东北大学学报(自然科学版) ›› 2022, Vol. 43 ›› Issue (11): 1613-1622.DOI: 10.12068/j.issn.1005-3026.2022.11.013

• 资源与土木工程 • 上一篇    下一篇

基于PHF-LSM模型岩石分段水力压裂应力阴影效应

李明, 陈昭, 赵岐, 梁力   

  1. (东北大学 资源与土木工程学院, 辽宁 沈阳110819)
  • 发布日期:2022-12-06
  • 通讯作者: 李明
  • 作者简介:李明(1980-),男,辽宁沈阳人,东北大学副教授; 梁力(1955-),男,辽宁丹东人,东北大学教授,博士生导师.
  • 基金资助:
    中央高校基本科研业务费专项资金资助项目(N2001015).

The Stress Shadow Effect of Multistage Hydraulic Fracturing of Rock Material Based on PHF-LSM Model

LI Ming, CHEN Zhao, ZHAO Qi, LIANG Li   

  1. School of Resources & Civil Engineering, Northeastern University, Shenyang 110819, China.
  • Published:2022-12-06
  • Contact: LI Ming
  • About author:-
  • Supported by:
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摘要: 采用PHF-LSM(permeability-based hydraulic fracture-level set method)水力压裂数值计算模型,模拟并分析了均质与分层岩石材料中分段压裂过程引起的应力阴影效应.通过与单一裂缝诱发应力理论解的对比,验证了PHF-LSM考虑应力阴影效应的可行性.以此模型为基础分析了单一裂缝发展过程中,岩石材料参数与初始应力条件对诱发应力场的影响,以及均质与分层岩石材料的多裂缝起裂过程中不同压裂间距与压裂顺序产生的应力阴影效应.数值计算结果表明:泊松比、抗拉强度与孔隙率的增加会增大裂缝引起的诱发应力与净压力比值的峰值,而弹性模量和水平主应力差的增大会减小该峰值;裂缝间距的扩大可以减弱裂缝间应力阴影效应;两步压裂与顺序压裂的裂缝总面积均大于同时压裂时的面积,但顺序压裂与两步压裂会带来更高的起裂压力;产层厚度与压裂间距的减小会增大应力阴影效应.

关键词: 分段水力压裂;应力阴影;PHF-LSM模型;分层岩石材料

Abstract: The PHF-LSM(permeability-based hydraulic fracture-level set method)hydraulic fracturing numerical model is used to simulate and analyze the stress shadow effect caused by staged fracturing in homogeneous and layered rock materials. Compared with the theoretical solution of single crack induced stress, the feasibility of considering stress shadow effect in PHF-LSM is verified. Based on this model, the influence of rock material parameters and initial stress conditions on induced stress field during the development of single fracture, and the stress shadow effect caused by different fracturing spacing and fracturing sequence during the initiation of multiple fractures in homogeneous and layered rock materials were analyzed. The numerical results show that the increase of Poisson′s ratio, tensile strength and porosity will increase the peak value of the ratio of induced stress to net pressure, while the increase of elastic modulus and horizontal principal stress difference will decrease the peak value. The expansion of crack spacing can weaken the stress shadow effect between cracks. The total fracture area of the two-step fracturing and the sequential fracturing are larger than that of simultaneous fracturing, but sequential fracturing and two-step fracturing will cause higher fracture initiation pressure. The decrease of pay layer thickness and fracturing spacing will increase the stress shadowing effect.

Key words: multistage hydraulic fracturing; stress shadow; PHF-LSM model; layered rock material

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