The Application of Seismic Attribute Analysis Technique in Coal Field Exploration

Minor faults, subsidence column and gob are very important in the coal mining, because they can cause flooding accident, coal bed broken, fissures added, and gas accumulated. All of these factors will increase the coal mining risk. The coalfield is located in eastern China. The coal seams belong to Permian strata, and the depth range from 500 to 1000 meters and the thickness of coal is about 2-5 meters. After years of conventional seismic exploration and coal mining, the distribution of geological structure underground and the faults with fault throw greater than 5 meters have been clearly known on the whole, but minor faults with fault throw less than 5 meter remain unknown. The subsidence columns have been also found in coal mining, which can cause flooding accident by connecting the coal seam and the water in Ordovician limestone. There are lots of coal tunnels in the underground that have been drilled before seismic exploration, and in some mines, the caving zone and the surface reservoirs are made by the collapse of upper strata after coal mining. These geological phenomena are very important for the safety and efficient coal mining, so how to identify those phenomena is the focus in this paper.

With the increasing mechanization of coal mining, the coal exploration’s requirements are increasing. In order to find out the minor faults with 2-3 meters fault-throw, the coal filed conducted a high-precision 3D seismic exploration in 2007 . By using the multi-attributes analysis method, we achieve a very good results in identify the minor fault with 2-3 meters fault-throw. After about four years coal mining, the predicted faults with high-precision 3D seismic data have been verified in the coal mining. The match rate of predicted minor faults with a fault throw within 2-3 meters and the actual is up to 85%, but the rate using the conventional seismic method is only 20%.

The subsidence column can cause the safety accidents by connecting the water in Ordovician limestone, and its diameter ranges from less than ten meters to hundreds of meters, and even a few kilometers. It is easy to identify the big subsidence column in the seismic profile, but the small one with diameter less than 20 meters is hard to find. But it becomes easy to identify the small one by using seismic attributes technique, as well as to delineate the gob, caving zone and the coal tunnels.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California