柯坪地区石灰窑剖面下寒武统的沥青特征及横向输导层

Asphalt characteristics and transverse transport layer of Lower Cambrian in lime kiln section in Keping area

塔里木盆地下寒武统深层盐下白云岩储层是中国未来油气勘探的重点层位。柯坪地区下寒武统直接出露地表且地层较为连续无间断,为研究塔里木盆地深层碳酸盐岩油气问题提供了直观的对比对象。本次研究,基于柯坪地区石灰窑剖面下寒武统的沥青实勘,明确下寒武统沥青赋存特征及油气历史充注过程。研究结果表明:(1)石灰窑剖面下寒武统存在大量沥青充填于孔-缝-洞中,是油气运移的重要路径;(2)肖尔布拉克组中上部存在多期沥青充填裂缝和包裹砾石的现象,证实多期次的油气充注;(3)玉尔吐斯组存在一期沥青脉,肖尔布拉克组中上部存在多期沥青充注,结合舒探1井取芯层段的沥青显示和孔隙特征,证实了肖尔布拉克组中部的高孔渗层段为有效油气横向输导层。

The Lower Cambrian subsalt dolomite reservoir in Tarim Basin is the key direction of future oil and gas exploration in China.The lower Cambrian in Keping area is directly exposed to the surface and the strata are relatively continuous without discontinuity,which provides an intuitive contrast object for studying the oil and gas problems of deep carbonate rocks in Tarim Basin.In this study,the occurrence characteristics of Lower Cambrian bitumen and historical oil and gas injection process were clarified based on the field exploration of the Shihuiyao outcrop in Keping area.The results show that:(1)there is a large amount of bitumen filling in pore-fracture-cave of Shihuiyao outcrop in the Lower Cambrian,which is an important path of oil and gas migration;(2)The phenomenon of multi-stage bitumen filling fractures and gravels in the middle and upper part of The Xiaoerbulak Formation confirms multi-stage oil and gas injection;(3)There are single-stage bitumen vein in The Yuertusi Formation,and multi-stage bitumen charging exists in the middle and upper part of The Xiaoerbulak Formation.Combined with the bitumen display and pore characteristics of the core section in well Shutan 1,it is confirmed that the high porosity and permeability layer in the middle and upper part of the Xiaoerbulake Formation is an effective horizontal oil-gas transport layer.