Casing old well sidetrack drilling device and method

Abstract

The invention belongs to the field of petroleum drilling, and particularly relates to a casing old well sidetrack drilling device and method, and the device comprises a drill rod which is tripped into a casing; the upper end of the spiral drill collar is connected with the drill rod; the upper end of the common drill collar is connected with the lower end of the spiral drill collar; the whipstock is tripped into the lower part of the casing pipe and is set at the lower position of the casing pipe; the milling cone is connected with the lower end of the common drill collar, and the milling cone is used for windowing and repairing the casing towards the inclined side direction at the position of the whipstock; the screw rod is connected with the drill bit, and the screw rod can replace the milling cone to be connected with the lower end of the common drill collar and enable the drill bit to perform sidetrack drilling along a window formed in the oblique side direction. According to the method, windows can be directly formed in the casing pipe of the original target layer well section, the problem that an original well hole and an original fish head cannot be found does not exist, pressure, oil-water channeling and complex process links do not exist, the purposes of replacing the well bottom of an old well, perfecting a well pattern, exploiting remaining oil between wells, improving the recovery efficiency and the like are achieved, and the operation cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the field of oil drilling, and in particular to a device and method for sidetracking of an old casing well. Background Art

[0002] At present, in order to resume production in old wells with 5-inch casing in China, indirect means such as pulling out casing, milling sections, expanding pipes as technical casings, lifting windows to open windows, etc. are adopted, and then 5-inch casing is lowered to continue deepening drilling operations. These existing means will bring about the disadvantages of complicated procedures for drilling to the target layer, great difficulty in construction, increased potential accidents, damage to the original wellbore structure, shortened well life cycle, and increased operating costs, which seriously restrict the effect and progress of increasing reserves and production by long-stopping wells with 5-inch casing. In addition, the wellbore mechanism formed by deepening drilling is different, so there are factors such as windows, deflector technology, rigidity and composite wellbore formed by upper casing, which leads to differences in drilling tool combination and pipe string matching combination in the completion process, limited displacement during circulation and drilling, difficulty in carrying cuttings at the bottom of the well, and accumulation of cuttings on the lower well wall to form a cuttings bed, which can easily cause complex situations in subsequent projects, and greater difficulty in the process and technology of window opening and side drilling of small wells.

[0003] For example, the paper "Side Drilling Technology of Φ127mm Casing by Section Milling in Tahe Oilfield" introduces the side drilling technology of 127mm casing in Tahe Oilfield, which uses a 150mm section miller to sectionally mill 178mm casing, then cements the open hole section milled out, and then uses a 150mm drill bit to side drill and run 127mm casing. This process is cumbersome, has a long construction period, and is risky. It damages the upper casing and wellbore structure, causing the upper formation to penetrate the lower target formation, resulting in pressure crossover and pollution.

[0004] The paper "Slim Hole Directional Drilling Technology for Casing Window Opening and Side Drilling in Lungu 40C Well" introduces the method of opening a window in the 177.8mm casing of the Tarim Oilfield, running a 127mm casing, and then deepening the drilling in the 127mm casing. The method adopted is to open a window in the original well casing, run a tail pipe to deepen the drilling, and no window opening and side drilling in the 127mm casing is used.

[0005] The paper "Analysis of Difficulties and Improvement Directions for Ultra-deep Directional Wells in 104.8mm Ultra-small Holes in Halahatang" introduces the process of opening a window in the 177.8mm casing in Tarim Oilfield, running a 127mm casing, and then deepening the drilling in the 127mm casing. This was achieved by side-drilling the original 177.8mm casing through a window, running a 127mm casing, and then deepening the drilling. This process involves opening a window in the upper casing, which is cumbersome and opens the upper strata of the reservoir, causing pressure cross-talk and interlayer contamination.

[0006] Therefore, the prior art needs to be improved. Summary of the invention

[0007] The purpose of the present invention is to effectively solve the problem of small borehole window side drilling in 5-inch casing long-stop wells and inefficient wells, and propose a device and method for side drilling in old casing wells. The device and method achieve the goals of replacing the bottom of the old well, improving the well network, exploiting the remaining oil between wells, and improving the recovery rate, greatly reducing the operating cost, which is only 30% to 50% of the operating cost of a new well; in addition, the device and method will also promote the development of a series of technologies such as small borehole oil production, operation, and fracturing.

[0008] In order to solve the above technical problems or achieve the above objectives, the present invention adopts the following specific technical solutions:

[0009] According to one aspect of the present invention, a device for sidetracking in an old casing well is provided, comprising:

[0010] A drill pipe, which is lowered into the casing;

[0011] A spiral drill collar, the upper end of which is connected to the drill pipe;

[0012] A common drill collar, the upper end of which is connected to the lower end of the spiral drill collar;

[0013] A deflector, which is lowered into the lower part of the casing and is set at the lower position of the casing;

[0014] A milling cone, which is connected to the lower end of a common drill collar and which opens and repairs the casing in an oblique direction at the position of the bevel guide;

[0015] A screw rod is connected to a drill bit, and the screw rod can replace a milling cone to be connected to the lower end of a common drill collar and enable the drill bit to perform side drilling along a window formed by the milling cone on the casing along an oblique side direction.

[0016] In one embodiment of the present invention, the old casing well is a 5-inch casing old well.

[0017] In one embodiment of the present invention, the drill rod is made of carbon steel.

[0018] In one embodiment of the present invention, the drill rod is one or both of a common drill rod with a diameter of 60.3 mm and a special coupling drill rod with a diameter of 73 mm.

[0019] In one embodiment of the present invention, the diameters of the spiral drill collar and the ordinary drill collar are both 88.9 mm.

[0020] In one embodiment of the present invention, the diameters of the deflector and the milling cone are both 105 mm.

[0021] In one embodiment of the present invention, the diameter of the screw is 88.9 mm, and the diameter of the drill bit is 105 mm.

[0022] In one embodiment of the present invention, the screw is further connected to an MWD trajectory control tool.

[0023] In one embodiment of the present invention, the diameter of the MWD trajectory control tool is 34.8 mm or 38 mm.

[0024] In one embodiment of the present invention, the deflection guiding direction of the deflector is a right deflection direction.

[0025] According to another aspect of the present invention, there is provided a method for sidetracking an old well with casing using the device for sidetracking an old well with casing as described above, comprising the following steps:

[0026] 1) Well cleaning stage: Use drill pipe and drilling tool combination to clean the old well casing until it meets the window opening requirements. Combined with the cleaning condition of the old well casing, the window opening position is determined according to the window opening position selection principle;

[0027] 2) Window opening stage: Drill pipe, spiral drill collar, common drill collar, deflector and milling cone are put into the treated casing, the deflector is set at the lower position of the casing and the milling cone is used to open and repair the casing in the oblique direction at the position of the deflector;

[0028] 3) Side drilling stage: A combination tool of drill pipe, spiral drill collar, ordinary drill collar, screw and drill bit is put into the side drilling stage and the combination tool is used to perform side drilling along the window in the oblique direction of the casing to reach the target well depth.

[0029] In one embodiment of the present invention, the old casing well is a 5-inch casing old well.

[0030] In one embodiment of the present invention, the drill pipe used in step 1), step 2) and step 3) is made of carbon steel.

[0031] In one embodiment of the present invention, the drill rod is one or both of a common drill rod with a diameter of 60.3 mm and a special coupling drill rod with a diameter of 73 mm.

[0032] In one embodiment of the present invention, in step 1), the casing of the old well is subjected to well cleaning treatment, including using a drill pipe to perform ash squeezing and channel exploration treatment, and using a drill tool combination formed by a well cleaning gauge, a milling cone and a shaper to be lowered into the drill pipe to perform casing diameter clearing, pipe scraping, channel drilling, ash squeezing and casing pressure testing.

[0033] In one embodiment of the present invention, the diameters of the spiral drill collar and the ordinary drill collar used in step 2) and step 3) are both 88.9 mm.

[0034] In one embodiment of the present invention, the diameters of the deflector and the milling cone are both 105 mm.

[0035] In one embodiment of the present invention, between step 2) and step 3), the milling cone is disassembled and replaced with a screw rod and a drill bit.

[0036] In one embodiment of the present invention, in step 3), the sidetracking stage includes a combined tool formed by a drill pipe, an auger drill collar, a common drill collar, a screw and an MWD trajectory control tool connected thereto and a drill bit for orientation, azimuth twisting and drilling.

[0037] In one embodiment of the present invention, the diameter of the MWD trajectory control tool is 34.8 mm or 38 mm.

[0038] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0039] Under the premise of meeting the purpose of drilling, the present invention has developed tools such as PT26 special coupling drill pipe, small-sized spiral drill collar, and miniature series drill bits, and directly opened windows in the casing of the original target layer. There is no problem of not being able to find the original wellbore and the original fish head, and there is no pressure and oil-water crosstalk and complex process links. The present invention uses a window-opening tool to directly open a window in the 5-inch casing of the original well. Compared with other methods, the construction process of the present invention is simple and efficient, with fewer links, small wellbore and small tools, light drilling rig load, and less waste liquid and waste chips. In addition, the present invention is simple to operate and highly practical. It is expected to be promoted and applied 20 wells each year in the next 3-5 years, saving more than 6 million yuan in new drilling, ground process and other costs for a single well, and a single well is expected to increase oil production by more than 1,000 tons per year. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0041] Figure 1 The schematic structural diagram of a casing sidetracking device provided by the present invention is shown.

[0042] Reference numerals list

[0043] 1 casing, 2 drill pipe, 3 spiral drill collar, 4 ordinary drill collar, 5 milling cone, 6 guide bevel, 7 window DETAILED DESCRIPTION

[0044] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present invention, it is easy for those skilled in the art to appreciate that multiple modifications are feasible without actually departing from the teaching of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other replacements, modifications, changes and deletions may be made to the design, operating conditions and parameters of the following exemplary embodiments.

[0045] like Figure 1 As shown, the present invention provides a device for side drilling in an old casing well, comprising: a drill pipe 2, which is lowered into the casing 1; a spiral drill collar 3, the upper end of which is connected to the drill pipe 2; a common drill collar 4, the upper end of which is connected to the lower end of the spiral drill collar 3; a deflector 6, which is lowered into the lower part of the casing 1 and is sealed at the lower position of the casing 1; a milling cone 5, which is connected to the lower end of the common drill collar 4 and the milling cone 5 opens and repairs the casing 1 in an oblique direction at the position of the deflector 6; a screw (not shown), which is connected to a drill bit (not shown), and the screw can replace the milling cone 5 to be connected to the lower end of the common drill collar 4 and enable the drill bit to perform side drilling along the window 7 formed by the milling cone 5 on the casing 1 in the oblique direction.

[0046] Through the above technical scheme of the present invention, the present invention can directly open a window in the casing of the original target layer well section, and there is no problem of not being able to find the original wellbore and the original fish head, and there is no pressure and oil-water cross-talk and complex process links. The present invention achieves the purposes of replacing the bottom of the old well, improving the well network, exploiting the remaining oil between wells, and improving the recovery rate, greatly reducing the operating cost.

[0047] In the above device, preferably, the old casing well is a 5-inch casing old well.

[0048] In the above device, preferably, the drill rod 2 is made of carbon steel.

[0049] In the above device, preferably, the drill rod 2 is one or both of a common drill rod with a diameter of 60.3 mm and a special coupling drill rod with a diameter of 73 mm. More preferably, the drill rod 2 is a special coupling drill rod with a diameter of 73 mm, or the drill rod 2 is a common drill rod with a diameter of 60.3 mm connected to a special coupling drill rod with a diameter of 73 mm.

[0050] In the above device, preferably, the diameters of the spiral drill collar 3 and the ordinary drill collar 4 are both 88.9 mm.

[0051] In the above device, preferably, the diameters of the deflector 6 and the milling cone 5 are both 105 mm.

[0052] In the above device, preferably, the diameter of the screw is 88.9 mm, which is the same as the diameter of the spiral drill collar 3 and the ordinary drill collar 4 for connection. Preferably, the diameter of the drill bit is 105 mm.

[0053] In the above device, preferably, the screw rod is also connected to an MWD (Measurement While Drilling) trajectory control tool.

[0054] In the above device, preferably, the diameter of the MWD trajectory control tool is 34.8 mm or 38 mm.

[0055] In the above device, preferably, Figure 1 As shown, the deflection direction of the deflector is the right deflection direction.

[0056] In addition, the present invention provides a method for sidetracking an old well with casing using the device for sidetracking an old well with casing as described above, comprising the following steps:

[0057] 1) Well cleaning stage: Use drill pipe and drilling tool combination to clean the old well casing until it meets the window opening requirements. Combined with the cleaning condition of the old well casing, the window opening position is determined according to the window opening position selection principle;

[0058] 2) Window opening stage: Drill pipe, spiral drill collar, common drill collar, deflector and milling cone are put into the treated casing, the deflector is set at the lower position of the casing and the milling cone is used to open and repair the casing in the oblique direction at the position of the deflector;

[0059] 3) Side drilling stage: A combination tool of drill pipe, spiral drill collar, ordinary drill collar, screw and drill bit is put into the side drilling stage and the combination tool is used to perform side drilling along the window in the oblique direction of the casing to reach the target well depth.

[0060] In the above method, preferably, the old casing well is a 5-inch casing old well.

[0061] In the above method, preferably, the drill pipe used in step 1), step 2) and step 3) is made of carbon steel.

[0062] In the above method, preferably, the drill rod is one or both of a common drill rod with a diameter of 60.3 mm and a special coupling drill rod with a diameter of 73 mm. More preferably, the drill rod 2 is a special coupling drill rod with a diameter of 73 mm, or the drill rod 2 is a common drill rod with a diameter of 60.3 mm connected to a special coupling drill rod with a diameter of 73 mm.

[0063] In the above method, preferably, in step 1), the casing of the old well is subjected to well cleaning treatment, including using a drill pipe to perform ash squeezing and channel exploration treatment, and using a drill tool combination formed by a well cleaning gauge, a milling cone and a shaper to be lowered into the drill pipe to perform casing diameter clearing, pipe scraping, channel drilling, ash squeezing and casing pressure testing.

[0064] In the above method, preferably, the diameters of the spiral drill collar and the ordinary drill collar used in step 2) and step 3) are both 88.9 mm.

[0065] In the above method, preferably, the diameters of the deflector and the milling cone are both 105 mm.

[0066] In the above method, preferably, between step 2) and step 3), the method further includes disassembling the milling cone and replacing it with a screw rod and a drill bit.

[0067] In the above method, preferably, in step 3), the sidetracking stage includes a combined tool formed by a drill pipe, an auger drill collar, a common drill collar, a screw and an MWD trajectory control tool connected thereto and a drill bit for orientation, azimuth twisting and drilling.

[0068] In the above method, preferably, the diameter of the MWD trajectory control tool is 34.8 mm or 38 mm.

[0069] The above technical solution of the present invention is described in detail below through specific embodiments.

[0070] like Figure 1 As shown, a device for side drilling in an old well with a 5-inch casing provided in an embodiment of the present invention comprises: a drill pipe 2, which is lowered into a casing 1, wherein the drill pipe 2 adopts a special coupling drill pipe with a diameter of 73 mm; a spiral drill collar 3, the upper end of which is connected to the drill pipe 2, the spiral drill collar 3 avoids sticking and adopts a drill collar with a diameter of 88.9 mm; a common drill collar 4, the upper end of which is connected to the lower end of the spiral drill collar 3, the common drill collar 4 adopts a drill collar with a diameter of 88.9 mm and applies drilling pressure; a deflector 6, which is lowered into the casing 1. The lower part of the casing 1 is sealed in the lower position of the casing 1, the diameter of the deflector 6 is 105mm and the deflection direction is the right deflection direction; the milling cone 5, the diameter of the milling cone 5 is 105mm and the milling cone 5 is connected to the lower end of the ordinary drill collar 4 and the milling cone 5 opens and repairs the casing 1 in the right deflection direction at the position of the deflector 6; the screw (not shown), the screw is connected to the drill bit (not shown), the screw can replace the milling cone 5 to be connected to the lower end of the ordinary drill collar 4 and enable the drill bit to perform side drilling along the window 7 formed by the milling cone 5 on the casing 1 along the deflection direction.

[0071] When the above-mentioned device of the present invention is used, first, the well is cleared. In the well clearing stage, a special coupling drill pipe with a diameter of 73mm is used to squeeze out ash and explore the channel. The special coupling drill pipe with a diameter of 73mm is lowered into a drilling tool combination formed by tools such as a well clearing gauge, a milling cone, and a shaper with a diameter of 105mm. The casing diameter, scraping, channeling, squeezing ash, casing pressure testing and other well clearing processes are carried out until the window opening requirements are met. In combination with the well clearing situation of the old well casing, the window opening position is determined according to the window opening position selection principle. Secondly, the window is opened. In the window opening stage, a special coupling drill pipe 2 with a diameter of 73mm, a spiral drill collar 3 with a diameter of 88.9mm, and an ordinary drill collar 4 with a diameter of 88.9mm are lowered into tools such as a guide 6 and a milling cone 5 with a diameter of 105mm. The guide 6 is sealed at the lower position of the casing 1, and the milling cone 5 opens and repairs the casing 1 in the oblique direction at the position of the guide 6. Finally, the milling cone 5 is removed and replaced with a screw and a drill bit. A special coupling drill pipe 2 with a diameter of 73 mm, a spiral drill collar 3 with a diameter of 88.9 mm, an ordinary drill collar 4 with a diameter of 88.9 mm, a screw with a diameter of 88.9 mm, an MWD (measurement while drilling) trajectory control tool with a diameter of 38 mm, and a drill bit with a diameter of 105 mm are connected and lowered to perform operations such as orientation, azimuth twisting, and drilling, so that the entire device can perform side drilling along the window 7 in the right oblique direction and reach the target well depth.

[0072] In addition, optionally, in the above embodiment, the special coupling drill rod with a diameter of 73 mm used in the present invention can be replaced by an ordinary drill rod with a diameter of 60.3 mm, or a composite drill rod composed of an ordinary drill rod with a diameter of 60.3 mm connected to a special coupling drill rod with a diameter of 73 mm can be used. The diameter or specification of the MWD trajectory control tool can also be 34.8 mm instead of 38 mm.

[0073] It can be seen that, under the premise of meeting the purpose of drilling, the present invention has developed tools such as PT26 special coupling drill pipe, small-size spiral drill collar, and micro-series drill bits, and directly opened windows in the casing of the original target layer well section, so there is no problem of not being able to find the original wellbore and the original fish head, and there is no pressure and oil-water cross-talk and complex process links. The present invention achieves the purposes of replacing the bottom of the old well, improving the well network, exploiting the remaining oil between wells, and improving the recovery rate, greatly reducing the operating cost.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced by equivalents without departing from the spirit and scope of the present invention, it should be included in the protection scope of the claims of the present invention.

Claims

1. A device for side drilling in old casing wells. It is characterized in that include: A drill pipe, the drill pipe is lowered into the casing; A spiral drill collar, the upper end of which is connected to the drill pipe; A common drill collar, the upper end of which is connected to the lower end of the spiral drill collar; A deflector, which is lowered into the lower part of the casing and is set at the lower position of the casing; A milling cone, the milling cone is connected to the lower end of the common drill collar and the milling cone performs window opening and window repair on the casing in an oblique direction at the position of the deflector; A screw rod is connected to a drill bit, and the screw rod can replace the milling cone to be connected to the lower end of the common drill collar and enable the drill bit to perform side drilling along a window formed by the milling cone on the casing along an oblique side direction.

2. The device for sidetracking in an old well with casing according to claim 1, It is characterized in that The old casing well is a 5-inch casing old well.

3. The device for sidetracking in an old well with casing according to claim 2, It is characterized in that The drill rod is made of carbon steel.

4. The device for sidetracking in an old well with casing according to claim 3, It is characterized in that The drill rod is one or both of a common drill rod with a diameter of 60.3 mm and a special coupling drill rod with a diameter of 73 mm.

5. The device for sidetracking in an old casing well according to claim 2, It is characterized in that The diameters of the spiral drill collar and the ordinary drill collar are both 88.9 mm.

6. The device for sidetracking in an old well with casing according to claim 5, It is characterized in that The diameters of the deflector and the milling cone are both 105 mm.

7. The device for sidetracking in an old well with casing according to claim 6, It is characterized in that The diameter of the screw is 88.9 mm, and the diameter of the drill bit is 105 mm.

8. The device for sidetracking in an old casing well according to claim 2, It is characterized in that The screw is also connected to an MWD trajectory control tool.

9. The device for sidetracking in an old well with casing according to claim 8, It is characterized in that The diameter of the MWD trajectory control tool is 34.8 mm or 38 mm.

10. The device for sidetracking in an old casing well according to claim 1, It is characterized in that The deflection guide direction of the deflector is the right deflection direction.

11. A method for sidetracking an old well with a casing using the device for sidetracking an old well with a casing as claimed in any one of claims 1 to 10, It is characterized in that The following steps are involved: 1) Well cleaning stage: Use drill pipe and drilling tool combination to clean the old well casing until it meets the window opening requirements. Combined with the cleaning condition of the old well casing, the window opening position is determined according to the window opening position selection principle; 2) Window opening stage: Drill pipe, spiral drill collar, common drill collar, deflector and milling cone are put into the treated casing, the deflector is set at the lower position of the casing and the milling cone is used to open and repair the casing in the oblique direction at the position of the deflector; 3) Side drilling stage: A combination tool of drill pipe, spiral drill collar, ordinary drill collar, screw and drill bit is put into the side drilling stage and the combination tool is used to perform side drilling along the window in the oblique direction of the casing to reach the target well depth.

12. The method according to claim 11, It is characterized in that The old casing well is an old casing well with 5 inches.

13. The method according to claim 12, It is characterized in that The drill pipes used in step 1), step 2) and step 3) are made of carbon steel.

14. The method according to claim 13, It is characterized in that The drill rod is one or both of a common drill rod with a diameter of 60.3 mm and a special coupling drill rod with a diameter of 73 mm.

15. The method according to claim 14, It is characterized in that In step 1), the casing of the old well is treated by well cleaning, including using a drill pipe to squeeze out ash and explore the channel, and using a drill tool combination formed by a well cleaning gauge, a milling cone and a shaper to perform casing diameter cleaning, pipe scraping, channel drilling, ash squeezing and casing pressure testing.

16. The method according to claim 12, It is characterized in that The diameters of the spiral drill collar and the ordinary drill collar used in step 2) and step 3) are both 88.9 mm.

17. The method according to claim 16, It is characterized in that In step 2), the diameters of the deflector and the milling cone are both 105 mm.

18. The method according to claim 11, It is characterized in that Between step 2) and step 3), the milling cone is disassembled and replaced with a screw rod and a drill bit.

19. The method according to claim 11, It is characterized in that In step 3), the sidetracking stage includes a combination tool formed by a drill pipe, an auger drill collar, a common drill collar, a screw and an MWD trajectory control tool connected thereto and a drill bit for orientation, azimuth twisting and drilling.

20. The method according to claim 19, It is characterized in that The diameter of the MWD trajectory control tool is 34.8 mm or 38 mm.

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