地震数学模型技术在煤矿采区地震勘探观测系统设计中的应用

根据安徽淮南某煤矿的地质构造特点及煤层赋存形态,在三维地震测区中部选择了一条典型地质剖面,据此建立了陡倾角二维地震数学模型,并从波动方程出发确立了模型的三维地震观测系统。通过对正演模拟得到的炮集记录、叠加剖面、偏移剖面上的波场特征的分析,确定了适合勘探区地质条件的采集和处理方法。对该二维模型数据的处理结果表明,叠后偏移手段不适合陡倾角区煤层地震资料的处理,而叠前时间偏移可有效保证陡倾角勘探区块的地质目标成像。根据陡倾角目的层及逆掩断层区域开展地震勘探的难点问题,提出了适当调整观测系统、提高空间采样密度等措施。根据多年在淮南矿区开展采区三维地震勘探的工作经验,认为该区最佳观测系统为方位角特性好、共面元道集内炮检距分布均匀的八线八炮制束状规则观测系统。

Application of Seismic Mathematical Model in Coalmine Winning District Seismic Prospecting Observation System Design

According to geological structural features and coal seam hosting configuration in a Huainan coalmine, Anhui, a typical geological section was selected from the middle part of 3D seismic prospecting area, hereby a steep dipping 2D seismic mathematical model has established, and starting from wave equation determined the 3D seismic observation system of the model. Through analysis of wave field characteristics on the shot set records, stacked sections, migrated sections derived from forward modeling, determined data acquisition and processing methods which are propitious to prospecting area geological conditions. The processed results of the 2D model demonstrated that the poststack migration is unsuitable to steep dipping target, while prestack time migration can ensure geological target imaging in steep dipping prospecting area effectively. In allusion to hard nuts to carry out seismic prospecting in steep dipping target and thrust areas, put forward measures of to regulate observation system in the right way, increase spatial sampling density etc. According to carry out winning district 3D seismic prospecting experiences in Huainan mining area in many years, considered that the best observation system is the system with good position angle characters, 8 lines 8 shots fascicular and regular system with evenly distributed offsets in common surface element trace gather.