地震勘探中煤层隐伏露头的解释精度

Discussion on Seismic Prospecting Buried Coal Outcrop Interpretation Accuracy

煤层露头的解释精度直接影响储量的圈定,而影响煤层露头解释精度既有资料品质因素,也有反射波标定、煤层厚度、上覆地层厚度、不整合角度、钻网控制精度等因素。通过正演模拟可知,煤层露头与上覆地层的不整合角度(α)越大,地震时间剖面上不整合点的位置与煤层露头位置越接近,在α≥15°时,二者的位置差小于5 m。以新疆某勘查区为例,通过对煤层反射波稳定标志层的标定,结合正演模拟确定其不整合点位置,依次解释了该区八道湾组、三工河组及西山窑组各煤层的露头位置、摆动范围及形态,位置误差基本控制在15 m范围内。

The interpretation accuracy of coal outcrop can directly impact reserve estimation, while the impacting factors have data quality, also including reflection calibration, coal thickness, overburden thickness, unconformable angle and drilling network control precision etc. Through forward modeling can know that the larger the unconformable angle（α） between coal outcrop and overlying strata, the closer the coal outcrop unconformity point on seismic time section, when α ≥15 °, the position error is less than 5m. Taking a prospecting area in Xinjiang as example, through the calibration of coal seam reflection stable marker, combined with forward modeling determined the unconformity point position. Thus the position of coal seam outcrops in Badaowan, Sangonghe and Xishanyao formations,swing range and configuration have been interpreted successively. The position error is controlled basically within 15 m range.