A tool for balancing multi-formation drill bit impact loads

Abstract

This utility model discloses a tool for balancing impact loads on drill bits in multiple formations. The lower end of a splined shaft extends movably into a splined sleeve, and the two are connected via a spline joint. The lower end of the splined shaft is connected to the upper end of an extension shaft, which in turn extends movably into a lower connector. A sealing sleeve is connected to the lower end of the splined sleeve, and the lower end of the sealing sleeve is connected to the lower connector. An installation chamber is formed between the extension shaft, the lower connector, and the sealing sleeve. A limiting step is provided on the outer circumference of the extension shaft within the installation chamber. A piston is installed in the installation chamber to the left of the limiting step, and a mechanical elastic element and a hydraulic elastic element are installed in the installation chamber to the right of the piston. This utility model's high and low drilling pressure balancing can automatically switch according to the real-time stress conditions of the drill bit, achieving optimal application effects when the drill bit is working in different formations. It achieves the purpose of isolating impact loads under different formations and drilling pressures during drilling, preventing drill string breakage, and ensuring the safety and stability of oil and gas extraction.

Description

Technical Field

[0001] This utility model relates to a tool for balancing the impact load of multi-formation drill bits, belonging to the technical field of oil and gas extraction equipment. Background Technology

[0002] In oil and gas drilling operations, the drill bit must first cut through the rock to reach the predetermined well depth before subsequent extraction operations can proceed. During drilling, due to the need for rock breaking, the drill bit pressure is typically an intermittent impact load with an impact nature. The reaction force of this load is borne by the drill string connected to the drill bit. Over long-term use, the drill string is highly susceptible to fatigue failure, leading to drill string breakage and posing a significant risk to drilling operations. Therefore, a tool is needed to balance the drill bit pressure, isolate the adverse effects of the impact load on the drill string, and prevent drill string breakage.

[0003] With the development and utilization of oil and gas resources, oil and gas drilling and production must continuously expand to new blocks, new depths, and new formations. The development direction of horizontal wells, ultra-deep wells, and shale formations has led to a gradual diversification of drilling technologies, and the formation structure during drilling is becoming more diverse and variable.

[0004] The current diversity of geological formations means that the required drilling pressure impact load varies when drill bits penetrate different layers such as sedimentary rock, gravel, soft rock, and hard rock, which places higher demands on the drill bit's drilling pressure balancing impact load operation.

[0005] In summary, the diversification and complexity of drilling processes have led to variable drill bit pressure requirements. Traditional drill pressure balancing tools require manual identification of formations and tool selection, and cannot adaptively adjust drill pressure. Furthermore, current drill bits cannot adapt to the impact of drill pressure in different formations, making load balancing difficult. Utility Model Content

[0006] The purpose of this invention is to provide a tool for balancing the impact load of drill bits in multiple formations. This tool can be used simultaneously in different formations and with different drilling pressures during drilling, meeting the different drilling requirements in a single operation, achieving the purpose of balancing the impact load during drill bit drilling, preventing drill string breakage, and ensuring the safety and stability of oil and gas extraction.

[0007] The technical solution of this utility model is as follows: A tool for balancing the impact load of multi-stratum drill bits includes a spline shaft. The lower end of the spline shaft extends movably into a spline sleeve, and the two are connected by a spline pair. The lower end of the spline shaft is connected to the upper end of an extension shaft. The lower end of the extension shaft extends movably into a lower connector. A sealing sleeve is connected to the lower end of the spline sleeve, and the lower end of the sealing sleeve is connected to the lower connector. An installation chamber is formed between the extension shaft, the lower connector, and the sealing sleeve. A limiting step is provided on the outer periphery of the extension shaft in the installation chamber. A piston is installed in the installation chamber on the left side of the limiting step. The length of the installation chamber is greater than the length of the piston. A mechanical elastic element and a hydraulic elastic element are installed in the installation chamber on the right side of the piston. The two ends of the mechanical elastic element abut against the upper end face of the limiting step and the lower connector, respectively.

[0008] In the aforementioned tool for balancing the impact load of multi-stratum drill bits, sealing grooves are provided on the inner and outer walls of the piston and in the inner hole at the upper end of the lower connector, and sealing elements are inserted into the sealing grooves.

[0009] In the aforementioned tool for balancing multi-stratum drill bit impact loads, the upper end of the spline shaft has an internal thread, the lower end is threaded to the extension shaft, the two ends of the sealing sleeve are threaded to the spline sleeve and the lower connector respectively, and the lower end of the lower connector has an external thread.

[0010] In the aforementioned tool for balancing multi-stratum drill bit impact loads, the outer periphery of the spline shaft has a variable diameter structure with a larger upper diameter and a smaller lower diameter. When the lower end face of the spline sleeve contacts the upper end face of the extension shaft, there is a gap between the outer periphery step of the spline shaft and the upper end face of the spline sleeve.

[0011] In the aforementioned tool for balancing multi-formation drill bit impact loads, the outer periphery of the extension shaft has a double-step structure with gradually decreasing dimensions, and the second step is a limiting step.

[0012] The beneficial effects of this invention are as follows: Compared with the prior art, the multi-formation drill bit impact load balancing tool of this invention, during the drilling process, forces the spline shaft to move inward under pressure due to the drill bit impact load. The space of the mechanical and hydraulic elastic elements is compressed, generating a reaction force to counteract the drill bit impact load. At the same time, by utilizing the buffering characteristics of the elastic elements, dynamic balance is achieved during the drilling process, isolating the impact load from the upper drilling tools and preventing drilling accidents.

[0013] When the drill bit pressure requirement is low, a single mechanical elastic element is used to balance the reaction force of rock formations with low impact load requirements, such as soft rock or sedimentary rock formations, to achieve drill bit pressure balance. When the drill bit pressure requirement is high, a combination of mechanical and hydraulic elastic elements is used to obtain a higher force to balance the reaction force of rock formations such as hard rock or gravel layers, thus achieving drill bit pressure balance.

[0014] This invention's high and low drilling pressure balancing mechanism can automatically switch according to the real-time stress conditions of the drill bit, achieving optimal application results when the drill bit is working in different formations. It isolates impact loads under different formations and drilling pressures during drilling, preventing drill string breakage and ensuring the safety and stability of oil and gas extraction. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the structure connecting the spline shaft and the spline sleeve via a spline pair.

[0017] Reference numerals: 1-Splined shaft, 2-Splined sleeve, 3-Extension shaft, 4-Lower connector, 5-Sealing sleeve, 6-Limiting step, 7-Piston, 8-Mechanical elastic element, 9-Hydraulic elastic element, 10-Seal. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0019] An embodiment of this utility model: A tool for balancing the impact load of multi-stratum drill bits includes a spline shaft 1, the lower end of which extends movably into a spline sleeve 2 and is connected to the other via a spline pair. The lower end of the spline shaft 1 is connected to the upper end of an extension shaft 3, and the lower end of the extension shaft 3 extends movably into a lower connector 4. A sealing sleeve 5 is connected to the lower end of the spline sleeve 2, and the lower end of the sealing sleeve 5 is connected to the lower connector 4. An installation chamber is formed between the extension shaft 3, the lower connector 4, and the sealing sleeve 5. A limiting step 6 is provided on the outer periphery of the extension shaft 3 in the installation chamber. A piston 7 is installed in the installation chamber on the left side of the limiting step 6, and the length of the installation chamber on the left side is greater than the length of the piston 7. A mechanical elastic element 8 and a hydraulic elastic element 9 are installed in the installation chamber on the right side of the piston 7. The two ends of the mechanical elastic element 8 abut against the upper end face of the limiting step 6 and the lower connector 4, respectively.

[0020] Sealing grooves are provided on the inner and outer walls of the piston 7 and in the inner hole at the upper end of the lower connector 4. A sealing element 10 is inserted into the sealing groove to seal the installation chamber on the right side, preventing the hydraulic elastic element 9 from overflowing and preventing the drilling fluid in the drilling fluid passage hole inside the tool from seeping into the installation chamber.

[0021] The upper end of the spline shaft 1 has an internal thread for easy connection to the upper drill bit. The outer thread of the lower end of the spline shaft 1 is threaded to the inner thread of the extension shaft 3. The inner threads of the two ends of the sealing sleeve 5 are respectively threaded to the outer threads of the spline sleeve 2 and the lower connector 4. The lower end of the lower connector 4 has an external thread for easy connection to the lower drill bit.

[0022] The spline shaft 1 has a variable diameter structure with a larger diameter at the top and a smaller diameter at the bottom, forming a step on its outer circumference. When the lower end face of the spline sleeve 2 contacts the upper end face of the extension shaft 3, there is a gap between the step on the outer circumference of the spline shaft 1 and the upper end face of the spline sleeve 2. This gap is the travel distance of the spline shaft 1. When the spline shaft 1 moves downward and its outer step abuts against the upper end face of the spline sleeve 2, the spline shaft 1 cannot continue to move downward. As the drill bit continues to drill downward, the lower connector 4, the sealing sleeve 5, and the spline sleeve 2 will descend accordingly, increasing the gap between the step on the spline shaft 1 and the upper end face of the spline sleeve 2.

[0023] The outer periphery of the extension shaft 3 has a double-step structure with gradually decreasing dimensions. The second step is a limiting step 6. The space between the limiting step 6 and the first step is the mounting chamber on the left side, i.e., the mounting chamber of the piston 7. Figure 1 As shown, the distance the piston 7 moves is between the end of the piston 7 and the first step.

[0024] This utility model's multi-formation drill bit impact load balancing tool is directly installed between the drill bit and the upper drilling tool via threaded connections at both ends of the drill string. During normal drilling, torque is transmitted through the spline movement between the spline shaft 1 and the spline sleeve 2. Under pressure, the spline shaft 1 moves inward into the tool, compressing the space between the mechanical elastic element 8 and the hydraulic elastic element 9, generating a reaction force to counteract the drill bit impact load. Simultaneously, utilizing the buffering characteristics of the elastic elements, dynamic balance is achieved during the drilling process, isolating the impact load from the upper drilling tool and preventing drilling accidents.

[0025] When the drill bit penetrates soft rock or sedimentary rock layers, where impact load requirements are low, the spline shaft 1 undergoes a small displacement movement into the tool under pressure. The space of the mechanical elastic element 8 is compressed, generating a small reaction force to balance the drilling pressure. The hydraulic elastic element 9, due to the movement distance of its internal piston 7, moves in the opposite direction, balancing the area change caused by fluid compression. The hydraulic elastic element 9 is then in a non-working state.

[0026] When the drill bit penetrates hard rock or gravel layers—strata requiring high impact loads—the spline shaft 1 undergoes significant displacement into the tool under pressure. This compresses the space of the mechanical elastic element 8, generating a reaction force to balance the drilling pressure. The piston 7 moves in the opposite direction to its maximum distance, and the hydraulic elastic element 9 engages, generating a reaction force to balance the drilling pressure. The combined reaction forces of the mechanical and hydraulic elastic elements 8 achieve the desired balance against the high drill bit impact load.

[0027] The following are the various components that constitute this utility model:

[0028] Spline shaft 1: Connects to the drill bit via a drill string connection thread. A spline structure is provided on the outer circumference of the middle section, which mates with the spline sleeve 2 to transmit motion torque. Sealing surfaces and connecting threads are provided at both ends of the spline structure. The sealing surfaces, through their mating with the spline sleeve 2 and the seal 10, achieve sealing of the tool's internal cavity. The connecting threads connect and seal with the extension shaft 3 and the seal 10. The inner bore has drilling fluid flow holes. (The spline structure is preferably an involute spline.)

[0029] Spline sleeve 2: A spline structure is provided on the right side of the inner hole, which cooperates with the spline shaft 1 to transmit motion torque. A sealing groove structure is provided on the left side of the inner hole, which seals the tool cavity through cooperation with the spline shaft 1 and the seal 10. The two end faces cooperate with the spline shaft 1 and the extension shaft 3 respectively to achieve the upper and lower limits of the tool.

[0030] Extension shaft 3: The inner hole is provided with a connecting thread to connect and seal with the splined shaft 1 and the seal 10. A piston moving surface is provided in the middle of the outer circumference to allow the piston 7 to move. A spring limiting step 6 is provided on the right side of the piston moving surface to compress and release the mechanical elastic element 8 during movement. A sealing surface is provided on the right outer circumference to mate with the lower connector 4. The inner hole is provided with a drilling fluid passage.

[0031] Piston 7: Both its inner and outer surfaces are provided with sealing grooves, which cooperate with the seal 10 to achieve internal and external sealing. During operation, piston 7 is in a free state, and its movement balances the internal cavity pressure.

[0032] Sealing sleeve 5: Threads are provided on both sides, connecting to spline sleeve 2 and lower connector 4 respectively, to transmit torque and pressure. (The thread structure is a tapered self-sealing thread.)

[0033] Lower connector 4: Connects to the upper drill string via a drill string connection thread. The inner bore has a drilling fluid passage. The left end inner bore has a sealing groove, which cooperates with the extension shaft 3 and the seal 10 to achieve an inner cavity seal. The outer circumference has threads, connecting to the sealing sleeve 5.

[0034] The extension shaft 3, piston 7, sealing sleeve 5, and lower connector 4 form a sealed cavity, inside which mechanical elastic element 8 and hydraulic elastic element 9 are installed.

[0035] The tool of this utility model is a dynamic balancing tool that can adapt to various formations (soft formations, hard formations, gravel layers, etc.) and different drilling pressure impacts. During the drilling process, it can automatically adjust, buffer and offset the impact load of the drill bit, protect the drill string, prevent breakage, and improve drilling safety and efficiency.

[0036] Two types of compressible elastic elements (mechanical and hydraulic) achieve dynamic balance of impact loads through an internal piston mechanism. When the formation and drilling pressure change, "adaptive load balance" is achieved through either "mechanical elastic element 8 acting alone" or "mechanical elastic element 8 + hydraulic elastic element 9 acting together". This allows for "real-time balance of impact loads" during drilling.

Claims

1. A tool for balancing multi-stratum drill bit impact loads, characterized in that: The device includes a spline shaft (1), the lower end of which extends into a spline sleeve (2) and is connected to the other end via a spline pair. The lower end of the spline shaft (1) is connected to the upper end of an extension shaft (3), and the lower end of the extension shaft (3) extends into a lower connector (4). A sealing sleeve (5) is connected to the lower end of the spline sleeve (2), and the lower end of the sealing sleeve (5) is connected to the lower connector (4). An installation chamber is formed between the extension shaft (3), the lower connector (4), and the sealing sleeve (5). A limiting step (6) is provided on the outer periphery of the extension shaft (3) in the installation chamber. A piston (7) is installed in the installation chamber on the left side of the limiting step (6). The length of the installation chamber is greater than the length of the piston (7). A mechanical elastic element (8) and a hydraulic elastic element (9) are installed in the installation chamber on the right side of the piston (7). The two ends of the mechanical elastic element (8) abut against the upper end face of the limiting step (6) and the lower connector (4), respectively.

2. The tool for balancing multi-stratum drill bit impact loads according to claim 1, characterized in that: Sealing grooves are provided on the inner and outer walls of the piston (7) and in the inner hole at the upper end of the lower connector (4), and sealing elements (10) are inserted into the sealing grooves.

3. The tool for balancing multi-stratum drill bit impact loads according to claim 1, characterized in that: The upper end of the spline shaft (1) is provided with an internal thread, and the lower end is threaded to the extension shaft (3). The two ends of the sealing sleeve (5) are threaded to the spline sleeve (2) and the lower connector (4) respectively. The lower end of the lower connector (4) is provided with an external thread.

4. The tool for balancing multi-stratum drill bit impact loads according to claim 1, characterized in that: The outer periphery of the spline shaft (1) has a variable diameter structure with a larger upper diameter and a smaller lower diameter. When the lower end face of the spline sleeve (2) contacts the upper end face of the extension shaft (3), there is a gap between the outer periphery step of the spline shaft (1) and the upper end face of the spline sleeve (2).

5. A tool for balancing multi-stratum drill bit impact loads according to claim 1, characterized in that: The outer periphery of the extension shaft (3) is a double-step structure with gradually decreasing size, and the second step is a limiting step (6).

Images