Regularities of Fractured Tight Sandstone Gas Reservoirs Damaged by Work Fluids
-
摘要: 塔里木克深区块裂缝性致密砂岩储层具有埋藏深,孔隙度、渗透率低,裂缝发育,非均质性强等特征,不经过压裂增产措施难以达到工业开采价值。钻完井以及增产改造过程储层与工作液及其所携带的固体颗粒相接触,容易引起储层渗透率降低,从而导致产能降低。以人工劈缝的储层岩心为评价岩心,使用储层成像测井资料确定岩心裂缝宽度,对裂缝性致密砂岩储层钻井液/压裂液损害进行了评价。实验结果表明,在围压低于4.5 MPa的情况下,模拟裂缝岩心渗透率保持不变,模拟裂缝岩心渗透率与缝宽呈三次方关系;随着裂缝宽度的增加,压裂液伤害程度逐渐减小,但是钻井液伤害程度先增大后减小,存在一个伤害峰值;此外,一步酸可以显著提高裂缝渗透率,解除钻井液/压裂液伤害。该研究对低伤害新型工作液的研发以及储层保护措施的优化具有一定的指导意义。Abstract: The fractured tight sandstone gas reservoir in Block Keshen, Tarim Basin, is deeply buried, and has those features such as low porosity and permeability, developed fractures and strong heterogeneity. The reservoir, if not stimulated by fracturing operation, is of no commercial value. Contact of the reservoir with work fluids during drilling/completion operations and stimulation process results in reduction in formation permeability because of the invasion of the solid particles in the fluids into the formation, thereby causing decrease in the productivity of the reservoir. In laboratory experiments, reservoir cores with artifcial fractures were used to evaluate reservoir damage caused by drilling/fracturing fluids, and the width of the fractures was determined by imaging logging data of the reservoir. Experimental results showed that when the confning pressure was less than 4.5 MPa, the permeability of the cores with artifcial fractures, which has cubic relation with fracture width, remained constant. As the width of the fractures increased, the permeability damage caused by fracturing fluid decreased. However, permeability damage caused by drilling fluid frst increased and then decreased when the fracture width was increasing, showing a peak value of permeability damage. Furthermore, acid can be used to remarkably increase the permeability of the fractures, thereby removing damage caused by drilling/fracturing fluids. This study is useful in guiding the development of new low damaging work fluids and the optimization of reservoir protection measures.
-
[1] 朱金智, 游利军, 李家学, 等. 油基钻井液对超深裂缝性致密砂岩气藏的保护能力评价[J]. 天然气工业, 2017, 37(2):62-68.ZHU Jinzhi, YOU Lijun, LI Jiaxue, et al. Damage evaluation on oil-based drill-in fluids for ultra-deep fractured tight sandstone gas reservoirs[J]. Natural Gas Industry, 2017, 37(2):62-68. [2] GUZMÁN J D, PINEDA D, FRANCO C A, et al. Effect of nanoparticle inclusion in fracturing fluids applied to tight gas-condensate reservoirs:Reduction of Methanol loading and the associated formation damage[J]. Journal of Natural Gas Science & Engineering, 2017, 40:347-355. [3] LEI M, HUANG W, LI N. The damage mechanism of oil-based drilling fluid for tight sandstone gas reservoir and its optimization[J]. Journal of Petroleum Science and Engineering, 2017(158):616-625. [4] LIANG T, GU F, YAO E, et al. Formation damage due to drilling and fracturing fluids and its solution for tight naturally fractured sandstone reservoirs[J]. Geofluids, 2017:1-9. [5] THOMAS D C, HSING H M, MENZIE D E. Evaluation of core damage caused by oil-based drilling and coring fluids[C]//SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, 1984. [6] QUTOB H, BYRNE M. Formation damage in tight gas reservoirs[C]//SPE European Formation Damage Conference and Exhibition. Society of Petroleum Engineers, 2015. [7] 刘建坤. 低渗透砂岩气藏压裂液伤害机理研究[D]. 北京:中国科学院研究生院, 2011. LIU Jiankun.Study on damage mechanism of fracturing fluid in low permeability sandstone gas reservoir[D]. Beijing:Graduate University of Chinese Academy of Sciences, 2011. [8] 张路锋, 周福建, 张士诚, 等. 基于压力脉冲法的储层基质压裂液伤害评价[J]. 油气地质与采收率, 2018(3):1-7. ZHANG Lufeng, ZHOU Fujian, ZHANG Shicheng, et al.Experimental study on reservoir matrix damage caused by fracturing fluids based on transient pressure transmission method[J]. Petroleum Geology and Recovery Efficiency, 2018(3):1-7. [9] 张路锋, 牟建业, 贺雨南, 等. 高温高压碳酸盐岩油藏酸蚀裂缝导流能力实验研究[J]. 西安石油大学学报(自然科学版), 2017, 32(4):93-97. ZHANG Lufeng, MU Jianye, He Yunan, et al. Experimental study on diversion capacity of acid fractures in high temperature and high pressure carbonate reservoir[J]. Journal of Xi'an Shiyou University(Natural Science Edition), 2017, 32(4):93-97. [10] 叶艳, 鄢捷年, 邹盛礼, 等. 碳酸盐岩裂缝性储层钻井液损害评价新方法[J]. 石油学报, 2008(5):752-756. YE Yan, YAN Jienian, ZOU Shengli, et al. A novel method for evaluating damage of drilling fluidto fractured carbonate reservoir[J]. Acta Petrolei Sinica, 2008(5):752-756. [11] PERKINS T K, KERN L R. Widths of hydraulic fractures[J]. Journal of Petroleum Technology, 1961, 13(9):937-949. [12] SALIMI S, GHALAMBOR A. Experimental study of formation damage during underbalanced-drilling in naturally fractured formations[J]. Energies, 2011, 4(10):1728-1747. [13] KING G E. Hydraulic fracturing 101:what every representative, environmentalist, regulator, reporter, investor, university researcher, neighbor and engineer should know about estimating frac risk and improving frac performance in unconventional gas and oil wells[C]//SPE hydraulic fracturing technology conference. Society of Petroleum Engineers, 2012. [14] HASKETT S E, NARAHARA G M, HOLDITCH S A. A method for simultaneous determination of permeability and porosity in low-permeability cores[C]//SPE formation evaluation, 1988, 3(3):651-658. [15] AL-MUNTASHERI G A. A critical review of hydraulicfracturing fluids for moderate-to ultralow-permeability formations over the last decade[C]//SPE Production & Operations, 2014, 29(04):243-260. [16] HU Y T, CHUNG H C, MAXEY J E. What is more important for proppant transport, viscosity or elasticity?[C]//SPE Hydraulic Fracturing Technology Conference. Society of Petroleum Engineers, 2015.
点击查看大图
计量
- 文章访问数: 469
- HTML全文浏览量: 142
- PDF下载量: 164
- 被引次数: 0