石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (1): 229-240.doi: 10.11743/ogg20220119

• 方法技术 • 上一篇    下一篇

深层页岩油水平井密切割裂缝均衡扩展数值模拟

朱海燕1(), 徐鑫勤1, 钟安海2, 张钦希3   

  1. 1.成都理工大学 油气藏地质及开发工程国家重点实验室,四川 成都 610059
    2.中国石化 胜利油田分公司 石油工程技术 研究院,山东 东营 257000
    3.中国石化 胜利油田分公司 纯梁采油厂,山东 东营 257000
  • 收稿日期:2020-07-20 修回日期:2021-12-01 出版日期:2022-02-01 发布日期:2022-01-28
  • 第一作者简介:朱海燕(1984—),男,博士、教授、博士生导师,石油钻采岩石力学的教学和科研工作。E?mail:zhuhaiyan040129@163.com
  • 基金项目:
    国家自然科学基金项目(51874253);国家自然科学基金联合基金项目(U20A20265)

Numerical simulation of evenly propagating hydraulic fractures with smaller cluster spacing in the horizontal well YYP1 for deep shale oil in the Shengli Oilfield

Haiyan Zhu1(), Xinqin Xu1, Anhai Zhong2, Qinxi Zhang3   

  1. 1.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,Sichuan 610059,China
    2.Petroleum Engineering Technology Research Institute,Shengli Oilfield Company,SINIOPEC,Dongying,Shandong 257000,China
    3.Chunliang Oil Production Plant,Shengli Oilfield Company,SINOPEC,Dongying,Shandong 257000,China
  • Received:2020-07-20 Revised:2021-12-01 Online:2022-02-01 Published:2022-01-28

摘要:

中国页岩油储层非均质性强、粘度高和可改造性差,水平井分段多簇射孔体积压裂难以形成复杂的裂缝网络,单缝“缝控储量”低,必须寻求新的工艺突破。通过增加单个压裂段内的射孔簇簇数,使多个射孔簇裂缝在射孔段内均衡扩展,对页岩储层进行密切割,实现页岩油储层的充分改造,是中国页岩油高效开发的关键。考虑数千米长压裂管柱与射孔孔眼的摩阻以及多裂缝之间流体的竞争分配,建立页岩油水平井密切割多裂缝动态扩展的渗流-应力-损伤模型,并通过现场压裂施工数据验证其正确性。根据胜利油田页岩油储层的地质工程特征,开展射孔簇簇数、射孔孔眼数量、压裂施工参数等对多裂缝流体流量分配、应力干扰及裂缝几何形态影响的数值模拟研究发现:单簇裂缝扩展时,裂缝诱导应力最优波及距离为10 m左右;簇间距为10 m时,三簇裂缝均衡扩展射孔密度为20 孔/m,施工排量为12 m3/min,压裂液粘度为30 mPa·s;4个射孔簇时,压裂液均匀分配和裂缝均衡扩展的簇间距为10 m。此项研究为胜利油田页岩油勘探开发的突破奠定了理论基础。

关键词: 密切割, 多裂缝, 均衡扩展, 诱导应力, 渗流-应力-损伤模型, 水平井, 页岩油, 胜利油田

Abstract:

Shale oil in China is generally high in viscosity and stored in highly heterogeneous shale reservoirs, which often respond poorly to stimulation of staged volume fracturing (each stage) with multi?perforation clusters. Increasing the cluster number in each fracturing stage of a horizontal well to evenly facilitate fracture propagation has been considered an effective solution to the problem. This study is focused on the friction of fluids flowing through several thousand meters of fracturing strings and the perforation holes as well as the competition among fractures for the fluids, to establish a seepage-stress-damage model for the description of dynamic propagation of the fractures. The effectiveness of the model is demonstrated with actual fracturing data in the Shengli Oilfield, where numerical simulations were carried out to investigate the impact of different numbers of perforation clusters and perforation holes as well as varying fracturing parameters on fluid distribution, stress, and fracture geometry based on geological characteristics of shale oil reservoirs in the area. Findings include: The optimal propagation distance for crack?induced stress is ~10 m for fractures created by single perforation cluster. With a 10 m cluster spacing and three clusters, evenly propagated fractures can be achieved with a perforating density of 20 holes per meter with fluid displacement at 12 m3/min and fracturing fluid viscosity at 30 mPa·s. With four perforating clusters for each fracturing stage, the optimal cluster spacing is 10 m for an uniform distribution of fluid and even propagation of fractures being achieved. This study lies down a theoretical foundation for effective shale oil exploitation in the Shengli Oilfield.

Key words: smaller cluster spacing, multi fractures, even propagation, induced stress, seepage-stress-damage model, horizontal well, shale oil, Shengli oilfield

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