A coiled tubing lateral drilling method

Abstract

This invention relates to a coiled tubing sidetracking method, comprising the following steps: S1, when the original wellbore contains crude oil tubing, a directional drilling rig is installed in the original wellbore using a coiled tubing directional drilling system, passing through the crude oil tubing; when the original wellbore does not contain crude oil tubing, a directional drilling rig is installed in the original wellbore using a tubing string directional drilling rig system; S2, after the directional drilling rig is set in the original wellbore, when the sidetracking point is located in the casing section of the original wellbore, a window opening operation is performed in the casing section of the original wellbore using a coiled tubing connection to a window opening tool string, and after the window opening operation is completed, test drilling continues; when the sidetracking point is located in the open hole section of the original wellbore, a test drilling operation is performed in the open hole section of the original wellbore using a coiled tubing connection to a window opening tool string; S3, after the window opening operation and test drilling operation are completed in the original wellbore, a formation drilling tool string is used to drill into the formation using a coiled tubing connection. This invention facilitates the achievement of the goal of installing a directional drilling rig, opening a window, and drilling in a single trip using coiled tubing sidetracking.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of drilling technology, in particular to a coiled tubing through tubing sidetracking method. BACKGROUND

[0002] The current coiled tubing sidetracking technology has become one of the important technologies for sidetracking old wells in oilfields. The coiled tubing directional sidetracking in 5.5in casing has been carried out in the field in China, which fully demonstrates the characteristics of fast coiled tubing tripping, continuous circulation, and pressure operation. However, the current domestic coiled tubing sidetracking is carried out after the oil / gas pipe string in the wellbore is tripped out, which has the following three defects:

[0003] Firstly, the existing wellbore tubing string needs to be tripped out, which requires the cooperation of a conventional workover rig, increasing the operation cost and cycle;

[0004] Secondly, directly using coiled tubing to sidetrack in a large-diameter casing requires a larger diameter coiled tubing, and the coiled tubing equipment is also more large-scale, resulting in equipment that is too wide, too high, and too heavy;

[0005] Thirdly, the combination of the wellbore and coiled tubing sizes in shallow wells is applied in deep wells, considering the limitation of the drum capacity, the pipe diameter of the long coiled tubing is small, and it is difficult to move the cuttings and transfer the drilling pressure during drilling in deep wells, so the coiled tubing drilling technology is limited in deep wells. SUMMARY

[0006] In order to solve one or more of the above technical problems, the present application provides a coiled tubing through tubing sidetracking method.

[0007] The technical scheme for solving the above technical problems is as follows: a coiled tubing through tubing sidetracking method, comprising the following steps:

[0008] S1, when the original wellbore has an oil pipe, a coiled tubing whipstock system is used to pass through the oil pipe and lower a whipstock into the original wellbore; when the original wellbore does not have an oil pipe, a tubing string whipstock system is used to lower a whipstock into the original wellbore;

[0009] S2, after the whipstock is set and sealed in the original wellbore, when the sidetracking point is located in the casing section of the original wellbore, a coiled tubing connected windowing tool string is used to perform windowing operation on the casing section of the original wellbore; when the sidetracking point is located in the open hole section of the original wellbore, a coiled tubing connected windowing tool string is used to perform drilling operation on the open hole section of the original wellbore;

[0010] S3, after the windowing operation and drilling operation in the original wellbore are completed, a coiled tubing connected formation drilling tool string is used to drill the formation.

[0011] The continuous pipe lateral drilling method of the present application promotes continuous pipe lateral drilling to further reduce cost and increase efficiency, realizes the goal of drilling in one trip, and promotes continuous pipe drilling technology to expand to a wider drilling field, realizes smaller continuous pipe strings and more branch small hole drilling, reduces the use of workover machines and other supporting equipment, and promotes the realization of smaller size hole underbalanced continuous pipe drilling.

[0012] Based on the above technical solutions, the present application can be further improved as follows.

[0013] Further, the continuous pipe whipstock system comprises a connector, a motor head, a direction finder, an azimuth instrument and a whipstock, the connector is used for connecting with the end of the continuous pipe, the motor head, the direction finder, the azimuth instrument and the whipstock are connected in series, and the motor head is connected with the connector.

[0014] The beneficial effect of the above further scheme is that the connector is connected with the end of the continuous pipe, and the whipstock can be lowered into the original wellbore by using the continuous pipe.

[0015] Further, in S1, when the original wellbore is provided with a crude oil pipe, the lowering of the whipstock into the original wellbore by using the continuous pipe whipstock system comprises the following steps: suspending the crude oil pipe from the wellhead Christmas tree, installing a well control device on the wellhead Christmas tree, connecting the four-gate blowout preventer of the continuous pipe with the well control device through the wellhead cross, connecting the other two interfaces of the wellhead cross with the choke manifold and the kill manifold, respectively, connecting the four-gate blowout preventer, the continuous pipe blowout preventer and the blowout pipe with the injection head, butt-jointing the continuous pipe with the drum of the continuous pipe truck, connecting the end of the continuous pipe with the connector of the continuous pipe whipstock system, making the continuous pipe whipstock system pass through the injection head, the blowout pipe, the blowout preventer, the wellhead cross, the well control device and the crude oil pipe in sequence, and lowering the whipstock into the predetermined position, and then adjusting the azimuth of the whipstock by using the direction finder according to the measurement value of the azimuth instrument, and completing the setting of the whipstock in the original wellbore.

[0016] The beneficial effect of the above further scheme is that when the continuous pipe is lowered and passes through the crude oil pipe, the well control device needs to be connected in advance to prevent well control accidents.

[0017] Further, in S1, the output shaft of the direction finder in the continuous pipe whipstock system can rotate relative to the body of the direction finder, and the azimuth instrument and the whipstock connected with the output shaft of the direction finder also rotate, and when the measurement value of the azimuth instrument shows that the azimuth of the whipstock meets the design requirement, the whipstock is set.

[0018] Further, the tubing string whipstock system comprises a tubing string, a matching tool, an azimuth instrument and a whipstock, the matching tool is connected with the end of the tubing string, the azimuth instrument is connected with the matching tool, and the whipstock is connected with the azimuth instrument.

[0019] The beneficial effect of the further scheme is that the matching tool is used to connect the tubing string, and the tubing string is used to lower the whipstock in the well.

[0020] Further, in S1, when the original wellbore does not have a crude oil pipe, the whipstock system is used to lower the whipstock in the original wellbore, which comprises the following steps: installing a well control device on the wellhead Christmas tree, then lowering the whipstock to a predetermined position by using the tubing string whipstock system, then rotating the tubing string at the wellhead to adjust the azimuth of the whipstock according to the measurement of the azimuth instrument, and finally completing the setting of the whipstock in the original wellbore; suspending the tubing string as a coiled tubing drilling string on the Christmas tree, connecting the four-gate blowout preventer with the well control device through the wellhead cross, connecting the other two interfaces of the wellhead cross with the choke manifold and the kill manifold, connecting the four-gate blowout preventer, the coiled tubing blowout preventer box, the blowout pipe and the injection head, and connecting the coiled tubing with the drum of the coiled tubing truck.

[0021] Further, the windowing tool string comprises a connector, a motor head, a deflector, a screw drill and a milling bit, the connector is connected with the end of the coiled tubing, the motor head, the deflector, the screw drill and the milling bit are connected in sequence, and the motor head is connected with the connector.

[0022] Further, in S2, when the sidetracking point is located in the cased well section in the original wellbore, the coiled tubing is used to connect the windowing tool string to perform the windowing operation on the cased well section in the original wellbore, which comprises the following steps: the windowing tool string mills the casing along the guide surface of the whipstock, and after completing the casing windowing, continues to perform the drilling operation on the formation.

[0023] When the sidetracking point is located in the open hole section in the original wellbore, the coiled tubing is used to connect the windowing tool string to perform the drilling operation on the open hole section in the original wellbore, which comprises the following steps: the windowing tool string performs the drilling operation on the open hole section in the original wellbore along the guide surface of the whipstock.

[0024] Further, the formation drilling tool string comprises a connector, a motor head, a deflector, a borehole trajectory measuring tool, a screw drill and a milling bit, the connector is connected with the end of the coiled tubing, the motor head, the deflector, the borehole trajectory measuring tool, the screw drill and the milling bit are connected in sequence, and the motor head is connected with the connector.

[0025] Further, in S3, the formation is drilled by connecting the formation drilling tool string with the coiled tubing, including: the formation drilling tool string passes through the new wellbore drilled by the windowing tool string, continues to drill the formation at the well bottom, the wellbore trajectory is fed back in real time by the wellbore trajectory measuring tool during the formation drilling, the tool face angle is adjusted in real time by the orienter, and the formation is directionally drilled to the target.

[0026] The coiled tubing through tubing sidetracking method of the present application utilizes the production tubing string of the original wellbore (i.e. the original tubing), or when the original wellbore has no original tubing, a tubing string is newly lowered into the larger casing of the original wellbore. The whipstock is lowered into the original tubing with the coiled tubing, or the whipstock is lowered into the tubing string, and then the casing and the formation are windowed by the coiled tubing with a milling bit, and the drilling data and the wellbore trajectory are identified by the inclination trajectory measuring tool in the tool string, and the tool face angle is adjusted by the orienter in the coiled tubing drilling tool to reach the target of the wellbore design trajectory. When the first wellbore sidetracking is completed, the whipstock is reversed by the coiled tubing or the tubing string, and more branch wellbores are drilled. By switching the coiled tubing whipstock system (or the tubing string whipstock system), the windowing tool string and the formation drilling tool string, more sizes of coiled tubing can be selected to meet the sidetracking construction requirements, the purpose of coiled tubing sidetracking short radius / ultra-short radius wellbores is achieved, and the cost of old well sidetracking is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The structure diagram of the coiled tubing through tubing sidetracking method of the present application is shown in the figure.

[0028] Figure 2 The structure diagram of the coiled tubing whipstock system of the present application is shown in the figure.

[0029] Figure 3 The structure diagram of the tubing string whipstock system of the present application is shown in the figure.

[0030] Figure 4 The structure diagram of the windowing tool string of the present application is shown in the figure.

[0031] Figure 5 The structure diagram of the formation drilling tool string of the present application is shown in the figure.

[0032] In the drawings, the components represented by the respective reference numerals are listed as follows:

[0033] 1. Coiled tubing truck; 2. Coiled tubing; 3. Injection head; 4. Coiled tubing blowout preventer box and blowout preventer pipe; 5. Four-gate blowout preventer; 6. Wellhead four-way valve; 7. Well control unit; 8. Original wellbore; 9-1. Oil tubing; 9-2. Tubing string; 10. Directional switch; 11-1. Coiled tubing directional switch system; 11-2. Tubing string directional switch system; 11-3. Window opening tool string; 11-4. Formation drilling tool string; 12. New wellbore; 13. Connector; 14. Motor head; 15. Directional switch; 16. Azimuth measuring instrument; 17. Matching tools; 18. Screw drill string; 19. Milling drill bit; 20. Wellbore trajectory measurement tool. Detailed Implementation

[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0035] Example 1

[0036] This embodiment describes a method for side-drilling through coiled tubing, such as... Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, it includes the following steps:

[0037] S1, when the original wellbore 8 has crude oil pipe 9-1, the inclined device 10 is installed in the original wellbore 8 by using the continuous tubing directional device system 11-1 through the crude oil pipe 9-1.

[0038] S2, After the directional drilling tool 10 is set in the original wellbore 8, when the side drilling point is located in the casing section of the original wellbore 8, the window opening tool string 11-3 is connected to the coiled pipe 2 to perform window opening operation on the casing section of the original wellbore 8.

[0039] S3. After the window opening and test drilling operations are completed in the original wellbore 8, the formation drilling tool string 11-4 is connected to the coiled tubing 2 to drill the formation.

[0040] Specifically, such as Figure 2 As shown, the coiled tubing directional guide system 11-1 of this embodiment includes a connector 13, a motor head 14, a directional guide 15, a azimuth measuring instrument 16, and a directional guide 10. The connector 13 is used to connect to the end of the coiled tubing 2. The motor head 14, the directional guide, the azimuth measuring instrument 16, and the directional guide 10 are connected in series. The motor head 14 is connected to the connector 13. By connecting the connector to the end of the coiled tubing, the directional guide can be lowered into the existing wellbore using the coiled tubing.

[0041] like Figure 1As shown in S1, when the original wellbore 8 has an oil pipe 9-1, the inclined device 10 is installed in the original wellbore 8 through the oil pipe 9-1 using the coiled tubing directional system 11-1. This includes: suspending the oil pipe 9-1 from the wellhead tree; installing the well control device 7 on the wellhead tree; connecting the four-valve blowout preventer 5 of the coiled tubing to the well control device 7 via the wellhead four-way connector 6; connecting the other two ports of the wellhead four-way connector 6 to the choke manifold and the kill manifold, respectively; connecting the four-valve blowout preventer 5, the coiled tubing blowout preventer box to the blowout preventer pipe 4 and the injection head 3; and then... Pipe 2 connects to the roller of coiled tubing 1, and the end of coiled tubing 2 connects to connector 13 of coiled tubing directional guide system 11-1. This allows coiled tubing directional guide system 11-1 to sequentially pass through injection head 3, coiled tubing blowout preventer box and blowout preventer pipe 4, four-gate blowout preventer 5, wellhead four-way connector 6, well control device 7, and crude oil tubing 9-1, lowering the directional guide 10 to the predetermined position. Subsequently, the orientation device 15 adjusts the orientation of the directional guide 10 using motor head 14 based on the measurement values ​​from the orientation measuring instrument 16, completing the setting of the directional guide 10 in the original wellbore 8. When the coiled tubing is lowered and passes through the crude oil tubing, the well control device must be connected first to prevent well control accidents.

[0042] Specifically, in the continuous tube inclinometer system 11-1, the output shaft of the inclinometer 15 can rotate relative to the inclinometer 15 itself. The azimuth measuring instrument 16 and the inclinometer 10 connected to the output shaft of the inclinometer 15 also rotate. When the measurement value of the azimuth measuring instrument 16 shows that the azimuth of the inclinometer 10 meets the design requirements, the inclinometer 10 is set.

[0043] like Figure 4 As shown, the window opening tool string 11-3 includes a connector 13, a motor head 14, an orienter 15, a screw drill 18, and a milling drill bit 19. The connector 13 is used to connect to the end of the continuous pipe 2. The motor head 14, the orienter 15, the screw drill 18, and the milling drill bit 19 are connected in series. The motor head 14 is connected to the connector 13.

[0044] In S2, when the side drilling point is located in the casing section of the original wellbore 8, the window opening tool string 11-3 is connected to the coiled tubing 2 to perform window opening operation on the casing section of the original wellbore 8, including: the window opening tool string 11-3 mills the casing along the guide slope of the directional tool 10, and after the casing window is opened, drilling continues to the formation.

[0045] like Figure 5As shown, the formation drilling tool string 11-4 includes a connector 13 for connecting with the end of the coiled tubing 2, a motor head 14, a deflector 15, a borehole trajectory measuring tool 20, a screw drill 18, and a milling bit 19, which are connected in series, and the motor head 14 is connected with the connector 13. In S3, the formation is drilled by the formation drilling tool string 11-4 connected by the coiled tubing 2, including that the formation drilling tool string 11-4 passes through the new borehole 12 drilled by the windowing tool string 11-3, and continues to drill the formation at the bottom of the well, and the borehole trajectory is fed back in real time by the borehole trajectory measuring tool 20 during the formation drilling, and the tool face angle is adjusted in real time by the deflector 15, so as to realize the directional drilling of the formation. The borehole curvature radius is determined by the whipstock 10, the diameter of the oil pipe 9-1, the bendable passability of the borehole trajectory measuring tool 20, and the bending angle of the screw drill 18.

[0046] The coiled tubing through tubing sidetracking method of the embodiment promotes the cost reduction and efficiency increase of the coiled tubing sidetracking well, realizes the goal of drilling the whipstock in one trip, drilling the window in one trip, and drilling the formation in one trip, and promotes the expansion of the coiled tubing drilling technology to a wider drilling field. The coiled tubing whipstock system can realize a smaller coiled tubing size, reduces the use of supporting equipment such as a workover rig, and promotes the realization of smaller size borehole underbalanced coiled tubing drilling.

[0047] Embodiment 2

[0048] A coiled tubing through tubing sidetracking method of the embodiment, as shown in Figure 1 、 Figures 3-5 includes the following steps:

[0049] S1, when the oil pipe 9-1 is not left in the original wellbore 8, the whipstock 10 is lowered into the original wellbore 8 by using the tubing string whipstock system 11-2;

[0050] S2, after the whipstock 10 is set in the original wellbore 8, when the sidetracking point is located in the open hole section in the original wellbore 8, the open window tool string 11-3 connected by the coiled tubing 2 is used to perform a drilling test operation on the open hole section in the original wellbore 8;

[0051] S3, after the windowing operation and the drilling test operation are completed in the original wellbore 8, the formation is drilled by using the formation drilling tool string 11-4 connected by the coiled tubing 2.

[0052] As shown in Figure 3As shown, the tubing string whipstock system 11-2 of the embodiment includes a tubing string 9-2, a matching tool 17 connected to the end of the tubing string 9-2, an azimuth instrument 16 connected to the matching tool 17, and a whipstock 10 connected to the azimuth instrument 16. The tubing string can be connected by using the matching tool, and the whipstock can be run into the well by using the tubing string.

[0053] Reference Figure 1 As shown, in S1, when the original wellbore 8 does not have the original tubing 9-1, the tubing string whipstock system 11-2 is used to run the whipstock 10 into the original wellbore 8, which includes installing the well control device 7 on the wellhead Christmas tree, and then using the tubing string whipstock system 11-2 to run the whipstock 10 into the original wellbore 8 to a predetermined position, Figure 1 The position of the original tubing 9-1 in the original wellbore 8 is the position of the tubing string 9-2 in the tubing string whipstock system 11-2. Then, the tubing string 9-2 is rotated at the wellhead according to the measurement of the azimuth instrument 16 to adjust the azimuth of the whipstock 10, and the setting of the whipstock 10 in the original wellbore 8 is completed; the tubing string 9-2 is hung on the Christmas tree as the tubing string for continuous pipe 2 drilling, the four-ram blowout preventer 5 is connected to the well control device 7 through the wellhead cross, and the other two interfaces of the wellhead cross 6 are connected to the choke manifold and the kill manifold, respectively, the four-ram blowout preventer 5, the continuous pipe blowout preventer box, and the blowout pipe 4 are connected to the injection head 3, and the continuous pipe 2 is connected to the drum of the continuous pipe truck 1.

[0054] As shown, Figure 4 The windowing tool string 11-3 includes a connector 13 connected to the end of the continuous pipe 2, a motor head 14, a deflector 15, a screw drill 18, and a milling bit 19 connected in series, and the motor head 14 is connected to the connector 13.

[0055] In S2, when the sidetracking point is located in the open hole section in the original wellbore 8, the open hole section in the original wellbore 8 is drilled by using the continuous pipe 2 to connect the windowing tool string 11-3, which includes: the windowing tool string 11-3 drills the open hole section in the original wellbore 8 along the deflection surface of the whipstock 10. The drilling depth of the open hole section in the original wellbore 8 drilled by using the continuous pipe 2 to connect the windowing tool string 11-3 is 5-10 m.

[0056] As shown, Figure 5As shown, the formation drilling tool string 11-4 includes a connector 13 for connecting with the end of the coiled tubing 2, a motor head 14, a deflector 15, a borehole trajectory measuring tool 20, a screw drill 18 and a milling bit 19 connected in series, and the motor head 14 is connected with the connector 13. In S3, the formation is drilled by the formation drilling tool string 11-4 connected with the coiled tubing 2, including that the formation drilling tool string 11-4 passes through the new borehole 12 drilled by the windowing tool string 11-3, continues to drill the formation at the bottom of the well, and the borehole trajectory is fed back in real time by the borehole trajectory measuring tool 20 during the formation drilling, and the tool face angle is adjusted in real time by the deflector 15, so that the formation is directionally drilled to the target. The borehole curvature radius is determined by the whipstock 10, the diameter of the tubing string 9-2, the bendable passability of the borehole trajectory measuring tool 20 and the bending angle of the screw drill 18.

[0057] The coiled tubing through tubing sidetracking method of the embodiment promotes the cost reduction and efficiency increase of the coiled tubing sidetracking well, realizes the goal of one-trip drilling of the whipstock, one-trip drilling of the window and one-trip drilling of the drilling, and promotes the extension of the coiled tubing drilling technology to a wider drilling field. The tubing string whipstock system can pull out the whipstock through the tubing string, rotate by a certain angle, and rotate the azimuth of the lower whipstock, so as to realize multi-lateral drilling.

[0058] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0059] In addition, the terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0063] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A coiled tubing lateral drilling method, characterized by, The method comprises the following steps: S1, when the original wellbore remains the oil pipe, the whipstock is lowered into the original wellbore by using the coiled tubing whipstock system; when the original wellbore does not remain the oil pipe, the whipstock is lowered into the original wellbore by using the tubing string whipstock system; S2, after the whipstock is set in the original wellbore, when the lateral drilling point is located in the cased well section in the original wellbore, the coiled tubing is used to connect the windowing tool string to perform the windowing operation on the cased well section in the original wellbore, and after the windowing operation is completed, the drilling operation is continued; when the lateral drilling point is located in the open hole section in the original wellbore, the coiled tubing is used to connect the windowing tool string to perform the drilling operation on the open hole section in the original wellbore; S3, after the windowing operation and the drilling operation are completed in the original wellbore, the coiled tubing is used to connect the formation drilling tool string to drill the formation; The coiled tubing whipstock system comprises a connector, a motor head, a direction finder, a direction indicator and a whipstock, the connector is used to connect with the end of the coiled tubing, the motor head, the direction finder, the direction indicator and the whipstock are connected in sequence, and the motor head is connected with the connector. The tubing string whipstock system comprises a tubing string, a matching tool, a direction finder and a whipstock, the matching tool is used to connect with the end of the tubing string, the direction finder is connected with the matching tool, and the whipstock is connected with the direction finder.

2. The coiled tubing lateral drilling method of claim 1, wherein, In S1, when the original wellbore remains the oil pipe, the whipstock is lowered into the original wellbore by using the coiled tubing whipstock system, which comprises the following steps: the wellhead Christmas tree is suspended with the oil pipe, the well control device is installed on the wellhead Christmas tree, the four-blade blowout preventer of the coiled tubing is connected with the well control device through the wellhead cross, the other two interfaces of the wellhead cross are connected with the choke manifold and the kill manifold respectively, the four-blade blowout preventer, the coiled tubing blowout preventer and the blowout preventer pipe and the injection head are connected, the coiled tubing is connected with the drum of the coiled tubing truck, the end of the coiled tubing is connected with the connector of the coiled tubing whipstock system, the coiled tubing whipstock system passes through the injection head, the coiled tubing blowout preventer and the blowout preventer pipe, the four-blade blowout preventer, the wellhead cross, the well control device, the oil pipe in sequence, and the whipstock is lowered to the predetermined position, then the direction of the whipstock is adjusted according to the measurement value of the direction indicator by using the direction finder, and the setting of the whipstock in the original wellbore is completed.

3. The coiled tubing lateral drilling method of claim 1, wherein, In S1, the output shaft of the direction finder in the coiled tubing whipstock system can rotate relative to the body of the direction finder, the direction indicator and the whipstock connected with the output shaft of the direction finder also rotate, and when the measurement value of the direction indicator shows that the direction of the whipstock meets the design requirement, the whipstock is set.

4. The coiled tubing lateral drilling method of claim 1, wherein, In S1, when the original wellbore does not have a crude oil pipe, the whipstock is lowered into the original wellbore by using a tubing string whipstock system, including: installing a well control device on the wellhead Christmas tree, then lowering the whipstock to a predetermined position by using the tubing string whipstock system, subsequently rotating the tubing string at the wellhead to adjust the orientation of the whipstock according to the measurement of the azimuth instrument, and completing the setting of the whipstock in the original wellbore; suspending the tubing string as a coiled tubing drilling string on the Christmas tree, connecting the four-gate blowout preventer to the well control device through the wellhead cross, connecting the other two interfaces of the wellhead cross to the choke manifold and the kill manifold respectively, connecting the four-gate blowout preventer, the coiled tubing blowout preventer box, the blowout pipe and the injection head, and butting the coiled tubing to the drum of the coiled tubing truck.

5. The coiled tubing lateral drilling method of claim 1, wherein, The windowing tool string comprises a connector, a motor head, a deflector, a screw drill and a milling bit, the connector is used for connecting with the end of the coiled tubing, the motor head, the deflector, the screw drill and the milling bit are connected in sequence, and the motor head is connected with the connector.

6. A coiled tubing lateral drilling method as defined in any one of claims 1 to 5 wherein, In S2, when the sidetracking point is located in the cased hole section in the original wellbore, the windowing operation is performed on the cased hole section in the original wellbore by using the coiled tubing connected windowing tool string, including: milling the casing along the deflection surface of the whipstock by the windowing tool string, and continuing the drilling operation on the formation after the windowing operation is completed; When the sidetracking point is located in the open hole section in the original wellbore, the drilling operation is performed on the open hole section in the original wellbore by using the coiled tubing connected windowing tool string, including: drilling the open hole section in the original wellbore along the deflection surface of the whipstock by the windowing tool string.

7. The coiled tubing lateral drilling method of claim 1, wherein, The formation drilling tool string comprises a connector, a motor head, a deflector, a borehole trajectory measuring tool, a screw drill and a milling bit, the connector is used for connecting with the end of the coiled tubing, the motor head, the deflector, the borehole trajectory measuring tool, the screw drill and the milling bit are connected in sequence, and the motor head is connected with the connector.

8. The coiled tubing lateral drilling method of claim 7, wherein, In S3, the formation is drilled by using the coiled tubing connected formation drilling tool string, including: the formation drilling tool string passes through the new borehole drilled by the windowing tool string, and continues to drill the formation at the bottom of the well, the borehole trajectory is fed back in real time by the borehole trajectory measuring tool during the formation drilling, the tool face angle is adjusted in real time by the deflector, and the directional drilling target of the formation is realized.

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