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The formation of boreholes in tectonically deformed coal (TDC) seams is challenging, hindering the efficient exploitation of coalbed methane (CBM) resources. The reciprocating multi-stage reaming drilling technology presents a promising solution for realizing the formation of horizontal wells in TDC seams that are broken, high-pressure, and collapse-prone. To investigate it, an engineering-geological model was established to conduct physical simulation tests of multi-stage reaming drilling in horizontal wells of the TDC seams using the 11–2 TDC seam of Zhangji Mine in the Huainan Mining District as the geological prototype. Reformed tectonic coal was used to simulate the natural stratum, and drilling parameters were recorded. The test obtained a 110 mm borehole to simulate the reality of 550 mm, and the final hole was 284% of the initial one, which achieved the target and completed the design requirements. During the process, the drilling thrust force and drilling speed remained stable, while the torque increased progressively, and the unsupported borehole wall remained intact after completion. The laboratory results demonstrate that the reciprocating multi-stage reaming drilling technology can be applied in TDC seams.HighlightsThe multi-stage reaming drilling technology improves coal methane resource exploitation by forming horizontal wells in tectonically deformed coal seams.Engineering-geological model, simulation tests using samples of tectonic coal confirm technology's suitability for tectonic coal seams.Completed experimental simulation of multi-stage reaming drilling in the laboratory to provide a reference example for field drilling.

Reaming is a processing method for widening pilot holes such as drill holes and press holes to obtain a highly accurate finish. However, in machining using a regular-pitch reamer, polygonal deformation of the borehole occurs. This deformation is also called a spiral mark because the polygonal shape twists in the feed direction. Although several papers have dealt with vibration phenomena during reaming, countermeasures to date have not been sufficient. In previous studies, the authors considered polygonal deformation of a machined hole during reaming as a self-excited vibration caused by a time delay and clarified its mechanism. In the present study, we theoretically and experimentally investigated the suppression of polygonal deformation by optimizing the angular arrangement of the cutting edges of irregular-pitch reamers for an 8-flute reamer. In addition, we suggested a new evaluation standard to reduce the calculation load and to evaluate the optimum angular arrangement of the irregular-pitch cutting edges of reamers with other numbers of flutes.

The connecting hole sleeve of the engine bracket is an important component to ensure the reliable installation of the satellite engine. In actual production, the inner and outer connecting hole sleeves of the bracket are connected by gluing and screwing, and finally the fastening components are installed by drilling and reaming. The traditional adhesive curing cycle standard does not apply to this situation. In this paper, the influence of different curing time on the reaming operation of the connecting hole sleeve was studied through the development of the process test. The test conclusions have reached the shortest curing period of the glue that can ensure sufficient connection strength of the hole sleeve, and put forward suggestions for improvement. The test method in this article has reference significance for related research in other industries.

The geothermal production well often experiences a decline in performance during the production period. The decline of performance can be caused by several factors such as wellbore problem or scale deposition inside the wellbore. Well intervention is a method used to restore the performance of production well. One production well in the Patuha Geothermal Field experienced a decline in performance due to calcite scaling. This well had an initial production of 12.7 MW (based on well testing) but experienced a decline in performance to 2 MW. Several well intervention works have been carried out in this well, such as work over mechanical reaming and acidizing, bullhead acidizing, and well washing. In 2024, the rigless well intervention method was carried out in this well using coil tubing unit for mechanical reaming, hydraulic jetting, and feed zone acidizing. Mechanical reaming was carried out with several bit size to clean out the well. Hydraulic jetting was carried out to optimize the well clean out, but the hydraulic jetting bottom hole assembly (BHA) could not pass to the liner section. Acidizing using a new approach that combined the milling BHA was carried out to dissolve the scale in the feed zone. The results show that the well performance increased by 133% from its previous condition after the rigless well intervention.

During the assembly process of a large-scale aircraft fuselage, critical bearing areas require the drilling of intersecting holes, which are commonly processed using traditional single-edged reamers by most domestic manufacturers. To improve the efficiency and accuracy of the finishing process for these holes, enhance the quality of the assembly, and further shorten the construction cycle for precision processing, improvements need to be made to traditional single-edge reamer machining methods. This paper proposes a new approach that uses stepped reamers to machine intersecting holes. By setting up an experimental platform to simulate actual processing conditions and optimize processing parameters, the study analyzes and compares the quality and efficiency of traditional reaming and stepped reaming modes. The results show that stepped reaming can improve processing efficiency by 50.6% compared to traditional machining while also reducing human intervention and minimizing quality risks. The findings from this research project can be extended to various aircraft fuselages or wings for precise drilling of intersecting holes, providing significant guidance for efficient and high-quality delivery of aircraft.

The beryllium bronze guide sleeve and the aluminum alloy valve body are assembled to form a beryllium bronze-aluminum alloy stepped hole which requires multiple positioning and tool changes during machining, resulting in lower machining efficiency and accuracy. The geometry error and surface quality of beryllium bronze-aluminum alloy stepped holes after reaming were studied in this research. The geometric error (cylindricity, concentricity and verticality) and diameters of the stepped holes were measured by using a three-coordinate measuring machine. The experimental results show that the PCD forming cutters has high geometric error and diameter stability when reaming beryllium bronze-aluminum alloy stepped holes. Under various cutting parameters, the cylindricity of stepped holes was guaranteed to be within 6μm, and the concentricity of stepped holes was guaranteed to be within 6μm, and verticality of stepped holes was guaranteed to be within 2μm. With the increase of spindle speed and feed per tooth, the diameters of beryllium bronze holes increase while the diameters of aluminum alloy holes decrease and then increase. As the cutting allowance increases, the diameters of the beryllium bronze holes and aluminum alloy holes decrease. The laser confocal microscope and scanning electron microscope were used to detect and analyze the surface quality of beryllium bronze-aluminum alloy stepped holes after reaming. The experimental results show that the surface roughness of the beryllium bronze-aluminum alloy stepped holes reamed by using the PCD forming cutter were less than 0.3μm, and the surface roughness of the beryllium holes were slightly larger than the aluminum holes. The fourth group of experimental parameters (spindle speed 1290r/min, feed per tooth 0.01mm/z, cutting allowance 0.06mm) was selected as the actual processing parameters. There are cavities on the surface of the initial stepped holes before reaming and the cavities basically disappear after reaming, so the surface quality of the beryllium bronze-aluminum alloy stepped holes has been greatly improved.

Rockburst has always been a worldwide tricky problem in the mining industry, and reaming borehole pressure relief technology has technological superiority in preventing and controlling rockbursts. To investigate the influence of different borehole parameters on the mechanical properties, crack evolution and energy change laws of specimens, confined compression experiments were performed on specimens with different borehole diameters, reaming lengths and spacing. First, the theoretical analysis of the reaming borehole pressure relief mechanism is conducted, illustrating the effect of borehole parameters determining the stress distribution characteristics around the borehole. Then, the effect of the borehole parameters on the mechanical behavior is analyzed in detail. The test results indicated that the larger the diameter, the reaming length and the smaller the borehole spacing, the lower the peak strength and elastic modulus. Furthermore, the relationship between failure behaviour and borehole diameters is analyzed based on the AE behavior and fracture characteristics. Finally, the analysis of internal energy evolution further confirmed that increasing the borehole diameter, reaming length, and reducing the borehole spacing can increase the dissipation strain energy to achieve a better pressure relief effect.HighlightsA new reaming borehole pressure relief technology is proposed, which could reduce the damage to the shallow anchored surrounding rock while achieving effective pressure relief of the deep surrounding rock.The prefabricated borehole specimens are tested to study the influence of borehole parameters on mechanical behavior.The energy evolution characteristics of specimens with prefabricated reaming boreholes are analyzed to better understand the pressure relief mechanism.

Low dimensional transition metal carbide and nitride (MXenes) have been emerging as frontier materials for energy storage and conversion. Ti3C2Tx was the first MXenes that discovered and soon become the most widely investigated among the MXenes family. Interestingly, Ti3C2Tx exhibits ultrahigh catalytic activity towards the hydrogen evolution reaction. In addition, Ti3C2Tx is electronically conductive, and its optical bandgap is tunable in the visible region, making it become one of the most promising candidates for the photocatalytic hydrogen evolution reaction (HER). In this review, we provide comprehensive strategies for the utilization of Ti3C2Tx as a catalyst for improving solar-driven HER, including surface functional groups engineering, structural modification, and cocatalyst coupling. In addition, the reaming obstacle for using these materials in a practical system is evaluated. Finally, the direction for the future development of these materials featuring high photocatalytic activity toward HER is discussed.

In order to solve the problem of deep hole processing, the inner reaming of small ends and large middle is difficult to process. Developed and designed a detachable deep hole variable diameter boring tool device with self-centering, replaceable tools, and capable of changing the same diameter of the guide block and the tool and with self-locking function. Introduce in detail the structural features, assembly conditions and design principles of the detachable deep hole variable diameter boring cutter device. It provides an effective solution for the processing of inner reaming in deep holes.

SiCp/Al, as a new material, is widely used for its excellent wear resistance, corrosion resistance and other properties. Micro-holes are important but difficult to obtain on this ceramic material especially in curved surface. In this paper, taking micro bearing bush as an example, a micro-EDM and in-situ micro-reaming method is put forward for preparing micro through holes and micro eccentric holes on SiCp/Al cambered surface, without secondary clamping or tool change. High machining efficiency, low wear and no recasting layer can be achieved by this method. Here, machining characteristics is studied in hole micro-EDM on SiCp/Al, small taper and high efficiency machining is realized by comparing four electrical discharge drilling technique. Carbon deposition and tool wear are related to electrical parameters according to experimental exploration. After determining the discharge gap, taper and recast layer thickness, a segmented tool is designed, which can use the lower part to perform micro-EDM with the taper of 1.04°, MRR is 0.069 mm 3 /min, and the TWR is 3.22%. Then only needs to continue feeding the tool, the upper part of the tool can be used to achieve reaming, which can fully remove the recast layer, and decreases the roughness of hole wall from Ra 1.452 μm to Ra 0.803 μm.