Automatic drilling stopping drilling tool for leakage formation

Abstract

The invention is suitable for the technical field of geological exploration, and provides a leakage stratum automatic stopping drilling tool which comprises an outer pipe, a drill rod connector is installed at the top of the outer pipe, an inclined hole is formed in the drill rod connector, an outer drill bit is installed at the bottom of the outer pipe, a connecting pipe is arranged in the outer pipe, and a spring seat is connected to the bottom of the connecting pipe. A spring is installed at the bottom of the spring seat, a connecting rod is further arranged below the connecting pipe, the top of the connecting rod is connected with a supporting seat, the bottom of the connecting rod is sequentially connected with a coring pipe and a check valve seat, a check valve ball is installed on the check valve seat, and the bottom end of the coring pipe is connected with an inner drill bit. According to the device, a circulation channel of drilling fluid is sealed in time when a leakage stratum is drilled through the telescopic drilling tool structure, the leakage amount of the drilling fluid into stratum cracks and holes can be remarkably reduced, the supplement cost of the drilling fluid is reduced, and the economical efficiency and efficiency of drilling operation are improved. And a safer and more stable underground environment is provided for drilling operation.

Description

Technical Field

[0001] The invention belongs to the technical field of geological exploration, and in particular relates to an automatic drilling stop tool for lost formations. Background Art

[0002] As a core tool in geological exploration, core drilling technology, through directional sampling of underground cores, provides an irreplaceable scientific basis for understanding the laws of Earth's evolution, exploring the distribution of mineral resources, and assessing geological hazard risks. However, in complex geological environments, drilling operations often face the technical bottleneck of "loose formations." The resulting loss of drilling fluid control not only causes direct economic losses but can also trigger cascading engineering disasters, severely restricting exploration efficiency and operational safety.

[0003] Engineering problems caused by drilling fluid loss exhibit a pronounced chain reaction. Initially, they manifest as material loss. At current market prices, high-performance drilling fluid costs approximately 2,000 to 5,000 yuan per cubic meter, and direct losses from a single hole loss often reach millions of yuan. This relay effect leads to a drastic drop in operational efficiency. In a southwestern metal mining exploration project, non-productive time due to fluid loss management accounted for 38% of the total project duration. This can ultimately lead to catastrophic failures. An investigation into a shale gas well collapse in 2018 revealed that the cause was a pressure system collapse caused by improperly managed fracture-induced fluid loss. This cascading effect also manifests itself in equipment loss. A drill tool system deprived of drilling fluid lubrication experiences significant changes in its vibration spectrum. Laboratory simulations have shown that abnormal vibration can shorten bearing life by 80%. Furthermore, reduced wellbore cleanliness exacerbates the risk of drill bit balling. Statistics show that balling can reduce ROP by 70% to 90%.

[0004] At present, in the process of geological core drilling, there are mainly the following common methods to deal with the problem of drilling fluid loss in the lost formation, but they all have certain defects:

[0005] Increasing drilling fluid density: This method balances formation pressure and prevents fluid loss into formation fractures. However, increasing drilling fluid density too high increases fluid flow resistance, increasing energy consumption during drilling, and subjecting the drill bit and drilling tools to greater pressure and friction, potentially damaging the tools and equipment and reducing drilling efficiency. Furthermore, for some formations with low fracture pressure, increasing drilling fluid density may exceed the fracture pressure, exacerbating fractures and leakage, and even leading to more serious downhole accidents.

[0006] Use of plugging materials: Plugging materials, such as fibrous substances and granular substances, are added to the drilling fluid to form a plugging layer in the fractures of the formation, preventing the drilling fluid from continuing to leak. However, the performance and application range of plugging materials are limited. Different types of leaking formations (such as fracture leakage, porous leakage, etc.) require different plugging materials. If the selection is inappropriate, the plugging effect will be greatly reduced. Secondly, in actual operation, the addition and mixing process of plugging materials is relatively complicated, and the dosage and mixing time need to be precisely controlled. Otherwise, the performance of the drilling fluid may deteriorate, affecting the normal progress of the drilling operation. Moreover, even if the plugging is successful, leakage may occur again during the subsequent drilling process, requiring repeated plugging operations, which increases operation time and cost.

[0007] Adjusting drilling parameters: By reducing drilling speed and bit pressure, the impact and pressure of the drilling fluid on the formation can be reduced, thereby lowering the risk of fluid loss. However, this approach has the disadvantage that lowering drilling parameters directly leads to decreased drilling efficiency, prolonged drilling cycles, and increased drilling costs. Especially in deep drilling or drilling in complex formations, excessively low drilling parameters can hinder smooth drilling operations and even prevent the desired drilling depth and objectives from being achieved.

[0008] In summary, the existing technical methods for dealing with the loss of drilling fluid in lost formations have certain limitations and shortcomings and cannot fundamentally and effectively solve this problem. Therefore, it is necessary to develop a new drilling tool structure to overcome the defects of the existing technology. Summary of the Invention

[0009] The purpose of the embodiments of the present invention is to provide a drilling tool that automatically stops drilling in a lost formation, aiming to solve the problems raised in the above-mentioned background technology.

[0010] The embodiment of the present invention is realized as follows: a drilling tool for automatically stopping drilling in a lost formation comprises an outer tube, a drill pipe joint is installed on the top of the outer tube, an inclined hole for inflow of drilling fluid is provided on the drill pipe joint, an outer drill bit is installed on the bottom of the outer tube, a connecting pipe is installed at one end of the inner part of the outer tube close to the drill pipe joint, and the top end of the connecting pipe is connected to the lower end of the drill pipe joint, the bottom of the connecting pipe is connected to a spring seat, the bottom of the spring seat is installed with a spring, and a spring is further provided below the connecting pipe. A connecting rod, the top of which is connected to a support seat, and the bottom of the connecting pipe is provided with a countersunk hole matching the support seat, the spring is connected to the boss at the lower end of the connecting rod, the bottom of the connecting rod is connected to the core tube and the check valve seat in sequence, a check valve ball is installed on the check valve seat, the diameter of the check valve ball is larger than the inner hole diameter of the check valve seat, and the ball is placed on the upper part of the check valve seat to block the center hole of the check valve seat; the bottom end of the core tube is connected to an inner drill bit, and always maintains a downward movement tendency under the thrust of the spring;

[0011] An annular gap is formed between the outer tube and the core tube, and the drilling fluid flows into the hole from the gap between the outer drill bit and the inner drill bit through the annular gap.

[0012] According to a further technical solution, the drill rod joint and the outer drill bit are both connected to the outer tube via threads.

[0013] According to a further technical solution, the connecting rod and the support seat are connected via threads.

[0014] According to a further technical solution, the core tube and the check valve seat are both connected to the connecting rod via threads.

[0015] According to a further technical solution, a liner is further provided inside the core tube, and the top of the liner is connected to the connecting rod through threads.

[0016] An embodiment of the present invention provides a drill tool that automatically stops drilling in leaking formations. This device uses a retractable drill tool structure to promptly seal the circulation path of the drilling fluid when encountering a leaking formation. This can significantly reduce the amount of drilling fluid lost into formation cracks and pores, reduce the cost of replenishing drilling fluid and the workload of frequent mixing, and improve the economy and efficiency of drilling operations. It provides a safer and more stable downhole environment for drilling operations, ensures the safety of personnel and equipment, and reduces potential safety risks and economic losses. It reduces the waste of drilling fluid and emissions to the surrounding environment, reduces the pollution and impact of drilling operations on the environment, meets the environmental protection requirements of sustainable development, and is conducive to promoting the development of the geological core drilling industry in a green and environmentally friendly direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic structural diagram of a drilling tool for automatically stopping drilling in a leaking formation provided by an embodiment of the present invention.

[0018] In the accompanying drawings: drill pipe joint 1; outer pipe 2; connecting pipe 3; support seat 4; connecting rod 5; spring seat 6; spring 7; core pipe 8; check valve seat 9; check valve ball 10; liner 11; outer drill bit 12; inner drill bit 13. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0021] like Figure 1As shown, an automatic drilling stop tool for lost formation provided by one embodiment of the present invention comprises an outer tube 2, a drill pipe joint 1 is installed on the top of the outer tube 2, an inclined hole for inflow of drilling fluid is provided on the drill pipe joint 1, an outer drill bit 12 is installed at the bottom of the outer tube 2, a connecting pipe 3 is installed at one end of the inner part of the outer tube 2 close to the drill pipe joint 1, and the top of the connecting pipe 3 is connected to the lower end of the drill pipe joint 1, the bottom of the connecting pipe 3 is connected to a spring seat 6, the bottom of the spring seat 6 is installed with a spring 7, and a connecting pipe 3 is also provided below the connecting pipe 3. Rod 5, the top of the connecting rod 5 is connected to the support seat 4, and the bottom of the connecting pipe 3 is provided with a countersunk hole matching the support seat 4, the spring 7 is connected to the boss at the lower end of the connecting rod 5, and the bottom of the connecting rod 5 is connected to the core tube 8 and the check valve seat 9 in sequence. A check valve ball 10 is installed on the check valve seat 9, the diameter of which is larger than the inner hole diameter of the check valve seat 9, and is placed on the upper part of the check valve seat 9 to block the center hole of the check valve seat 9; the bottom end of the core tube 8 is connected to the inner drill bit 13, and always maintains a downward movement trend under the thrust of the spring 7;

[0022] An annular gap is formed between the outer tube 2 and the core tube 8 , and the drilling fluid flows into the hole from the gap between the outer drill bit 12 and the inner drill bit 13 through the annular gap.

[0023] In an embodiment of the present invention, during use, the drill tool is connected via a drill pipe joint 1. The drilling fluid enters the interior of the outer tube 2 through the inclined hole on the drill pipe joint 1, flows within the annular gap between the outer tube 2 and the core tube 8, and ultimately flows into the hole through the gap between the outer drill bit 12 and the inner drill bit 13, and returns to the orifice via the gap between the outer tube 2 and the borehole. The drill pipe joint 1 is connected to the connecting tube 3 via threads, and transmits torque and drilling pressure to the various components at the bottom. The support seat 4, supported by the spring 7, abuts against the countersunk hole of the connecting tube 3. The connecting rod 5 and the support seat 4 are connected via threads, and the spring seat 6 is sleeved on the outside of the connecting rod 5. Under the thrust of the spring 7, the connecting rod 5 and the core tube 8 always maintain a downward movement trend. During the drilling process, under the action of formation resistance, the inner drill bit 13 moves upward to drive the core tube 8, the core tube 8 drives the connecting rod 5 upward, the connecting rod 5 drives the support seat 4 upward, and enters the countersunk hole at the bottom of the connecting pipe 3 to realize the upper limit. During the drilling process, the outer drill bit 12 and the inner drill bit 13 rotate together to crush the rock to obtain the core. The lower part of the connecting rod 5 is connected to the check valve seat 9, and a check valve ball 10 is arranged on the upper part of the check valve seat 9. The outer diameter of the check valve ball 10 is larger than the inner diameter of the check valve seat. The check valve seat 9 and the check valve ball 10 together form a check ball valve to ensure that the drilling fluid can flow out of the core tube 8 during the drilling process, and the external drilling fluid will not enter the core tube 8 to erode the core; when encountering a lost formation, the inner drill bit 13 loses the resistance of the formation. Under the thrust of the spring 7, the connecting rod 5 drives the core tube 8 downward, and the lower part of the core tube 8 presses against the inner wall of the outer drill bit 12, blocking the circulation path of the drilling fluid. At this time, the drilling fluid in the drill tool is retained inside the drill tool to ensure that there will be no large-scale leakage of drilling fluid. At the same time, the drilling fluid pressure rises instantly, and the pressure of the surface mud pump increases instantly until the pump stops working. The surface operator determines that a leakage formation has been encountered and can then carry out leakage formation treatment.

[0024] As a preferred embodiment of the present invention, the drill rod joint 1 and the outer drill bit 12 are both connected to the outer tube 2 via threads. The threaded connection facilitates assembly and disassembly of the components.

[0025] As a preferred embodiment of the present invention, the connecting rod 5 and the supporting seat 4 are connected via threads.

[0026] As a preferred embodiment of the present invention, the core tube 8 and the check valve seat 9 are both connected to the connecting rod 5 through threads.

[0027] As a preferred embodiment of the present invention, a liner 11 is further provided inside the core tube 8, and the top of the liner 11 is threadedly connected to the connecting rod 5. The liner 11 can be removed after coring is completed, thereby ensuring the integrity of the core.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A drilling tool for automatically stopping drilling in a lost formation, characterized in that: The top of the connecting rod is connected to the support seat, and the bottom of the connecting rod is provided with a countersunk hole matching the support seat, and the spring is connected to the boss of the lower end of the connecting rod, and the bottom of the connecting rod is connected to the core tube and the check valve seat in turn, and the check valve seat is installed on the check valve seat, the diameter of the check valve seat is larger than the inner hole diameter of the check valve seat, and is placed on the upper part of the check valve seat to block the center hole of the check valve seat; the bottom end of the core tube is connected to the inner drill bit, and always maintains a downward movement under the thrust of the spring; An annular gap is formed between the outer tube and the core tube, and the drilling fluid flows into the hole from the gap between the outer drill bit and the inner drill bit through the annular gap.

2. The automatic drilling stop tool for lost formation according to claim 1, characterized in that: The drill rod joint and the outer drill bit are both connected to the outer pipe through threads.

3. The automatic drilling stop tool for lost formation according to claim 1, characterized in that: The connecting rod and the supporting seat are connected via threads.

4. The automatic drilling stop tool for lost formation according to claim 1, characterized in that: The core pipe and the check valve seat are both connected to the connecting rod through threads.

5. The automatic drilling stop tool for lost formation according to claim 1, characterized in that: A liner is further provided inside the core pipe, and the top of the liner is connected to the connecting rod through threads.

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