准噶尔盆地车排子周缘新近系沙湾组砂体油气输导特征  

Hydrocarbon migration in sand layers of neogene shawan formation in Chepaizi and its surrounding areas, Junggar Basin

作　　者：吴康军[1,2] 刘洛夫[1,2] 曾丽媛[1,2] 高小跃[1,2] 徐正建[1,2] 周长啸 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)盆地与油藏研究中心,北京102249

出　　处：《中南大学学报（自然科学版）》2014年第12期4258-4266,共9页Journal of Central South University:Science and Technology

基　　金：国家重大科技专项(2011ZX05003-001)~~

摘　　要：准噶尔盆地车排子周缘新近系沙湾组具有较大的油气勘探潜力。运用地质分析、流体势分析和地球化学分析的方法,对沙湾组砂体的油气输导特征进行研究。最后,综合分析各种因素,建立新近系沙湾组砂体的油气输导模式。研究结果表明：沙一段、沙二段发育水进序列的扇三角洲分流河道砂体,在顺物源的南北方向上具有很好的连续性,在垂直物源的东西方向上受到河道间泥岩的阻隔而连续性变差。全区大面积砂地厚度比在0.5-0.9之间,砂体以泥质、钙—泥质胶结为主,原生孔隙占总孔隙空间的72%,最大喉道半径均值为33.82μm,总体评价为中高孔、特高渗并具有粗喉型喉道的特征,连通性好,为沙湾组的油气输导层。沙三段发育大套泥岩,不具备油气输导条件,为区域盖层。油气在沙湾组的深部具有较高的流体势能,油势从凹陷向凸起方向逐渐降低。来自邻近凹陷深部的油气沿断裂和不整合面运移至浅层后,经沙湾组的连通砂体由凸起的东南向西北方向运移而聚集成藏。The Shawan formation of Neocene around the Chepaizi uplift has great potential in oil exploration. The characteristics of hydrocarbon migration of Shawan formation were studied by means of geology, fluid potential analysis, and geochemistry. Hydrocarbon migration pattern in the Neocene sand bodies of Shawan formation was set up by comprehensive analysis on various factors. The results show that transgressive channel sand bodies of fan delta front developed in ShaⅠ and ShaⅡ members has good continuity in the north-south direction which is the direction along the sediments transportation. While, the channels are separated by the inter-channel mudstones, so that they are less continuous in the perpendicular direction to the provenance. The sandstone rate is between 0.5 and 0.9 in most areas. Sandstone＇s cementation matter is mainly mud and mud-calcite. The primary pores account for 72%, with the average largest throat radius being 33.82 μm. Therefore, the sand bodies are classified as meso-high porosity and high permeability type or coarse throat type. The pores are linked well with each other, and they could be the migration pathway. Large sets of mudstones developed in Sha Ⅲ member, which couldn＇t migrate any hydrocarbon, and could be the regional seal. The fluid potential in the deep layer is higher, and it decreases from the sag to the uplift. As a result, the hydrocarbon in the deep sag migrates upwards along faults and uncomformities firstly, and then keeps moving through the connected sand bodies towards the north-west direction, to be accumulated in the shallow layers.

关 键 词：砂体 油气输导 地化示踪 沙湾组 车排子凸起 

分 类 号：TE122[石油与天然气工程—油气勘探]