页岩储层的改进拉链式压裂裂缝间距优化
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摘要
针对改进拉链式压裂优化设计的要求,在假设岩石为均质、各向同性材料的基础上,建立诱导应力计算模型,得出近井地带最大诱导应力差计算公式及最佳裂缝间距表达式,确定了中间裂缝最佳起裂位置,并建立多裂缝缝间诱导应力差计算模型。研究表明:随着泊松比的增加,诱导应力差最大值减小,缝间最佳间距增大;随着缝内压力的增加,诱导应力差最大值增大,缝间最佳间距不变;裂缝高度增加,诱导应力差最大值不变,缝间最佳间距增加;当裂缝间距增加时,近井地带诱导应力差先增大后减小,井间裂缝交汇处的诱导应力差逐渐减小,诱导应力差值分布趋于均匀化。进行压裂设计时,在满足裂缝转向条件的前提下,可根据实际情况适当扩大缝间距离,增加远场裂缝网络的复杂性,提高改造体积。
According to the requirement of the improved zipper type fracturing optimization and design,assuming that the rock is homogeneous and isotropic,the calculation model of induced stress is established,obtaining the calculation model of maximum difference of induced stress around the wellbore and the expression of the optimum fracture spacing,ascertaining the optimum fracture initiation position of intermediate base cracks,and then the calculation model of difference of induced stress among multiple fractures is established.Researches show that as Poisson ratio increases,the maximum value of induced stress difference decreases and the optimum spacing among fractures increases;as the pressure of fracture increases,the maximum value of induced stress difference increases and the optimum spacing among fractures is invariant.However,as the fracture height increases,the maximum value of induced stress difference is invariant and the optimum spacing among fractures increases;as the fracture spacing increases,the induced stress difference around the wellbore firstly increases and then increases,and the induced stress of the line intersection of inter-well fracture gradually decreases,and the induced stress difference seems distribute evenly.For fracturing design,on the premise of fracture reorientation,we the fracture spacing can be appropriately enlarge according to practical situation,and increase the complexity of fracture network in far-field,and improve volume.
According to the requirement of the improved zipper type fracturing optimization and design,assuming that the rock is homogeneous and isotropic,the calculation model of induced stress is established,obtaining the calculation model of maximum difference of induced stress around the wellbore and the expression of the optimum fracture spacing,ascertaining the optimum fracture initiation position of intermediate base cracks,and then the calculation model of difference of induced stress among multiple fractures is established.Researches show that as Poisson ratio increases,the maximum value of induced stress difference decreases and the optimum spacing among fractures increases;as the pressure of fracture increases,the maximum value of induced stress difference increases and the optimum spacing among fractures is invariant.However,as the fracture height increases,the maximum value of induced stress difference is invariant and the optimum spacing among fractures increases;as the fracture spacing increases,the induced stress difference around the wellbore firstly increases and then increases,and the induced stress of the line intersection of inter-well fracture gradually decreases,and the induced stress difference seems distribute evenly.For fracturing design,on the premise of fracture reorientation,we the fracture spacing can be appropriately enlarge according to practical situation,and increase the complexity of fracture network in far-field,and improve volume.
引文
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[16]翁定为,姚飞,李阳,等.重复压裂裂缝转向时油藏数值模拟研究[J].石油钻采工艺,2006(6):65-67.
[17]张公社,赵蓓,石惠宁,等.重复压裂裂缝转向的ANSYS有限元模拟[J].石油天然气学报,2009(6):141-144.
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[3]朱正喜,曹会,陈沙沙.国内水力喷射压裂工艺技术应用研究进展[J].石油矿场机械,2014,43(12):82-87.
[4]李小刚,苏洲,杨兆中,等.页岩气储层体积缝网压裂技术新进展[J].石油天然气学报,2014(7):154-159.
[5]王学正,韩永亮,王海霞,等.侧钻水平井分段压裂完井技术在气田的应用[J].石油矿场机械,2014,43(12):44-47.
[6]East L E,Soliman M Y,Augustine J R.Methods for enhancing far-field complexity in fracturing operations[R].SPE133380,2010.
[7]Rafiee M,Soliman M Y,Pirayesh E.Hydraulic fracturing design and optimization:a modification to zipper frac[R].SPE159786,2012.
[8]陈勉.页岩气储层水力裂缝转向扩展机制[J].中国石油大学学报(自然科学版),2013(5):88-94.
[9]Green A E,Sneddon I N.The distribution of stress in the neighbourhood of a flat elliptical crack in an elastic solid[J].Mathematical Proceedings of the Cambridge Philosophical Society,1950,46(1):159-163.
[10]Zhao H F,Chen H;Liu G H;New insight into mechanisms of fracture network generation in shale gas reservoir[J].Journal of Petroleum Science and Engineering,2013(110):193-198.
[11]程万,金衍,陈勉,等.页岩储层水平井分段压裂裂缝间距设计方法及影响因素分析[J].科学技术与工程,2014(15):43-46.
[12]邵尚奇,田守嶒,李根生,等.水平井缝网压裂裂缝间距的优化[J].石油钻探技术,2014(1):86-90.
[13]尹建,郭建春,曾凡辉.水平井分段压裂射孔间距优化方法[J].石油钻探技术,2012(5):67-71.
[14]李玉伟,艾池,张博文,等.同步体积压裂对井间裂缝特性的影响[J].断块油气田,2013(6):779-782.
[15]刘洪,胡永全,赵金洲,等.重复压裂气井诱导应力场模拟研究[J].岩石力学与工程学报,2004(23):4022-4027.
[16]翁定为,姚飞,李阳,等.重复压裂裂缝转向时油藏数值模拟研究[J].石油钻采工艺,2006(6):65-67.
[17]张公社,赵蓓,石惠宁,等.重复压裂裂缝转向的ANSYS有限元模拟[J].石油天然气学报,2009(6):141-144.