Effect of acidification on the microstructure and physical properties of shale

Authors

CHEN Liuyu, Mining College, Guizhou University, Guiyang 550025, China; Engineering Center for Safe Mining Technology Under Complex Geologic Condition, Guiyang 550025, China; Institute of Gas Disaster Prevention and Coalbed Methane Development of Guizhou University, Guiyang 550025, China
LI Xijian, Mining College, Guizhou University, Guiyang 550025, China; Engineering Center for Safe Mining Technology Under Complex Geologic Condition, Guiyang 550025, China; Institute of Gas Disaster Prevention and Coalbed Methane Development of Guizhou University, Guiyang 550025, ChinaFollow
SHEN Zhonghui, State Key Laboratory for the Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China
XU Shiqing, Mining College, Guizhou University, Guiyang 550025, China
MA Shengxiang, Mining College, Guizhou University, Guiyang 550025, China; Engineering Center for Safe Mining Technology Under Complex Geologic Condition, Guiyang 550025, China; Institute of Gas Disaster Prevention and Coalbed Methane Development of Guizhou University, Guiyang 550025, China
YIN Xin, Mining College, Guizhou University, Guiyang 550025, China; Engineering Center for Safe Mining Technology Under Complex Geologic Condition, Guiyang 550025, China; Institute of Gas Disaster Prevention and Coalbed Methane Development of Guizhou University, Guiyang 550025, China

Abstract

As the main shale gas reservoir in Guizhou, it is proved that Longmaxi Formation has good shale gas accumulation conditions and resource development potential. In order to reveal the response law of acidification on the micropore structure and physical properties of Longmaxi Formation shale in Guizhou, the difference in physical properties of shale microstructures before and after acidification, such as pore volume, porosity, specific surface area and pore size distribution was quantitatively characterized by X-ray diffraction(XRD) analysis, mercury intrusion measurement, low-temperature nitrogen adsorption and nuclear magnetic resonance(NMR) experiment. The structural characteristics of the shale pores before and after acidification were analyzed. The results show that: Acidification increases the pore volume, porosity, specific surface area and pore size of shale. After the acidification, the hysteresis loop of the shale in dehydration curve and the low-temperature nitrogen absorption-desorption curve increase significantly, acidification increases the pore volume of the ink bottle hole; Due to the influence of acidification, the development direction of shale dominant pores is from meso-pores and mesopores around 110 nm to mesopores and most macro pores around 2 800 nm. The number of meso-pores decreases, the number of macro-pores increases, and the connectivity of shale pores is significantly better; Acidification has obvious chemical dissolution and etching effects on minerals and clay components in shale pore fractures, and has obvious effect on volumetric transformation of shale pore fractures, increasing permeability of shale reservoirs, thereby improving the migration and seepage ability of shale gas; The accompanying hydration under shale acidification plays an important role in the cracking, expansion and failure of the shale pores along the bedding plane, but the hydration mechanism under shale acidification needs further study.

Keywords

shale gas, acidification, hydration, micropore structure, corrosion, Longmaxi Formation, Guizhou Province

DOI

10.3969/j.issn.1001-1986.2020.03.015

Recommended Citation

CHEN Liuyu, LI Xijian, SHEN Zhonghui, et al. (2020) "Effect of acidification on the microstructure and physical properties of shale," Coal Geology & Exploration: Vol. 48: Iss. 3, Article 16.
DOI: 10.3969/j.issn.1001-1986.2020.03.015
Available at: https://cge.researchcommons.org/journal/vol48/iss3/16

Reference

[1] ANOVITZ L M,COLE D R. Characterization and analysis of porosity and pore structures[J]. Reviews in Mineralogy and Geochemistry,2015,80:161-164.

[2] 郭平,王德龙,汪周华,等. 页岩气藏储层特征及开发机理综述[J]. 地质科技情报,2012,31(6):118-122. GUO Ping,WANG Delong,WANG Zhouhua,et al. Investigation on the characteristics and development mechanism of shale gas reservoirs[J]. Geological Science and Technology Information,2012,31(6):118-122.

[3] 邹才能,董大忠,王社教,等. 中国页岩气形成机理、地质特征及资源潜力[J]. 石油勘探与开发,2010,37(6):641-653. ZOU Caineng,DONG Dazhong,WANG Shejiao,et al. The formation mechanism,geological characteristics and resource potential of shale gas in China[J]. Petroleum Exploration and Development,2010,37(6):641-653.

[4] BERNARD S,HORSFIELD B,SCHULZ H-M,et al. Sherwood geochemical evolution of organic-rich shales with increasing maturity:A STXM and TEM study of the Posidonia shale (Lower Toarcian,northern Germany)[J]. Marine and Petroleum Geology,2012,31(1):70-89.

[5] SUN Wenjibin,ZOU Yujun,WU Zhonghu,et al. Fractal analysis of pores and the pore structure of the Lower Cambrian Niutitang shale in northern Guizhou Province:Investigations using NMR,SEM and image analyses[J]. Marine and Petroleum Geology,2019,99(1):416-428.

[6] MAO Ruiyong,ZHANG Jie,PEI Peng,et al. Adsorption characteristics of clay-organic complexes and their role in shale gas resource evaluation[J]. Energy Science & Engineering,2019,7(1):108-119.

[7] 赵博,文光才,孙海涛,等. 煤岩渗透率对酸化作用响应规律的试验研究[J]. 煤炭学报,2017,42(8):2019-2025. ZHAO Bo,WEN Guangcai,SUN Haitao,et al. Experimental study on the response law of coal rock permeability to acidification[J]. Journal of China Coal Society,2017,42(8):2019-2025.

[8] YUAN Liang. Theory and practice of integrated coal production and gas extraction[J]. International Journal of Coal Science & Technology,2015,2(1):3-11.

[9] WIJAYA N,SHENG J J. Effect of desiccation on shut-in benefits in removing water blockage in tight water-wet cores[J]. Fuel,2019,244:314-323.

[10] 杜秋浩,刘晓丽,王维民,等. 超临界CO₂-水-煤相互作用后冲击载荷下煤的动态响应[J]. 煤炭学报,2019,44(11):3453-3462. DU Qiuhao,LIU Xiaoli,WANG Weimin,et al. Dynamic response of coal under impact load after supercritical CO₂-water-coal interaction[J]. Journal of China Coal Society,2019,44(11):3453-3462.

[11] HASSANI A,KAMALI M R. Optimization of acid injection rate in high rate acidizing to enhance the production rate:An experimental study in Abteymour oil field,Iran[J]. Journal of Petroleum Science and Engineering,2017,156:553-562.

[12] SHI Xian,XU Hongxing,YANG Liu. Removal of formation damage induced by drilling and completion fluids with combination of ultrasonic and chemical technology[J]. Journal of Natural Gas Science and Engineering,2017,37:471-478.

[13] 李胜,罗明坤,范超军,等. 基于核磁共振和低温氮吸附的煤层酸化增透效果定量表征[J]. 煤炭学报,2017,42(7):1748-1756. LI Sheng,LUO Mingkun,FAN Chaojun,et al. Quantitative characterization of coal seam acidification enhancement based on NMR and low temperature nitrogen adsorption[J]. Journal of China Coal Society,2017,42(7):1748-1756.

[14] 李瑞,王坤,王于健. 提高煤岩渗透性的酸化处理室内研究[J]. 煤炭学报,2014,39(5):913-917. LI Rui,WANG Kun,WANG Yujian. Indoor study on acidification for enhancing the permeability of coal[J]. Journal of China Coal Society,2014,39(5):913-917.

[15] JIANG Yongdong,LUO Yahuang,LU Yiyu,et al. Effects of supercritical CO₂ treatment time,pressure,and temperature on microstructure of shale[J]. Energy,2016,97:173-181.

[16] MISHRA V,ZHU Ding,HILL A D. An acid-placement model for long horizontal wells in carbonate reservoirs[J]. SPE 107780,2007:1-9.

[17] 周林波,宋志峰,张俊江,等. MX井深层白云岩储层非均匀酸化压裂技术[J]. 特种油气藏,2017,24(6):161-164. ZHOU Linbo,SONG Zhifeng,ZHANG Junjiang,et al. Nonuniform acid fracturing technology for deep dolomite reservoir in well MX[J]. Special Oil and Gas Reservoir,2017,24(6):161-164.

[18] 郭建春,苟波,王坤杰,等. 川西下二叠统超深气井网络裂缝酸化优化设计[J]. 天然气工业,2017,37(6):34-41. GUO Jianchun,GOU Bo,WANG Kunjie,et al. An optimal design of network fracture acidifcation for ultradeep gas wells in the Lower Permian strata of the western Sichuan basin[J]. Natural Gas Industry,2017,37(6):34-41.

[19] 康毅力,杨斌,李相臣,等. 页岩水化微观作用力定量表征及工程应用[J]. 石油勘探与开发,2017,44(2):301-308. KANG Yili,YANG Bin,LI Xiangchen,et al. Quantitative characterization of micro-forces in shale hydration and field applications[J]. Petroleum Exploration and Development,2017,44(2):301-308.

[20] ISRAELACHVILI J N. Intermolecular and surface forces[M]. Singapore:Elsevier(Singapore) Pte Ltd.,2012.

[21] 易同生,高弟. 贵州龙马溪组页岩气储层特征及其分布规律[J]. 煤田地质与勘探,2015,43(3):22-27. YI Tongsheng,GAO Di. Characteristics and distribution pattern of shale gas reservoir in Longmaxi Formation in Guizhou Province[J]. Coal Geology & Exploration,2015,43(3):22-27.

[22] JARVIE D M,HILL R J,RUBLE T E,et al. Unconventional shale-gas systems:The Mississippian Barnett shale of northcentral Texas as one model for thermogenic shale gas assessment[J]. AAPG Bulletin,2007,91(4):475-499.

[23] 程克明,王铁冠. 天然气源岩地球化学特征[J]. 天然气地球科学,1993(2/3):49-94. CHENG Keming,WANG Tieguan. Geochemical characteristics of natural gas source rocks[J]. Natural Gas Geoscience,1993(2/3):49-94.

[24] 周庆华,宋宁,王成章,等. 湖南花垣页岩气区块地质评价与勘探展望[J]. 天然气地球科学,2014,25(1):130-140. ZHOU Qinghua,SONG Ning,WANG Chengzhang,et al. Geological evaluation and exploration prospect of shale gas block in Huayuan,Hunan[J]. Natural Gas Geoscience,2014,25(1):130-140.

[25] 吉利明,邱军利,张同伟,等. 泥页岩主要黏土矿物组分甲烷吸附实验[J]. 地球科学,2012,37(5):1043-1050. JI Liming,QIU Junli,ZHANG Tongwei,et al. Study on methane adsorption of main clay mineral components of shale shale[J]. Earth Science,2012,37(5):1043-1050.

[26] 张慧,晋香兰,吴静,等. 四川盆地龙马溪组页岩有机质的纳米孔隙[J]. 煤田地质与勘探,2018,46(3):47-53. ZHANG Hui,JIN Xianglan,WU Jing,et al. Nano-pores of organic matter in Longmaxi Formation shale in Sichuan basin[J]. Coal Geology & Exploration,2018,46(3):47-53.

[27] HOU Peng,GAO Feng,JU Yang,et al. Changes in pore structure and permeability of low permeability coal under pulse gas fracturing[J]. Journal of Natural Gas Science and Engineering,2016,34:1017-1026.

[28] WAN Haichao,FU Xuehai,JIAN Kuo,et al. Changes in coal pore structure and permeability during N₂ injection[J]. Journal of Natural Gas Science and Engineering,2015,27:1234-1241.

[29] 李希建,沈仲辉,李维维,等. 黔北凤冈地区牛蹄塘组页岩气勘探与开发潜力[J]. 天然气工业,2016,36(12):72-79. LI Xijian,SHEN Zhonghui,LI Weiwei,et al. The potential of shale gas exploration and exploitation in Niutitang Formation in northern Guizhou[J]. Natural Gas Industry,2016,36(12):72-79.

[30] 张超谟,陈振标,张占松,等. 基于核磁共振T₂谱分布的储层岩石孔隙分形结构研究[J]. 石油天然气学报,2007,29(4):80-86. ZHANG Chaomo,CHEN Zhenbiao,ZHANG Zhansong,et al. Study on pore fractal structure of reservoir rocks based on NMR T₂ spectral distribution[J]. Journal of Oil and Gas Technology,2007,29(4):80-86.

[31] 薛华庆,周尚文,蒋雅丽,等. 水化作用对页岩微观结构与物性的影响[J]. 石油勘探与开发,2018,45(6):1075-1081. XUE Huaqing,ZHOU Shangwen,JIANG Yali,et al. Effects of hydration on the microstructure and physical properties of shale[J]. Petroleum Exploration and Development,2018,45(6):1075-1081.

[32] VIANI B E,LOW P F,ROTH C B. Direct measurement of the relation between interlayer force and interlayer distance in the swelling of montmorillonite[J]. Journal of Colloid & Interface Science,1983,96(1):229-244.

[33] 隋微波,田英英,姚晨昊. 页岩水化微观孔隙结构变化定点观测实验[J]. 石油勘探与开发,2018,45(5):894-901. SUI Weibo,TIAN Yingying,YAO Chenhao. 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):894-901.

[34] GHANBARI E,DEHGHANPOUR H. Impact of rock fabric on water imbibition and salt diffusion in gas shale[J]. International Journal of Coal Geology,2015,138:55-67.