川东北地区嘉一段-上二叠统录井分层探讨

川东北地区由于位于四川盆地边缘，受沉积相变化和构造运动的影响，该区特别是其中部嘉一段-上二叠统横向变化大，录井分层困难。为此，基于对地层岩性组合、测井电性以及镜下生物特征的分析，分别探讨了下三叠统飞仙关组四段与上下邻层、飞仙关组与上二叠统长兴组、长兴组与上二叠统龙潭组的录井分层问题。研究认为：①要做到准确快速地地质分层，必须要在区域上建立一套行之有效的分层标准，既便于现场录井人员掌握，又能在电性上具有横向对比的特点；②不论是依据现场岩屑还是测井曲线，遇到地层横向变化差异较大时，都应从沉积相和构造运动这两大影响因素进行宏观综合考虑；③在分层岩性、电性特征均不明显的情况下，特别是川东北地区局部构造上，飞仙关组与长兴组石灰岩与石灰岩接触分层十分困难，可选样做分析化验，并综合利用多种手段来进行分层。

A DISCUSSION ON LOGGING STRATIGRAPHIC DIVISION FROM THE FIRST MEMBER OF JIALINGJIANG FORMATION TO UPPER PERMIAN IN NORTHEASTERN SICHUAN BASIN

Logging stratigraphic division is difficult in the northeastern Sichuan Basin due to the influences of variation of sedimentary facies and tectonic movement, especially in the interval from the first member of Jialingjiang Formation to the Upper Permian with significant lateral variation of lithology. Based on analyses of the lithologic associations, logging electric properties and microscopic biological properties, this paper discusses the logging stratigraphic division of the 4th member of the Upper Triassic Feixianguan Formation from the overlying and underlying strata, the Feixianguan Formation from the Upper Permian Changxing Formation, and the Changxing Formation from the Upper Permian Longtan Formation. The following understandings are achieved. ① Accurate and rapid stratigraphic division needs a set of effectual regional standards that are both convenient for field application and laterally correlatable in electric properties; ② Whether the field cuttings or logs are used as the basis for stratigraphic division, sedimentary facies and tectonic movement should be considered when the lateral variations of strata are very large; ③ When both the lithologic and electric properties are insignificant, it is very difficult to divide the Feixianguan limestone from the Changxing limestone, especially on the local structures in the northeastern Sichuan Basin, thus various methods should be integrated and laboratory test should be performed.