边界层对致密油藏逆向渗吸的数值模拟

doi:10.11743/ogg20200319

摘要/Abstract

摘要： 致密油藏开发过程中一般采用水平井多段体积压裂方法进行开采，近井基质被缝网充分切割，极大的增加了基质与裂缝的接触面积，压裂液或水通过缝网与基质发生逆向渗吸，因此无论压裂过程还是注水吞吐开发过程都不能忽视逆向渗吸作用的影响，另外由于致密储层流动规律不同于普通油藏，这导致致密油藏的逆向渗吸与常规油藏的逆向渗吸作用存在许多不同，为了准确模拟裂缝性致密储层中的渗吸作用，首先采用耗散粒子动力学的方法验证了致密储层微纳米喉道中渗吸过程中边界层的存在并得到渗吸过程中边界层厚度的变化规律，然后利用孔隙网络模型计算考虑边界层的关键渗流参数，主要包括渗透率、毛管力曲线及相渗曲线；并将计算获得的关键渗流参数应用到表征致密储层复杂缝网的数值模拟模型中，模拟结果显示边界层对渗吸作用具有抑制作用，当考虑边界层后储层的渗吸能力大幅度减弱，致密储层的渗吸采收率可能仅为不考率渗吸时的3/8而已，因此应当重视致密储层中边界层的存在，否则可能会高估储层的流动能力。

关键词: 边界层, 双重介质, 逆向渗吸, 数值模拟, 体积压裂, 致密油, 油藏开发

Abstract: Multi-stage volume fracturing of horizontal wells is common in the development of tight oil reservoirs,where the matrix near wellbore is fully cut by and in large-scale contact with the fracture network,resulting in reverse imbibition of fracturing fluid or water into the matrix through the fracture network.Therefore,the reverse imbibition effect shouldn't be ignored in both fracturing and water-flooding.In addition,due to the difference of flow pattern between tight and ordinary reservoirs,the factors contributing to the reverse imbibition effects are accordingly different in the two distinct reservoirs.To accurately simulate the imbibition in fractured tight oil reservoirs,we apply the Dissipative Particle Dynamic(DPD)method to verify the existence of boundary layers during the imbibition in nano-scale pore throats in tight reservoirs,and discover the variation pattern of the boundary layer thickness;then calculate the critical seepage parameters with boundary layers considered via the pore network model,mainly including permeability,capillary pressure curve and relative permeability curve;and finally incorporate these parameters into the numerical simulation model to characterize complex fracture networks in tight reservoirs.The simulation results show that the boundary layers serve to greatly reduce imbibitions-the imbibition recovery in tight reservoirs with boundary layers is only 3/8 of that without considering imbibition.In conclusion,the boundary layer in tight reservoirs deserves great attention;otherwise,the flow potential of these reservoirs may be overestimated.

Key words: boundary layer, dual media, reverse imbibition, numerical simulation, volume fracturing, tight oil, reservoir development

中图分类号:

TE321

徐中一,方思冬. 边界层对致密油藏逆向渗吸的数值模拟[J]. 石油与天然气地质, 2020, 41(3): 638-646. doi: 10.11743/ogg20200319 Xu Zhongyi,Fang Sidong. Numerical simulation on tight oil reservoir reverse imbibition with boundary layers[J]. Oil & Gas Geology, 2020, 41(3): 638-646. doi: 10.11743/ogg20200319

参考文献

[1] 邹才能,陶士振,袁选俊,等.非常规油气纳米孔储层特征及连续油气聚集机理[C].广州:中国矿物岩石地球化学学会,2011. Zou Caineng,Tao Shizheng,Yuan Xuanjun et al.Characteristics of unconventional oil and gas nanopore reservoirs and mechanism of continuous oil and gas accumulation[C].Guangzhou:Chinses Society for Mineralogy Petrology and Geochemistry,2011.
[2] 朱如凯,邹才能,吴松,等.中国陆相致密油形成机理与富集规律[J].石油与天然气地质,2019,40(6):1168-1184. Zhu Rukai,Zou Caineng,Wu Songtao,et al.Mechanism for generation and accumulation of continental tight oil in China[J].Oil & Gas Geology,2019,40(6):1168-1184.
[3] 周磊,王永诗,于雯泉,等.基于物性上、下限计算的致密砂岩储层分级评价-以苏北盆地高邮凹陷阜宁组一段致密砂岩为例[J].石油与天然气地质,2019,40(6):1308-1316. Zhou Lei,Wang Yongshi,Yu Wenquan,et al.Classification assessment of tight sandstone reservoir based on calculation of lower and upper limits of physical properties-A case study of the tight sandstone reservoir in the 1st member of funing formation in Gaoyou Sag,North Jiangsu Basin[J].Oil & Gas Geology,2019,40(6):1308-1316.
[4] 李士奎,刘卫东,张海琴,等.低渗透油藏自发渗吸驱油实验研究[J].石油学报,2007,02(24):109-112. Li Shikui,Liu Weidong,Zhang Haiqin,et al.Experimental study of spontaneous imbibition in low-permeability reservoir[J].Acta Petrolei Sinica,2007,02(24):109-112.
[5] 杨善文.基于耗散粒子动力学对表面活性剂油水界面性质的研究[D].大庆:东北石油大学,2018. Yang Shanwen.Research on Oil-Water interface characteristics in the presence of surfactant using dissipative particle dynamics[D].Daqing:Northeast Petroleum University,2018.
[6] Groot R D,Warren P B.Dissipative particle dynamics:Bridging the gap between atomistic and mesoscopic simulation[J].The Journal of Chemical Physics.1997,107(11):4423-4435.
[7] 田虓丰,程林松,李翔龙,等.考虑微观孔喉结构的相对渗透率计算方法[J].陕西科技大学学报(自然科学版),2014,32(6):100-104. Tian Xiaofeng,Cheng Linsong,Li Xianglong,et al.A new method to calculate relative permeability considering the effect of pore-throat distribution[J].Journal of Shanxi University of Science& Technology.2014,32(6):100-104.
[8] Maurice L,Huggins.Solutions of long chain compounds[J].Journal of Chemical Physics,1941,9(5):440-441.
[9] Paul J,Flory.Thermodynamics of high polymer solutions[J].Journal of Chemical Physics,1941,9(8):660-661.
[10] 邹才能,陶士振,杨智,等.中国非常规油气勘探与研究新进展[J].矿物岩石地球化学通报,2012,31(4):312-322. Zou Caineng,Tao Shizheng,Yang Zhi,et al.New Advance in Unconventional Petroleum Exploration and Research in China[J].Bulletin of Mineralogy,Petrology and Geochemistry.2012,31(4):312-322.
[11] 徐中一,程林松,曹仁义,等.基于裂缝性致密储层关键渗流参数的逆向渗吸速度计算[J].地球科学-中国地质大学学报,2017,42(8):1431-1440. Xu Zhongyi,Cheng Linsong,Cao Renyi,et al.Characterization of key tight oil parameters and mass transfer of counter-current imbibition in fractured tight oil reservoirs[J].Earth Science,2017,42(8):1431-1440.
[12] 李洋.微尺度下非线性流动特征及降低流动阻力的研究[D].廊坊:中国科学院研究生院(渗流流体力学研究所),2010. Li Yang.Study of Microscale nonlinear flow characteristics and flow resistance reducing methods[D].Langfang:Institute of porous flow and Fluid Mechanics,Chinese Academy of Sciences,2010.
[13] 许丽.砂岩油藏孔隙网络模型构造及应用研究[D].成都:西南石油大学,2015. Xu Li.Pore network model construction of sandstone reservoir and application[D].Chengdu:Southwest Petroleum University,2015.
[14] 高辉,朱耿,王博仑,等.鄂尔多斯盆地延长组致密砂岩储层微观孔喉特征差异及其成因[J].石油与天然气地质,2019,40(2):302-312. Gao Hui,Zhu Geng,Wang Bolun,et al.Differences and origin of micropore throat characteristics for tight sandstone reservoir of Yanchang Formation,Ordos Basin[J].Oil & Gas Geology,2019,40(2):302-312.
[15] Valvatne P H,Piri M,Lopez X,et al.Predictive pore-scale modeling of single and multiphase Flow[J].Transport in Porous Meida 2005,58(1-2):23-41.
[16] Blunt M J,Jackson M D,Piri M,et al.Detailed physics,predictive capabilities and macroscopic consequences for pore-network models of multiphase flow[J].Advances in Water Resources,2002,25(8-12):1069-1089.
[17] 徐中一,程林松,曹仁义,等.利用径向积边界元方法计算动态逆向渗吸累积采收率[J].油气地质与采收率,2017,24(5):58-63. Xu Zhongyi,Cheng Linsong,Cao Renyi et al.Using the radical intergration boundary element method to calculate cumulative recovery efficiency of dynamic counter current imbibition[J].Petroleum Geology and Recovery Efficiency,2017,24(5):58-63.
[18] 方思冬,战剑飞,黄世军,等.致密油藏多角度裂缝压裂水平井产能计算方法[J].油气地质与采收率,2015,22(3):84-89. Fang Sidong,Zhang Jianfei,Huang Shijun,et al.A Computational method for productivity of arbitrary angular fractured horizontal well in tight oil reservoirs[J].Petroleum Geology and Recovery Efficiency,2015,22(3):84-89.
[19] 贾品,程林松,黄世军,等.水平井体积压裂缝网表征及流动耦合模型[J].计算物理,2015,32(6):685-692. Jia Pin,Cheng Linsong,Huang Shijun,et al.Characterization and flow coupling model of volume fracturing fracture network in horizontal well[J].Chinese Jornal of Computational Physics.2015,32(6):685-692.
[20] 姚旭.致密油水平井分段压裂裂缝延伸规律数值模拟[J].大庆石油地质与开发,2019,38(6):162-168. Yao Xu.Numerical simulation of the fracture extension law for the staged fracturing in the tight-oil horizontal well[J].Petroleum Geology & Oilfield Development in Daqing,2019,38(6):162-168.
[21] 顾岱鸿,田冷,董俊林.基于分形反常扩散的体积压裂水平井渗流新模型[J].大庆石油地质与开发,2019,38(4):61-69. Gu Daihong,Tian Leng,Dong Junlin.A new percolating model for the SRV horizontal well based on fractal and anomalous diffusion[J].Petroleum Geology & Oilfield Development in Daqing,2019,38(4):61-69.
[22] 王勇.体积压裂中的岩石脆性指数及其数值模拟[J].大庆石油地质与开发,2019,38(4):76-81. Wang Yong.Rock brittleness index and its numerical simulation in SRV fracturing[J].Petroleum Geology & Oilfield Development in Daqing,2019,38(4):76-81.
[23] 曲宝龙.真三轴岩心暂堵转向压裂物理模拟实验[J].大庆石油地质与开发,2019,38(4):82-89. Qu Baolong.Physical simulating experiment of the temporary-block diversion fracturingfor the true triaxial core[J].Petroleum Geology & Oilfield Development in Daqing,2019,38(4):82-89.