坳陷湖盆湖岸线的确定方法--以志丹地区延长组为例

Determination method of lake shoreline in depressed-type lacustrine basin:taking the Yanchang formation of Zhidan area as an example

通过岩心、测井曲线等资料的研究,对志丹地区延长组沉积相进行了专项研究。结果认为三角洲平原和前缘在岩性、沉积构造、测井曲线、生物化石、沉积组合特征等方面均具有不同的特征,三角洲平原与前缘的界限就是湖岸线的位置。结果显示志丹地区长1油层组、长2、长3、长4+5油层组北部主要发育三角洲平原亚相,长2、长3、长4+5南部为三角洲前缘亚相,长6、长8、长9、长10为三角洲前缘亚相,长7北部为三角洲前缘亚相。

In light of such data as core and logging curve, etc, facies in Yanchang formation of Zhidan area were studied. The result shows that the delta plain is different from delta front in lithology, sedimentary structure, paleo-biology fossil, sediment combination character, etc. The borderline between the delta plain and delta front is the position of lake shoreline, and the result shows that the delta plain was developed in the study area of Chang 1, in the north of the study areas of Chang 2, Chang 3, Chang 4＋5 of the Yanchang formation; delta front was developed in south of the study area in Chang 2, Chang 3, Chang 4＋5 and in Chang 6, Chang 8, Chang 9, Chang 10, and in north of the study area in Chang 7.