Instability mechanism and anti-sloughing drilling fluid technique for deep coal seam of Tarim basin

Authors

LI Heng, State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China
HE Shiming, State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, ChinaFollow
TANG Ming, State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China
LI Ning, Research Institute of Petroleum Engineering, Tarim Oilfield Company, Korla 841008, China
YANG Pei, Research Institute of Petroleum Engineering, Tarim Oilfield Company, Korla 841008, China
ZHANG Zhen, Research Institute of Petroleum Engineering, Tarim Oilfield Company, Korla 841008, China

Abstract

In view of the complicated problems of drilling fluid leakage and hole collapse during the drilling of deep coalbed in Tarim basin, the microstructure and physical and chemical properties of coal were tested by vitrinite reflectance analysis, X ray diffraction and scanning electron microscope, and the mechanism of coal seam instability was confirmed. The fixed carbon content of the coal exceeds 60%, the vitrinite reflectance is greater than 1.1%, and coal have high degree of coalification, is brittle and easy to break. The total amount of clay mineral is less than 25%, and there is no strong water-sensitive mineral montmorillonite in clay. The cleat of coal is reticulated, whose width is mainly concentrated in 1-10 μm, easy to leak off. The instability type of coal and rocks was judged comprehensively as mechanical instability. Taking the microstructure of coal as the object and combining with the size distribution of drilling fluid materials, the asphaltic blocking agent was optimized and the asphaltic polysulfonate anti-collapse drilling fluid for coal seam was designed. Its performance test shows that the asphaltic polysulfonate anti-collapse drilling fluid has low filtration loss and thin mud cake, can effectively block most of coal cleats, reduce drilling fluid invasion, and prevent coal seam collapse. The research results can provide technical support for safe and efficient drilling in the deep coal seam in Tarim basin.

Keywords

coal seam, mechanism of the wall instability, blockage performance, anti-collapse drilling fluid

DOI

10.3969/j.issn.1001-1986.2019.04.032

Recommended Citation

LI Heng, HE Shiming, TANG Ming, et al. (2019) "Instability mechanism and anti-sloughing drilling fluid technique for deep coal seam of Tarim basin," Coal Geology & Exploration: Vol. 47: Iss. 4, Article 33.
DOI: 10.3969/j.issn.1001-1986.2019.04.032
Available at: https://cge.researchcommons.org/journal/vol47/iss4/33

Reference

[1] 唐跃. 中国煤层气资源与前景[C]//中国地质学会2013年学术年会论文摘要汇编. 北京:中国地质学会,2013:505-506.

[2] 李小刚,杨兆中,梁知,等. 深埋煤层气藏水力压裂增产技术探讨[J]. 天然气与石油,2011,29(6):46-48. LI Xiaogang,YANG Zhaozhong,LIANG Zhi,et al. Study on hydraulic fracturing stimulation technique for deep buried CBM reservoir[J]. Natural Gas and Oil,2011,29(6):46-48.

[3] CLARK J. CERA:Natural gas poised to overtake oil use by 2025[J]. Oil & Gas Journal,2004,102(9):20-21.

[4] GUNTER W D,MAVOR M J,ROBINSON J R. CO₂ storage and enhanced methane production:Field testing at Fenn-Big Valley,Alberta,Canada,with application[J]. Greenhouse Gas Control Technologies,2005:413-421.

[5] 朱庆忠,杨延辉,左银卿,等. 中国煤层气开发存在的问题及破解思路[J]. 天然气工业,2018,38(4):96-100. ZHU Qingzhong,YANG Yanhui,ZUO Yinqing,et al. CBM development in China:Challenges and solutions[J]. Natural Gas Industry,2018,28(4):96-100.

[6] 孙延明,张遂安,杨红军,等. 影响煤层气钻井工程的工程地质因素分析[J]. 中国煤炭地质,2016,28(12):62-66. SUN Yanming,ZHANG Sui'an,YANG Hongjun,et al. Analysis of engineering geological factors impacting CBM well drilling engineering[J]. Coal Geology of China,2016,28(12):62-66.

[7] 冯永超,武星星,党冰华,等. 泾河油田延安组煤层特性与井壁失稳机理[J]. 钻井液与完井液,2015,32(6):46-49. FENG Yongchao,WU Xingxing,DANG Binghua,et al. Coal seam characteristics and borehole instability mechanism in Yan'an Formation of Jinghe oilfield[J]. Drilling Fluid & Completion Fluid,2015,32(6):46-49.

[8] 孙正财,刘向君,梁利喜,等. 煤层气井割理煤岩井壁稳定性影响因素分析[J]. 煤炭科学技术,2018,46(4),117-122. SUN Zhengcai,LIU Xiangjun,LIANG Lixi,et al. Analysis om impact factors of borehole wall stability of coalbed methane well[J]. Coal Science and Technology,2018,46(4),117-122.

[9] SHI Zhijun,ZHAO Yongzhe,QI Hongjun,et al. Research and application of drilling technology of extended-reach horizontally-intersected well used to extract coalbed methane[J]. Procedia Earth & Planetary Science,2011,3:446-454.

[10] 陆小霞,黄文辉,王佳旗,等. 沁水盆地柿庄北深部煤层煤体结构发育特征[J]. 煤田地质与勘探,2014,42(3):8-11. LU Xiaoxia,HUANG Wenhui,WANG Jiaqi,et al. The development characteristics of deep coal structure in northern Shizhuang area[J]. Coal Geology & Exploration,2014,42(3):8-11.

[11] 李文华,白向飞,杨金和,等. 烟煤镜质组平均最大反射率与煤种之间的关系[J]. 煤炭学报,2006,31(3):342-345. LI Wenhua,BAI Xiangfei,YANG Jinhe,et al. Cor-respondence between mean maximum reflectance of vitrinite and classification of bituminous coals[J]. Journal of China Coal Society,2006,31(3):342-345.

[12] 金振奎,王春生,王濮,等. 华北地区石炭系-二叠系煤岩储集性能的控制因素[J]. 石油勘探与开发,2007,34(5):534-540. JIN Zhenkui,WANG Chunsheng,WANG Pu,et al. Controlling factors of reservoir ability of Carboniferous and Permian coal rocks,North China[J]. Petroleum Exploration and Development,2007,34(5):534-540.

[13] YAO Boyuan,LI Deping. Features and correct application of coal vitrinite reflectance index[J]. Journal of Coal Science & Engineering,2012,18(4):400-406.

[14] 中国煤炭工业协会,全国煤炭标准化技术委员会. 镜质体反射率的煤化程度分级:MT/T 1158-2011[S]. 北京:煤炭工业出版社,2011.

[15] SMITH J R,SMITH J W. A relationship between the carbon and hydrogen content of coals and their vitrinite reflectance[J]. International Journal of Coal Geology,2007,70(1):79-86.

[16] MARINO J,MARSHAK S,MASTERLERZ M. Evidence for stratigraphically controlled paleogeotherms in the Illinois basin based on vitrinite-reflectance analysis:Implications for interpreting coal-rank anomalies[J]. AAPG Bulletin,2015,99(10):1803-1825.

[17] 金新. 煤矿井下定向钻进防塌乳液研究[J]. 煤田地质与勘探,2017,45(1):158-161. JIN Xin. Research on collapse prevention emulsions used in directional drilling in coal mine[J]. Coal Geology & Exploration,2017,45(1):158-161.