水驱油藏乳液中盐水对沥青质沉淀的影响

doi:10.3969/j.issn.1006-6535.2024.01.016

摘要/Abstract

摘要： 油藏注水开发中极易形成油包水乳液,而盐水对乳液中沥青质沉淀的影响机理尚不明确。针对上述问题,在自制实验用油及油包水乳液的基础上,采用分光光度法和油水共注法,分别开展了静态离心实验和动态驱替实验,研究了乳液中含水量、盐类型及盐质量浓度对沥青质沉淀的影响,揭示了盐水作用下沥青质沉淀机理。研究表明:当乳液中含水量由10%增至50%时,沥青质的不稳定性增加,沉淀质量分数由4.5%增至10.6%,但沉淀强度却在减弱。低芳香度的沥青质更容易在水-油界面处沉淀,主要是被界面处水分子表面的杂原子吸附而沉淀。沥青质沉淀量随盐质量浓度的增加呈先增大后降低趋势,当盐质量浓度达到40 000 mg/L时,沥青质沉淀量达到最大。MgCl₂、CaCl₂、NaCl和KCl对沥青质沉淀量的影响程度依次减弱。驱替过程中40.0%质量分数蒸馏水的乳液的渗透率下降幅度最大,其次为20.0%质量分数MgCl₂乳液,而20.0%蒸馏水和20.0%NaCl乳液的渗透率下降幅度最小。动态驱替中盐水对沥青质沉淀的影响小于静态实验,但含水量的增加会增大沥青质沉淀,降低岩心渗透率。研究成果对提高沥青质油藏注水开发效果有重要意义。

关键词: 乳液, 沥青质沉淀, 盐质量浓度, 水驱油藏, 渗透率, 吸光度

Abstract: Water-in-oil emulsions are very easy to form in reservoir water injection development, and the mechanism of the effect of brine on asphaltene precipitation in emulsions is not clear. To address the above problems, based on the self-made experimental oil and water-in-oil emulsions, static centrifugal experiments and dynamic displacement experiments were carried out by spectrophotometry and simultaneous oil-water injection method, respectively, to study the effects of water cut, salt type, and salt mass concentration on asphaltene precipitation in emulsions, and reveal the mechanism of asphaltene precipitation under the action of salt water. Research shows that when the water cut in emulsion increases from 10% to 50%, the asphaltene instability increases and the mass fraction of precipitation increases from 4.5% to 10.6%, but the precipitation intensity weakens. Asphaltenes with low aromaticity are more likely to precipitate at the water/oil interfaces mainly because of adsorption by heteroatoms on the water surfaces at the interface. Asphaltene precipitation tends to increase and decrease with the increase of salt mass concentration, reaching the maximum when the salt mass concentration reaches 40 000 mg/L. MgCl₂, CaCl₂, NaCl, and KCl affect the amount of asphaltene precipitation from high to low. The emulsion with a 40% volumetric concentration of distilled water shows the most significant decrease in permeability during the flooding, followed by a 20% mass concentration of MgCl₂ emulsion, while the 20% distilled water and 20% NaCl emulsions show the smallest decrease in permeability. The effect of brine on asphaltene precipitation in the dynamic displacement is smaller than that in the static experiment. Still, the increase in water cut increases asphaltene precipitation and decreases core permeability. The research results are significant in improving the development effect of water injection in asphaltene reservoirs.

Key words: emulsion, asphaltene precipitation, salt mass concentration, water flooding reservoir, permeability, absorbance

中图分类号:

TE357.6

宋君, 李海燕, 宋伟, 刘亦菲, 李金海, 潘悦文, 刘俊龙. 水驱油藏乳液中盐水对沥青质沉淀的影响[J]. 特种油气藏, 2024, 31(1): 123-130.

Song Jun, Li Haiyan, Song Wei, Liu Yifei, Li Jinhai, Pan Yuewen, Liu Junlong. Effect of Brine on Asphaltene Precipitation in Emulsions of Water Flooding Reservoirs[J]. Special Oil & Gas Reservoirs, 2024, 31(1): 123-130.

参考文献

[1]周晋冲,张彬,雷征东,等.低渗透油藏不稳注水岩心实验及增油机理[J].新疆石油地质,2022,43(4):491-495.
ZHOU Jinchong,ZHANG Bin,LEI Zhengdong,et al.Core experiment and stimulation mechanism of unstable waterflooding in low permeability reservoirs[J].Xinjiang Petroleum Geology,2022,43(4):491-495.
[2]雷浩.低渗储层CO₂驱油过程中沉淀规律及防治对策研究[D].北京:中国石油大学(北京),2017.
LEI Hao.Deposition mechanisms and reservoir protection countermeasures of a low-permeability formation in CO₂ flooding process[D].Beijing: China University of Petroleum(Beijing),2017.
[3]GOLKARI A, RIAZI M.Experimental investigation of miscibility conditions of dead and live asphaltenic crude oil CO₂ systems[J].Journal of Petroleum Exploration and Production Technology,2017,7(2):597-609.
[4]ALIZADEH S, SULEYMANI M. A mechanistic study of emulsion flooding for mobility control in the presence of fatty acids: effect of chain length [J].Fuel,2020,276:110-118.
[5]文江波,罗海军.原油-水两相体系乳化特性研究进展[J].科学技术与工程,2021,21(17):6971-6979.
WEN Jiangbo,LUO Haijun.Progress in studies of emulsification of crude oil-water two-phase system[J].Science Technology and Engineering,2021,21(17),6971-6979.
[6]赵一潞,康万利,殷夏,等.长庆油包水乳状液的稳定性与沥青质含量的关系[J].石油学报(石油加工),2018,34(3):592-599.
ZHAO Yilu,KANG Wanli,Yin Xia,et al.Relationship between the stability of Changqing water in oil emulsions and asphaltene content[J].Acta Petrolei Sinica(Petroleum Processing Section),2018,34(3):592-599.
[7]TCHOUKOV P,YANG F,XU Z,et al.Role of asphaltenes in stabilizing thin liquid emulsion films[J]. Langmuir,2014,30(11):3024-3033.
[8]SZTUKOWSKI D M,JAFARI M,ALBOUDWAREJ H, et al. Asphaltene self-association and water-in-hydrocarbon emulsions [J].Journal of Colloid Interface Science, 2003, 265(1): 179-186.
[9]TAVAKKOLI M,CHEN A,SUNG C A,et al.Effect of emulsified water on asphaltene instability in crude oils[J].Energy & Fuels,2016,30(5):3676-3686.
[10] ASLAN S, FIROOZABADI A.Effect of water on deposition, aggregate size, and viscosity of asphaltenes[J].Langmuir,2014,30(13):3658-3664.
[11] SINA A, BAHRAM S S. Experimental investigation of the brine effect on asphaltene precipitation and deposition during water injection in porous media using static and dynamic system[J].Energy & Fuels,2021,35(2):11141-11153.
[12] LING N N,HABER A,GRAHAM B F,et al.Quantifying the effect of salinity on oilfield water-in-oil emulsion stability[J].Energy & Fuels,2018,32(9):10042-10049.
[13] KUNDU P, AGRAWAL A, MATEEN H, et al. Stability of oil in water macro-emulsion with anionic surfactant: effect of electrolytes and temperature[J].Chemical Engineering and Science,2013,102(6):176-185.
[14] SAFARI M, RAHIMI A, GHOLAMI R, et al. Underlying mechanisms of shale wettability alteration by low salinity water injection (LSWI)[J].Journal of Dispersion Science Technology,2020,12(3):11-19.
[15] WEN J,LUO H,LONG Z,et al.Emulsification behaviors of crude oil-water system and its quantitative relationship with exergy loss rate[J].Journal of Petroleum Science and Engineering,2019,176(5):502-508.
[16] 唐梅荣,张同伍,白晓虎,等.孔喉结构对CO₂驱储层伤害程度的影响[J].岩性油气藏,2019,31(3):1-8.
TANG Meirong,ZHANG Tongwu,BAI Xiaohu,et al.Influence of pore throat structure on reservoir damage with CO₂ flooding[J].Lithologic Reservoirs,2019,31(3):1-8.
[17] MEHANA M, ABRAHAM J, FAHES M. The impact of asphaltene deposition on fluid flow in sandstone[J].Journal of Petroleum Science and Engineering,2019,174(4):676-681.
[18] 伍晓林,侯兆伟,杨勇,等.古龙1号乳液体系研制及性能评价[J].大庆石油地质与开发,2022,41(3):112-119.
WU Xiaolin,HOU Zhaowei,YANG Yong,et al.Development and performance evaluation for Gulong 1# emulsion system[J].Petroleum Geology & Oilfield Development in Daqing,2022,41(3):112-119.
[19] 刘俊凯,徐鑫,呼苏娟,等.沥青质沉积方式对储层渗透率的影响[J].大庆石油地质与开发,2023,42(2):91-98.
LIU Junkai,XU Xin,HU Sujuan,et al. Impact of asphaltene deposition patterns on reservoir permeability[J].Petroleum Geology & Oilfield Development in Daqing,2023,42(2):91-98.
[20] 高晓东,董平川,张友恒,等.井筒沥青质沉积位置预测方法[J].大庆石油地质与开发,2023,42(3):90-98.
GAO Xiaodong,DONG Pingchuan,ZHANG Youheng,et al. Prediction method for asphaltene deposition location in wellbore[J].Petroleum Geology & Oilfield Development in Daqing,2023,42(3):90-98.
[21] 袁斌,汪洋,白航航,等.CO₂非混相驱原油膨胀及沥青质沉淀影响因素[J].大庆石油地质与开发,2023,42(4):105-112.
YUAN Bin,WANG Yang,BAI Hanghang,et al. Influencing factors of crude oil expansion and asphaltene precipitation in immiscible CO₂ flooding[J].Petroleum Geology & Oilfield Development in Daqing,2023,42(4):105-112.
[22] 邸士莹,程时清,白文鹏,等.裂缝性致密油藏注水吞吐转不稳定水驱开发模拟[J].石油钻探技术,2022,50(1):89-96.
DI Shiying, CHENG Shiqing, BAI Wenpeng,et al.Simulation of transformation from water-injection huff and puff to unstable water-flooding in developing fractured tight reservoirs[J]. Petroleum Drilling Techniques,2022,50(1):89-96.
[23] 张志荣,陶国亮,SNOWDONLloyd R,等.沥青质大分子的结构及其测定方法综述[J].石油实验地质,2023,45(5):963-972.
ZHANG Zhirong,TAO Guoliang,SNOWDON Lloyd R,et al.Review on molecular structures of asphaltene macromolecules and instrumental analytical approaches[J].Petroleum Geology & Experiment,2023,45(5):963-972.
[24] 李二庭,靳军,陈亮,等.准噶尔盆地南缘井筒堵塞物中沥青质分子组成研究[J].石油实验地质,2022,44(2):306-313.
LI Erting,JIN Jun,CHEN Liang,et al.Molecular composition of asphaltene in wellbore blockage on the southern margin of Junggar Basin[J].Petroleum Geology & Experiment,2022,44(2):306-313.
[25] 张旭,张瑞,马若楠,等.纳米颗粒F-SiO₂对地层原油中沥青质沉淀抑制效果[J].大庆石油地质与开发,2023,42(6):91-98.
ZHANG Xu,ZHANG Rui,MA Ruonan,et al.Inhibition effect of F-SiO₂ nanoparticles on asphaltene precipitation in strata oil[J].Petroleum Geology & Oilfield Development in Daqing,2023,42(6):91-98.