4D Seismic Characteristics in Coal Mine Gobs: A Case Study from the Zhangji Coal Mine in Huainan Coalfield

doi:10.19657/j.geoscience.1000-8527.2020.028

Abstract

Abstract:

Gob subsidence is an important geological problem in coal mines, and can seriously impact coal production and represent a potentially-lethal safety risk. Therefore, detection of gob subsidence is important to ensure sustainable coal mining. Due to the complex seismic and geological conditions in the gob subsidence area, it is hard to identify accurately the gob boundary with conventional three-dimensional (3D) seismic exploration methods. Therefore, we propose a new, model-driven gob identification method based on four-dimensional (4D) seismic characteristics, and use the Zhangji coal mine in the Huainan coalfield as an example. In this method: (1) geological models before and after coal seam mining are established and forward modeling is performed; (2) the prestack time migration (PSTM) sections of the synthetic seismic data are used to back-analyze the seismic features of the gobs, which are identified according to the seismic feature variations caused by the gobs; (3) the seismic features of the gob areas (in synthetic seismic data) are used to guide the gob identification in real seismic data; (4) through seismic interpretations, the gob areal extent is constrained. Analysis of the real 4D seismic data from Zhangji coal mining area shows that the continuity of the gob reflection decreases, and the reflection is displaced at the gob boundary. Therefore, this detection method (based on the 4D seismic difference) can effectively detect the gobs and delineate their boundary.

Key words: gob area, 4D seismics, forward modeling, Huainan coalfield

CLC Number:

YUAN Hao, LIU Jiapeng, JIANG Zaixing. 4D Seismic Characteristics in Coal Mine Gobs: A Case Study from the Zhangji Coal Mine in Huainan Coalfield[J]. Geoscience, 2021, 35(04): 1018-1023.

Figures/Tables 9

Fig.1 Structural map of the Zhangji coal mine in Huainan coalfield[18]

Fig.2 Stratigraphic column of the main coal seams in the Zhangji coal mine[19]

Table 1 Statistics of the main coal seams in the Zhangji coal mine

主要可采煤层编号	煤层厚度范围/m	煤层平均厚度/m	煤层顶底板主要岩性
13-1	0~8.280.0	4.78	砂岩、泥岩
11-2	0.78~3.95	2.61	砂质泥岩
8	0.60~6.03	3.11	砂质泥岩

Fig.3 Pre-mining geological model of coal seam L13 (F1 denoting fault, L8, L11 and L13 denoting coal seams)

Fig.4 PSTM section of geological model in Fig.3 (Symbology as in Fig.3)

Fig.5 Post-mining geological model of coal seam L13 (Symbology as in Fig.3)

Fig.6 PSTM section corresponding to model in Fig.5 (Symbo-logy as in Fig.3, and Tf denoting the post-mining ring-like faults)

Fig.7 Pre-mining PSTM section of coal seam 13-1 in the cross-line direction (T3-T5 denoting the reflections of coal seams 8, 11-2 and 13-1, respectively)

Fig.8 Post-mining PSTM section of coal seam 13-1 in the cross-line direction (Tf denoting the post-mining ring-like fault, other symbology as in Fig.7)

References 19

[1]	高远, 赵伟, 李红. 煤矿采空区四维地震勘探技术研究[J]. 合肥工业大学学报, 2009, 32(9):1391-1398.
[2]	祁民, 张宝林, 梁光河, 等. 高分辨率预测地下复杂采空区的空间分布特征[J]. 地球物理学进展, 2006, 21(1):256-262.
[3]	王芳. 重磁勘探新方法[J]. 地质与资源, 2004, 13(3):183-186.
[4]	郑元满, 姚长利, 张晨. 重磁三维自动反演软件系统的分析与设计[J]. 现代地质, 2012, 26(6):1225-1230.
[5]	易兵, 刘四新, 薛建. 高分辨率电法在复杂采空塌陷区的探测研究[J]. 河南科学, 2007, 25(6):1026-1028.
[6]	胡承林. 综合物探技术在煤矿采空区的应用研究[D]. 成都:成都理工大学, 2011: 1-76.
[7]	李瑞强. 煤矿采空区的地震波场特征研究[D]. 太原:太原理工大学, 2011: 1-103.
[8]	张刚, 贾正元. 直流电法电位测量中提高计算精度的方法技术研究[J]. 现代地质, 2012, 26(6) : 1206-1211.
[9]	杨双安, 宁书年. 老窑采空区的地震探测与研究[J]. 中国煤田地质, 2004, 16(1):44-47.
[10]	程建远, 孙洪星, 赵庆彪, 等. 老窑采空区的探测技术与实例研究[J]. 煤炭学报, 2008, 33(3):251-255.
[11]	冯世民, 冯鑫, 李雅玲. 三维地震勘探资料在老窑采空区的分析及效果[J]. 科技信息, 2012(19):431-432.
[12]	易维启, 李明, 云美厚, 等. 时移地震方法概论 [M]. 北京: 石油工业出版社, 2002: 15-20.
[13]	GOUVEIA W P, JOHNSTON D H, SOLBERG A, et al. Jotun 4D: characterization of fluid contact movement from time-lapse seismic and production logging tool data[J]. The Leading Edge, 2004, 23(11):1187-1194. DOI URL
[14]	MACBETH C, STEPHEN K D, MCINALLY A. The 4D seismic signature of oil-water contact movement due to natural production in a stacked turbidite reservoir[J]. Geophysical Prospecting, 2005, 53(2):183-203. DOI URL
[15]	HELGERUD M B, MILLER A C, JOHNSTON D H, et al. 4-D in the deepwater Gulf of Mexico: Hoover, Madison, and Marshall fields[J]. The Leading Edge, 2011, 30(9):1008-1018. DOI URL
[16]	宋传中, 朱光, 刘国生, 等. 淮南煤田的构造厘定及动力学控制[J]. 煤田地质与勘探, 2005, 33(1):11-15.
[17]	张国明, 邱志诚, 魏廷双. 张集井田层滑构造在三维地震中的表现特征[J]. 中国煤炭地质, 2011, 23(4):48-51.
[18]	解国爱, 姚素平, 王光扣, 等. 淮南张集煤矿层滑构造分类及形成机制探讨[J]. 大地构造与成矿学, 2013, 37(1):11-19.
[19]	李晖, 郑刘根, 刘桂建. 淮南张集矿区煤中微量元素的含量分布特征分析[J]. 岩石矿物学杂志, 2010, 30(4):696-700.