›› 2013, Vol. 34 ›› Issue (6): 1-1.

• 论文 •    

层间滑移对缝高延伸影响的模拟分析

赵金洲,彭 瑀,李勇明   

  1. (西南石油大学 油气藏地质及开发工程国家重点实验室,成都 610500)
  • 出版日期:2019-01-01 发布日期:1905-07-14

Modeling Analysis of Effect of Interlayer Slip on Fracture Height Growth

ZHAO Jinzhou, PENG Yu, LI Yongming   

  1. (State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China)
  • Online:2019-01-01 Published:1905-07-14

摘要: 由不整合面和薄夹层形成的结构弱面会造成层间滑移,从而抑制水力裂缝的垂向延伸。其裂缝几何形态往往扭曲成含有水平组分的复杂裂缝,因而无法使用常规方法进行模拟与定量分析。为确定层间滑移对裂缝高度的控制作用,在非连续分布正应力等效平面缝的理论基础上,考虑静态和动态两种应力强度因子,建立了包含净压力、缝高、地层应力、断裂韧性、水平段长度及其距裂缝中心距离等参数的数学模型。编程计算的结果显示,垂向扭曲结构形成的压降有可能高于隔层应力差,层间滑移对缝高延伸有显著的控制作用,在压裂选井选层中应考虑将起裂点布置在薄层附近的适当位置,以达到减小缝高延伸、增加缝长的目的。

Abstract: Structural weak surfaces formed by geological structures such as unconformity and thin interlayer, etc. will lead to interlayer slip and restrain the growth of hydraulic fracture height. The fractures geometrics tend to distorting into complex fractures with horizontal components, which could not be modeled and quantitatively analyzed by conventional method. In order to determine the effect of the interlayer slip on hydraulic fracture height growth, this paper presents dynamic and static stress intensity factors to develop a mathematical model based on the theory of equivalent planar fracture. The mathematical model involves a series of parameters such as net pressure, fracture height, in?situ stress, fracture toughness, horizontal interval length and its distance from central fracture. The computed result shows that the pressure drops formed by vertical distorting structure could be higher than the stress difference of interlayers or barriers, and the interlayer slip has a significant controlling effect on the hydraulic fracture height growth. Therefore, in the process of well? and layer?selection for hydraulic fracturing, the fracturing starting?up position should be properly arranged near the thin layers so as to decrease the fracture height propagation and increase the fracture length

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