基于小角X射线散射页岩油储层介孔特征研究
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摘要
采用不同极性有机溶剂对取自东营凹陷地区泥页岩样品进行了逐次抽提处理,使用小角X射线散射表征技术对处理前后样品进行介孔分布特征表征和分析。结果显示,正己烷溶剂抽提效果较弱,极性较强的氯仿、甲醇/丙酮/氯仿混合溶剂及二氯甲烷/甲醇混合溶剂能够萃取出孔隙中赋存的有机质,二硫化碳/N-甲基吡咯烷酮混合溶剂由于极性太强对孔隙进行改造和破坏。经溶剂抽提后样品主峰位置分布在10 nm左右,最可几孔径值和中值孔径尺度分别介于6.7~14.5 nm和15.9~22.9 nm之间,细介孔体积百分比分布在9.5%~32.3%范围内。在泥页岩生烃阶段,粘土矿物为油气储存提供了有效储集空间,高粘土矿物相对含量的泥页岩对应的介孔分布曲线向更小孔径处集中,细介孔体积百分比与分形维数参数之间均存在明显的正相关关系,可见与粘土矿物有关的孔隙比表面趋向于粗糙化,比表面积趋大,为油气的赋存提供有利的条件。自然演化样品及热模拟样品介孔分布表征揭示了泥页岩从低成熟向高成熟热演化阶段转化的过程中,细介孔体积占介孔总体积百分比呈现出先增大后减小的趋势,而粗介孔与之相反。
Shale pores were often entirely or partially filled by organic matters in its oil window. In this study, successive solvent extraction was used to extract organic matters in shale samples from the Dongying sag by using a range of organic solvents with varying polarities and chemical structures. Small angle X-ray scattering method was used to characterize and analyze the mesoporous distribution of shale before and after solvent extraction. Results show that the extraction effect of hexane was weak. Strong polar solvent such as chloroform, the mixture of methanol, acetone and chloroform(MAC) and the mixture of dichloromethane and methanol can improve the extraction ability of organic matter. Mixed solvent of carbon disulfide and N-methyl-2-pyrrolidinone(CS2-NMP) can change and destroy pore structures. Diameter of maximum peak point of shale sample after solvent extraction was about 10 nm. The most probable aperture and average pore size were in the range of 6.7~14.5 nm and 15.9~22.8 nm, respectively. The relative percentage content of fine mesopores was in the range of 9.5%~32.3%. In the stage of hydrocarbon generation, clay minerals provide effective reservoir space for hydrocarbon. The corresponding pore distribution curve of shale with high clay mineral content was concentrated in the smaller pores. There was a significantly positive correlation between the relative percentage content of fine mesoporous and parameters of fractal dimension. The specific surface of pore related to clay minerals tended to be rough, which provided favorable conditions for the occurrence of hydrocarbon. The distribution characteristics of mesoporous in the thermal simulation and natural evolutionary samples reveal that the percentage content of fine mesoporous shows a trend of increasing first and then decreasing in the process of thermal evolution of shale. In contrast, thick mesoporous shows an opposite trend.
Shale pores were often entirely or partially filled by organic matters in its oil window. In this study, successive solvent extraction was used to extract organic matters in shale samples from the Dongying sag by using a range of organic solvents with varying polarities and chemical structures. Small angle X-ray scattering method was used to characterize and analyze the mesoporous distribution of shale before and after solvent extraction. Results show that the extraction effect of hexane was weak. Strong polar solvent such as chloroform, the mixture of methanol, acetone and chloroform(MAC) and the mixture of dichloromethane and methanol can improve the extraction ability of organic matter. Mixed solvent of carbon disulfide and N-methyl-2-pyrrolidinone(CS2-NMP) can change and destroy pore structures. Diameter of maximum peak point of shale sample after solvent extraction was about 10 nm. The most probable aperture and average pore size were in the range of 6.7~14.5 nm and 15.9~22.8 nm, respectively. The relative percentage content of fine mesopores was in the range of 9.5%~32.3%. In the stage of hydrocarbon generation, clay minerals provide effective reservoir space for hydrocarbon. The corresponding pore distribution curve of shale with high clay mineral content was concentrated in the smaller pores. There was a significantly positive correlation between the relative percentage content of fine mesoporous and parameters of fractal dimension. The specific surface of pore related to clay minerals tended to be rough, which provided favorable conditions for the occurrence of hydrocarbon. The distribution characteristics of mesoporous in the thermal simulation and natural evolutionary samples reveal that the percentage content of fine mesoporous shows a trend of increasing first and then decreasing in the process of thermal evolution of shale. In contrast, thick mesoporous shows an opposite trend.
引文
邓春萍,王汇彤,陈建平,等.2005.煤系烃源岩不同极性溶剂抽提物基本地球化学特征[J].石油勘探与开发,32(1):48-52.
郭绍辉,李术元,陈志伟,等.2000.低熟烃源岩的超强混合溶剂抽提及其地球化学意义[J].中国石油大学学报自然科学版,24(3):50-53.
胡海燕.2013.富有机质Woodford页岩孔隙演化的热模拟实验[J].石油学报,34(5):820-825.
姜在兴,张文昭,梁超,等.2014.页岩油储层基本特征及评价要素[J].石油学报,35(1):184-196.
焦堃,姚素平,吴浩,等.2014.页岩气储层孔隙系统表征方法研究进展[J].高校地质学报,20(1):151-161.
李志宏,吴忠华,吴自玉,等.2006.小角X光散射中干涉效应的判断与处理[J].光散射学报,17(4):384-387.
刘四兵,朱建辉,沈忠民,等.2009.三元、超临界及氯仿抽提物有机地球化学特征对比-以渤海湾盆地东营凹陷沙四段为例[J].石油实验地质,31(1):92-96.
潘磊,肖贤明,周秦.2015.可溶有机质对表征页岩储层特性的影响[J].天然气地球科学,26(9):1729-1736.
宋晓夏,唐跃刚,李伟,等.2014.基于小角X射线散射构造煤孔隙结构的研究[J].煤炭学报,39(4):719-724.
孙超,姚素平,李晋宁,等.2016.东营凹陷页岩油储层特征[J].地质论评,62(6):1497-1510.
王茂桢,柳少波,任拥军,等.2015.页岩气储层粘土矿物孔隙特征及其甲烷吸附作用[J].地质论评,61(1):207-216.
王维,陈兴,蔡泉,等.2007.小角X射线散射(SAXS)数据分析程序SAXS1.0[J].核技术,30(7):571-575.
许敏,郭绍辉,李术元,等.2001.烃源岩的溶剂抽提研究[J].中国石油大学学报自然科学版,25(3):49-51.
薛莲花,杨巍,仲佳爱,等.2015.富有机质页岩生烃阶段孔隙演化-来自鄂尔多斯延长组地质条件约束下的热模拟实验证据[J].地质学报,89(5):970-978.
杨峰,宁正福,王庆,等.2014.页岩纳米孔隙分形特征[J].天然气地球科学,25(4):618-623.
赵洋,王忠,李瑞那,等.2014.基于小角散射的柴油机排气颗粒的孔隙结构分析[J].农业工程学报,30(15):68-74.
朱晓军,蔡进功.2012.泥质烃源岩的比表面与有机质关系研究进展及意义[J].石油与天然气地质,33(3):375-384.
邹才能,杨智,崔景伟,等.2013.页岩油形成机制、地质特征及发展对策[J].石油勘探与开发,40(1):14-26.
Cai Y D,Liu D M,Pan Z J,et al.2013.Pore structure and its impact on CH4,adsorption capacity and flow capability of bituminous and subbituminous coals from Northeast China[J].Fuel,103:258-268.
Chalmers G R,Bustin R M and Power I M.2012.Characterization of gas shale pore systems by porosimetry,pycnometry,surface area,and field emission scanning electron microscopy/transmission electron microscopy image analyses:Examples from the Barnett,Woodford,Haynesville,Marcellus,and Doig units[J].Aapg Bulletin,96(6):1099-1119.
Clarkson C R,Freeman M,He L,et al.2012.Characterization of tight gas reservoir pore structure using USANS/SANS and gas adsorption analysis[J].Fuel,95(1):371-385.
Cohaut N,Blanche C,Dumas D,et al.2000.A small angle X-ray scattering study on the porosity of anthracites[J].Carbon,38(9):1391-1400.
Diduszko R,Swiatkowski A and Trznadel B J.2000.On surface of micropores and fractal dimension of activated carbon determined on the basis of adsorption and SAXS investigations[J].Carbon,38(8):1153-1162.
Kuila U,McCarty D K,Derkowski A,et al.2014.Nano-scale texture and porosity of organic matter and clay minerals in organic-rich mudrocks[J].Fuel,135(6):359-373.
Nishikawa K.2003.Chapter 11-pore structure analyses of carbons by small-angle X-ray scattering[J].Carbon Alloys,175-188.
Prasad M,Mba K,McEvoy T E,et al.2011.Maturity and impedance analysis of organic-rich shales[J].SPE Reserv.Eval.Eng.14(5):533-43.
Radlinski A P,Mastalerz M,Hinde A L,et al.2004.Application of SAXS and SANS in evaluation of porosity,pore size distribution and surface area of coal[J].International Journal of Coal Geology,59(3-4):245-271.
Sun C,Yao S P,Li J N,et al.2017.Characteristics of pore structure and effectiveness of shale oil reservoir space in Dongying Sag,Jiyang Depression,Bohai Bay Basin[J].Journal of Nanoscience and Nanotechnology,17(9):6781-6790.
Valenza J J,Drenzek N,Marques F,et al.2013.Geochemical controls on shale microstructure[J].Geology,41(5):611-614.
Yang F,Ning Z F and Liu H Q.2014.Fractal characteristics of shales from a shale gas reservoir in the Sichuan Basin,China[J].Fuel,115(1):378-384.
Yao Y B,Liu D M,Tang D Z,et al.2009.Fractal characterization of seepage-pores of coals from China:An investigation on permeability of coals[J].Computers&Geosciences,35(6):1159-1166.
Zargari S,Canter K L and Prasad M.2015.Porosity evolution in oil-prone source rocks[J].Fuel,153:110-117.
郭绍辉,李术元,陈志伟,等.2000.低熟烃源岩的超强混合溶剂抽提及其地球化学意义[J].中国石油大学学报自然科学版,24(3):50-53.
胡海燕.2013.富有机质Woodford页岩孔隙演化的热模拟实验[J].石油学报,34(5):820-825.
姜在兴,张文昭,梁超,等.2014.页岩油储层基本特征及评价要素[J].石油学报,35(1):184-196.
焦堃,姚素平,吴浩,等.2014.页岩气储层孔隙系统表征方法研究进展[J].高校地质学报,20(1):151-161.
李志宏,吴忠华,吴自玉,等.2006.小角X光散射中干涉效应的判断与处理[J].光散射学报,17(4):384-387.
刘四兵,朱建辉,沈忠民,等.2009.三元、超临界及氯仿抽提物有机地球化学特征对比-以渤海湾盆地东营凹陷沙四段为例[J].石油实验地质,31(1):92-96.
潘磊,肖贤明,周秦.2015.可溶有机质对表征页岩储层特性的影响[J].天然气地球科学,26(9):1729-1736.
宋晓夏,唐跃刚,李伟,等.2014.基于小角X射线散射构造煤孔隙结构的研究[J].煤炭学报,39(4):719-724.
孙超,姚素平,李晋宁,等.2016.东营凹陷页岩油储层特征[J].地质论评,62(6):1497-1510.
王茂桢,柳少波,任拥军,等.2015.页岩气储层粘土矿物孔隙特征及其甲烷吸附作用[J].地质论评,61(1):207-216.
王维,陈兴,蔡泉,等.2007.小角X射线散射(SAXS)数据分析程序SAXS1.0[J].核技术,30(7):571-575.
许敏,郭绍辉,李术元,等.2001.烃源岩的溶剂抽提研究[J].中国石油大学学报自然科学版,25(3):49-51.
薛莲花,杨巍,仲佳爱,等.2015.富有机质页岩生烃阶段孔隙演化-来自鄂尔多斯延长组地质条件约束下的热模拟实验证据[J].地质学报,89(5):970-978.
杨峰,宁正福,王庆,等.2014.页岩纳米孔隙分形特征[J].天然气地球科学,25(4):618-623.
赵洋,王忠,李瑞那,等.2014.基于小角散射的柴油机排气颗粒的孔隙结构分析[J].农业工程学报,30(15):68-74.
朱晓军,蔡进功.2012.泥质烃源岩的比表面与有机质关系研究进展及意义[J].石油与天然气地质,33(3):375-384.
邹才能,杨智,崔景伟,等.2013.页岩油形成机制、地质特征及发展对策[J].石油勘探与开发,40(1):14-26.
Cai Y D,Liu D M,Pan Z J,et al.2013.Pore structure and its impact on CH4,adsorption capacity and flow capability of bituminous and subbituminous coals from Northeast China[J].Fuel,103:258-268.
Chalmers G R,Bustin R M and Power I M.2012.Characterization of gas shale pore systems by porosimetry,pycnometry,surface area,and field emission scanning electron microscopy/transmission electron microscopy image analyses:Examples from the Barnett,Woodford,Haynesville,Marcellus,and Doig units[J].Aapg Bulletin,96(6):1099-1119.
Clarkson C R,Freeman M,He L,et al.2012.Characterization of tight gas reservoir pore structure using USANS/SANS and gas adsorption analysis[J].Fuel,95(1):371-385.
Cohaut N,Blanche C,Dumas D,et al.2000.A small angle X-ray scattering study on the porosity of anthracites[J].Carbon,38(9):1391-1400.
Diduszko R,Swiatkowski A and Trznadel B J.2000.On surface of micropores and fractal dimension of activated carbon determined on the basis of adsorption and SAXS investigations[J].Carbon,38(8):1153-1162.
Kuila U,McCarty D K,Derkowski A,et al.2014.Nano-scale texture and porosity of organic matter and clay minerals in organic-rich mudrocks[J].Fuel,135(6):359-373.
Nishikawa K.2003.Chapter 11-pore structure analyses of carbons by small-angle X-ray scattering[J].Carbon Alloys,175-188.
Prasad M,Mba K,McEvoy T E,et al.2011.Maturity and impedance analysis of organic-rich shales[J].SPE Reserv.Eval.Eng.14(5):533-43.
Radlinski A P,Mastalerz M,Hinde A L,et al.2004.Application of SAXS and SANS in evaluation of porosity,pore size distribution and surface area of coal[J].International Journal of Coal Geology,59(3-4):245-271.
Sun C,Yao S P,Li J N,et al.2017.Characteristics of pore structure and effectiveness of shale oil reservoir space in Dongying Sag,Jiyang Depression,Bohai Bay Basin[J].Journal of Nanoscience and Nanotechnology,17(9):6781-6790.
Valenza J J,Drenzek N,Marques F,et al.2013.Geochemical controls on shale microstructure[J].Geology,41(5):611-614.
Yang F,Ning Z F and Liu H Q.2014.Fractal characteristics of shales from a shale gas reservoir in the Sichuan Basin,China[J].Fuel,115(1):378-384.
Yao Y B,Liu D M,Tang D Z,et al.2009.Fractal characterization of seepage-pores of coals from China:An investigation on permeability of coals[J].Computers&Geosciences,35(6):1159-1166.
Zargari S,Canter K L and Prasad M.2015.Porosity evolution in oil-prone source rocks[J].Fuel,153:110-117.