore may be at an angle to the vertical.International patent application WO 94/03698 describes the various technologies education branched trunks. Usually in the main wellbore is established fixed support slightly below the level of the proposed branch. This can be done by setting the packer in the main wellbore. Then in the main wellbore, stallaert downhole diverter is then used as a guide for one or more of a router, which cut a window in the casing of the main wellbore and cut around the seam until the start of the construction of branched stem that can last, if you do not want further cutting of the casing. The mill, which cuts through the window, can be used for drilling of the reservoir, if you want a relatively short branched trunk. As an alternative, then the router can be removed from the well and into the well insert boring tool. Drilling tool for reservoir will be sent downhole diverter through a window cut in the casing of the main wellbore and drilling the branch wellbore new tool can begin.It was suggested several technologies for education of the window. For example, it was proposed to use the mill of the initial stage of the eruption of the window in the casing string and then replace it with the main mill for cutting larger part of the window. It was also proposed to use combined aggregates cutters for cutting window, such as an end mill and followed by one or more of the mill type cutter for watermelons. In each case, however, it is necessary to perform the track or path, which limited the following drilling branch wellbore at the desired depth, the drilling rig is removed. Then in the bifurcated wellbore can be inserted casing. And again casing will be directed inclined surface borehole standoff, and when the direction of the casing through a window cut in the casing of the main wellbore, branched wellbore almost no difficulty. The above method provides satisfactory results, if the downhole steering tool used to guide the router is also used for the direction of the casing in the bifurcated wellbore. However, there are a number of practical considerations about the undesirability of the use of downhole steering tool for this purpose.Firstly, you may also need to retrieve the downhole diverter for re-use or re-opening of the main wellbore. Obviously, if the fixing casing installed in the branch wellbore, proceeds from a window up in the main wellbore, removing downhole diverter will become impossible after installing the branch wellbore.Secondly, if the downhole diverter is used to direct obego contact between the casing and borehole standoff. The surface downhole diverter long and has a small angle of inclination. This small angle is obtained at the point where the casing is deflected from the main wellbore, heading into the bifurcated wellbore. Accordingly, there may be contact essentially over the entire surface between the casing and at least part of the surface of the borehole standoff. Such contact will cause significant friction when moving the casing string ("puff") and can complicate the installation.Thirdly, if casing for branch wellbore must be cut at the point where it enters the main wellbore, the presence of downhole diverter complicates the operation of cutting. Or casing and the entire downhole diverter must be cut to the appropriate router or, if you use washing equipment or thin mill for cutting the casing, downhole diverter should be so designed to enter the flushing tool or thin mill for cutting casing branch wellbore. This creates limitations when designing downhole diverter, which is Noah columns. For example, referring to the method shown in Fig. 5A-5H application WO 94/03698, it should be noted that the downhole diverter has an external diameter substantially smaller than the internal diameter of the main wellbore. The resulting gap between the borehole whipstock and the casing main wellbore used for thin-wall milling cutter, which is used to remove excess cement and casing branch wellbore. However, the gap provided between the downhole whipstock and the casing of the main wellbore, means that the downhole diverter has no lateral support at its upper end. In practice, the downhole diverter is usually much smaller angle relative to the axis of the main wellbore than in schematic image of Fig. 5A-5H and accordingly the problem of insufficient support at the upper end of the downhole diverter becomes more acute.With the purpose of solving the above problems, the present invention creates a method of forming and fixing the casing branch wellbore, in which after drilling a branch wellbore using a downhole diverter for directing presage wellbore. Direction of the casing lateral wellbore from a main wellbore into the bifurcated wellbore downhole diverter is replaced by a suitable deflector for deflection of the casing from the main wellbore into the bifurcated wellbore. The diameter of the main body of the deflector may be less than the greatest outer overall diameter borehole standoff, which was used initially, and slightly smaller than the inner diameter of the casing of the main wellbore. If necessary, the deflector may be provided with one or more legs that fade out from the main body to engage with the casing of the main wellbore. In the case of using such supports, they can be easily cut during the subsequent removal of the excess of the casing and cement. The use of such a deflector, in particular, promotes the use of removal tools end portion of the casing branch wellbore, which is located in the main wellbore and washing equipment.The above-described method, being very appropriate, as it allows you to remove downhole uklonite the columns, which may be injected into a lateral wellbore. This is because the baffle casing has a diameter less than the inner diameter of the casing string in the main wellbore, and accordingly, the path along which he can change the direction of the casing branch wellbore, is located somewhat closer to the axis of the main wellbore than the path that has done Frazier, varesavi window. As a result, if the casing branch wellbore has a maximum nominal diameter that can pass through the main wellbore, the baffle casing cannot be installed at the point where the casing may pass through the window and branched further into the wellbore.The above problem can be overcome if casing is used for lateral wellbore that is less than the estimated diameter of the milling cutter, which was used for the formation of the hole of the window in the casing string. However, if you want as much as possible the diameter of the casing branch wellbore, created preferred embodiments of the present invention to solve the problems described above. In the first of the casing through the window, which was done previously. At this point, the reservoir, however, will not be cut to such an extent that allows the passage of the casing branch wellbore. Accordingly, this aspect of the present invention provides that after the installation of the baffle casing in the borehole is introduced a suitable tool and directed by the deflector casing trims the seam by combining the main and branched trunks bore opposite the vent. Removing this is achieved quickly and easily, and after removing the tool used for this purpose, and drilling a branch wellbore it can be entered casing, and directed by the baffle it will pass through the window in the bifurcated wellbore.According to the second variant, the baffle casing is installed at the point where there is a sufficient gap in the branch wellbore, providing the possibility of sending the casing branch wellbore in the bifurcated trunk, but where pre-made box is not wide enough for the passage of the casing branch wellbore. After installation of the vent of the casing into the well in tsennogo wellbore is introduced casing branch wellbore and is directed by the deflector through an extended window in the lateral wellbore.Under the third option, use the deflector, in which the surface of the deflector is composed of at least first and second parts of the surface, the first portion of the surface of the deflector passes downwards from the upper end of the deflector below the first relatively large angle to the axis of the deflector, and the second portion of the surface of the deflector passes upward from the full diameter of the baffle inward toward the axis of the deflector at an angle relative to the axis of the deflector, less than the angle of the first side of the baffle. In a preferred embodiment of the invention the first and second side surfaces are adjacent baffle. In other alternative embodiments of one or more additional parts of the surface of the deflector connect the first and second parts of the surface of the baffle between them. If one or more parts of the surface of the baffle between the first part of the surface of the baffle and the second part of the surface of the deflector, the angle, which is an additional part of the surface of the deflector is formed with the axis of the deflector increases progressively along the length of the surface of the deflector from the upper end of the deflector to its full diameter.The invention will become more clear from the m examples with reference to the accompanying drawings, are:
Fig. 1 schematically depicts the formation of a branch wellbore using a milling cutter, guided by the downhole diverter;
Fig. 2 shows the baffle casing installed in the well, shown in figure 1, after removal of the downhole diverter;
Fig. 3, 3A, 3B illustrate the problem of direction of the casing in the bifurcated wellbore with a deflector casing installed in the position shown in this figure;
Fig. 4, 4A, 4B depict an alternative position of the deflector casing;
Fig. 5 depicts an embodiment of a deflector;
Fig. 5A, 5B, 5C and 5D are schematic representation of cross-sections of figure 5 is shown in figure 5, the lines A-A, B-B, C-C, D-D.In Fig. 1 shows a shaft 1 well, which is fixed conventional steel casing 2. In the casing 2 has a suitable bearing, such as an anchor or downhole packer (not shown), to create a fixed bearing for the formation of branched stem 3. Downhole diverter 4 based via respective adapters, including the collector 5 for scrap, packer and creates a guide surface 6 for the direction the cutter is the expert in this field, required branched wellbore formed by the cutting of the casing 2 to form a window, after the drilling of the surrounding formation. The result is the passage, one side of which is formed by a surface 6 of the downhole steering tool, the diameter of the passage corresponds to the baseline diameter of the milling or drilling system. As it is clear to the experts, during the cutting operation, the upper end of the downhole diverter 4 abuts against the casing 2, and the largest outer diameter of the downhole diverter is the maximum of the casing 2 to provide maximum rigidity downhole diverter and maximum support for Fraser 7.As mentioned above, if the casing is inserted into the bifurcated shaft 3 wells along the surface 6 of the downhole diverter, there is no special problems. However, this eliminates the removal of the downhole diverter that leads to well-known problems.Accordingly, after drilling branched stem 3 of the well to the desired depth, preferably, the downhole diverter remove and replace it with the vent 8 of the casing, as shown in Fig. 2. The baffle is the ETP of the casing 2. Accordingly, around the baffle 8 there is an annular space. This space facilitates the use of a drilling tool when the cutting of the casing branch wellbore, which remains in the main wellbore after casing is inserted to the desired depth in the bifurcated wellbore. Although shown in solid annular space around the baffle 8, it should be understood that, if desired, can be used one or more relatively small supports, for example, at the upper end of the baffle for engagement with the wall of the casing and providing a support for the vent at this point. If you are using such support, they will be made in the form of relatively small protrusions extending from the main body of the deflector, and will be cut during subsequent retrieval operations.In Fig. 3 illustrates the problem with trying to send branched casing 10 side of the wellbore in the bifurcated shaft 3. If casing could be installed in the position shown, in which the left lower edge of the casing (as shown in Fig. 3) based on outside diameter poperechnyy cross-section along the line x-X of Fig. 3. However, the side casing 10 branch wellbore may not be installed in this position with the introduction of the leading edge of the casing on the inclined surface 9 of the deflector 8. This is because the width of the window casing at the point of the cross section V-V of insufficient diameter of casing 10 branch wellbore, which will take place at this point, as shown in Fig. 3B, which depicts a cross section V-V placed over it a position that the front edge of the casing 10 branch wellbore would if she had to rely on an inclined surface 9 in section V-V. it Will be seen that the diameter of the casing at the window exceeds the hole of the window at this point.One obvious solution to this problem is to install the surface 9 of the deflector 8 is even higher, by inserting a suitable adapter 11 under the deflector 8 of the casing. This device is shown in Fig. 4. It is seen that in this case, despite the fact that the aperture window is large enough for the passage of the casing (Fig. 4B), at the point where the inclined surface 9 comes in contact with the full diameter of the deflector 8, the gap 12 is insufficient (Fig. 4A) for the passage absat pass through the window casing branch wellbore, casing immediately stuck on the surface of the leaf stem 3 wells, and further movement of the casing will become impossible.To solve the described problems, preferred embodiment of the present invention offers the possible ways.First, if the deflector 8 is, as shown in Fig. 3, i.e. at the point where the gap 12 between the full diameter of the deflector 8 and the opposite wall of the branched stem 3 wells sufficient for the casing 10, the sections of the casing 2, which will prevent the passage of the casing 10 along the surface 9 of the deflector can be removed using a suitable tool. For example, in the well is introduced a suitable mill and is directed along the surface 9 to cut off the ends of the casing 2, which form the window, to the extent sufficient to ensure that the entry clearance to the casing 10 when it is moving upward along the surface 9.As another option, you can install the deflector 8 in the position shown in Fig. 4, i.e. in the position where the passage of the casing 10 branch wellbore through the window, when it rises on the surface 9, is provided with window, Kott into the well, to cut the seam opposite the lower end surface 9 to increase the gap 12 to a size sufficient to accommodate the casing 10. Such a tool can be moved along the surface 9 through the pre-cut window to enter the seam and trim it as needed. Then the tool can be removed, and along the surface 9 through the window and through the advanced gap 12 to insert the casing 10 in the bifurcated shaft 3 wells.Any of the methods described above overcomes the difficulties encountered in the previous prior art. However, at present it is believed that the method, according to which cut off the reservoir to the expansion of the gap 12, the preferred method of cutting the casing 2 to extend the window that was made previously.In Fig. 5 and 5A-5D shows another solution to the problem described above, by using the baffle 20, which has the surface of the deflector is composed of the first part 21 of the surface of the baffle and the second part 22 of the surface of the deflector. The first part 21 of the surface of the deflector passes from the upper end of the tool to the point 23 where it connects with the second part 22 of the surface of the deflector. The second part 22 of the surface of the Def is Ino pre-cut window casing so that casing lateral wellbore, focusing on the parts 21, 22 of the surface of the deflector may pass through a pre-cut window casing main wellbore. Until now the device shown in Fig. 5, corresponds to the device shown in Fig. 4. However, dividing the surface of the deflector to the first and second parts, the first part takes place at a large angle relative to the axis 25 of the deflector than the angle of the second part, the degree of the boundary surface between the casing branch wellbore and the wall 26 of the reservoir opposite the surface of the deflector is substantially reduced. Therefore, should be removed relatively small reservoir, to allow the casing string branch wellbore to enter into a lateral wellbore through the guide surfaces 21, 22 of the deflector. A relatively small number of layer, which should be deleted, but deleted the appropriate equipment to install the branch wellbore.Regardless of which of the above methods is used to install the casing branch wellbore within the branch wellbore, the construction titlevi casing branch wellbore is selected such that that part of the casing branch wellbore will remain in the main wellbore after casing branch wellbore is fully seated in the sidetrack. Then around casing branched stem in the usual way is cementing at least in the area of the branch wellbore adjacent to the main well bore and around a portion of the casing branch wellbore in the main wellbore adjacent to the branched trunk. In other words, the area of the junction between the main trunk and branch the wellbore is cement, starting from a level above the point where the bifurcated wellbore branches off from the main wellbore and further, to point at a distance from the main wellbore.Then in the main wellbore enter the appropriate tool, such as a washing tool or thin mill, to remove an annular zone of material having an outer diameter equal to the inner diameter of the casing 2 of the main wellbore. The deleted material is composed of cement, located in the main wellbore, the material of the casing where it passes che who eat casing, will be placed inside of the washing tool or thin-walled mill. After processing the annular space is completed, the flushing tool or thin mill can be removed, taking with him part of the material of casing pipes branch wellbore, which remained in the main wellbore at the beginning of the cementing operation. The deflector and, if necessary, located below the packer can then be removed using conventional methods. As a result, the full diameter of the main wellbore will be re-opened for the passage of equipment for branched wellbore. At the same time, the inner diameter of the casing lateral wellbore is possible, given the fact that the external diameter of the casing branched stem must have a clearance, allowing him pinning inside the casing of the main wellbore. 1. The method of forming and fixing the casing branch wellbore, comprising the following stages: placement support in the main wellbore at a point below the location of the formed branched stem; the installation on the support of the downhole steering tool; cutting of octera, directed downhole steering tool; removing the downhole diverter; installation on a support baffle having a main body, the diameter of which is smaller than the internal diameter of the casing string in the main wellbore; drilling the branch wellbore to the required depth; the introduction of the casing in the bifurcated wellbore by deflection of the casing from the main wellbore using a deflector up until the casing will not occupy a position in which the first part of the casing is a branch wellbore, and the second part of the casing is located in the main wellbore; cementing around these parts of the casing; remove ring of material from the main wellbore to separate the casing and cement at the junction between the main wellbore and the branch wellbore; removing the baffle from the main wellbore to reopen the main well bore for passage for branched wellbore.2. The method according to p. 1, including the removal of material from the casing main wellbore or from the reservoir after the installation of the baffle, but prior to installation of the casing branched stem SLE is Elenovo wellbore passes through the window, made by a mill, and including the additional step of removal of the reservoir from the branched wall of the wellbore in the zone of the window after you installed the baffle to ensure the passage of the casing in the bifurcated wellbore.4. The method according to p. 1, in which the deflector is positioned so that in the branch wellbore is formed a gap for the passage of the casing branch wellbore during its entry into the branched borehole, and including the additional step of increasing the window by removing excess casing from the main wellbore after it has been installed deflector, to ensure the passage of the casing in the bifurcated wellbore.5. The method according to any of paragraphs.1, 2 and 4, which use a deflector having a deflecting surface containing the first portion of the surface of the deflector, passing down from the upper end of the deflector below the first relatively large angle to the axis of the deflector, and the second part of the surface of the deflector, passing upward from the full diameter of the baffle inside to the axis of the deflector at an angle relative to the axis of the deflector, which is less than the angle of the first side surface of the deflector.
FIELD: mining industry.
SUBSTANCE: device has two bodies, laced between drilling pipes and rock-destroying element, drilling assembly changing assembly, mounted between bodies. Bodies are placed at a space between each other and interconnected moveably by drill angle changing assembly, made in form of bushing, inside of which a rubber bushing is placed, passing through inner hollows of bodies. Rubber bushing is provided with compacting element and elements for excluding its deformation. Value of space is selected from condition providing for drilling along planned trajectory, providing for exit from slanting portion into horizontal. Elements for excluding deformation of rubber bushing are made in form of steel rings. Fixing elements are made in form of two pairs of coaxial stops in lower and upper bodies respectively at angle of 90° to each other.
EFFECT: higher productiveness.
2 cl, 1 ex, 1 dwg
FIELD: drilling equipment.
SUBSTANCE: device has body, shaft, mounted in body on bearings, drive made in form of hollow spring-loaded rod with outer slits, movement converter made in form of outer bushing with spiral grooves, interacting with response shelves of inner hollow bushing, piston with compaction, spring-loaded ring, provided with slits and toothed half-sleeve. Outer bushing of movement converter is connected to body, and inner one is connected to piston and provided with toothed half-sleeve, interacting with toothed half-sleeve of spring-loaded rod. Rod spring is supported by body via stop ball bearing. Spring-loaded ring, interacting to response half-sleeve of shaft by toothed half-sleeve, is engaged with body by slits.
EFFECT: higher reliability.
FIELD: mining industry.
SUBSTANCE: drilling toll has body with thread and inner washing channel, as well as matrix, contacting pin by its inner surface and having outer end spherical surface, provided with rock-destroying means. Pin in body is mounted coaxially. Outer end spherical surface of matrix with rock-destroying means is made with diameter equal to outer diameter of drilling toll, and inner surface of matrix and outer surface of pin are made spherical, centers of which coincide with center of outer end spherical surface of matrix. Between inner surface of matrix and spherical pin, balls are mounted in recesses of contact surfaces. Recesses for balls made in matrix are elongated in vertical directions from ball center for distance L=(R+r)tgΨ, where R - radius of pin spherical outer surface, m; r - ball radius, m; Ψ - maximally possible angle of matrix rotation in vertical plane, in degrees.
EFFECT: higher reliability.
FIELD: oil and gas industry.
SUBSTANCE: device has body, provided with anchor, lowered on pipes to given depth, having guide and ring-shaped compaction of hydro-drive, and also made with possible displacement inside pipes and body by displacement means, hydraulic engine, passing through compaction, hollow of which is connected to destroying tool hollow, consisting of flexible shaft, provided with destroying head. Device also has tool for destroying casing column and tool for destroying rock, while hydro-drive consists of hollow leading and following shafts, made with possible rotation and longitudinal movement of the latter inside leading shaft until mounting in socket of leading shaft, forming non-pressurized couple cylinder-piston, while torque from leading shaft to following shaft is passed via ratchet gear, body has hydraulic channel, connecting guide hollow to ring-shaped well space, while on the side, opposite to output aperture of guide hydraulic deflector of piston-cylinder type is mounted on it, and in upper portion of body a cylindrical recess is present, made with possible hermetic mounting of leading shaft with rotation, while outside the body an anchor is mounted, being in threaded connection to sub connected to body, and engine is made with possible hermetic mounting in ring-shaped compaction, mounted above recess in body at a distance, lesser than total length of engine and leading shaft, while on the inner surface of body a stop is mounted made with possible interaction with shelves on outer surface of engine body. For making perforation channels in abrasive rocks rock-destroying tool is used, consisting of flexible shaft and chisel. As movement means flexible pipes are used, hollow of which connects to engine hollow.
EFFECT: higher reliability, higher efficiency.
7 cl, 5 dwg
FIELD: oil production, particularly for drilling oil and gas well cluster.
SUBSTANCE: method involves lowering pipe string into casing pipe, wherein pipe string has deflector connected to one end thereof; opening-out casing pipe within the necessary range; alternately lowering flexible tube having nozzle in pipe string up to reaching opened-out casing pipe area under the action of the deflector; supplying high-pressure liquid through flexible tube having nozzle simultaneously with translation thereof for necessary length to form additional well bores; initial removing flexible tube from pipe string and turning pipe string with deflector through necessary angle to obtain required number of additional well bores; final removing flexible pipe with nozzle out of casing pipe. The casing pipe is opened-out over the full diameter thereof within the necessary range and after casing pipe opening deflector is installed in opened area. After additional well bore forming and before pipe string with deflector rotation flexible tube with nozzle is removed from opened-out area of casing pipe.
EFFECT: reduced number of round-trip operations for well cluster forming under the action of liquid head and, as a result, reduced costs.
FIELD: drilling equipment, particularly for directional drilling, namely control devices adapted to control angle and reactive moment.
SUBSTANCE: control device has hollow central member and three hollow tubular noncoaxial members connected to hollow central member. Inner member is disposed in center between the first and the second members. The first and the second members are connected with inner members by threaded connection. The first member is connected to spindle by threaded coupling, the second member is attached to engine body by threaded coupling and central member is connected to inner member by spline. Each of central member and the first member are provided with sectional contact seats located from spindle connection side, wherein a pair of sectional contact seats arranged from either sides of meridional spindle plane in drilling string curvature plane are defined between central and the first members. Sectional contact seats defined between central and the first members are spaced a distance L from the nearest edges of sectional contact seats of central and the first members along central axis of the first member. The distance L is more or equal to spindle diameter D. Angular deviation of the sectional contact seat formed in the first member from meridian spindle plane in drilling string curvature plane is oppositely directed relative reactive drilling bit moment.
EFFECT: increased stability and angle of gerotor engine deflection and increased accuracy of non-uniform well bottom zone penetration.
2 cl, 10 dwg
FIELD: oil and gas well drilling equipment with the use of hydraulic downhole motors.
SUBSTANCE: support-and-centering member is made as metal hub with blades connected to spindle connector. Spindle connector has support cone formed on outer surface thereof and adapted to provide rigid connection with metal hub from inner surface thereof. Support cone of the connector is formed from side of conical thread connecting spindle body with connector. Spindle connector has splines to connect thereof with metal hub. Metal hub is pressed with pressing cone, retaining washer and nut from another side thereof. Metal hub may be installed concentrically or eccentrically to spindle connector axis or outer surface thereof may be differently shaped and arranged eccentrically, concentrically or obliquely with respect to spindle connector axis.
EFFECT: reduced costs of spindle usage.
FIELD: drilling equipment, particularly for deflecting the direction of boreholes.
SUBSTANCE: device includes deflecting wedge with fastening mechanism made as corrugated tube with one sealed end and sub disposed between deflecting wedge and fastening mechanism. Device also has channel to supply fluid into corrugated tube, movable joint between sub and wedge and cutting tool. Device also comprises holding unit for deflecting wedge installed in the sub and made as a piston with rod and fixing means arranged in hydraulic cylinder. Hydraulic cylinder interior communicates with that of corrugated tube. Upper rod part is installed to cooperate with lower part of the wedge from guiding plane side. Channel for flushing fluid supplying is made as hydraulic line connecting drill pipe interior and that of cutting tool with corrugated tube interior, wherein the cutting tool is secured to upper part of deflecting wedge by means of shear bolt.
EFFECT: increased rigidity of deflecting wedge fixation in casing pipe of the well.
3 cl, 2 dwg
FIELD: well construction, particularly to built cluster wells.
SUBSTANCE: method involves lowering pipe string provided with deflector on end thereof in casing pipe; perforating the casing pipe within previously selected interval; performing the following alternating operations including lowering flexible pipe with nozzle in casing string into above perforation area under the action of the deflector, supplying pressurized liquid through flexible pipe with nozzle, translating thereof to form additional well bores having predetermined depths and lifting the flexible pipe after the predetermined number of well bores forming, finally removing the flexible pipe from the casing pipe. Before casing pipe lowering casing pipe is provided with retained guide. The guide includes process case with through orifices and bush. Formed on inner surface of process case are guiding slots and cylindrical recess located in through orifice area. The bush is inserted in the recess to seal through orifices. The bush is restricted from axial downward displacement by rest. During the lowering operation performing through orifices are arranged within above perforation interval and casing pipe is secured, deflector provided with a number of guiding channels and spring-loaded inserts displaces the bush up to the rest and the spring-loaded inserts cooperate with guiding slots to bring outlet orifices of guiding channels in register with through orifices. To obtain demanded number of well bores flexible pipe with nozzle is removed only from pipe string and deflector after each additional well bore creation.
EFFECT: reduced number of trip operations during well construction.
4 dwg, 1 ex
FIELD: oil and gas production industry, particularly multilateral well construction.
SUBSTANCE: method involves lowering pipe string provided with diverter at end thereof; cutting casing pipe within predetermined interval; lowering flexible pipe with nozzle until flexible pipe enters into opened casing pipe zone under the action of the diverter in alternation with supplying pressurized liquid via flexible pipe provided with nozzle; performing translational flexible pipe movement to create additional well bores having necessary lengths along with removing the flexible pipe to create predetermined number of additional bores. Before casing pipe lowering in the well the casing pipe is provided with acid-soluble insert arranged opposite to formation to be opened. Casing pipe cutting is performed around the full perimeter thereof for necessary length within predetermined opening interval by solving the acid-soluble insert during acid supplying through pipe string into above predetermined interval. After that the diverter having several diverting channel is installed in the interval. After each additional well bore forming flexible string with nozzle is removed only from the pipe string and diverter to create predetermined number of additional bores. After that the flexible pipe with nozzle is finally removed from the casing pipe.
EFFECT: reduced number of trips.