Citation: | JIANG Changbao,LI Lin,YIN Wenming,et al. Research on evolution characteristics of shale pore-fracture and permeability under freeze-thaw cycles[J]. Coal Science and Technology,2023,51(S1):18−26. DOI: 10.13199/j.cnki.cst.QNTK21-1135 |
Shale gas reservoirs have ultra-low permeability, and liquid nitrogen fracturing has attracted much attention as a promising reservoir permeability enhancement technology. This paper took the Longmaxi Formation shale in southern Sichuan as the research object, and studied the physical response of the water-bearing shale core under the freezing-thawing cycle of liquid nitrogen (LN2), which was a cryogenic fluid. The LN2 freeze-thaw cycle treatment was carried out for the shale in the water-bearing state, scanning electron microscope (SEM) was used to observe the microscopic pore and fracture structure of shale samples before and after the LN2 freeze-thaw cycle, digital image processing technology and fractal theory were used to quantitatively analyze the pore-fracture changes at the same location, and then porosity and permeability tests were performed, computer tomography (CT) was used to show the macroscopic fracture failure process of shale samples with the LN2 freeze-thaw cycle, finally discussed the cracking mechanism of liquid nitrogen freezing and thawing. The results showed that the liquid nitrogen freeze-thaw cycle treatment could effectively promote the initiation and expansion of pores and cracks. When the liquid nitrogen froze and thawed, the shale generated new cracks under the action of thermal stress and frost heave force, and the pores and cracks developed steadily increased with the number of freeze-thaw cycles. The cumulative increase in shale porosity under the freeze-thaw cycle was 54.6%, and the increase in permeability was very significant (up to 3 orders of magnitude).
[1] |
KONTOROVICH A E,EPOV M I,EDER L V. Long-term and medium-term scenarios and factors in world energy perspectives for the 21st century[J]. Russian Geology & Geophysics,2014,55(5/6):534−543.
|
[2] |
BENTLEY R W. Global oil & gas depletion: An overview[J]. Energy Policy,2002,30(3):189−205. doi: 10.1016/S0301-4215(01)00144-6
|
[3] |
刘慧芳,安海忠,梅 洁. 美国页岩气开发状况及影响分析[J]. 资源与产业,2012,14(6):81−87. doi: 10.3969/j.issn.1673-2464.2012.06.015
LIU Huifang,AN Haizhong,MEI Jie. Development and effect of shale gas in the united states[J]. Resources & Industries,2012,14(6):81−87. doi: 10.3969/j.issn.1673-2464.2012.06.015
|
[4] |
VIDIC R D,Brantley S L,VANDENBOSSCHE J M,et al. Impact of shale gas development on regional water quality[J]. Science,2013,340:826−826.
|
[5] |
JAVADPOUR F. Nanopores and apparent permeability of gas flow in mudrocks (shales and siltstone)[J]. Journal of Canadian Petroleum Technology,2009,48(8):16−21. doi: 10.2118/09-08-16-DA
|
[6] |
CHEN Y F,JIANG C B,YIN G Z,et al. Permeability evolution under true triaxial stress conditions of Longmaxi shale in the Sichuan Basin, Southwest China[J]. Powder Technology,2019,354:601−614. doi: 10.1016/j.powtec.2019.06.044
|
[7] |
孙张涛,吴西顺. 页岩气开采中的水力压裂与无水压裂技术[J]. 国土资源情报,2014(5):51−55.
SUN Zhangtao,WU Xishun. Review on hydraulic fracturing and non-aqueous fracturing in shale gas development[J]. Land and Resources Information,2014(5):51−55.
|
[8] |
黄中伟, 李根生, 蔡承政, 等. 岩石液氮低温致裂实验及在油气开采中应用前景[A]. 第十二届全国岩石破碎工程学术大会[C]. 沈阳, 2014: 158-162.
HUANG Zhongwei, LI Gensheng, CAI Chengzheng, et al. Experiment of liquid nitrogen cryogenic cracking on rock and its application prospect in oil & gas exploration and production[A]. The 12th National Academic Conference on Rock Crushing Engineering[C]. Shenyang, 2014: 158-162.
|
[9] |
CAI C Z,HUANG Z W,LI G S,et al. Feasibility of reservoir fracturing stimulation with liquid nitrogen jet[J]. Journal of Petroleum Science & Engineering,2016,144:59−65.
|
[10] |
WU X G,HUANG Z W,LI R,et al. Investigation on the damage of high-temperature shale subjected to liquid nitrogen cooling[J]. Journal of Natural Gas Science and Engineering,2018,57:284−294. doi: 10.1016/j.jngse.2018.07.005
|
[11] |
GRUNDMANN S R , RODVELT G D , DIALS G A , et al. Cryogenic nitrogen as a hydraulic fracturing fluid in the devonian shale[A]. SPE Eastern Regional Meeting. Society of Petroleum Engineers[C]. Pittsburgh, 1998, 51067.
|
[12] |
JIANG L,CHENG Y F,HAN Z Y,et al. Effect of liquid nitrogen cooling on the permeability and mechanical characteristics of anisotropic shale[J]. Journal of Petroleum Exploration & Production Technology,2019,9(1):111−124.
|
[13] |
CAI C Z,LI G S,HUANG Z W,et al. Experiment of coal damage due to super-cooling with liquid nitrogen[J]. Journal of Natural Gas Science & Engineering,2015,22:42−48.
|
[14] |
QIN L,ZHAI C,LIU S M,et al. Changes in the petrophysical properties of coal subjected to liquid nitrogen freeze-thaw-A nuclear magnetic resonance investigation[J]. Fuel,2017,194:102−114. doi: 10.1016/j.fuel.2017.01.005
|
[15] |
翟 成,徐吉钊. 液氮循环致裂技术强化煤层气抽采的研究与应用展望[J]. 工矿自动化,2020,46(10):1−8. doi: 10.13272/j.issn.1671-251x.17669
ZHAI Cheng,XU Jizhao. Research on cyclic liquid nitrogen fracturing technology for enhancing coalbed methane drainage and its application prospect[J]. Industry and Mine Automation,2020,46(10):1−8. doi: 10.13272/j.issn.1671-251x.17669
|
[16] |
LI Z F,XU H F,ZHANG C Y. Liquid nitrogen gasification fracturing technology for shale gas development[J]. Journal of Petroleum Science and Engineering,2016,138:253−256. doi: 10.1016/j.petrol.2015.10.033
|
[17] |
陶 静. 液氮预注后页岩压裂的损伤破裂机理研究[D]. 徐州: 中国矿业大学, 2020.
TAO Jing. Study on damage mechanics of shale nitrogen fracturing after liquid nitrogen pre-conditioning[D]. Xuzhou: China University of Mining and Technology, 2020.
|
[18] |
VINEGAR H J. X-Ray CT and NMR imaging of rocks[J]. Journal of Petroleum Technology,1986,38(3):257−259. doi: 10.2118/15277-PA
|
[19] |
JIANG C B,LIU X D,WANG W S,et al. Three-dimensional visualization of the evolution of pores and fractures in reservoir rocks under triaxial stress[J]. Powder Technology,2021,378(PA):585−592.
|
[20] |
王 豪. 页岩热致裂缝形成机理及数值模拟研究[D]. 西安: 西安石油大学, 2021.
WANG Hao. The formation mechanism and numerical simulation of thermally induced fractures in shale[D]. Xi'an: Xi'an Shiyou University, 2021.
|
[21] |
DEBASHIS D,BRIJES M,Neel G. Understanding the influence of petrographic parameters on strength of differently sized shale specimens using XRD and SEM[J]. International Journal of Mining Science and Technology,2021,31(5):953−961. doi: 10.1016/j.ijmst.2021.07.004
|
[22] |
YANG R,SHENG H,YI J Z. Nano-scale pore structure and fractal dimension of organic-rich Wufeng-Longmaxi shale from Jiaoshiba area, Sichuan Basin: Investigations using FE-SEM, gas adsorption and helium pycnometry[J]. Marine and Petroleum Geology,2016,70:27−45. doi: 10.1016/j.marpetgeo.2015.11.019
|
[23] |
LIU X F,NIE B S. Fractal characteristics of coal samples utilizing image analysis and gas adsorption[J]. Fuel,2016,182:314−322. doi: 10.1016/j.fuel.2016.05.110
|
[24] |
MAJID B,OMID A H,LEVI K J,et al. Quantitative analysis of statistical properties of organic-rich mudstone using large field-of-view SEM images[J]. Journal of Natural Gas Science and Engineering,2021,95:104238. doi: 10.1016/j.jngse.2021.104238
|
[25] |
SUI W B,TIAN Y Y,YAO C H. Investigation of microscopic pore structure variations of shale due to hydration effects through SEM fixed-point observation experiments[J]. Petroleum Exploration and Development,2018,45(5):955−962. doi: 10.1016/S1876-3804(18)30099-5
|
[26] |
孙文峰. 页岩储层多尺度结构特征及表征方法研究[D]. 大庆: 东北石油大学, 2017.
SUN Wenfeng. Research on multi-scale structural characteristics and characterization methods of shale reservoirs[D]. Daqing: Northeast Petroleum University, 2017.
|
[27] |
SONG Y J,TAN H,YANG H M,et al. Fracture evolution and failure characteristics of sandstone under freeze-thaw cycling by computed tomography[J]. Engineering Geology,2021,294:106370. doi: 10.1016/j.enggeo.2021.106370
|
[28] |
贾海梁. 多孔岩石及裂隙岩体冻融损伤机制的理论模型和试验研究[D]. 武汉: 中国地质大学, 2016.
JIA Hailiang. Theoretical damage models of porous rocks and hard jointed rocks subjected to frost action and further experimental verifications[D]. Wuhan: China University of Geosciences, 2016.
|
[29] |
JIANG C B,WANG Y F,DUAN M K,et al. Experimental study on the evolution of pore-fracture structures and mechanism of permeability enhancement in coal under cyclic thermal shock[J]. Fuel,2021,304:121455. doi: 10.1016/j.fuel.2021.121455
|
[30] |
刘泉声,黄诗冰,康永水,等. 裂隙冻胀压力及对岩体造成的劣化机制初步研究[J]. 岩土力学,2016,37(6):1530−1542. doi: 10.16285/j.rsm.2016.06.002
LIU Quansheng,HUANG Shibing,KANG Yongshui,et al. Preliminary study of frost heave pressure and its influence on crack and deterioration mechanisms of rock mass[J]. Rock and Soil Mechanics,2016,37(6):1530−1542. doi: 10.16285/j.rsm.2016.06.002
|
[31] |
乔 趁,王 宇,宋正阳,等. 饱水裂隙花岗岩周期冻胀力演化特性试验研究[J]. 岩土力学,2021,42(8):2141−2150.
QIAO Chen,WANG Yu,SONG Zhengyang,et al. Experimental study on the evolution characteristics of cyclic frost heaving pressure of saturated fractured granite[J]. Rock and Soil Mechanics,2021,42(8):2141−2150.
|
[1] | MA Yankun, HU Mingye, ZHANG Xi, YANG Wenwang, YAN Zewen, ZHANG Zhen. Experimental study on correlation between compressibility and permeability of on-load lignite pore structure[J]. COAL SCIENCE AND TECHNOLOGY, 2025, 53(S1): 165-172. DOI: 10.12438/cst.2023-0955 |
[2] | DING Yunna, LI Bobo, CHENG Qiaoyun, DUAN Shulei, SONG Haosheng. Evolution mechanism of shale microfracture apparent permeability considering dynamic slippage[J]. COAL SCIENCE AND TECHNOLOGY, 2023, 51(11): 129-138. DOI: 10.12438/cst.2023-0090 |
[3] | FENG Zeyu, DONG Xianshu, CHEN Ruxia. The relationship between permeability and pore structure of coal slime filter cake based on fractal characteristics[J]. COAL SCIENCE AND TECHNOLOGY, 2023, 51(10): 312-322. DOI: 10.13199/j.cnki.cst.2022-2207 |
[4] | XU Hui, MU Yi, NIU Chao. Study on optimization of permeability coefficient of structural fractal for mine water inflow[J]. COAL SCIENCE AND TECHNOLOGY, 2021, 49(10): 228-232. |
[5] | XUE Haiteng, LI Xijian, CHEN Liuyu, IU Yu. Micro-pore fractal characteristics of outburst coal in Western Guizhou and its influence on permeability[J]. COAL SCIENCE AND TECHNOLOGY, 2021, 49(3): 118-122. DOI: 10.13199/j.cnki.cst.2021.03.015 |
[6] | LI Bobo, WANG Bin, YANG Kang, REN Chonghong, YUAN Mei, XU Jiang. Study on fractal characteristics of coal and rock pore fissure structure and permeability model[J]. COAL SCIENCE AND TECHNOLOGY, 2021, 49(2): 226-231. DOI: 10.13199/j.cnki.cst.2021.02.026 |
[7] | DENG Ende, JIANG Bingren, GAO Wei, FU Wei. Study on pore structure and fractal characteristics of shale from coal measures of Longtan Formation in western Guizhou[J]. COAL SCIENCE AND TECHNOLOGY, 2020, 48(8): 184-190. |
[8] | Xi ZhaodongTang Shuheng Zhang Songhang Li Jun, . Pore structure and fractal features of sapropelite[J]. COAL SCIENCE AND TECHNOLOGY, 2016, (11). |
[9] | WEI Zhen SUN Hong-wei ZHU Qiao-yu LIU Yan-hua LU Li-jiang, . Analysis on complexity of fault structure based on regression model[J]. COAL SCIENCE AND TECHNOLOGY, 2015, (3). |