库车坳陷西部古近系库姆格列木群层序-体系域

Sequence and systems tract of Paleogene Kumugeliemu Group in Western Kuqa Depression,Tarim Basin

应用层序地层学理论,在层序-体系域格架内对库车坳陷西部库姆格列木群各岩性段进行分析对比和沉积古地理恢复,建立层序-体系域格架内的储盖组合和配置体系,对有利储集砂体分布区进行预测。库姆格列木群三级层序Esq1低位体系域和Esq2低位—水进体系域发育两套粗碎屑砂体,Esq1和Esq2层序的盐岩、膏岩和泥岩广泛分布,封盖能力好,与两套砂岩储集层构成优质储盖组合。从有利储集体分布来看,北部山前带向盆地推进的河流体系、西部温宿凸起东缘的扇三角洲体系及南部英买古低隆起带的下切谷充填、河流三角洲体系形成有利储集砂体,坳陷北缘克拉苏—大北区带、南部秋里塔格—却勒及其以南地区、西部温宿凸起北部及东部地区是勘探的有利目标区。

Sequence stratigraphy is used for analytical comparison and palaeogeographic reconstruction of lithologic sections in Paleogene Kumugeliemu Group in western Kuqa depression under the framework of sequence and systems tract, to establish the reservoir-caprock assemblage and allocation system and to predict the distribution of favorable reservoir sandstones. Two sets of coarse fragment sands are developed in the 3^rd order sequences Esql lowstand systems tract and Esq2 lowstand to transgressive systems tract. The widely distributed salt and gypsum muddy section of Esql and Esq2 has good sealing and forms good reservoir-caprock assemblage with the two reservoirs in the bottom sand section of Kumugeliemu Group. According to the reservoir sandbody distribution, the forwarding fluvial system at mountain front to the north, fan delta at east flank of Wensu uplift to the west and the downcut valley filling and fluvial delta system at Yingmai low paleo-uplift to the south form favorable reservoir sandbodies. KelaswDabei zone on north margin of the depression, Qiulitage-Quele and its muthward parts, and northern and eastern Wensu uplift are the favorable plays.