A method and apparatus for core drilling with casing.

Abstract

This invention discloses a core drilling rig and casing drilling method and apparatus, relating to the field of geological drilling technology. The method employs a core drilling rig and casing drilling technique without altering the rig structure. Drilling begins with a casing and casing drill bit, using a core extraction method. When drilling reaches a certain depth and cannot continue, the casing and casing drill bit are placed directly inside the hole, and a wireline coring tool is used. Drilling then begins from inside the casing using wireline coring. After drilling to a certain depth, if the fractured or quicksand layer has not been penetrated, casing drilling continues. After drilling to a certain depth, wireline coring is used again. These two methods are used repeatedly in combination until a stable stratum is reached, at which point wireline coring is switched back for normal drilling. This method solves drilling difficulties in quicksand and fractured layers, such as the inability to form a hole, saving construction costs, reducing labor intensity, and improving drilling efficiency.

Description

Technical Field

[0001] This invention relates to the field of geological drilling technology, and in particular to a core drilling rig casing drilling method and apparatus. Background Technology

[0002] Currently, in small-diameter core drilling, facing thick Quaternary overburden in some areas, conventional core drilling methods are simply unsuitable when encountering clay layers, quicksand layers, silt layers, or partially loose and fractured strata. Furthermore, conventional drilling methods often result in drilling accidents such as stuck drill bits and drill string burial, leading to low construction efficiency and high costs. Sometimes, even sacrificing efficiency and cost makes it difficult to continue drilling. Alternatively, after drilling to a certain depth, considering borehole structure issues, frequent casing runs are not feasible, resulting in delayed casing runs. Finally, due to the poor stability of the overlying strata, drilling failures occur. Borehole collapse and drill bit burial render previous work completely useless, necessitating restarting the drilling. However, even restarting often leads to the same problems, sometimes requiring repeated casing runs to achieve the drilling objective. Furthermore, the core drilling rigs commonly used for core drilling often have low torque and lifting capacity, making them unsuitable for larger diameter boreholes. Using high-torque rigs is impractical and extremely costly. Therefore, to successfully penetrate the overburden, it is essential to explore a reliable and practical drilling technique that meets the requirements of drilling operations and solves this technical challenge, ultimately achieving the designed borehole depth. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a core drilling rig casing drilling method and device. This method has the advantages of simple operation, simple supporting structure, safe operation, low accident rate, effective simplification and protection of the borehole structure, reduction of construction costs and labor intensity of workers, improvement of drilling efficiency, and wide process adaptability.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a core drilling rig casing drilling method, comprising the following steps:

[0006] The first step is to connect the core drilling rig's power head directly to the casing using a reducing connector, connect the casing to the drill bit, turn on the mud pump, and start drilling downwards using the conventional single-tube core drilling method. When drilling to the depth of the first hole, if the drilling rig torque increases and the drilling becomes difficult, it can be determined that the casing is already filled with core.

[0007] The second step is to remove the casing and casing drill bit, pour out the first core sample obtained during drilling, and re-insert it into the hole.

[0008] If the casing drill bit can reach the depth of the first hole drilled previously or near it, the casing casing with the casing drill bit can be used to continue drilling. If the drill torque is found to be too high when drilling to the depth of the third hole, continuing to drill will increase the drilling risk and drilling should not be continued.

[0009] If the position of the drill bit being lowered differs significantly from the depth of the first hole, assuming that position is the depth of the second hole, and the depth of the first hole is greater than the depth of the second hole, it can be determined that a collapse has occurred inside the hole, and continuing to drill will pose a risk of hole wall collapse, stuck drill bit, or burying drill bit.

[0010] When encountering either of the above two situations, the casing should be disconnected from the connection between the borehole and the power head, and the wireline coring tool should be connected and lowered into the borehole for wireline coring. When drilling to the first or third borehole depth, the wireline coring tool assembly should be removed, the casing tool should be reconnected, and casing drilling should continue.

[0011] The third step is to repeatedly drill in the first and second steps until the fourth hole depth of bedrock or stable strata is encountered. Then, directly put the casing and drill bit into the hole, lower the wireline coring tool and drill normally until the designed hole depth is reached.

[0012] Fourth, if the strata are very complex, increase the borehole diameter while meeting geological requirements;

[0013] Fifth, following the above method, add one or two more layers of tubing.

[0014] The present invention also provides an apparatus based on the above-described core drilling method for casing drilling, comprising a core drilling rig, a borehole holder, a casing, and a casing drill bit; the power head of the core drilling rig is connected to one end of the casing, and the other end of the casing is connected to the casing drill bit; the borehole holder is disposed above the borehole opening, and the borehole holder is used to prevent the casing from falling into the borehole.

[0015] Optionally, it also includes a core drill bit, a core drill inner tube assembly, a core drill outer tube, and a wireline core drill rod; the core drill inner tube assembly is disposed inside the core drill outer tube, the core drill outer tube is disposed inside the casing, the top of the core drill inner tube assembly is connected to the power head through the wireline core drill rod, and the bottom of the core drill inner tube assembly is connected to the core drill bit.

[0016] Optionally, a retrieval assembly is provided at the top of the inner tube assembly of the core drill bit, and the retrieval assembly is connected to the core wire rope.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] (1) This technical method can satisfy both the core sampling requirement and the drilling objective;

[0019] (2) This technical method does not require changes to the drilling rig structure or the addition of drilling rig accessories;

[0020] (3) This technical method can be used to perform core drilling and casing installation simultaneously, which can effectively protect the borehole wall and improve the quality and efficiency of hole formation.

[0021] (4) This technical method can basically meet the requirements for core extraction and will not result in repeated crushing or repetitive labor operations.

[0022] (5) This technical method is simple to operate, easy to learn and master, and will not cause major drilling accidents;

[0023] (6) When the strata are particularly loose, prone to collapse, and prone to accidents such as stuck drill or buried drill, the combination of casing drilling and wireline drilling can meet the drilling requirements and achieve the drilling purpose.

[0024] (7) Using this technology will not have a significant impact on the drilling structure;

[0025] (8) This process method has a wide range of applications and can be promoted to many fields to solve drilling technical problems such as thick overburden, difficulty in drilling or poor drilling quality, and easy drilling accidents.

[0026] (9) This technical method has no special requirements for mud; conventional mud can be used for wall protection.

[0027] (10) By adopting this technical method, construction costs can be reduced to the greatest extent, labor intensity of workers can be reduced, and hole formation efficiency can be improved. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the drilling depth of the core drilling rig and casing drilling method and apparatus of the present invention when drilling to the first hole depth;

[0030] Figure 2 This is a schematic diagram of the first hole depth and the second hole depth in the core drilling method and apparatus of the present invention;

[0031] Figure 3 This is a schematic diagram of the drilling method and apparatus of the core drilling rig of the present invention when drilling to the third hole depth;

[0032] Figure 4 This is a schematic diagram of the structure of the core drilling rig and casing drilling method and device of the present invention, which is used to extract the second core after drilling to the third hole depth.

[0033] Figure 5 This is a schematic diagram of the second core lifting process in the core drilling method and device of the present invention;

[0034] Figure 6 This is a schematic diagram of the structure of the core drilling rig casing drilling method and device of the present invention for obtaining a second core sample;

[0035] Figure 7 This is a schematic diagram of the structure of the core drilling rig and casing drilling method and device of the present invention, which is used to extract the second core after drilling to the fourth hole depth.

[0036] Explanation of reference numerals in the attached drawings: 1. Casing drill bit; 2. First core; 3. Casing casing; 4. Wellhead clamp; 5. Power head; 6. Core drilling rig; 7. Core drill bit; 8. Second core; 9. Inner tube assembly of the core drill bit; 10. Outer tube of the core drill bit; 11. Wireline core drill rod; 12. Retrieval device assembly; 13. Core wire rope; 14. Overburden. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figures 1 to 7 As shown, this embodiment provides a core drilling rig casing drilling method and apparatus. The apparatus used in the core drilling rig casing drilling method of this embodiment includes a core drilling rig 6, a borehole holder 4, a casing 3, a casing drill bit 1, a core drill bit 7, a core drill inner tube assembly 9, a core drill outer tube 10, a wireline core drill rod 11, a retrieval device assembly 12, and a core wire rope 13. The power head 5 of the core drilling rig 6 is connected to one end of the casing 3, and the other end of the casing 3 is connected to the casing drill bit 1. The borehole holder 4 is disposed above the borehole opening and is used to prevent the casing 3 from falling into the borehole.

[0039] When using this technique, the core drilling rig 6 power head 5 is directly connected to the casing 3 using a reducing connector. The casing is connected to the casing drill bit 1. The mud pump is turned on, and drilling begins according to the conventional single-tube coring method. When drilling reaches the first hole depth A, [the following is observed]. Figure 1If increased drilling torque and difficulty in advancing the borehole are observed, it can be determined that the casing is full of core material. At this point, the casing 3 and casing drill bit 1 should be removed, and the core material extracted during drilling should be emptied and lowered back into the hole. If the casing 3 and casing drill bit 1 can be lowered to or near the previously drilled first hole depth A, drilling can continue using the casing with the drill bit. If the position of the lowered casing drill bit differs significantly from the first hole depth A, assuming this position is the second hole depth B (first hole depth A > second hole depth B), see... Figure 2 At this point, it can be determined that a collapse has occurred inside the hole. Continuing to drill will risk hole wall collapse, drill bit jamming, or burying the drill bit. If the casing can be drilled down to near the first hole depth A and normal drilling continues, then when drilling reaches the third hole depth C, [the following is observed]. Figure 3 If the drilling torque is found to be too high, continuing drilling will increase the drilling risk and should not be continued. In either of these situations, the casing 3 must be disconnected from the connection between the casing and the power head 5 at the borehole opening, and the wireline coring drill rod 11 and the outer tube 10 of the coring tool should be connected and lowered into the borehole for wireline coring drilling. See [link to relevant documentation]. Figure 4 , Figure 5 and Figure 6 When drilling reaches the first hole depth A or the third hole depth C, remove and disconnect the wireline coring drilling assembly, reconnect the casing drilling assembly, and continue casing drilling, repeating the process. Figures 1 to 6 Drilling continued using technical methods until the fourth hole depth D was encountered, at which point... Figure 7 The casing 3 and casing drill bit can be directly placed into the hole, and the wireline coring drill bit can be lowered for normal drilling until the designed hole depth is reached. If the strata are very complex, the hole diameter can be increased while meeting geological requirements. By adding one or two more casing layers using the above method, drilling technical problems such as easy collapse of the overburden 14, stuck drill bit, and buried drill bit can be solved. This drilling technology method has been applied in multiple boreholes and has achieved good results.

[0040] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0041] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method of core drill follow-up pipe drilling, characterized by, The method comprises the following steps: In the first step, the core drill power head is directly connected with the tail pipe casing through a variable diameter joint, the tail pipe casing is connected with the tail pipe drill head, the mud pump is turned on, and the drilling is started according to the conventional single pipe coring drilling mode. When the drilling reaches the first hole depth, it is found that the drilling torque increases and the drilling footage is difficult, which indicates that the tail pipe casing is filled with core. In the second step, the tail pipe casing and the tail pipe drill head are removed, the first core obtained by extrusion during internal drilling is poured out, and the tail pipe casing is reinserted into the hole. If the tail pipe drill head can be lowered to the first hole depth or the vicinity thereof, the tail pipe casing with the tail pipe drill head is used to continue drilling. When the drilling reaches the third hole depth, the drilling torque is too large, and the drilling cannot be continued. If the position of the tail pipe drill head is greatly different from the first hole depth, and the first hole depth is greater than the second hole depth, it is determined that the hole has collapsed, and the drilling cannot be continued. When the above two conditions are encountered, the tail pipe casing is removed from the connection between the hole mouth and the power head, the rope coring drilling tool is connected, and the rope coring drilling is used. When the drilling reaches the first hole depth or the third hole depth, the rope coring drilling tool assembly is removed, the casing drilling tool is reconnected, and the casing drilling is continued. In the third step, the drilling is repeated according to the first step and the second step until the bedrock or the stable stratum is drilled to the fourth hole depth, the tail pipe casing and the drill tool are directly placed in the hole, the rope coring drilling is used, and the drilling is continued until the designed hole depth is reached. In the fourth step, when the stratum is very complex, the hole diameter is increased under the condition of meeting the geological requirements. In the fifth step, one or two layers of tail pipe casings are added according to the above method.

2. A coring rig follow-up drilling device for implementing the coring rig follow-up drilling method according to claim 1, characterized in that, The core drill, the hole mouth gripper, the tail pipe casing and the tail pipe drill head are connected. The power head of the core drill is connected with one end of the tail pipe casing, the other end of the tail pipe casing is connected with the tail pipe drill head, and the hole mouth gripper is arranged above the hole mouth to prevent the tail pipe casing from falling into the hole.

3. The core rig follow-up drilling apparatus according to claim 2, characterized by, The coring drill head, the coring drill tool inner pipe assembly, the coring drill tool outer pipe and the rope coring drill rod are further included. The coring drill tool inner pipe assembly is arranged in the coring drill tool outer pipe, the coring drill tool outer pipe is arranged in the tail pipe casing, the top of the coring drill tool inner pipe assembly is connected with the power head through the rope coring drill rod, and the bottom of the coring drill tool inner pipe assembly is connected with the coring drill head.

4. The core rig follow-up drilling apparatus according to claim 3, characterized in that, The top of the coring drill tool inner pipe assembly is provided with a fisher assembly connected with the coring wire rope.

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