鄂西渝东地区飞仙关组层序地层学研究

Research on Sequence Stratigraphy in Feixianguan Formation of Western Hubei and Eastern Chongqing Area

为探讨礁滩储集岩的分布规律,以层序地层学理论与方法系统研究了鄂西渝东地区下三叠统飞仙关组层序地层。详细介绍了层序划分及层序界面的识别标志。下三叠统飞仙关组总体是在大的海退背景下沉积的一套碳酸盐岩,识别出2个三级层序,每个三级层序发育海侵体系域(TST)和高位体系域(HST)。对比发现有利的储集层主要发育在层序Ⅱ的台地边缘鲕滩和台地内鲕滩。飞四段的局限台地相,具有很好的孔渗性,成为最有利的储集层。

To clarify the distribution of reservoir rocks,sequence stratigraphy was used in the study of the Triassic Feixianguan Formation in the eastern Sichuan Basin.Sequence division and identification were based on exposed surfaces and upward shallowing trends.The lower Triassic Feixianguan Formation formed during the transgression was characterized by long term sea level change of carbonate rocks.According to the mentioned identification signs of sequence boundary,2 III sequences and 4 parasequence sets were identified in Feixianguan Formation,each sequence was divided into transgressive system tracts(TST) and highland system tracts(HST).Stratigraphic correlation shows that the favorable reservoirs are characterized mainly in the second sequence by platform margin oolitic facies and intra-platform oolitic facies.Extensive dolomitization of restricted platform facies is good porosity and permeability,and they are beneficial exploration targets.It provides a guidance for further exploration of the Sichuan Basin.