鄂尔多斯盆地北部上古生界天然气聚集规律

鄂尔多斯盆地北部上古生界是一个独立的含油气系统,发育完整的生储盖组合,利于天然气的聚集。位于乌审旗一带的大型生气中心,具有面积大、生气强度大、总资源量丰富的特点,为天然气的富集提供了物资基础。分布广泛,十分发育的河流、扇三角洲及潮坪等多种成因类型的砂体,为大中型圈闭的形成提供了广阔的空间,有利生储盖组合,为气田的形成创造了优越的条件;位于生气中心内及附近区域构造较高部位的大中型砂岩发育带有利于天然气的运移聚集,因而成为天然气的富集区带;岩性圈闭和构造-岩性圈闭面积大、含气层段多,成为该区主要的圈闭类型。根据以上特点分析认为,伊陕斜坡东段(新街-乌审旗-红石桥),杭锦旗断阶南部和天环坳陷(布伦庙地区)为今后的三大勘探目标区和主攻方向,首选目标则为新街-乌审旗-红石桥地区。

ACCUMULATION REGULARITY OF UPPER PALEOZOIC GAS IN NORTH ORDOS BASIN

The Upper Paleozoic of north Ordos Basin is an independent gas system with a complete source reservoir cap rock assemblage.Gas generation centre along Wushen Flag is characterized by large distribution area,big gas generation intensity and abundant gas resources.Sandbodies deposited in rvier channels,fan deltas and tidal flat are favourable for the formation of larg and mid scale traps;the source reservoir cap rock assemblage within the same stratum is favourable to form gasfield;large and mid scale sandbodies at the higher part of the gas generation centre are suitable for gas migration and accumulation.Trap types of the study area are mainly lithologic and structural lithologic traps.It is suggested that Xinjie Wushen Flag Hongshiqiao in the east section of Yishaan Slope,the south part of Hangjing Flag fault terrace and Tianhuan Depression are the targets for gas exploration.