高阶煤煤层气储层裂缝发育程度及渗透性定量评价
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摘要
通过煤岩样品扫描电镜室内实验,描述了研究区域煤岩裂缝发育形态并定量描述了裂缝长度、宽度、高度、密度等参数,建立了裂缝渗透性定量评价指标并研究了其影响因素。结果表明,该区优势裂缝方向为NE向,但局部构造复杂区发育NW向或近EW向裂缝,裂缝组以NE向平行裂缝为主,偶见NW向斜交裂缝,局部发育交叉裂缝和曲折裂缝,裂缝局部被黏土矿物或方解石填充;煤岩主、次裂缝长度和高度基本相似,次裂缝宽度和密度值明显低于主裂缝;提出的裂缝渗透指数能够有效表征裂缝渗透性,渗透率随裂缝渗透指数增加而增加。当裂缝渗透指数大于150时,为煤层气开发有利区;当裂缝渗透指数小于100时,需要采用水平井分段压裂工艺改善开发效果。
Through SEM indoor experiments of coal-rock, this paper quantitatively describes the parameters of fractures such as length, width, height, density of fractures, establishes quantitative evaluation parameter for fracture permeability, and its influencing factors are studied. The results show that the advantage fracture direction is NE, while the EW direction or NW direction fractures develop in local structural complex area. And the fracture groups are mainly parallel with each other and lie in NW direction,occasional oblique in NW direction. And cross or winding fractures develop in local areas and some fractures are filled with clay mineral and calcite. The length and height of main and secondary fractures of coal rock are similar, and the width and density of secondary fractures are obviously lower than that of main fractures. The fracture permeability index proposed in this paper can effectively characterize the permeability of fractures, and the permeability increases with the increase of the fracture permeability index. When the fracture permeability index is greater than 150, it is a favorable area for CBM development. When the fracture permeability index is less than 100, it is necessary to adopt horizontal well fracturing technology to improve the development effect.
Through SEM indoor experiments of coal-rock, this paper quantitatively describes the parameters of fractures such as length, width, height, density of fractures, establishes quantitative evaluation parameter for fracture permeability, and its influencing factors are studied. The results show that the advantage fracture direction is NE, while the EW direction or NW direction fractures develop in local structural complex area. And the fracture groups are mainly parallel with each other and lie in NW direction,occasional oblique in NW direction. And cross or winding fractures develop in local areas and some fractures are filled with clay mineral and calcite. The length and height of main and secondary fractures of coal rock are similar, and the width and density of secondary fractures are obviously lower than that of main fractures. The fracture permeability index proposed in this paper can effectively characterize the permeability of fractures, and the permeability increases with the increase of the fracture permeability index. When the fracture permeability index is greater than 150, it is a favorable area for CBM development. When the fracture permeability index is less than 100, it is necessary to adopt horizontal well fracturing technology to improve the development effect.
引文
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[5]王濡岳,丁文龙,龚大建,等.渝东南-黔北地区下寒武统牛蹄塘组页岩裂缝发育特征与主控因素[J].石油学报,2016,37(7):832-845.
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[8]蓝宝锋,蒋立伟,钱铮,等.考虑孔隙和微裂缝的煤层气储层压汞曲线分析模型[J].矿物岩石,2017,37(1):111-119.
[9]张建勋,王有智.构造作用对煤岩孔隙结构及煤层气扩散方式的影响[J].非常规油气,2017,4(2):40-47.
[10]尹帅,丁文龙,刘建军,等.沁水盆地南部地区山西组煤系地层裂缝发育特征及其与含气性关系[J].天然气地球科学,2016,27(10):1855-1868.
[11]宫伟力,李晨.煤岩结构多尺度各向异性特征的SEM图像分析[J].岩石力学与工程学报,2010,29(增1):2681-2689.
[12]贾慧敏,孙世轩,毛崇昊,等.基于煤岩应力敏感性的煤层气井单相流产水规律研究[J].煤炭科学技术,2017,45(12):189-193.
[2]赖锦,王贵文,孙思勉,等.致密砂岩储层裂缝测井识别评价方法研究进展[J].地球物理学进展,2015,30(4):1712-1724.
[3]商琳,戴俊生,冯建伟,等.砂泥岩互层裂缝发育的地层厚度效应[J].新疆石油地质,2015,36(1):35-41.
[4]冯建伟,戴俊生,马占荣,等.低渗透砂岩裂缝参数与应力场关系理论模型[J].石油学报,2011,32(4):664-671.
[5]王濡岳,丁文龙,龚大建,等.渝东南-黔北地区下寒武统牛蹄塘组页岩裂缝发育特征与主控因素[J].石油学报,2016,37(7):832-845.
[6]王艿川,赵靖舟,丁文龙,等.渝东南地区龙马溪组页岩裂缝发育特征[J].天然气地球科学,2015,26(4):760-770.
[7]岳锋,焦伟伟,郭淑军.渝东南牛蹄塘组页岩裂缝及其分布控制因素[J].煤田地质与勘探,2015,43(6):39.
[8]蓝宝锋,蒋立伟,钱铮,等.考虑孔隙和微裂缝的煤层气储层压汞曲线分析模型[J].矿物岩石,2017,37(1):111-119.
[9]张建勋,王有智.构造作用对煤岩孔隙结构及煤层气扩散方式的影响[J].非常规油气,2017,4(2):40-47.
[10]尹帅,丁文龙,刘建军,等.沁水盆地南部地区山西组煤系地层裂缝发育特征及其与含气性关系[J].天然气地球科学,2016,27(10):1855-1868.
[11]宫伟力,李晨.煤岩结构多尺度各向异性特征的SEM图像分析[J].岩石力学与工程学报,2010,29(增1):2681-2689.
[12]贾慧敏,孙世轩,毛崇昊,等.基于煤岩应力敏感性的煤层气井单相流产水规律研究[J].煤炭科学技术,2017,45(12):189-193.