A casing-assisted running device and method for shallow complex formations

Abstract

The present invention provides an assisted casing running device for shallow, complex formations, comprising: a support frame including side support beams and a top support beam; a drilling workbench; a hoisting mechanism connected to the top support beam, capable of providing downward pressure for the casing; and a horizontal adjustment mechanism, capable of providing a horizontal offset force for casing running. The hoisting mechanism can be used to hoist the casing and lower it into the wellbore. The horizontal adjustment mechanism can be used to horizontally adjust the casing when encountering resistance during casing running. Under the downward pressure provided by the hoisting mechanism, the casing can bypass the resistance point and be smoothly run. The present invention also provides an assisted casing running method for shallow, complex formations.

Description

Technical Field

[0001] The invention belongs to the technical field of oil drilling, and in particular relates to a casing auxiliary running device and method for shallow complex formations. Background Art

[0002] In oil drilling operations, casing and cementing are commonly used for mid-well completion. However, drilling operations often encounter difficulties in running casing into complex shallow formations. Shallow formations often have poor cementation, are loose and prone to leakage, contain gravel and water, and are prone to creep. This often results in irregular wellbores during the drilling process, making it difficult to run the guide tube or casing. This is especially true for the first few casings, which have a low deadweight and poor ability to overcome the resistance. Hard pressure can damage the casing, and currently used methods such as reaming and cementing the wellbore are ineffective.

[0003] For shallow, loose, leaky, gravel-containing, water-containing, and creep-prone formations, lowering conduits or surface casing is often used to isolate the unstable upper formations. However, due to poor formation stability, creep, and wellbore irregularities, lowering conduits or casing is often difficult. The industry generally uses conventional methods such as eye expansion and cementing the wellbore wall to deal with this drilling complexity. In addition, due to the long treatment time and low cement retention rate, the treatment effect is poor, and this technical problem cannot be fundamentally solved. For shallow casing, due to its low deadweight, its deadweight cannot overcome the above-mentioned lowering resistance. Using hard pressure at the wellhead often leads to problems such as casing buckle deformation or casing damage, which has a significant impact on drilling efficiency and can even cause the oil well to be scrapped.

[0004] Existing casing-assisted running tools are either only for the lower wellbore, or the process is complex and cannot be applied to shallow loose formations. For example, Chinese patent document CN107386980A discloses a device for assisting casing running, which mainly solves the problem of casing running in horizontal wells with irregular wellbore trajectories due to large friction. Its process is complex, the operation efficiency is low, and the technical reliability is low. Chinese patent document CN112814570A discloses a self-driven rotary casing running tool, which can assist casing running by providing a rolling body at the lower end of the screw and connecting a drill-grinding guide shoe. However, its operation process is complex, the reliability is low, and it is not suitable for shallow loose and unstable formations, which can easily cause drilling complexity and affect operation efficiency.

[0005] Therefore, there is an urgent need for a new method and device for assisting the running of casing in shallow complex formations that is simple, easy to operate, and highly operational, so as to meet the needs of safe drilling and improve the success rate and efficiency of casing running. Summary of the Invention

[0006] In response to the technical problems mentioned above, the present invention aims to propose a casing auxiliary running device for shallow and complex formations, which can provide horizontal offset force and running power for casing running, so that the casing can avoid obstruction points and be run smoothly, which is very beneficial to improving the casing running efficiency and improving operational efficiency.

[0007] To this end, according to a first aspect of the present invention, there is provided a device for assisting casing lowering into shallow complex formations, comprising: a support frame comprising side support beams and a top support beam; a drilling workbench; a hoisting mechanism connected to the top support beam, which can provide downward pressure for the casing; and a horizontal adjustment mechanism, which can provide a horizontal offset force for the casing lowering; wherein, the casing can be hoisted and lowered into the wellbore by the hoisting mechanism, and the casing can be horizontally adjusted by the horizontal adjustment mechanism when encountering resistance during casing lowering, and under the action of the downward pressure provided by the hoisting mechanism, the casing can bypass the resistance point and be lowered smoothly.

[0008] In one embodiment, the hoisting mechanism includes: a crown block pulley block installed on the top support beam; a top drive mechanism connected to the bottom of the crown block pulley block through a first steel wire rope, which can increase the downward pressure of the casing and press the casing downward; a casing head for connecting the casing, and the casing head is connected to the lower end of the top drive mechanism.

[0009] In one embodiment, the horizontal adjustment mechanism includes: a pneumatic winch installed on the drilling workbench, which is used to provide driving force; a fixed pulley installed on the top support beam; a movable pulley connected to the side support beam; a double-ear annular sling for being sleeved on the casing; and a second steel wire rope; wherein, one end of the second steel wire rope is connected to the pneumatic winch, and the other end is connected to the double-ear annular sling after passing through the fixed pulley and the movable pulley in sequence. By winding the second steel wire rope by the pneumatic winch, it can provide horizontal pulling force to the double-ear annular sling, thereby adjusting the casing in the horizontal direction.

[0010] In one embodiment, the movable pulley is arranged at the lower end of the drilling work platform and close to the wellhead, and the second steel wire rope passes through the drilling work platform and then bypasses the movable pulley.

[0011] In one embodiment, the circumferential length of the double-eared loop sling is at least 10 cm greater than the outer diameter of the sleeve.

[0012] In one embodiment, the double-ear loop sling has a load-bearing capacity greater than 5 tons.

[0013] In one embodiment, the vertical displacement of the movable pulley is less than 5 cm.

[0014] In one embodiment, the movable pulley is connected to the side support beam via a double-ear steel cable, and the length of the double-ear steel cable is less than 10 cm.

[0015] According to a second aspect of the present invention, there is provided a method for assisting casing running in a shallow complex formation, comprising the following steps:

[0016] Drilling to medium completion depth in complex shallow formations and running casing into the wellhead;

[0017] Providing the aforementioned casing auxiliary running device for shallow complex formations and placing it at the wellhead;

[0018] The casing is hoisted by the hoisting mechanism, and is lowered into the wellbore after passing through the double-eared annular hoist of the horizontal adjustment mechanism. When encountering resistance during the lowering process, the horizontal adjustment mechanism is activated to adjust the casing in the horizontal direction, and under the downward pressure provided by the hoisting mechanism, the casing can bypass the resistance point and be lowered smoothly.

[0019] In one embodiment, before running the casing, the horizontal adjustment mechanism is adjusted so that the double-ear steel cable, the movable pulley and the double-ear annular sling in the horizontal adjustment mechanism are at the same height.

[0020] Compared with the prior art, the advantages of this application are:

[0021] According to the method for assisting casing lowering in shallow complex formations of the present invention, a device for assisting casing lowering in shallow complex formations is used, which can provide horizontal offset force to the casing through a horizontal adjustment mechanism, and provide downward pressure power through a top drive mechanism. As a result, while the casing obtains sufficient horizontal offset force to be able to perform horizontal adjustment, it also obtains power to overcome the friction resistance during lowering, so that the end of the casing can bypass the resistance point by pulling and pressing at the same time, and the problem of the casing's own weight overcoming the resistance difference is solved by appropriate downward pressure, and finally the casing is smoothly lowered, the upper complex layer is sealed, and the drilling safety problem caused thereby is effectively solved. The use of a device for assisting casing lowering in shallow complex formations can greatly improve the success rate of casing lowering, which is very beneficial to improving the efficiency of casing lowering operations, and the process is simple, the reliability is strong, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described below with reference to the accompanying drawings.

[0023] Figure 1 The structure of the casing-assisted running device for shallow complex formations according to the present invention is schematically shown.

[0024] In this application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn to scale. DETAILED DESCRIPTION

[0025] The present invention will be described below with reference to the accompanying drawings.

[0026] In this application, it should be noted that the directional terms or qualifiers "upper", "lower", etc. used in this application are all directed to the attached drawings to which they are referred. Figure 1 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific situation.

[0027] Figure 1 The structure of the casing auxiliary running device 100 according to the present invention is schematically shown. Figure 1 As shown, the casing auxiliary lowering device 100 for shallow complex formations includes a support frame 1, a drilling workbench 2, a hoisting mechanism 3, and a horizontal adjustment mechanism 5. The support frame 1 serves as a support structure for placement at the wellhead position. The support frame 1 includes a side support beam 11 and a top support beam 12. The drilling workbench 2 is fixedly connected to the support frame 1. Preferably, the drilling workbench 2 is fixedly installed at a lower middle position of the support frame 1. The hoisting mechanism 3 is connected to the top support beam 12, and the hoisting mechanism 3 can provide downward pressure for the casing 4. The horizontal adjustment mechanism 5 can provide a horizontal offset force for the lowering of the casing 4. During the casing lowering operation, the casing 4 can be hoisted and lowered into the wellbore by the hoisting mechanism 3. The casing 4 can be horizontally adjusted by the horizontal adjustment mechanism 5 when encountering resistance during the lowering of the casing. Under the downward pressure provided by the hoisting mechanism 3, the lower end of the casing 4 can bypass the resistance point 8 by pulling and pressing, thereby achieving smooth lowering of the casing 4.

[0028] In one embodiment, in order to ensure the stability of the drilling work platform 2 , a plurality of cross-distributed connecting rods may be provided at the lower end of the drilling work platform 2 , thereby forming a stable structure at the lower end of the drilling work platform 2 .

[0029] According to the present invention, Figure 1 As shown, the hoisting mechanism 3 includes a crown block pulley block 31, a first wire rope 32, a top drive mechanism 33, and a casing head 34. The crown block pulley block 31 is mounted on the top support beam 12 and is movable to move the casing 4 to a position aligned with the wellhead. The top drive mechanism 33 is connected below the crown block pulley block 31 via the first wire rope 32. The top drive mechanism 33 provides downward force on the casing 4, thereby compressing it. The casing head 34 is connected to the lower end of the top drive mechanism 33 and is used to connect the casing 4.

[0030] According to the present invention, Figure 1As shown, the horizontal adjustment mechanism 5 includes a pneumatic winch 51, a fixed pulley 52, a movable pulley 54, a double-eared loop sling 55, and a second steel wire rope 56. The pneumatic winch 51 is fixedly mounted on the drilling platform 2 and provides driving force. The fixed pulley 52 is mounted on the top support beam 12. Preferably, to avoid affecting the movement of the crown block pulley assembly 31, the fixed pulley 52 is positioned to one side of the crown block pulley assembly 31. The movable pulley 54 is connected to the side support beam 11. The double-eared loop sling 55 is designed to be looped over the casing 4. One end of the second steel wire rope 56 is connected to the pneumatic winch 51, and the other end passes through the fixed pulley 52 and movable pulley 54 in sequence before being connected to the double-eared loop sling 55. As a result, the second steel wire rope 56 forms an S-shaped loop around the fixed pulley 52 and movable pulley 54. By winding the second steel wire rope 56 with the pneumatic winch 51 , the second steel wire rope 56 can generate a horizontal pulling force (close to horizontal) on the double-eared annular sling 55 , thereby adjusting the casing 4 in the horizontal direction.

[0031] Preferably, the movable pulley 54 is arranged at the lower end of the drilling platform 2 and near the wellhead, and the second wire rope 56 passes through the drilling platform 2, then around the movable pulley 54, and then connects to the double-ear annular sling 55. This ensures that the lateral offset force generated by the horizontal adjustment mechanism 5 can be effectively transmitted downward.

[0032] According to the present invention, the circumferential length of the double-eared loop sling 55 is at least 10 cm greater than the outer diameter of the casing 4. This allows the casing 4 to be lowered into the wellbore through the double-eared loop sling 55 without hindering the running of the casing 4. Preferably, the two ears of the double-eared loop sling 55 and the second wire rope 56 can be connected by a large hook (not shown).

[0033] In addition, the bearing capacity of the double-ear annular sling 55 is greater than 5 tons to ensure that the lateral offset force generated by the horizontal adjustment mechanism 5 can effectively adjust the sleeve 4.

[0034] According to the present invention, the vertical displacement of the movable pulley 54 is less than 5 cm to ensure that the lateral offset force generated by the horizontal adjustment mechanism 5 can be effectively transmitted downward.

[0035] In one embodiment, the movable pulley 54 can be connected to the side support beam 11 of the support frame 1 through a double-ear steel cable 53, and the length of the double-ear steel cable 53 is less than 10 cm. Thus, the vertical displacement of the movable pulley 54 is ensured to be less than 5 cm.

[0036] As an alternative, the movable pulley 54 may be directly connected to the side support beam 11 of the support frame 1 via a large hook (not shown), thereby ensuring that the vertical displacement of the movable pulley 54 is less than 5 cm.

[0037] In order to ensure that the lateral offset force generated by the horizontal adjustment mechanism 5 can be effectively transmitted downward, before the casing 4 is lowered, the horizontal adjustment mechanism 5 is adjusted so that the double-ear steel cable 53, the movable pulley 54 and the double-ear annular sling 55 are at the same height.

[0038] During actual operation, the casing auxiliary running device 100 for shallow complex formations according to the present invention generates horizontal pulling force through the horizontal adjustment mechanism 5 and acts on the casing 4, providing horizontal offset force for the running of the casing 4. At the same time, the top drive mechanism 33 in the hoisting mechanism 3 is used to press down the casing 4. In the process of running the casing 4, the downward pressure of the top drive mechanism 33 is appropriately adjusted within the range of the casing compressive strength, and the downward pressure of the top drive mechanism 33 is ensured to be within the bearing pressure range of the casing 4. Thus, the casing 4 is lowered using the casing auxiliary running device 100 for shallow complex formations, so that the casing 4 obtains sufficient horizontal offset force to be able to perform horizontal adjustment, and obtains power to overcome the friction resistance of the running through the top drive mechanism 44, so that the method of pulling and pressing can be adopted, so that the end of the casing 4 can bypass the resistance point 8, and the casing can be smoothly run.

[0039] The following describes a method for assisting casing running into a shallow complex formation according to the present invention. The method uses a device 100 for assisting casing running into a shallow complex formation and includes the following steps.

[0040] First, drilling is performed in a complex shallow formation 7 to a medium completion depth, and a guide pipe 6 is lowered into the wellhead.

[0041] In one embodiment, for example, before running casing 4, a drill bit with a diameter of 406.4 mm is used to drill to a depth of 970 m, and a guide pipe with a diameter of 609.6 mm is run to a depth of 20 m. The following describes a method for running casing 4 into a shallow, complex formation using the example of running casing 4 with a diameter of 339.7 mm.

[0042] A casing auxiliary running device 100 for shallow complex formations is provided and placed at the wellhead. Before running the casing 4, the horizontal adjustment mechanism 5 is adjusted so that the double-eared steel cable 53, the movable pulley 54 and the double-eared annular sling 55 are at the same height.

[0043] Next, the casing 4 is hoisted using the hoisting mechanism 3. The casing 4 is securely connected to the casing head 34 of the hoisting mechanism 3 to ensure proper circulation and downward pressure during lowering, thus avoiding complications downhole. The casing 4 is then hoisted to a position aligned with the wellhead using the overhead crane pulley block 31. The top drive mechanism 33 of the hoisting mechanism 3 then presses the casing 4 downward, allowing it to pass through the double-eared annular sling 55 in the horizontal adjustment mechanism 5 before being lowered into the wellbore.

[0044] During the lowering process of the casing 4, due to the instability of the shallow strata, the bottom end of the casing 4 and the stratum 7 will form a stuck point (resistance point 8) and cannot pass through. At this time, the casing 4 encounters resistance. The horizontal adjustment mechanism 5 is started to adjust the casing in the horizontal direction, and the pneumatic winch 51 is started. The pneumatic winch 51 winds the second steel wire rope 56 so that the second steel wire rope 56 generates a nearly horizontal tension on the double-ear annular sling 55, thereby converting the vertical tension into hydraulic tension to adjust the casing 4 in the horizontal direction. At the same time, under the action of the downward pressure provided by the top drive mechanism 33, the casing 4 obtains the power to overcome the friction resistance of the lowering. Thus, the method of pulling and pressing is adopted, so that the end of the casing 4 can bypass the resistance point 8 and the casing 4 can be smoothly lowered.

[0045] According to the method for assisting casing lowering in shallow complex formations of the present invention, a device 100 for assisting casing lowering in shallow complex formations is used, which can provide a horizontal offset force to the casing 4 through the horizontal adjustment mechanism 5, and provide a downward pressure force through the top drive mechanism 44. In this way, while the casing 4 obtains sufficient horizontal offset force to be able to perform horizontal adjustment, it also obtains the power to overcome the friction resistance during lowering, so that the end of the casing 4 can bypass the resistance point 8 by pulling and pressing at the same time, and the problem of the casing 4's own weight overcoming the resistance difference is solved by appropriate downward pressure, and finally the casing 4 is smoothly lowered, the upper complex layer is sealed, and the drilling safety problem caused thereby is effectively solved. The use of the device 100 for assisting casing lowering in shallow complex formations can greatly improve the success rate of casing 4 lowering, which is very beneficial to improving the efficiency of casing 4 lowering operations, and has a simple process, high reliability, and low cost.

[0046] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0047] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0048] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0049] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A casing-assisted running device for shallow complex formations, comprising: A support frame (1) comprising side support beams (11) and a top support beam (12); Drilling bench (2); a hoisting mechanism (3) connected to the top support beam, capable of providing downward pressure for the casing (4); A horizontal adjustment mechanism (5) capable of providing a horizontal offset force for lowering the casing, the horizontal adjustment mechanism comprising: a pneumatic winch (51) mounted on the drilling workbench for providing a driving force, a fixed pulley (52) mounted on the top support beam, a movable pulley (54) connected to the side support beam, a double-ear annular sling (55) for being sleeved on the casing, and a second steel wire rope (56), wherein one end of the second steel wire rope is connected to the pneumatic winch, and the other end of the second steel wire rope is connected to the double-ear annular sling after passing through the fixed pulley and the movable pulley in sequence, and the second steel wire rope is wound by the pneumatic winch so as to provide a horizontal pulling force to the double-ear annular sling, thereby adjusting the casing in the horizontal direction; The casing can be hoisted and lowered into the wellbore through the hoisting mechanism, and the casing can be horizontally adjusted when encountering resistance during lowering through the horizontal adjustment mechanism. Under the downward pressure provided by the hoisting mechanism, the casing can bypass the resistance point and be lowered smoothly.

2. The device according to claim 1, characterized in that The hoisting mechanism comprises: A crown block pulley assembly (31) mounted on the top support beam; A top drive mechanism (33) is connected to the bottom of the overhead crane pulley assembly via a first steel wire rope (32), and is capable of increasing downward pressure on the casing to thereby press the casing downward; A casing head (34) is used for connecting a casing, and the casing head is connected to the lower end of the top drive mechanism.

3. The device according to claim 1 or 2, characterized in that The movable pulley is arranged at the lower end of the drilling work platform and close to the wellhead. The second steel wire rope passes through the drilling work platform and then passes around the movable pulley.

4. The device according to claim 1 or 2, characterized in that The circumferential length of the double-ear annular sling is at least 10 cm greater than the outer diameter of the sleeve.

5. The device according to claim 4, characterized in that The load-bearing capacity of the double-ear annular sling is greater than 5t.

6. The device according to claim 1 or 2, characterized in that The vertical displacement of the movable pulley is less than 5 cm.

7. The device according to claim 1 or 2, characterized in that The movable pulley is connected to the side support beam via a double-ear steel cable (53), and the length of the double-ear steel cable is less than 10 cm.

8. A method for assisting casing running in shallow complex formations, comprising the following steps: Drilling to a medium completion depth in a complex shallow formation and running a guide pipe (6) into the wellhead; Providing a casing auxiliary running device for shallow complex formations according to any one of claims 1 to 7, and placing it at the wellhead; The casing is hoisted by the hoisting mechanism, and is lowered into the wellbore after passing through the double-eared annular hoist of the horizontal adjustment mechanism. When encountering resistance during the lowering process, the horizontal adjustment mechanism is activated to adjust the casing in the horizontal direction, and under the downward pressure provided by the hoisting mechanism, the casing can bypass the resistance point and be lowered smoothly.

9. The method according to claim 8, characterized in that Before running the casing, the horizontal adjustment mechanism is adjusted so that the double-ear steel cable, the movable pulley and the double-ear annular sling in the horizontal adjustment mechanism are at the same height.

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