Construction method of large-diameter gas pipeline well

Abstract

The application discloses a large-diameter gas pipeline well construction method, which comprises the following steps: step 1: drilling an upper well hole downward from the ground surface above a chamber until the lower end of the upper well hole reaches the upper end of a bedrock, then lowering a surface casing into the upper well hole, and continuously drilling a middle well hole downward through the upper well hole until the interval between the lower end of the middle well hole and the upper end of the chamber is 10-30 m; step 2: lowering an upper production casing into the middle well hole and performing well cementation treatment on the upper production casing; and step 3: drilling a lower well hole upward from the chamber, with the upper end of the lower well hole being connected to the middle well hole, and filling a lower production casing into the lower well hole upward until the upper end of the lower production casing at the uppermost end is connected to the lower end of the upper production casing at the lowermost end, and performing well cementation treatment on the lower well hole to complete the construction of the large-diameter gas pipeline well, which is convenient to construct and can avoid the collapse of drilling mud into the chamber.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of gas well construction, and particularly relates to a large-diameter gas pipeline well construction method. BACKGROUND

[0002] Gas outburst is one of the safety problems faced by coal mines. In order to ensure the safety production of the mine and reduce the occurrence of gas accidents, gas must be prevented and treated. At present, some mines have begun to use large-diameter gas direct drainage hole technology to prevent and treat gas. Since this technology adopts long-distance drilling, the construction period is short, and the drainage effect is good, it has been widely popularized in many mines, and has gradually become the main technical means for preventing and treating gas in mines. In the past, similar engineering construction was to first construct the gas drainage hole, and then connect the original roadway with the gas drainage hole through the construction of the connecting roadway, so that the gas drainage hole can play a role. Although this construction method can achieve the effect of gas drainage, welding operation is often required in the process of connecting the pipeline well in the connecting roadway, which is contrary to the no open flame operation in the coal mine air return roadway. SUMMARY

[0003] In order to solve the above technical problems, the purpose of the present application is to provide a large-diameter gas pipeline well construction method which is convenient to construct and can avoid "mud lane collapse".

[0004] In order to achieve the above purpose, the technical scheme of the present application is as follows: a large-diameter gas pipeline well construction method, comprising the following steps,

[0005] Step 1: drilling an upper hole downward from the surface above the chamber until the lower end of the upper hole reaches the upper end of the bedrock, and then lowering a surface casing into the upper hole, and continuing to drill a middle hole downward through the upper hole until the spacing between the lower end of the middle hole and the upper end of the chamber is 10-30m;

[0006] Step 2: lowering an upper production casing into the middle hole and performing well cementing treatment on it;

[0007] Step 3: drilling a lower hole downward from the chamber until the lower hole is connected to the middle hole, and filling a lower production casing into the lower hole from bottom to top until the upper end of the lower production casing at the uppermost end is connected to the lower end of the upper production casing at the lowermost end, and performing well cementing treatment on the lower hole to complete the construction of the large-diameter gas pipeline well.

[0008] In the step 1, the drilling process of the upper hole and the middle hole comprises the following steps:

[0009] Step 1.1: drilling a pilot hole downward at the surface in the middle part above the chamber until the spacing between the lower end of the pilot hole and the upper end of the chamber is 10-30m;

[0010] Step 1.2: reaming the pilot hole at the upper end of the pilot hole to form a first reaming section, the depth of the first reaming section reaching the upper end of the bedrock, the first reaming section being an upper well hole, and lowering a surface casing into the upper well hole and cementing the surface casing;

[0011] Step 1.3: continuing to ream the pilot hole at the lower end of the upper well hole until the pilot hole is reamed to the lower end of the pilot hole, and a second reaming section is formed after reaming, the second reaming section being a middle well hole.

[0012] The step 2 specifically comprises the following steps:

[0013] Step 2.1: lowering an upper production casing into the second reaming section until the position of the upper end of the upper production casing is close to the position of the upper end of the surface casing;

[0014] Step 2.2: injecting cement slurry into the annulus between the upper production casing and the second reaming section and the surface casing to cement the well;

[0015] Step 2.3: lowering a drill bit into the bottom of the middle well hole to remove the cement slurry that has penetrated into the bottom, and then pumping the slurry to clean the bottom of the middle well hole.

[0016] The step 3 specifically comprises the following steps:

[0017] Step 3.1: drilling a lane hole that penetrates the interior of the chamber by air drilling at the middle of the bottom of the middle well hole;

[0018] Step 3.2: pre-reaming the lane hole by water drilling from the bottom of the middle well hole;

[0019] Step 3.3: reverse reaming from the lane hole in the chamber upwardly until the lower end of the middle well hole is connected, i.e., the construction of a lower well hole is completed;

[0020] Step 3.4: filling a lower production casing into the lower well hole from the chamber downwardly, and the uppermost lower production casing is connected with the lowermost upper production casing, until the lowermost lower production casing in the lower well hole extends out of the chamber;

[0021] Step 3.5: injecting cement slurry into the annular gap between the lower well hole and the lower production casing to cement the well.

[0022] The depth of the pilot hole is 18-22 m from the lower end of the pilot hole to the upper end of the chamber.

[0023] The water amount of the water drilling in the step 3.2 is only required to keep the drilling wet.

[0024] The annular gap between the lower production casing and the lower borehole in the step 3.5 is cemented by injecting cement slurry in the following way: a template is arranged at the lower end of the annular gap to form an annular chamber, the cement slurry is injected into the chamber until the chamber is filled with the cement slurry, and the template is removed after the cement slurry is solidified.

[0025] The uppermost upper production casing and the lowermost upper production casing are connected through threads.

[0026] The upper borehole has a larger diameter than the middle borehole, and the two boreholes are coaxially arranged.

[0027] The lower borehole has the same diameter as the middle borehole, and the two boreholes are coaxially arranged.

[0028] Compared with the prior art, the beneficial effects of the present application are that the guide hole, the first hole expanding section and the second hole expanding section in the present application are drilled by mud as drilling fluid, but in the later construction process of the lower borehole, mud is prevented from being poured into the chamber, so the roadway hole is drilled by using air drilling technology, which requires mud and water, and when the roadway hole is pre-expanded, the drilling is performed by the water drilling method, the water amount of which only keeps the drilling site wet (which is convenient for drilling and can also cool the drill bit), but the water amount is relatively small, so the risk of mud breaking the roadway does not exist, and the upper production casing is conveniently connected with the lower production casing without welding, which is safer. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a construction schematic diagram of the first step in the embodiment of the present application.

[0030] Figure 2 It is a construction schematic diagram of the second step in the embodiment of the present application.

[0031] Figure 3 It is a construction schematic diagram of the third step in the embodiment of the present application.

[0032] Figure 4 It is a construction schematic diagram of the fifth step in the embodiment of the present application.

[0033] Figure 5 It is a construction schematic diagram of the sixth step in the embodiment of the present application.

[0034] Figure 6 It is a construction schematic diagram of the seventh step in the embodiment of the present application.

[0035] Figure 7It is a schematic view of the construction after the seventh step in the embodiment of the present application.

[0036] Figure 8 It is a schematic view of the construction of the eighth and ninth steps in the embodiment of the present application.

[0037] Figure 9 It is a schematic view of the construction of the tenth step in the embodiment of the present application.

[0038] In the figure: 1 chamber, 2 upper borehole, 3 bedrock, 4 surface casing, 5 middle borehole, 6 upper production casing, 7 lower borehole, 8 lower production casing, 9 pilot hole, 10 lane hole, 11 reverse drill bit. DETAILED DESCRIPTION

[0039] The principles and features of the present application are described below in conjunction with the accompanying drawings, and the examples are used to explain the present application, but not to limit the scope of the present application. In the following paragraphs, the present application is described in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present application will be more apparent from the following description and claims. It should be noted that the drawings are very simplified and use non-precise proportions, only to facilitate, clarify the purpose of assisting the description of the embodiments of the present application.

[0040] The present application discloses a large-diameter gas pipeline well construction method, comprising the following steps,

[0041] Step 1: drilling an upper borehole 2 downward from the ground surface above the chamber 1 until the lower end of the upper borehole 2 reaches the upper end of the bedrock 3, then lowering a surface casing 4 into the upper borehole 2, and continuing to drill a middle borehole 5 downward through the upper borehole 2 until the spacing between the lower end of the middle borehole 5 and the upper end of the chamber 1 is 10-30m;

[0042] Step 2: lowering an upper production casing 6 into the middle borehole 5 and performing cementing treatment on it;

[0043] Step 3: drilling a lower borehole 7 from the chamber 1 downward to the upper end of the middle borehole 5, and filling a lower production casing 8 into the lower borehole 7 from the lower end upward until the upper end of the lower production casing 8 at the uppermost end is connected with the lower end of the upper production casing 6 at the lowermost end, and performing cementing treatment on the lower borehole 7 to complete the construction of the large-diameter gas pipeline well.

[0044] In the step 1, the drilling process of the upper borehole 2 and the middle borehole 5 includes the following steps:

[0045] Step 1.1: drilling a pilot hole 9 downward at the ground surface in the middle part above the chamber 1 until the spacing between the lower end of the pilot hole 9 and the upper end of the chamber 1 is 10-30m;

[0046] Step 1.2: reaming the pilot hole 9 at the upper end to form a first reaming section, the depth of the first reaming section reaching the upper end of the bedrock 3, the first reaming section being the upper well hole 2, and lowering the surface casing 4 into the upper well hole 2 and cementing the surface casing 4;

[0047] Step 1.3: continuing to ream the pilot hole 9 at the lower end of the upper well hole 2 until the lower end of the pilot hole 9 is reamed, and a second reaming section is formed, the second reaming section being the middle well hole 5.

[0048] The step 2 specifically comprises the following steps:

[0049] Step 2.1: lowering the upper production casing 6 into the second reaming section until the position of the upper end of the upper production casing 6 is close to the position of the upper end of the surface casing 4;

[0050] Step 2.2: injecting cement slurry into the annulus between the upper production casing 6 and the second reaming section and the surface casing 4 to cement the well;

[0051] Step 2.3: lowering a drill bit into the bottom of the middle well hole 5 to remove the cement slurry that has penetrated into the bottom, and then pumping the slurry to clean the bottom of the middle well hole 5.

[0052] The step 3 specifically comprises the following steps:

[0053] Step 3.1: drilling a lane hole 10 that penetrates the chamber 1 by air drilling at the middle of the bottom of the middle well hole 5;

[0054] Step 3.2: pre-reaming the lane hole 10 by water drilling from the bottom of the middle well hole 5;

[0055] Step 3.3: reverse reaming from the lane hole 10 in the chamber 1 downward to the lower end of the middle well hole 5 to complete the construction of the lower well hole 7;

[0056] Step 3.4: filling the lower production casing 8 into the lower well hole 7 from the chamber 1 downward, and the uppermost lower production casing 8 is connected to the lowermost upper production casing 6, until the lowermost lower production casing 8 in the lower well hole 7 extends out of the chamber 1;

[0057] Step 3.5: injecting cement slurry into the annular gap between the lower well hole 7 and the lower production casing 8 to cement the well.

[0058] The depth of the pilot hole 9 is 18-22m from the lower end to the upper end of the chamber 1.

[0059] The water quantity of the water spraying drilling in the step 3.2 can be any quantity that can keep the drilling wet.

[0060] The annular gap between the lower production casing 8 and the lower borehole 7 in the step 3.5 is injected with cement slurry for cementing in the following way: a template is arranged at the lower end of the annular gap to form an annular chamber, cement slurry is injected into the chamber until the chamber is filled with the cement slurry, and the template is removed after the cement slurry is solidified (for details of the cementing method, refer to the cementing device disclosed in the document CN214836253U “A well cementing device for large-diameter drilling and segmented pipe lowering”).

[0061] The uppermost upper production casing 6 and the lowermost upper production casing 6 are connected through threads.

[0062] The upper borehole 2 has a larger diameter than the middle borehole 5, and the two are coaxially distributed.

[0063] The lower borehole 7 has the same diameter as the middle borehole 5, and the two are coaxially distributed.

[0064] Embodiment

[0065] There is a cable hole, and the depth from the top of the chamber to the ground surface is 530 m. Therefore, the hole is designed to have a depth of 530 m, a Φ720 × 20 mm production casing is lowered, and the upper end of the bedrock layer is 50 m away from the ground surface. The hole construction is completed in the following steps:

[0066] First step: A Φ311 drill bit is used in combination with a Φ194 screw drill and an MWD while-drilling directional instrument to perform a pilot hole construction on the ground surface above the chamber. The final hole depth of the pilot hole is 510 m, and the depth of 510-530 m is a pressure-bearing layer reserved at the top of the chamber to withstand the liquid column pressure in the drilling hole during the early construction process to prevent lane collapse.

[0067] Second step: A Φ960 mm and a Φ1400 mm combined roller bit are used to ream the upper end of the pilot hole (first reaming section), the reaming depth is 55 m, a Φ1140 × 20 mm surface casing is lowered, and the surface casing is cemented.

[0068] Third step: A Φ960 mm combined roller bit is used to continue drilling and reaming to a depth of 510 m (i.e., the second reaming section, which reams to the lower end of the pilot hole), a Φ720 × 20 mm upper production casing is lowered, a female thread is reserved at the lowermost end of the upper production casing (to be connected to a male thread at the upper end of the lower production casing later), and the upper production casing is cemented.

[0069] Fourth step: after the cementing is completed, the drill bit is lowered to sweep the cement in the hole, and the cement is swept to a depth of 510 m, and the bucket is used to clean the mud in the hole;

[0070] Fifth step: a Ф340mm air hammer is used to drill a hole section from 510m to 530m (a lane hole is drilled, and the lower end of the lane hole is connected to the chamber), and the "dry hole penetrates the lane" to connect the chamber;

[0071] Sixth step: a Ф660mm combination drill bit is used to ream the hole section from 510m to 530m (pre-reaming), and water is sprayed into the hole during reaming to cool the drill bit, and the cuttings fall into the chamber;

[0072] Seventh step: a Ф960mm combination drill bit is installed upside down in the chamber, and is rotated during upward drilling to achieve the reverse reaming function of a conventional drill (the reverse drill bit 11 drills upward to expand the hole), and the hole section from 510m to 530m is reamed to Ф960mm (which is coaxial and the same diameter as the second reaming section, i.e., the edges are aligned);

[0073] Eighth step: a Φ720x20mm production casing with a length of 1.5m is connected by a thread connection in the chamber for 21.5m, and a male thread is reserved at the upper end of the production casing;

[0074] Ninth step: the production casing is lifted to 510m by the upward lifting method and is connected to the upper female thread (for details, refer to the document CN113445937A "Large-diameter drilling casing connection construction method"), and the lower end of the production casing extends into the chamber by 1.5m, and a flange is arranged at the end (used for connection with the gas pipeline in the lane in the later stage);

[0075] Tenth step: cementing is performed between the hole section from 510m to 530m and the outer wall of the Φ720x20mm production casing (for details, refer to the cementing device disclosed in the document CN214836253U "Large-diameter drilling casing connection construction method"), and the cementing is completed, and the large-diameter gas pipeline well construction is completed.

[0076] The large-diameter gas pipeline well construction method provided by the embodiment can avoid the collapse of drilling mud into the chamber.

[0077] It should be noted that the above detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs.

[0078] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0079] It is to be understood that the terms "first", "second", and the like, used herein do not necessarily connote any order, quantity, composition or importance, but are used to distinguish one element from another, and are more especially used to distinguish an element having a same name (to the extent possible) from another element having a same name. It is to be understood that the terms "including", "comprising", "consisting" and "consisting essentially of" to the extent they can be recited in the description or claims, are used herein to specify the presence of stated features, steps or components but do not preclude the presence or addition of one or more other features, steps, components or groups thereof.

[0080] Also, as used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, it is to be understood that the use of a singular herein, for example, "a" or "an", does not exclude a plurality, and vice versa. Further, as used herein, the term "coupled" or "connected" or "connected to" includes an electrical connection, a magnetic connection, a mechanical connection, a communication connection (e.g., communicatively coupled), or any combination of these, unless expressly specified otherwise. In addition, it is to be understood that the use of "or" in the

[0081] Further, the terms "include," "includes" and "including" are intended to be inclusive and mean that there can be additional items that are not specifically recited. The description herein of any contemplated limitations is by way of example only, and thus the limitation(s) of examples should not be considered to narrow the scope of the application, but the application is to be given the broadest interpretation available.

[0082] Spatially relative terms, such as "beneath", "below", "lower", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device described herein is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0083] For example, if the device in the drawing is inverted, the device described as "above" other devices or structures can then be oriented "below" such other devices or structures. Thus, exemplary terms such as "above" can encompass both an "above" and "below" orientation. The devices can also be oriented in other ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0084] The above description is only the preferred embodiment of the present application, not any form of limitation to the present application; anyone skilled in the art can easily implement the present application according to the drawings and the above description; however, anyone skilled in the art can make some changes, modifications and equivalent variations of the above-mentioned technical contents within the scope of the technical solutions of the present application, and all the equivalent embodiments of the present application are still within the protection scope of the present application.

Claims

1. A large-diameter gas pipeline well construction method, characterized in that: The steps include: Step 1: Drill an upper wellbore (2) downward from the surface above the chamber (1) until the lower end of the upper wellbore (2) reaches the upper end of the bedrock (3), insert a surface casing (4) into the upper wellbore (2), and continue drilling a middle wellbore (5) downward through the upper wellbore (2) until the distance between the lower end of the middle wellbore (5) and the upper end of the chamber (1) is 10-30m; Step 2: inserting an upper production casing (6) into the middle wellbore (5) and performing cementing treatment on the casing; Step 3: Drilling a lower wellbore (7) from the bottom to the top of the chamber (1), the upper end of which is connected to the middle wellbore (5), and filling the lower production casing (8) into the lower wellbore (7) from the bottom to the top, until the upper end of the uppermost lower production casing (8) is connected to the lower end of the lowermost upper production casing (6), and cementing the lower wellbore (7) to complete the construction of the large-diameter gas pipeline well; The step 3 specifically includes the following steps: Step 3.1: drilling a tunnel hole (10) communicating with the interior of the chamber (1) in the middle of the bottom of the middle wellbore (5) by air drilling; Step 3.2: Pre-expanding the tunnel hole (10) from the bottom of the middle well hole (5) by means of water-spraying drilling, wherein the amount of water sprayed in the water-spraying drilling is sufficient to keep the drilled hole moist; Step 3.3: Reversely expand the tunnel hole (10) in the chamber (1) from bottom to top until it is expanded to abut against the lower end of the middle well hole (5), thus completing the construction of the lower well hole (7); Step 3.4: Fill the lower production casing (8) from the inside of the chamber (1) into the lower wellbore (7) from the bottom up, and dock the uppermost lower production casing (8) with the lowermost upper production casing (6) until the lowermost lower production casing (8) in the lower wellbore (7) extends into the chamber (1); Step 3.5: Inject cement slurry into the annular gap between the lower wellbore (7) and the lower production casing (8) to perform well cementing.

2. The large-diameter gas pipeline well construction method according to claim 1, characterized in that: The drilling process of the upper wellbore (2) and the middle wellbore (5) in step 1 includes the following steps: Step 1.1: Drill a guide hole (9) downward from the ground surface in the middle of the upper part of the chamber (1) until the distance between the lower end of the guide hole (9) and the upper end of the chamber (1) is 10-30m; Step 1.2: Reaming is performed at the upper end of the guide hole (9) to form a first reaming section, the depth of the first reaming section reaching the upper end of the bedrock (3), the first reaming section being the upper wellbore (2), and a surface casing (4) is lowered into the upper wellbore (2), and the surface casing (4) is cemented; Step 1.3: Continue to expand the guide hole (9) at the lower end of the upper wellbore (2) until the hole is expanded to the lower end of the guide hole (9), and a second expansion section is formed after expansion. The second expansion section is the middle wellbore (5).

3. The large-diameter gas pipeline well construction method according to claim 2, characterized in that: The step 2 specifically includes the following steps: Step 2.1: inserting an upper production casing (6) into the second reaming section until the upper end of the upper production casing (6) is close to the upper end of the surface casing (4); Step 2.2: injecting cement slurry into the annular gap between the upper production casing (6), the second reaming section and the surface casing (4) for cementing; Step 2.3: A drill bit is lowered into the bottom of the middle well hole (5) to sweep away the cement slurry that has seeped into the bottom thereof, and then the slurry is lifted to clean the bottom of the middle well hole (5).

4. The large-diameter gas pipeline well construction method according to claim 2, characterized in that: The distance between the lower end of the guide hole (9) and the upper end of the chamber (1) is 18-22m.

5. The large-diameter gas pipeline well construction method according to claim 1, characterized in that: The method of injecting cement slurry into the annular gap between the lower production casing (8) and the lower wellbore (7) in step 3.5 is as follows: a template is set at the lower end of the annular gap to seal and enclose it to form an annular chamber, cement slurry is injected into the chamber until it is filled with cement slurry, and the template is removed after the cement slurry solidifies.

6. The large-diameter gas pipeline well construction method according to any one of claims 1 to 5, characterized in that: The upper production casing (6) at the lower end and the lower production casing (8) at the upper end are connected via threads.

7. The large-diameter gas pipeline well construction method according to any one of claims 1 to 5, characterized in that: The aperture of the upper wellbore (2) is larger than the aperture of the middle wellbore (5), and the two are coaxially distributed.

8. The large-diameter gas pipeline well construction method according to any one of claims 1 to 5, characterized in that: The aperture of the lower wellbore (7) is equal to the aperture of the middle wellbore (5), and the two are coaxially distributed.

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