Forward alternating operation method for directional drilling and fracturing of composite rock stratum

Abstract

The invention provides a forward alternate operation method for directional drilling and fracturing of a composite rock stratum, and relates to the technical field of coal mining. The composite rock stratum directional drilling and fracturing forward alternating operation method comprises the steps that a drilling site in a roadway is determined according to disaster prevention and fracturing requirements under a mine, and directional drilling parameters are determined; the number of drilling segments and the length L of each drilling single segment are determined according to a roof rock stratum histogram and lithologic hydrological characteristics of the construction site; a drilling machine is arranged at the tapping position, the tapping straight drilling angle is adjusted, and the coordinates of tapping points are determined; and drilling construction of drilling single-section drilling is carried out, and hole washing is carried out on the drilled single-section drilling in the drilling retreating process. According to the forward alternate operation method for directional drilling and fracturing of the composite rock stratum, the problems that due to the fact that the hole diameter is reduced due to argillization hole collapse and dislocation deformation of the soft and hard composite rock stratum after drilling, layer penetrating and hole forming are conducted for a long time, a packing tool is jammed, and staged fracturing is not successful are effectively solved, and the success rate of full-drilling staged fracturing is increased.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to a composite rock stratum directional drilling and fracturing forward alternating operation method. Background Art

[0002] Directional drilling is a complex process involving the coordination of multiple equipment and materials. Understanding the equipment and materials required can help ensure the success and safety of the fracturing operation. By using specialized tools and materials, combined with an experienced construction team, the safe exploitation of underground resources can be effectively guaranteed. Directional drilling refers to the technology of drilling non-linear holes along a predetermined path to accurately reach one or more target areas.

[0003] The roof of coal seams in my country's coal mines is generally composed of soft interlayers and hard and difficult-to-cross rock layers, which causes strong roof pressure during coal mining. The sudden collapse of the roof causes strong hurricanes in the tunnel and even impact ground pressure disasters. Roof fracturing related process technology is an effective means to solve the above disaster prevention problems. Its drilling-fracturing collaborative process method is crucial to the construction effect of disaster prevention schemes. At present, the fracturing construction process is single and the directional drilling design is relatively blind and conservative, resulting in poor safety and economic applicability and low construction efficiency.

[0004] The existing conventional drilling and fracturing technology in underground coal mines, due to the uneven geological distribution characteristics of sedimentary rock strata in coal-bearing strata, uses open-hole drilling without casing protection, which generally suffers from the problems of mudstone necking, hole collapse, and bedding dislocation and deformation. Summary of the invention

[0005] The invention provides a composite rock stratum directional drilling and fracturing forward alternating operation method, which is used to solve the problem that the prior art cannot adapt to the construction requirements of complex geological conditions.

[0006] The present invention provides a composite rock formation directional drilling and fracturing forward alternating operation method, and the composite rock formation directional drilling and fracturing forward alternating operation method comprises: Step S100, determining the drilling location in the tunnel according to the disaster prevention fracturing requirements of the mine, and determining the directional drilling parameters; Step S200, determining the number of drilling sections and the length L of each drilling section according to the top rock columnar diagram and lithology and hydrology characteristics of the construction site; Step S300, placing the drilling machine at the drilling position, adjusting the drilling angle, and determining the coordinates of the drilling point; Step S400, performing drilling construction of the drilling single segment drill, and washing the hole of the drilling single segment after drilling is completed during the drilling withdrawal process; Step S500, performing a one-way isolation fracturing operation on the drilled single segment after hole washing, and withdrawing the fracturing isolation tool after fracturing is completed; Step S600, repeating steps S400 and S500 in sequence until the last drilling single segment is completed.

[0007] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, after step S600, the method further includes: The completed borehole mouth section is sealed with cement slurry.

[0008] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, the directional drilling parameters include drilling depth, height and horizontal displacement offset.

[0009] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, the length L of each drilling single segment can be the same or different.

[0010] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, the length L of each drilling single segment is 30-50m.

[0011] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, while executing the step of washing the hole of the drilled single segment during the drill withdrawal process, it also includes: The drill bit is controlled to rotate so as to trim the wellbore wall of the drilled single segment where the fracturing operation is completed.

[0012] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, the distance between the sealer and the bottom of the hole of the drilling single segment is greater than or equal to 40m.

[0013] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, the sealer is a rubber cartridge sealer.

[0014] According to a composite rock formation directional drilling and fracturing forward alternating operation method provided by the present invention, the drill bit rotates at a constant speed during the drilling withdrawal process.

[0015] According to a forward alternating operation method for directional drilling and fracturing of composite rock formations provided by the present invention, the water pressure output for hole washing gradually increases in the direction close to the hole mouth.

[0016] The composite rock stratum directional drilling and fracturing forward alternating operation method provided by the present invention effectively solves the problem that after a long period of drilling and penetration, soft and hard composite rock strata will suffer from mud collapse and dislocation deformation, resulting in a reduction in the aperture, thereby causing the sealing tool to be stuck and the staged fracturing to fail, thereby improving the success rate of full-borehole staged fracturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 The present invention provides a schematic flow diagram of a composite rock formation directional drilling and fracturing forward alternating operation method.

[0019] Figure 2 The present invention provides a schematic diagram of a specific process of a composite rock stratum directional drilling and fracturing forward alternating operation method. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0022] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0023] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present utility model refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0024] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0025] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0026] Figure 1 FIG. 1 is a flow chart of a composite rock stratum directional drilling and fracturing forward alternating operation method provided by the present invention, such as Figure 1 As shown, the composite rock formation directional drilling and fracturing forward alternating operation method includes the following steps: Step S100, determining the drilling location in the tunnel according to the disaster prevention fracturing requirements of the mine, and determining the directional drilling parameters; Directional drilling parameters include the drilling depth, height and horizontal displacement offset. Of course, directional drilling parameters are not limited to these, but also include the borehole inner diameter, vertical well section length, inclination section length and other drilling parameters.

[0027] Step S200, determining the number of drilling sections and the length L of each drilling section according to the top rock columnar diagram and lithology and hydrology characteristics of the construction site; The length L of each drilling segment can be the same or different, which is determined according to the top rock column diagram and lithology and hydrology characteristics of the construction site. Determining the number of drilling segments and the length L of each drilling segment according to the top rock column diagram and lithology and hydrology characteristics of the construction site has the following advantages: On the one hand, the length and number of fracturing stages can be determined more accurately, thereby improving the effectiveness and efficiency of hydraulic fracturing.

[0028] On the one hand, the number of drilling sections and the length L of each drilling section can be determined according to the top rock column diagram and lithological and hydrological characteristics of the construction site. Reasonable determination of the number of sections and the length of each section can reduce unnecessary construction costs and difficulties.

[0029] On the other hand, by rationally designing the spacing between staged fracturing points and the inclination of drilling holes, roof collapse can be more effectively controlled, thereby improving the safety of operations.

[0030] Step S300, placing the drilling machine at the drilling position, adjusting the drilling angle, and determining the coordinates of the drilling point; Step S400, drilling construction of a single-segment drill is performed, and during the drilling withdrawal process, the hole of the completed single-segment drill is washed; During the drilling withdrawal process, the hole washing of the completed drilling section can timely carry out the rock powder and rock cuttings broken by the drill bit from the borehole, keep the bottom of the hole clean, and prevent the rapid precipitation of rock powder from causing the blocking accident of the isolation tool. In addition, the hole washing of the completed drilling section can form a mud skin on the inner wall of the borehole to protect the hole wall: when washing the hole, the flushing fluid is used to form a thin and dense mud skin on the hole wall, which can prevent the hole wall from collapsing or falling off.

[0031] Step S500, performing a one-way isolation fracturing operation on the drilled single segment after hole washing, and withdrawing the fracturing isolation tool after fracturing is completed; Step S600, repeating steps S400 and S500 in sequence until the last drilling single segment is completed.

[0032] The composite rock stratum directional drilling and fracturing forward alternating operation method provided by the present invention effectively solves the problem that after a long period of drilling and penetration, soft and hard composite rock strata will suffer from mud collapse and dislocation deformation, resulting in a reduction in the aperture, thereby causing the sealing tool to be stuck and the staged fracturing to fail, thereby improving the success rate of full-borehole staged fracturing.

[0033] In one embodiment of the present invention, after step S600, the composite rock formation directional drilling and fracturing forward alternating operation method further includes: Step S700: Use cement slurry to solidify and seal the hole mouth section of the completed drilled hole.

[0034] By sealing the borehole mouth section of the completed borehole, safety accidents such as water gushing from the rock formation or accumulation of toxic and harmful gases can be prevented, thus meeting the safety requirements of underground coal mines.

[0035] In one embodiment of the present invention, the length L of each drilling single segment is 30-50 m, which is specifically determined according to the top rock columnar diagram and lithology and hydrology characteristics of the construction site.

[0036] In one embodiment of the present invention, while performing the step of washing the hole of the completed drilling single segment during the drill withdrawal process, the composite rock formation directional drilling and fracturing forward alternating operation method further includes: The drill bit is controlled to rotate to trim the wellbore wall of the single segment drilled to complete the fracturing operation.

[0037] Preferably, the drill bit rotates at a constant speed during the drill withdrawal process. Due to the geologically uneven distribution characteristics of sedimentary rock layers in coal-bearing strata, open-hole drilling using small-diameter or directional long-hole drilling generally suffers from mudstone necking, hole collapse, and bedding dislocation and deformation. By controlling the rotation of the drill bit during the drill withdrawal process, the drill bit can trim the well wall of the drilled single segment that has completed the fracturing operation to prevent the hole from collapsing or the hole diameter from shrinking.

[0038] In a specific embodiment of the present invention, the composite rock formation directional drilling and fracturing forward alternating operation method comprises the following steps: Step S100, determining the drilling location in the tunnel according to the disaster prevention fracturing requirements of the mine, and determining the directional drilling parameters; Step S200, determining the number of drilling sections and the length L of each drilling section according to the top rock columnar diagram and lithology and hydrology characteristics of the construction site; Step S300, placing the drilling machine at the drilling position, adjusting the drilling angle, and determining the coordinates of the drilling point; Step S400, drilling construction of drilling single segment drilling is performed, and the hole of the drilling single segment after drilling is completed is washed during the drilling withdrawal process; the drill bit is controlled to rotate to trim the well wall of the drilling single segment after the fracturing operation is completed; Step S500, performing a one-way isolation fracturing operation on the drilled single segment after hole washing, and withdrawing the fracturing isolation tool after fracturing is completed; Step S600, repeating steps S400 and S500 in sequence until the last drilling single segment is completed; Step S700: Use cement slurry to solidify and seal the hole mouth section of the completed drilled hole.

[0039] In one embodiment of the present invention, the distance between the hole sealer and the bottom of the hole of the drilling single segment is greater than or equal to 40m. The composite rock formation directional drilling fracturing forward alternating operation method of the present invention can improve the success rate of full-bore segment fracturing because it adopts the forward drilling fracturing process. Preferably, the hole sealer is a rubber cartridge hole sealer, and the use of the rubber cartridge hole sealer for fracturing simplifies the fracturing process and has the characteristics of strong operability, high construction success rate, good reliability, and low cost.

[0040] In one embodiment of the present invention, during the drill withdrawal process, the water pressure of the hole washing output gradually increases in the direction close to the hole mouth, which helps to improve the permeability of the coal rock and the complexity of the pore structure, thereby more effectively washing the hole and removing slag.

[0041] In a specific embodiment of the present invention, Figure 2 FIG. 1 is a specific flow chart of a composite rock stratum directional drilling and fracturing forward alternating operation method provided by the present invention. Figure 2 As shown, the composite rock formation directional drilling and fracturing forward alternating operation method includes the following steps: Step S100, determining the drilling location in the tunnel according to the disaster prevention fracturing requirements of the mine, and determining the drilling depth to be 500m and the drill bit diameter to be 120mm; Step S200, determining the number of drilling sections to be 10 and the length of each drilling section to be 50 m according to the top rock columnar diagram and lithology and hydrology characteristics of the construction site; Step S300, placing the drilling machine at the drilling position, adjusting the drilling angle, and determining the coordinates of the drilling point; Step S400, drilling construction of drilling single-stage drilling is performed, and during the drilling withdrawal process, the hole of the completed drilling single-stage is washed, and the medium for washing the hole is downhole clean water; the drill bit is controlled to rotate to trim the well wall of the drilling single-stage that has completed the fracturing operation; Step S500, a one-way isolation fracturing operation is performed on the drilled single segment after the hole is washed, and the fracturing isolation tool is withdrawn after the fracturing is completed; the fracturing medium is downhole clean water, and the isolation fracturing time is not less than 1 hour.

[0042] Step S600, repeating steps S400 and S500 in sequence until the last drilling single segment is completed; Step S700: Use cement slurry to solidify and seal the hole mouth section of the completed drilled hole.

[0043] The composite rock stratum directional drilling and fracturing forward alternating operation method provided by the present invention effectively solves the problem that after a long period of drilling and penetration, soft and hard composite rock strata will suffer from mud collapse and dislocation deformation, resulting in a reduction in the aperture, thereby causing the sealing tool to be stuck and the staged fracturing to fail, thereby improving the success rate of full-borehole staged fracturing.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A forward alternating operation method for directional drilling and fracturing in composite rock formations, characterized in that: include: Step S100, determining the drilling location in the tunnel according to the disaster prevention fracturing requirements of the mine, and determining the directional drilling parameters; Step S200, determining the number of drilling sections and the length L of each drilling section according to the top rock columnar diagram and lithology and hydrology characteristics of the construction site; Step S300, placing the drilling machine at the drilling position, adjusting the drilling angle, and determining the coordinates of the drilling point; Step S400, performing drilling construction of the drilling single segment drill, and washing the hole of the drilling single segment after drilling is completed during the drilling withdrawal process; Step S500, performing a one-way isolation fracturing operation on the drilled single segment after hole washing, and withdrawing the fracturing isolation tool after fracturing is completed; Step S600, repeating steps S400 and S500 in sequence until the last drilling single segment is completed.

2. The composite rock stratum directional drilling and fracturing forward alternating operation method according to claim 1, characterized in that: After step S600, the method further includes: The completed borehole mouth section is sealed with cement slurry.

3. The composite rock stratum directional drilling and fracturing forward alternating operation method according to claim 1, characterized in that: The directional drilling parameters include drilling depth, height and horizontal displacement offset.

4. The composite rock formation directional drilling and fracturing forward alternating operation method according to claim 1, characterized in that: The length L of each drilling single segment may be the same or different.

5. The composite rock formation directional drilling and fracturing forward alternating operation method according to claim 1, characterized in that: The length L of each drilling single segment is 30-50m.

6. The composite rock stratum directional drilling and fracturing forward alternating operation method according to any one of claims 1 to 5, characterized in that: While performing the step of washing the hole of the drilled single segment during the drill withdrawal process, the method further includes: The drill bit is controlled to rotate so as to trim the wellbore wall of the drilled single segment where the fracturing operation is completed.

7. The composite rock stratum directional drilling and fracturing forward alternating operation method according to any one of claims 1 to 5, characterized in that: The distance between the hole sealer and the bottom of the hole of the drilling single segment is greater than or equal to 40m.

8. The composite rock stratum directional drilling and fracturing forward alternating operation method according to claim 7, characterized in that: The hole sealer is a rubber tube hole sealer.

9. The forward alternating operation method for directional drilling and fracturing in composite rock formations according to claim 7, characterized in that: The drill bit rotates at a constant speed during the drilling withdrawal process.

10. The composite rock stratum directional drilling and fracturing forward alternating operation method according to claim 7, characterized in that: During the drilling withdrawal process, the water pressure of the hole flushing output gradually increases in the direction close to the hole mouth.

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