| 聚能射流侵彻页岩储层损伤裂隙形成机制 |
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| 引用本文： | 牟恭雨,罗宁,申涛,梁汉良,柴亚博,翟成.聚能射流侵彻页岩储层损伤裂隙形成机制[J].爆炸与冲击,2023,43(3):85-101. |
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| 作者姓名： | 牟恭雨 罗宁 申涛 梁汉良 柴亚博 翟成 |
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| 作者单位： | 1.中国矿业大学深部岩土力学与地下工程国家重点实验室，江苏 徐州 221116 |
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| 基金项目： | 国家重点研发计划（2020YFA0711800）；国家自然科学基金（12072363）；徐州市重点研发计划（KC21301）；爆炸科学与技术国家重点实验室开放基金（KFJJ22-02M） |
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| 摘 要： | 为研究药型罩对聚能射孔弹侵彻页岩储层的射孔和损伤致裂效果的影响机理，建立了射孔弹-空气-页岩三维模型，设置药型罩的锥角分别为50°、60°、70°和80°，壁厚分别为0.5、1.0和1.5 mm，材料分别为铜、钢、钛和钨。利用ANSYS/LS-DYNA软件进行数值计算，分别从射流速度与形态、页岩射孔效果及页岩孔裂隙形成规律特征等进行系统性分析。研究结果表明：在射孔弹结构中，随着药型罩锥角的减小，射流速度提高、杵体速度降低、侵彻深度增大同时开孔孔径减小。在一定范围内，适当减小药型罩的壁厚，可以提高射流速度、减小杵体质量、增大侵彻深度和开孔倾斜度。药型罩材料对射流速度、杵体结构和页岩射孔效果均有显著影响，其中钨药型罩射孔弹的侵彻深度最大但开孔孔径最小，钛药型罩射孔弹的侵彻深度最小但开孔倾斜度最大，铜比钢药型罩射孔弹的侵彻深度略大但开孔孔径略小。通过研究不同对照组的页岩孔裂隙形成规律特征发现，页岩孔裂隙发育主要发生在杵体对页岩的再扩孔阶段，减小射流初始扩孔孔径、增大杵体直径、提高杵体速度，可以促进页岩孔裂隙发育程度。
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| 关 键 词： | 聚能射孔 页岩储层 药型罩 裂隙扩展 射孔弹-空气-页岩三维模型 |
| 收稿时间： | 2022-04-27 |
Mechanism of damage-induced fracture formation in shale reservoir penetrated by shaped charge jet |
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| Affiliation: | 1.State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China2.State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China3.School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China4.School of Safety Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China |
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| Abstract: | To study the influence mechanism of shaped charge liner on the perforation and damage-induced fracturing effect of shale reservoir by shaped charge penetration, a three-dimensional perforating charge-air-shale model was established. The cone angles of the liner are 50°, 60°, 70°, and 80°. The liner thicknesses are 0.5 mm, 1.0 mm, and 1.5 mm. And the materials of the liner are copper, steel, titanium, and tungsten. The numerical calculation was carried out using the ALE-Lagrangian coupling method in the non-linear program ANSYS/LS-DYNA. The ALE method was used to describe shell, explosive, liner, and air, while the Lagrangian method was used to describe the shale reservoir. A systematic analysis was carried out on the aspects of jet velocity and shape, shale perforation effect, and fracture extension characteristics of shale. The results show that with the decrease of the cone angle of the liner, the jet velocity and penetration depth increase, and the pestle velocity and perforation diameter decrease. In a certain range, with the decreasing liner thickness, the jet velocity, penetration depth, and perforation inclination increase, and the mass of the pestle decrease. The liner material significantly influences the jet velocity, pestle structure, and shale perforation effect. Among them, the penetration depth of perforating charge with a tungsten liner is the largest, but the perforation diameter is the smallest, the penetration depth of perforating charge with a titanium liner is the smallest, but the perforation inclination is the largest, and the penetration depth of perforating charge with a copper liner is slightly larger than that with a steel liner, but the perforation diameter is slightly smaller. Because the detonation pressure has an obvious difference before and after the detonation wave transmitted to the end of the explosive, which affects the jet velocity and penetration depth, the charge with a shell has a greater jet velocity and penetration depth than the charge without a shell. By comparing the fracture extension characteristics of shale in different groups, it is found that the fracture extension of shale mainly occurs in the stage of re-reaming of a pestle on shale. It is concluded that the material and structure of the liner have a significant influence on the shaped charge jet and its penetration effect, which then affects the damage-induced fracture formation and extension in shale. The fracture extension of the shale can be promoted by reducing the initial perforation diameter of penetration, increasing the diameter of the pestle, and increasing the speed of the pestle. |
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