盐穴储库水平对接井造腔物理模拟实验

1.中国石油盐穴储气库技术研究中心;2.中国石油储气库分公司;3.华北石油管理局有限公司江苏储气库分公司

盐穴储库;对接井造腔;地层倾角;循环方式;垫层控制;腔体形态;排卤浓度

Physical simulation experiment on horizontal docking well leaching for salt cavern storage
WANG Jianfu1,JIN Zuoliang2,LI Jianguang2,JIA Jianchao3,ZHU Kuoyuan3,ZHOU Zhaoheng1

1.PetroChina Research Center of Salt-Cavern UGS Technology;2.PetroChina Gas Storage Company;3.Huabei Petroleum Administration Jiangsu Gas Storage Company

salt cavern storage, docking well leaching, formation dip, circulation mode, cushion control, cavern shape, brine concentration

DOI: 10.6047/j.issn.1000-8241.2024.08.009

备注

【目的】水平对接井造腔是一种高效的盐穴建造方法,采用垫层阻溶可以较好地控制对接井腔体形态。但该造腔方式尚未应用于对接井,其对腔体形态及排卤浓度的影响规律尚不明确,无法有效指导现场技术应用。【方法】基于现有盐企采卤方式特点及存在的问题,提出采用垫层阻溶双井交替注水、分阶段上提造腔管柱与垫层的对接井造腔方式。基于相似理论搭建实验平台,开展新造腔方式下的对接井造腔物理模拟实验,采用江苏淮安盐矿某一对接井现场实际数据验证了实验模型的准确性,随后分析了地层倾角、注水排量、垫层及管柱控制、注水循环方式对腔体形状及排卤质量浓度的影响。【结果】水平对接井造腔腔体形态呈U形,腔体体积大,排卤质量浓度高,相对于单直井具有显著优势;地层倾角的存在会增加水平通道高度,降低直井注水时的排卤质量浓度;大排量可扩展腔体体积,增大水平通道及两侧腔体尺寸;垫层控制对腔体形状影响较大,垫层长期停留在同一位置易出现平顶状畸形,而管柱控制对腔体形状影响较小;存在地层倾角时,注水循环方式会显著影响腔体形态与排卤质量浓度。【结论】水平对接井造腔是一种高效的造腔方式,具有腔体形状可控、排卤浓度高等优点,可作为未来盐穴储库造腔技术的主要发展方向,但室内实验研究具有局限性,应加强该造腔方式的现场试验研究。(图 12表3,参[18]
[Objective] Horizontal docking well leaching is prevalently applied among salt chemical enterprises for brine extraction. However, controlling the cavern shape becomes challenging when this technique is utilized, primarily due to the absence of dissolution inhibitor cushions. Although this cushion method is commonly employed in salt cavern storage to improve cavern shape control, it has not been applied to docking well leaching. To effectively guide the field application of this method, research into the influence patterns of dissolution inhibitor cushions on the cavern shapes resulting from docking well leaching and brine concentrations is necessary. [Methods] Based on the characteristics and deficiencies of brine extraction methods currently applied by salt enterprises, a novel approach for docking well leaching was introduced. This process involves alternating water injection between two wells equipped with dissolution inhibitor cushions and the phased lifting of tubing strings for leaching and cushions. Based on the similarity theory, an experimental platform was set up for physical simulations of docking well leaching using the proposed approach. The accuracy of the simulation results was verified through a comparison with field data collected from a docking well at Huai'an Salt Mine in Jiangsu Province. Furthermore, this study delved into the influence patterns of various factors on cavern shapes and mass concentrations in brine displacement, including formation dips, displacements, cushion and tubing string control, as well as water injection circulation modes. [Results] The caverns produced by horizontal docking well leaching optimized by dissolution inhibitor cushions exhibited U-shaped configurations with substantial volumes and high brine concentrations, surpassing those achieved by a single vertical well setup. The presence of formation dips led to elevated horizontal channels and decreased mass concentrations in brine displacement during water injection into the vertical well. Significant displacements contributed to increased cavern volumes, expanded horizontal channels, and enlarged caverns on both sides. Cushion control notably impacted cavern shapes, with prolonged retention at the same position leading to flat tops. Conversely, tubing string control had minimal influence on cavern shapes. Additionally, in the presence of formation dips, the water injection circulation modes notably influenced cavern shapes and mass concentrations in brine displacement. [Conclusion] The horizontal docking well leaching enhanced by dissolution inhibitor cushions offers an efficient way of leaching, showcasing benefits such as manageable cavern shapes and elevated brine concentrations. This technique stands out as a dominant area for the advancement of leaching methods in salt cavern storage. Nevertheless, given the constraints of laboratory research, future efforts should prioritize conducting field experiments. (12 Figures, 3 Tables, 18 References)
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