鄂尔多斯盆地苏里格地区下石盒子组致密砂岩储层微观孔隙结构及分形特征
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摘要
通过铸体薄片、扫描电镜观察、物性测试及高压压汞实验等手段,对苏里格地区下石盒子组致密砂岩储层微观孔隙结构进行了精细刻画及分类表征,计算了各类致密储层的分形维数并阐明了分形特征对于研究致密储层渗流特征的意义。结果表明:鄂尔多斯盆地苏里格地区上古生界下石盒子组致密砂岩储层孔隙度普遍小于12%,渗透率大多小于1×10~(-3)μm~2,储层孔隙结构复杂,主要发育粒间溶孔及粒内溶孔,同时可见少量的原生粒间孔、黏土微孔和微裂缝;研究区储层孔隙结构组合可划分为3种:大孔隙主导的Ⅰ型孔隙结构、小孔隙主导的Ⅱ型孔隙结构及大孔隙和小孔隙共同控制的Ⅲ型孔隙结构;储层宏孔的分形维数为2.941 6～2.994 0,中孔的分形维数为2.546 8～2.921 1,微孔的分形维数为2.053 6～2.893 5,说明孔隙结构的复杂程度为宏孔>中孔>微孔;在计算致密砂岩储层宏孔分形维数时,应注意对孔隙形态进行合理的简化,以避免在计算过程中造成较大误差;微孔分形维数小于2.5的储层渗透率通常小于1×10~(-3)μm~2,说明微孔数量多的储层渗流能力通常较差,而形态规则、分布均匀、受胶结物与自生黏土矿物改造较弱的、宏孔发育的、致密储层有利于天然气的充注与储集。
This research studies the characterization and classification of pore structure of the Xiashihezi Formation tight sandstones in Sulige area, as well as the fractal analysis of pore structure in tight sandstones. The results show the Xiashihezi Formation tight sandstone in Sulige area is characterized by low porosity(mostly smaller than 12%)and low permeability(mostly smaller than 1×10~(-3)μm~2); the sandstone has complex pore structure, dominated by intergranular and intragranular dissolution pores, as well as some primary intergranular pores, micropores within clay minerals and microfractures. There are three types of pore structure, type Ⅰ, dominated by large pores, type Ⅱ, dominated by small pores and type Ⅲ, dominated by both large and small pores; the development of pore structure are influenced by sedimentary and diagenesis, while diagenesis is a more important factors. In the Xiashihezi Formation tight reservoirs, high-quality reservoirs tend to develop near source rock where dissolution can strongly improve the porosity of reservoirs. Fractal dimensions of macropores are in the range of 2.941 6-2.994 0, those of mesopores range from 2.546 8-2.921 1, and those of micropores are in the range of 2.053 6-2.893 5. In the calculation of fractal dimensions of macropores, the morphologies of pores should be reasonablly simplified to avoid the deviation of fractal dimension. Reservoirs with fractal dimensions of micropores smaller than 2.5 rarely have permeability smaller than 1×10~(-3) μm~2, indicating that widely developed micropores are not good for percolation of reservoir. Overall, development of regular and homogeneously distributed macropores unmodified by cements and authigenic clay minerals is favorable for enhancing the percolation performance of tight reservoir.
This research studies the characterization and classification of pore structure of the Xiashihezi Formation tight sandstones in Sulige area, as well as the fractal analysis of pore structure in tight sandstones. The results show the Xiashihezi Formation tight sandstone in Sulige area is characterized by low porosity(mostly smaller than 12%)and low permeability(mostly smaller than 1×10~(-3)μm~2); the sandstone has complex pore structure, dominated by intergranular and intragranular dissolution pores, as well as some primary intergranular pores, micropores within clay minerals and microfractures. There are three types of pore structure, type Ⅰ, dominated by large pores, type Ⅱ, dominated by small pores and type Ⅲ, dominated by both large and small pores; the development of pore structure are influenced by sedimentary and diagenesis, while diagenesis is a more important factors. In the Xiashihezi Formation tight reservoirs, high-quality reservoirs tend to develop near source rock where dissolution can strongly improve the porosity of reservoirs. Fractal dimensions of macropores are in the range of 2.941 6-2.994 0, those of mesopores range from 2.546 8-2.921 1, and those of micropores are in the range of 2.053 6-2.893 5. In the calculation of fractal dimensions of macropores, the morphologies of pores should be reasonablly simplified to avoid the deviation of fractal dimension. Reservoirs with fractal dimensions of micropores smaller than 2.5 rarely have permeability smaller than 1×10~(-3) μm~2, indicating that widely developed micropores are not good for percolation of reservoir. Overall, development of regular and homogeneously distributed macropores unmodified by cements and authigenic clay minerals is favorable for enhancing the percolation performance of tight reservoir.
引文
[1] 邹才能,朱如凯,松涛,等.常规与非常规油气聚集类型、特征、机理及展望:以中国致密油和致密气为例[J].石油学报,2012,33(2):173-187.
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[3] 贾承造,郑民,张永峰.中国非常规油气资源与勘探开发前景[J].石油勘探与开发,2012,39(2):129-136.
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[8] Ross D J K,Bustin R M.The importance of shale composition and pore structure upon gas storage potential of shale gas reservoirs[J].Marine and Petroleum Geology,2009,26(6):916-927.
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[12] 杨仁超,王秀平,樊爱萍,等.苏里格气田东二区砂岩成岩作用与致密储层成因[J].沉积学报,2012,30(1):111-119.
[13] 赵靖舟,吴少波,武富礼.论低渗透储层的分类与评价标准:以鄂尔多斯盆地为例[J].岩性油气藏,2007,19(3):28-31.
[14] 兰朝利,何顺利,张君峰,等.苏里格气田储层 “甜点” 控制因素探讨[J].西安石油大学学报:自然科学版,2007,22(1):45-48.
[15] 李理.延川南地区下石盒子组致密砂岩气储层特征及成藏条件[J].中国煤炭地质,2013,28(8):20-23.
[16] 邓军,王庆飞,黄定华,等.鄂尔多斯盆地基底演化及其对盖层控制作用[J].地学前缘,2005,12(3):91-99.
[17] 邓军,王庆飞,黄帮飞,等.鄂尔多斯盆地演化与多种能源矿产分布[J].现代地质,2005,19(4):538-545.
[18] 李庆贤,李剑,王康东,等.苏里格低渗透砂岩大气田天然气充注运移及成藏特征[J].地质科技情报,2012,31(3):55-62.
[19] 彭威龙,庞雄奇,向才富,等.苏里格地区上古生界连续型致密砂岩气成藏条件及过程分析[J].地质科技情报,2016,35(3):180-185.
[20] 何自新,付金华,席胜利,等.苏里格大气田成藏地质特征[J].石油学报,2003,24(2):6-12.
[21] 杨华,席胜利,魏新善,等.苏里格地区天然气勘探潜力分析[J].天然气工业,2006,26(12):45-48.
[22] Folk R L.Petrology of sedimentary rocks[M].Austin,Texas:Hemphill Publishing Company,1974.
[23] Surdam R C.A new paradigm for gas exploration in anomalously pressured "tight gas sands" in the rocky mountain Laramide Basins[M]//Anon.AAPG memoir 67:Seals,traps,and the petroleum system.US:AAPG,1997:283-298.
[24] Pfeifer P.Fractal dimension as working tool for surface-roughness problems[J].Applications of Surface Science,1984,18(1/2):146-164.
[25] Yang F,Ning Z,Liu H.Fractal characteristics of shales from a shale gas reservoir in the Sichuan Basin,China[J].Fuel,2014,115:378-384.
[26] Zhou L,Kang Z.Fractal characterization of pores in shales using NMR:A case study from the Lower Cambrian Niutitang Formation in the Middle Yangtze Platform,Southwest China[J].Journal of Natural Gas Science and Engineering,2016,35:860-872.
[27] Lai J,Wang G.Fractal analysis of tight gas sandstones using high-pressure mercury intrusion techniques[J].Journal of Natural Gas Science and Engineering,2015,24:185-196.
[28] 吴浩,刘锐娥,纪友亮,等.致密砂岩储层孔喉分形特征及其与渗流的关系:以鄂尔多斯盆地下石盒子组盒8段为例[J].沉积学报,2017,35(1):151-162.
[29] Mandelbrot B B,Passoja D E,Paullay A J.Fractal character of fracture surfaces of metals[J].Nature,1984,308:721.
[30] 葛小波,李吉君,卢双舫,等.基于分形理论的致密砂岩储层微观孔隙结构表征:以冀中坳陷致密砂岩储层为例[J].岩性油气藏,2017,29(5):106-112.
[31] Zeng L.Microfracturing in the Upper Triassic Sichuan Basin tight-gas sandstones:Tectonic,overpressure,and diagenetic origins[J].AAPG Bulletin,2010,94(12):1811-1825.
[2] Dai J,Ni Y,Wu X.Tight gas in China and its significance in exploration and exploitation[J].Petroleum Exploration and Development,2012,39(3):277-284.
[3] 贾承造,郑民,张永峰.中国非常规油气资源与勘探开发前景[J].石油勘探与开发,2012,39(2):129-136.
[4] 金之钧,张金川.深盆气藏及其勘探对策[J].石油勘探与开发,1999,26(1):4-5.
[5] Law B E.Basin-centered gas systems[J].AAPG Bulletin,2002,86(11):1891-1919.
[6] 赖锦,王贵文,孟辰卿,等.致密砂岩气储层孔隙结构特征及其成因机理分析[J].地球物理学进展,2015,30(1):217-227.
[7] Clarkson C R,Freeman M,He L,et al.Characterization of tight gas reservoir pore structure using USANS/SANS and gas adsorption analysis[J].Fuel,2012,95:371-385.
[8] Ross D J K,Bustin R M.The importance of shale composition and pore structure upon gas storage potential of shale gas reservoirs[J].Marine and Petroleum Geology,2009,26(6):916-927.
[9] 陈杰,周改英,赵喜亮,等.储层岩石孔隙结构特征研究方法综述[J].特种油气藏,2005,12(4):11-14.
[10] 陈欢庆,曹晨,梁淑贤,等.储层孔隙结构研究进展[J].天然气地球科学,2013,24(2):227-237.
[11] 樊爱萍,赵娟,杨仁超,等.苏里格气田东二区山1段,盒8段储层孔隙结构特征[J].天然气地球科学,2011,22(3):482-487.
[12] 杨仁超,王秀平,樊爱萍,等.苏里格气田东二区砂岩成岩作用与致密储层成因[J].沉积学报,2012,30(1):111-119.
[13] 赵靖舟,吴少波,武富礼.论低渗透储层的分类与评价标准:以鄂尔多斯盆地为例[J].岩性油气藏,2007,19(3):28-31.
[14] 兰朝利,何顺利,张君峰,等.苏里格气田储层 “甜点” 控制因素探讨[J].西安石油大学学报:自然科学版,2007,22(1):45-48.
[15] 李理.延川南地区下石盒子组致密砂岩气储层特征及成藏条件[J].中国煤炭地质,2013,28(8):20-23.
[16] 邓军,王庆飞,黄定华,等.鄂尔多斯盆地基底演化及其对盖层控制作用[J].地学前缘,2005,12(3):91-99.
[17] 邓军,王庆飞,黄帮飞,等.鄂尔多斯盆地演化与多种能源矿产分布[J].现代地质,2005,19(4):538-545.
[18] 李庆贤,李剑,王康东,等.苏里格低渗透砂岩大气田天然气充注运移及成藏特征[J].地质科技情报,2012,31(3):55-62.
[19] 彭威龙,庞雄奇,向才富,等.苏里格地区上古生界连续型致密砂岩气成藏条件及过程分析[J].地质科技情报,2016,35(3):180-185.
[20] 何自新,付金华,席胜利,等.苏里格大气田成藏地质特征[J].石油学报,2003,24(2):6-12.
[21] 杨华,席胜利,魏新善,等.苏里格地区天然气勘探潜力分析[J].天然气工业,2006,26(12):45-48.
[22] Folk R L.Petrology of sedimentary rocks[M].Austin,Texas:Hemphill Publishing Company,1974.
[23] Surdam R C.A new paradigm for gas exploration in anomalously pressured "tight gas sands" in the rocky mountain Laramide Basins[M]//Anon.AAPG memoir 67:Seals,traps,and the petroleum system.US:AAPG,1997:283-298.
[24] Pfeifer P.Fractal dimension as working tool for surface-roughness problems[J].Applications of Surface Science,1984,18(1/2):146-164.
[25] Yang F,Ning Z,Liu H.Fractal characteristics of shales from a shale gas reservoir in the Sichuan Basin,China[J].Fuel,2014,115:378-384.
[26] Zhou L,Kang Z.Fractal characterization of pores in shales using NMR:A case study from the Lower Cambrian Niutitang Formation in the Middle Yangtze Platform,Southwest China[J].Journal of Natural Gas Science and Engineering,2016,35:860-872.
[27] Lai J,Wang G.Fractal analysis of tight gas sandstones using high-pressure mercury intrusion techniques[J].Journal of Natural Gas Science and Engineering,2015,24:185-196.
[28] 吴浩,刘锐娥,纪友亮,等.致密砂岩储层孔喉分形特征及其与渗流的关系:以鄂尔多斯盆地下石盒子组盒8段为例[J].沉积学报,2017,35(1):151-162.
[29] Mandelbrot B B,Passoja D E,Paullay A J.Fractal character of fracture surfaces of metals[J].Nature,1984,308:721.
[30] 葛小波,李吉君,卢双舫,等.基于分形理论的致密砂岩储层微观孔隙结构表征:以冀中坳陷致密砂岩储层为例[J].岩性油气藏,2017,29(5):106-112.
[31] Zeng L.Microfracturing in the Upper Triassic Sichuan Basin tight-gas sandstones:Tectonic,overpressure,and diagenetic origins[J].AAPG Bulletin,2010,94(12):1811-1825.
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