A borehole wall impact coring device
By designing a wall-impact coring device, multiple coring devices can operate simultaneously. The stable connection of the hard electrode and the optimization of the core tube solve the safety and efficiency problems of side-drilling coring in small wellbore, and improve the coring success rate and electrical logging accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA NAT PETROLEUM CORP
- Filing Date
- 2025-08-29
- Publication Date
- 2026-06-16
AI Technical Summary
The existing small-diameter side-drilled windowed well coring operations suffer from poor passability, frequent obstruction and jamming, insufficient electrode strength of the coring gun, and easy entanglement between the core tube and the recovery wire rope, resulting in low safety, low efficiency and limited coring volume, which makes it difficult to meet the needs of efficient oilfield development.
Design a wellbore impact coring device, which uses multiple coring device bodies connected in series, uses hard electrodes with detachable connections, optimizes the size and taper of the core cylinder, ensures electrode stability and core integrity, reduces contact with the wellbore, and installs explosives to assist coring.
It improves core sampling efficiency and safety, reduces downhole risks, enhances electrode tensile strength, ensures core integrity and originality, and reduces construction cycle and cost.
Smart Images
Figure CN224363913U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of oil and gas reservoir exploration technology and relates to a wellbore impact coring tool. Background Technology
[0002] To reduce the cost of new drilling and investment in surface infrastructure, small-diameter wells such as 152mm and 118mm are the main method for re-entering reservoirs by opening windows in old wells for side-drilling, which has become an important technical route for the economic development of old oilfields.
[0003] In existing small-bore side-drilled windowed well coring operations, percussion coring guns with an outer diameter of 89mm are commonly used. However, this outer diameter has poor maneuverability within the narrow annulus of a small wellbore. Especially after loading coring cartridges, the irregular shape of the gun body leads to frequent encounters with obstruction and jamming during the lowering process, threatening operational safety and significantly extending the construction period. Furthermore, only one coring gun can be carried down the well at a time, and after coring a single point, the drill string must be pulled out to replace the gun body, resulting in extremely limited coring capacity per trip, which is insufficient to meet the needs of efficient oilfield development.
[0004] The soft electrode structure used in existing coring guns is insufficiently strong under the high temperature, vibration, and friction conditions downhole, resulting in a high electrode damage rate and frequent failures in coring signal transmission, directly affecting the success rate of operations. Furthermore, after firing the coring gun, entanglement easily occurs between the core barrel and the retrieval wire rope, increasing the difficulty of on-site handling and increasing the risk of the core barrel falling into the well or losing rock samples, thus reducing the effective coring rate. This makes the traditional 89mm coring gun unsuitable for the safe and efficient coring requirements of small-diameter sidetracking. Utility Model Content
[0005] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a well wall impact coring device.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] This utility model provides a wellbore impact coring tool, including a coring tool body. The coring tool body is provided with several connection holes for installing a core tube. One end of the coring tool body is provided with a male connector or a gun tail cone, and the other end is provided with a female connector. The male connector, gun tail cone, and female connector are fixedly connected to the coring tool body. The male connectors and female connectors on two adjacent coring tool bodies are detachably connected. The coring tool body is detachably connected to a hard electrode for measuring the apparent resistivity of the formation rock.
[0008] Furthermore, the diameter of the connecting hole decreases continuously from top to bottom.
[0009] Furthermore, the outer diameter of the core extractor body is 70~80mm.
[0010] Furthermore, the height of the core tube is 50~60mm.
[0011] Furthermore, the outer diameter of the core tube is 30~40mm.
[0012] Furthermore, the inner diameter of the core tube is 10~20mm.
[0013] Furthermore, the depth of the core tube is 30~40mm.
[0014] Furthermore, the taper of the core tube is 21.59°.
[0015] Furthermore, the tail end of the core tube is used to mount explosives.
[0016] Furthermore, the connecting holes are adapted to the core tube, and the number of connecting holes is 20 to 24.
[0017] Compared with the prior art, the present invention has the following beneficial technical effects:
[0018] This invention relates to a wellbore impact coring device, which connects multiple coring device bodies in series via male and female connectors, enabling the simultaneous deployment of 2-3 devices in a single well operation during cable-driven coring. This significantly improves the efficiency of coring operations, greatly saving time and costs compared to traditional coring devices that can only operate individually at a time, while also reducing the risks associated with downhole operations.
[0019] This utility model discloses a wellbore impact coring device. The coring device body and hard electrode are detachably connected. It is used to measure the apparent resistivity of formation rocks. It significantly enhances the tensile strength of the electrode and can maintain a stable working state in harsh downhole environments, making it less prone to damage.
[0020] This utility model discloses a well wall impact coring device. The height of the core cylinder is optimized to help reduce the overall length of the equipment and avoid excessive contact with the well wall during the well running process.
[0021] This utility model discloses a well wall impact coring device, in which the outer and inner diameters of the core tube are optimized to ensure that the core tube can hold enough core and maintain good sealing, preventing damage to the core during the extraction process.
[0022] This invention relates to a wellbore impact coring device, in which the depth of the core tube is optimized to facilitate the complete extraction of the core.
[0023] This utility model discloses a wellbore impact coring device. The taper of the core tube is optimized to ensure the guidance and stability of the core tube during the impact process, prevent the core tube from deviating during coring, and improve the success rate and efficiency of coring.
[0024] This utility model discloses a wellbore impact-type core sampler. The tail end of the core tube is used to install explosives, which reduces the impact of drilling fluid on the core sample and ensures the originality and accuracy of the sample.
[0025] This utility model discloses a wellbore impact coring device. Two adjacent coring device bodies are connected by a male and female threaded connector, which not only enhances flexibility but also facilitates on-site maintenance and component replacement, thereby improving operational efficiency. Attached Figure Description
[0026] Figure 1 This is a front view of a wellbore impact coring device according to the present invention;
[0027] Figure 2 This is a top view of a wellbore impact coring device according to the present invention;
[0028] Figure 3 This is a schematic diagram of the core tube structure in an embodiment of this utility model.
[0029] Figure label:
[0030] 1-Coring device body; 2-Connecting hole; 3-Core cylinder. Detailed Implementation
[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. 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 should fall within the protection scope of the present invention.
[0032] Example 1
[0033] This utility model provides a small-diameter wellbore impact coring tool, such as... Figure 1 He Ru Figure 2 As shown, the device includes a core sampler body 1, which has several connection holes 2 for mounting a core cylinder 3. One end of the core sampler body 1 has a male connector or a gun tail cone, and the other end has a female connector. The male connector, gun tail cone, and female connector are fixedly connected to the core sampler body 1. The male and female connectors on adjacent core sampler bodies 1 are detachably connected. The core sampler body 1 is detachably connected to a hard electrode for measuring the apparent resistivity of the formation rock. Measuring the formation resistivity using a hard electrode ensures the accuracy of the core sampling location and the representativeness of the core sample.
[0034] In this embodiment, the diameter of the coring device body 1 is 76mm. To ensure good maneuverability and self-unsticking capability even in narrow wellbore environments, the 76mm diameter of the coring device body 1 considers both the minimum allowable clearance of the wellbore and the physical properties of the coring device itself, allowing for flexible movement even in complex well conditions. Furthermore, the coring device body 1 is made of high-strength, lightweight materials, such as aerospace-grade aluminum alloy, to ensure its durability under high pressure and high stress environments and to control its overall weight, facilitating operation and handling by personnel.
[0035] The core sampler body 1 has several connecting holes 2 for installing the core tube 3. The connecting holes 2 are arranged in a horizontal row, with their diameters gradually decreasing from top to bottom. This is to provide initial guidance when the core tube 3 enters the connecting holes, and to allow for rapid unlocking when the core tube 3 exits, preventing core loss due to locking failure during downhole operations. The number of connecting holes 2 is adapted to the number of core tubes 3; in this embodiment, one core sampler body 1 has 20 connecting holes.
[0036] The core sampler body 1 has a male connector and a female connector at both ends for connecting adjacent core sampler bodies 1. Two adjacent core sampler bodies 1 are connected by a threaded connection between the male and female connectors. Multiple core sampler bodies 1 can be connected together for simultaneous wellbore operations, increasing the number of core samples that can be obtained in a single operation and reducing the risks and costs associated with multiple well runs. One end of the core sampler body 1 is equipped with a male connector or a gun tail cone, and the other end has a female connector. The male connector, gun tail cone, and female connector all engage with the core sampler body 1 to ensure structural stability.
[0037] like Figure 3 As shown, the core tube 3, as a key component for collecting core samples, ensures maximum core recovery by optimizing its height, while also reducing its weight and volume for easier transportation and handling. The height of the core tube 3 is 5-6 mm; in this embodiment, the height is 5.35 cm, ensuring sufficient core length while minimizing damage to the core during the core extraction process.
[0038] The outer diameter of the core tube 3 is 30-40 mm. In this embodiment, the outer diameter of the core tube 3 is 3.19 cm. By reducing the outer diameter of the core tube 3, it can fit tightly with the connecting hole 2 on the core sampler body 1, thus enhancing the stability of the core tube 3. The smaller outer diameter helps to improve the core recovery rate because the contact area between the core tube 3 and the well wall is reduced, thus reducing wear on the core during the extraction process.
[0039] The inner diameter of the core tube 3 is 10-20 mm. In this embodiment, the inner diameter of the core tube 3 is 1.71 cm. By setting the inner diameter of the core tube 3, the integrity and quality of the core are ensured, and the core is also easy to retrieve and preserve. This reduces deformation of the core during the core extraction process and maintains the original state of the core.
[0040] The depth of the core tube 3 is 30~40mm. In this embodiment, the depth of the core tube 3 is 3.82cm. The depth of the core tube 3 is closely related to the ballistic design of the core sampler body 1. If the depth is too shallow, it may not be possible to obtain a complete core. If it is too deep, it will increase the length of the core sampler and affect its passage in the wellbore.
[0041] The taper of core tube 3 is 21.59°. By setting the taper of core tube 3, the contact mode of core tube 3 on the well wall is optimized, thereby improving the efficiency and success rate of core sampling.
[0042] In summary, the dimensions of core tube 3 have been carefully designed. Its height is optimized to 5.35cm, lower than traditional core tubes, which helps reduce the overall length of the equipment and avoids excessive contact with the wellbore during lowering. The outer diameter is 3.19cm and the inner diameter is 1.71cm, ensuring that core tube 3 can hold sufficient core material while maintaining good sealing, preventing damage during extraction. The depth of core tube 3 is 3.82cm; this greater depth compared to its width contributes to the complete extraction of the core. The bottom taper of core tube 3 is set at 21.59°, an angle chosen to create the optimal core extraction shape when penetrating the formation.
[0043] The tail end of core tube 3 is used to install explosives, which reduces the impact of drilling fluid on the core sample and ensures the originality and accuracy of the sample.
[0044] This utility model discloses a small-diameter wellbore impact coring device that employs hard electrodes, significantly enhancing the electrodes' tensile strength and enabling them to maintain stable operation in harsh downhole environments, making them less prone to damage. The hard electrodes are used on a 76mm core depth calibration electrode, matching the coring device body 1 to ensure the accuracy of electrical logging data. Combined with a 12.4mm high-strength cable and an 8K tension bar, the entire electrical logging system can withstand greater tensile forces, reducing engineering accidents caused by cable breakage or electrode damage and improving operational safety. Furthermore, the use of hard electrodes extends electrode lifespan and reduces maintenance costs.
[0045] This invention relates to a small-diameter wellbore impact coring device. Multiple coring device bodies 1 are connected in series, allowing for the simultaneous deployment of 2-3 devices in a single well operation during cable-driven coring. This significantly improves the efficiency of coring operations, enabling the collection of more than 72 core samples per well run. Compared to traditional coring devices that can only operate individually, this greatly saves time and costs, while also reducing downhole operational risks.
[0046] This utility model discloses a method for using a small-diameter well wall impact coring device:
[0047] First, the core sampler body 1 is connected to the hard electrode. Then, multiple core sampler bodies 1 are connected in series via male and female connectors to form a core sampler string. Next, the core tubes 3 are sequentially inserted into the core sampler bodies 1 according to the size and shape of the connecting holes 2, ensuring the stability and positioning accuracy of the core tubes 3. Subsequently, explosives are installed at the tail end of the core tubes 3, ready for core sampling. During operation, when the predetermined core sampling position is reached, the hard electrode measures the apparent resistivity of the formation rock to ensure the accuracy of the core sampling position. Then, the explosives are detonated, and the instantaneous high pressure and high-speed impact force generated by the explosion are used to extract the core from the wellbore and collect it into the core tubes 3.
[0048] In summary, this utility model provides a small-bore side-drilling wall impact coring tool, which can not only save a lot of drilling and surface construction costs, but also make use of old well sites, upper sections of old wells and geological data to achieve efficient and low-cost directional development.
[0049] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
Claims
1. A wellbore impact coring device, characterized in that: The device includes a core sampler body (1), which has several connection holes (2) for installing a core tube (3). One end of the core sampler body (1) is provided with a male connector or a gun tail cone, and the other end is provided with a female connector. The male connector, gun tail cone, and female connector are fixedly connected to the core sampler body (1). The male connector and female connector on two adjacent core sampler bodies (1) are detachably connected. The core sampler body (1) is detachably connected to a hard electrode for measuring the apparent resistivity of the formation rock.
2. The wellbore impact coring device according to claim 1, characterized in that: The diameter of the connecting hole (2) decreases continuously from top to bottom.
3. The wellbore impact coring device according to claim 2, characterized in that: The outer diameter of the core extractor body (1) is 70~80mm.
4. The wellbore impact coring device according to claim 3, characterized in that: The height of the core tube (3) is 50~60mm.
5. The wellbore impact coring device according to claim 4, characterized in that: The outer diameter of the core tube (3) is 30~40mm.
6. The wellbore impact coring device according to claim 5, characterized in that: The inner diameter of the core tube (3) is 10~20mm.
7. The wellbore impact coring device according to claim 6, characterized in that: The depth of the core tube (3) is 30~40mm.
8. The wellbore impact coring device according to claim 7, characterized in that: The taper of the core tube (3) is 21.59°.
9. The wellbore impact coring device according to claim 8, characterized in that: The tail end of the core tube (3) is used to install explosives.
10. The wellbore impact coring device according to claim 9, characterized in that: The connecting hole (2) is adapted to the core tube (3), and the number of connecting holes (2) is 20 to 24.