Study on resistivity experiments and conductive mechanism in low-permeability reservoirs with complex wettability
-
摘要:
低渗透岩性油气藏发育的黏土膜吸附原油造成了储层亲油，电阻率异常高，高阻油水层、水层的存在给储层流体性质识别带来了很大挑战.为了明确不同润湿性储层的电阻率响应特征以及微观导电机理，本文选取了鄂尔多斯盆地西部三叠系延长组长8段的岩心，模拟了油驱水、老化和水驱油过程，并测量了岩心薄片洗油后的接触角.实验结果表明，洗油后异常高阻岩心已表现为不完全亲水，然而，其测量的胶结指数m与正常电阻率岩心相差很小.油驱水至束缚水时，正常电阻率岩心的电阻增大率Ir与含水饱和度Sw的关系在双对数坐标下基本表现为直线的关系，而异常高阻岩心则表现为明显的凸曲线特征.且老化过程前后，异常高阻岩心的电阻率基本不变.结合对异常高阻岩心不同状态下的核磁共振T2谱的分析，表明在油驱水过程中，岩石的润湿性已经向亲油方向发生转变，老化过程对润湿性的改变影响很小.水驱油至残余油时，异常高阻岩心的Ir-Sw曲线表现为近似直线特征，反映出水驱油过程中岩石的导电结构并未发生改变.基于实验结果的分析与讨论，明确了一种适用于低渗透复杂润湿性储层的成藏模式及其导电机理，说明了高阻水层主要是亲油润湿性条件下的连续导电路径遭到破坏造成的.
Abstract:As clay membrane developed in low-permeability lithologic reservoirs absorbs oil, reservoirs become oil-wet, which results in abnormally high resistivity oil-water layers and water layers. Such layers bring great challenges to identification of oil and water layers. In order to make clear of the resistivity response characteristics and conductive mechanism in reservoirs with different wettability, cores were selected in Chang 8 formation, Yanchang group, Upper Triassic, the western Ordos Basin of China. Experiments were tested on these samples to simulate the process of oil displacing water, aging and water displacing oil. What's more, contact angles of thin sections after washing oil were also tested. The experimental results show that abnormally high resistivity cores are not completely water-wet after washing oil. However, the formation factors of abnormally high resistivity cores and normal resistivity cores have little difference. In the process of oil displacing water, the relationship between normal resistivity core resistivity index and water saturation is linear in log-log plot, while that of abnormally high resistivity cores is convex. The resistivity of abnormally high resistivity cores remains unchanged during aging process. Combining the analysis of Nuclear Magnetic Resonance (NMR) T2 spectra under different conditions, it can be inferred that wettability of abnormally high resistivity cores has become less water-wet after oil displacing water. What's more, the aging process has little effect on the wettability of abnormally high resistivity cores. In the process of water displacing oil, the relationship between abnormally high resistivity core resistivity index and water saturation is almost linear, which shows that conductive structure of rock is not changed. Based on the analysis and discussion of these experimental results, an accumulation model and the corresponding conductive mechanism are proposed for low-permeability reservoirs with complex wettability. It shows that abnormally high resistivity water layers are caused by the damage of continuous conductive path under oil-wet condition. The researches and experiments are of great importance for understanding the conductive mechanism, oil layers identification and the evaluation of water flooded formation in low-permeability reservoirs with complex wettability.
-
Key words:
- Resistivity experiment /
- Accumulation mode /
- Conductive mechanism /
- Wettability /
- Low-permeability
-
-
图 1
研究区长8段岩心荧光薄片图
Figure 1.
Fluorescence photomicrograph of a core sample from Chang 8 formation in the study area
图 3
洗油后岩心薄片润湿接触角实验结果
Figure 3.
Experimental results of contact angle after washing oil
图 5
油驱水过程Ir-Sw曲线实验结果
Figure 5.
Experimental results of Ir-Sw curve in oil displacing water process
图 6
异常高阻岩心老化前后电阻率对比
Figure 6.
Resistivity contrast of abnormally high resistivity cores before and after aging
图 7
异常高阻岩心A1和A2的油驱水和水驱油过程Ir-Sw曲线实验结果
Figure 7.
Abnormally high resistivity core experimental results of Ir-Sw curve in oil displacing water process and water displacing oil process
图 8
油驱水实验Ir-Sw曲线分析
Figure 8.
The analysis of Ir-Sw curves in oil displacing water process
图 10
异常高阻岩心A1不同状态下的核磁T2谱
Figure 10.
NMR T2 spectra of abnormally high resistivity core A1 under different conditions
图 11
水驱油实验Ir-Sw曲线分析
Figure 11.
The analysis of Ir-Sw curves in water displacing oil process
图 12
油驱水及水驱油过程岩石油水分布截面图
Figure 12.
The cross-sectional views of oil and water distribution in rocks
表 1
岩心孔隙度、渗透率和束缚水饱和度
Table 1.
Porosity, permeability and irreducible water saturation of cores
岩心编号 A1 A2 A3 A4 φ(%) 9.42 9.25 14 8.89 PERM (10-3μm2) 0.99 0.05 0.21 0.19 束缚水饱和度Swi(%) 41 55 50 60 
下载: 导出CSV
-
Anderson W G. 1986a. Wettability literature survey-part 2:wettability measurement. Journal of Petroleum Technology, 38(11):1246-1262. doi: 10.2118/13933-PA
Anderson W G. 1986b. Wettability literature survey-part 3:the effects of wettability on the electrical properties of porous media. Journal of Petroleum Technology, 38(12):1371-1378. doi: 10.2118/13934-PA
Archie G E. 1942. The electrical resistivity log as an aid in determining some reservoir of characteristics. Trans. A. I. M. E, 146:54-60. http://www.oalib.com/references/7449105
Donaldson E C, Siddiqui T K. 1989. Relationship between the Archie saturation exponent and wettability. SPE Formation Evaluation, 4(3):359-362. doi: 10.2118/16790-PA
Fan Y R, Deng S G, Liu B K. 1998. Experiment on rock resistivity in the process of fresh water drive. Well Logging Technology (in Chinese), 22(3):153-155.
Feng C, Mao Z Q, Shi Y J, et al. 2015. Correlation analysis of well logs and its application to identifying pay zones with complex wettability. Science Technology and Engineering (in Chinese), 15(21):117-122.
Gao C Q, Zhang C G, Mao Z Q. 1998. The effects of wettability on the electrical properties of rocks. Progress in Geophysics (in Chinese), 13(1):60-72. http://manu39.magtech.com.cn/Geoprog/EN/abstract/abstract6375.shtml
Ge X M, Fan Y R, Li J T, et al. 2015. Pore structure characterization and classification using multifractal theory-an application in tight reservoir of Santanghu basin in Western China. Journal of Petroleum Science and Engineering, 127:297-304. doi: 10.1016/j.petrol.2015.01.004
Ge X M, Fan Y R, Cao Y C, et al. 2016. Investigation of organic related pores in unconventional reservoir and its quantitative evaluation. Energy Fuels, 30(6):4699-4709. doi: 10.1021/acs.energyfuels.6b00590
Huang L J. 1995. Model evaluation of wettability effect on rock resistivity. Acta Geophysica Sinica (in Chinese), 38(3):405-410. https://www.researchgate.net/publication/297433686_Model_evaluation_of_wetability_effect_on_rock_resistivity
Kumar M, Sok R, Knackstedt M A, et al. 2010. Mapping 3D pore scale fluid distributions:how rock resistivity is influenced by wettability and saturation history. Petrophysics, 51(2):102-117. https://www.researchgate.net/profile/Christoph_Arns/publication/237837565_Mapping_fluid_distributions_in_3D_at_the_pore_scale_Quantifying_the_influence_of_wettability_and_saturation_history_on_rock_resistivity/links/0a85e52f2a37d22336000000.pdf?inViewer=true&disableCoverPage=true&origin=publication_detail
Liu T Y, Fu R S, Wang S M, et al. 2003. On a new conducting model combining rock wettability. Well Logging Technology (in Chinese), 27(2):99-103. https://www.researchgate.net/publication/296878456_On_a_new_conducting_model_combining_rock_wettability
Looyestijn W J, Hofman J. 2006. Wettability-index determination by nuclear magnetic resonance. SPE Reservoir Evaluation & Engineering, 9(2):146-153. https://www.researchgate.net/publication/238447367_Wettability-Index_Determination_by_Nuclear_Magnetic_Resonance
Mao Z Q, Zhang C G. 1995. The study of capillary and electrical properties of porous rock samples at reservoir conditions. Progress in Geophysics (in Chinese), 10(1):76-91.
Mao Z Q, Zhang C G, Lin C Z. 1997. The effect of wettability of reservoir on the log derived water saturation. Well Logging Technology (in Chinese), 21(1):50-54.
Morgan W B, Pirson S J. 1964. The effect of fractional wettability on the Archie saturation exponent.//SPWLA 5th Annual Logging Symposium. Midland, Texas.
Mungan N, Moore E J. 1968. Certain wettability effects on electrical resistivity in porous media. Journal of Canadian Petroleum Technology, 7(1):20-25. doi: 10.2118/68-01-04
Ouyang J, Mao Z Q, Xiu L J, et al. 2009. Study on Genetic Mechanism and Evaluation Method Via Well Logs in Low-Contrast Reservoirs (in Chinese). Beijing:Petroleum Industry Press.
Rasmus J C. 1986. A summary of the effects of various pore geometries and their wettabilities on measured and in-situ values of cementation and saturation exponents.//SPWLA 27th Annual Logging Symposium. Houston, Texas.
Sondenaa E, Bratteli F, Normann H P, et al. 1991. The effect of reservoir conditions, and wettability on electrical resistivity.//SPE Asia-Pacific Conference. Perth. Australia.
Stalheim S O, Eidesmo T, Rueslatten H. 1999. Influence of wettability on water saturation modelling. Journal of Petroleum Science and Engineering, 24(2-4):243-253. doi: 10.1016/S0920-4105(99)00046-7
Sweeney S A, Jennings H Y Jr. 1960. Effect of wettability on the electrical resistivity of carbonate rock from a petroleum reservoir. The Journal of Physical Chemistry, 64(5):551-553. doi: 10.1021/j100834a009
Tiab D, Donaldson E C. 1996. Petrophysics. Houston, TX:Gulf Publishing.
Trantham J C, Clampitt R L. 1977. Determination of oil saturation after waterflooding in an oil-wet reservoir the North Burbank Unit, Tract 97 Project. Journal of Petroleum Technology, 29(5):491-500. doi: 10.2118/5802-PA
Wang C T, Cai M L, Han X H, et al. 2008. SY/T 5385-2007, Measurement and calculation methods of rock resistivity parameters in laboratory (in Chinese). Beijing:Petroleum Industry Press.
Wang K W, Li N. 2009. Numerical simulation on effects of reservoir characteristics and saturation on T2 spectra of nuclear magnetic resonance. Acta Petrolei Sinica (in Chinese), 30(3):422-426. https://www.researchgate.net/publication/289965473_Numerical_simulation_on_effects_of_reservoir_characteristics_and_saturation_on_T2_spectra_of_nuclear_magnetic_resonance
Xiao L, Mao Z Q, Wang Z N, et al. 2012. Application of NMR logs in tight gas reservoirs for formation evaluation:A case study of Sichuan basin in China. Journal of Petroleum Science and Engineering, 81:182-195. doi: 10.1016/j.petrol.2011.12.025
Yang C M, Li H Q, Lu D W, et al. 2005. The relationship between rock resistivity and water saturation in water-drive-oil and oil-drive-water process. Journal of Jilin University (Earth Science Edition) (in Chinese), 35(5):667-671.
Zhang G Q, Huang C C, Hirasaki G J. 2000. Interpretation of wettability in sandstones with NMR analysis. Petrophysics, 41(3):223-233. https://www.researchgate.net/publication/239925148_Interpretation_of_wettability_in_sandstones_with_NMR_analysis
范宜仁, 邓少贵, 刘兵开. 1998.淡水驱替过程中的岩石电阻率实验研究.测井技术, 22(3):153-155. http://www.cnki.com.cn/Article/CJFDTOTAL-CJJS803.001.htm
冯程, 毛志强, 石玉江等. 2015.测井曲线相关性分析及其在复杂润湿性油层识别中的应用.科学技术与工程, 15(21):117-122. http://www.cnki.com.cn/Article/CJFDTOTAL-KXJS201521023.htm
高楚桥, 章成广, 毛志强. 1998.润湿性对岩石电性的影响.地球物理学进展, 13(1):60-72. http://www.cnki.com.cn/Article/CJFDTOTAL-DQWJ801.005.htm
黄隆基. 1995.润湿性对岩石电阻率影响的模型估算.地球物理学报, 38(3):405-410. http://manu39.magtech.com.cn/Geophy/CN/abstract/abstract4235.shtml
刘堂宴, 傅容珊, 王绍民等. 2003.考虑岩石润湿性的新导电模型研究.测井技术, 27(2):99-103. http://www.cnki.com.cn/Article/CJFDTOTAL-CJJS200302002.htm
毛志强, 章成广. 1995.油藏条件下孔隙岩样毛管和电学性质研究.地球物理学进展, 10(1):76-91. http://www.cnki.com.cn/Article/CJFDTOTAL-DQWJ501.006.htm
毛志强, 章成广, 林纯增. 1997.油层润湿性对测井计算的含水饱和度的影响.测井技术, 21(1):50-54. http://www.cnki.com.cn/Article/CJFDTOTAL-CJJS701.007.htm
欧阳健, 毛志强, 修立军等. 2009.测井低对比度油层成因机理与评价方法.北京:石油工业出版社.
王存田, 蔡敏龙, 韩学辉等. 2008. SY/T 5385-2007, 岩石电阻率参数实验室测量及计算方法.北京:石油工业出版社.
王克文, 李宁. 2009.储层特性与饱和度对核磁T2谱影响的数值模拟.石油学报, 30(3):422-426.
杨春梅, 李洪奇, 陆大卫等. 2005.不同驱替方式下岩石电阻率与饱和度的关系.吉林大学学报 (地球科学版), 35(5):667-671. http://www.cnki.com.cn/Article/CJFDTOTAL-CCDZ200505020.htm
-
图(12)
表(1)
计量
- 文章访问数:
- PDF下载数:
- 施引文献: 0