地震波法在煤层赋存条件解释中的应用

新疆含煤岩系大多沉积在中新生代拗陷型、断拗型及断陷型盆地中,煤层的赋存条件比较复杂,虽单层煤厚度可达100多m,但煤层沉积厚度在区域上变化较大,煤层煤组的尖灭、合并现象时有发生,使得新疆煤田煤组标定、归并工作变得非常复杂。根据新疆煤田地质特点和地震勘探中遇到的问题,结合实例探讨利用钻孔、单炮记录和折射波速度等资料确定煤层赋存情况的方法。利用折射波速度资料编制了新疆煤田勘查区地震波速度平面图,在钻孔验证的基础上,提出了在新疆哈密煤田依据其速度判断煤层赋存状态的辅助方法:①速度4 000～5800m/s的区域,其高速界面深度较浅,属无煤层赋存区;②速度3 000～4 000m/s,高速界面不明显,存在煤层赋存的可能性;③速度低于3 000m/s,其新近系、古近系及侏罗地层较厚、有煤层赋存的可能性,但煤层埋藏深度较深。

Application of Seismic Wave Method in Coal Seam Hosting Condition Interpretation

Most coal-bearing strata in the Xinjiang were deposited in the Mesozoic and Cenozoic down-warped,fault-depressed and faulted basins,coal seam hosting conditions are rather complex.Although single coal seam can be 100m or more thick,but thickness changes abruptly,wedge out and mergence of coal seams or coal groups are quite often.Thus demarcation and merging works of coal groups in Xinjiang coalfields are very intricate and difficult.According to issues in coal geological characteristics and seismic prospecting in Xinjiang,combined with using borehole,single-shot record and refraction wave velocity data to determine coal seam hosting conditions practices and discussions,have compiled a Xinjiang coalfield exploration area seismic wave velocity plane.Based on borehole experimental verification,an auxiliary method to judge coal seam hosting condition based on velocity put forward： ① velocity 4000-5800m/s areas,high-speed interface rather shallow,belong to coal barren area;②velocity 3000-4000m/s areas,highspeed interface not clear,coal seam hosting possibility existed;③velocity less than 3000m/s,while Neogene,Paleogene and Jurassic strata rather thick,coal seam hosting possibility existed,but depth rather deep.