石油学报 ›› 2012, Vol. 33 ›› Issue (5): 841-845.DOI: 10.7623/syxb201205014

• 油田开发 • 上一篇    下一篇

裂缝性地层射孔井破裂压力计算模型

赵金洲 任 岚 胡永全 王 磊   

  1. 西南石油大学油气藏地质及开发工程国家重点实验室 四川成都 610500
  • 收稿日期:2012-02-08 修回日期:2012-06-25 出版日期:2012-09-25 发布日期:2012-11-27
  • 通讯作者: 赵金洲
  • 作者简介:赵金洲,男,1962年10月生,1982年毕业于西南石油学院采油工程专业,现为西南石油大学教授、博士生导师,主要从事油气田开采和增产新技术新理论的研究。
  • 基金资助:

    国家自然科学基金项目(No. 51074138)、国家重大科技专项(2011ZX05014)和中央财政支持地方高校发展专项资金“石油与天然气工程国家一级学科”项目资助。

A calculation model of breakdown pressure for perforated wells in fractured formations

ZHAO Jinzhou REN Lan HU Yongquan WANG Lei   

  • Received:2012-02-08 Revised:2012-06-25 Online:2012-09-25 Published:2012-11-27

摘要:

水力压裂是提高低渗透油气藏采收率的重要技术手段,准确地预测压裂井的破裂压力是水力压裂成功实施的关键步骤。目前的破裂压力计算模型基本都是针对均质地层,对于裂缝性地层破裂压力的预测计算一直是个非常复杂的问题。受地层天然裂缝的作用和影响,在裂缝性地层射孔井中水力裂缝可能会发生3种破裂模式,分别为沿孔眼壁面岩石本体破裂、沿天然裂缝剪切破裂和沿天然裂缝张性破裂。基于弹性力学和岩石力学理论,结合天然裂缝与孔眼相交的空间位置关系,考虑水力裂缝可能发生的3种破裂模式,建立了裂缝性地层射孔井的破裂压力计算模型。实例计算表明,所建立的计算模型能用于准确计算裂缝性地层射孔井的破裂压力,同时也能用于解释裂缝性地层近井地带多裂缝形成机理。

关键词: 裂缝性地层, 射孔井, 破裂模式, 破裂压力, 天然裂缝, 多裂缝

Abstract:

Hydraulic fracturing is a significant stimulation technique to enhance hydrocarbon recovery from low-permeability reservoirs. The accurate prediction of breakdown pressure of fractured formations is a crucial step to make hydraulic fracturing success. Current calculation models of breakdown pressure are basically designed for homogeneous formations, and it has been a very complicated issue to predict breakdown pressure of fractured formations all the time. Affected by the intersection of natural fractures and perforations, three breakdown modes of hydraulic fractures may occur in perforated wells of fractured formations, namely breakdown along perforated rock bodies, shear breakdown and tension breakdown along natural fractures. Based on elasticity and lithomechanics theories and integrated with relation of natural fractures and perforations, we established a breakdown pressure calculation model for perforated wells in fractured formations by taking the above-mentioned three different breakdown modes into consideration. The calculation result shows that the established model can accurately calculate breakdown pressure of perforated wells in fractured formations and can also explain the extension mechanism of multi-fractures in areas adjacent to wellbore for perforated wells in fractured formations.

Key words: fractured formation, perforated well, breakdown mode, breakdown pressure, natural fracture, multi-fractures