柴西油泉子地区古近系下干柴沟组下段物源方向与沉积体系研究

目前普遍认为柴达木盆地西部油泉子地区在古近系下干柴沟组下段（E30）沉积时处于滨浅湖泥坪环境，砂岩不发育。但是对油6井E3^1的沉积微相研究表明，第一，该井在MSCl旋回至MSC3上升半旋回发育辫状河三角洲一滨浅湖沉积体系，累计发育111．0m厚的棕红色细砂岩和粉砂岩；第二，在MSC1上升半旋回的4579．0～4598．5m井段发育19．5m厚的棕色辫状河三角洲平原主水道细砂岩；第三，在MSC3上升半旋回的4429．5—4441．0m井段发育11．5m厚的棕色辫状河三角洲前缘分流水道粉砂岩；第四，在MSC4旋回发育滨浅湖-滩坝沉积体系，其中滩坝包括砂质滩坝和鲕粒滩。在综合研究该地区及其邻区的测井、录井资料和连井沉积体系演化剖面后排除了研究区物源的几种可能的来源方向，结合区域古地理背景，首次明确提出研究区E3^1的早期和中期物源是来自其东北的大风山西部一黑梁子地区，这一新认识对于深化该地区的石油地质认识、重新评价与预测优质碎屑岩储层具有重要的勘探实践意义。

Sedimentary Provenances and its System of the Xiaganchaigou Formation in Youquanzi Area,Qaidam Basin

Now people commonly consider that in the Youquanzi area there is no sandstone developed because it is in the lake surrounding in the lower segment of Ganchaigou formation （ E3^1 ）. But the E3^1 sedimentary facies of the well you6 shows that： first, this well develop braided river delta and lake depositional systems, the red brown sandstone is very developed, its total thick is 111.0 m between MSClcycle and the half cycle of increasing in MSC3. Second, there are 19.0m red brown sandstone developed in the half cycle of increasing in MSC1, which lies from the depth 4579.0 m to the 4598.5 m. Third, there are 11.5m red brown sandstone developed in the half cycle of increasing in MSC3, which lies from the depth 4429.5 m to the 4441.9 m. In the end, there is shallow lake and bar developed in the MSC4 cycle. The bar include sand bar and oolite bar. It point out at the first time that the sedimentary provenances in the youquanzi area come from the northeast of the study area in the early and middle period of the E3^1 after studying the well log data and the joint well depositional system evolution. This new cognition has important signification in the oil and gas exploration because it helps us to recognize youquanzi area petroleum geology condition deeply and to search for high quality clastic rock.