长岭断陷火石岭组原型盆地恢复及勘探方向分析

Restoration of Changling Rift Huoshiling Formation Basin Prototype and Analysis of Exploration Orientation

松辽盆地长岭断陷经多期改造致使现今残留盆地与盆地原型特征差异较大,拓展火石岭组油气勘探阵地受到一定的局限。在残留盆地特征研究基础上,依据该区地质背景及资料情况,在系统考虑各种方法适用范围及影响因素的前提下,针对不同的井或地区选用了镜质组反射率法、剖面趋势法等计算长岭断陷火石岭组的地层剥蚀量,并恢复了研究区该时期的盆地原型,表现为明显的半地堑和地垒的构造形态,并明确了原型盆地时期洼陷的位置及规模。在成藏地质条件分析基础上,指出西部斜坡带上火石岭组地层超覆带与西部、南部断阶带残留箕状洼陷内构造高部位(火山岩体)是该区油气勘探的有利方向。

Changling rift in Songliao Basin was transformed in a number of periods. As a result, the present-day remaining basin is significantly different from basin prototype, affecting further oil and gas exploration of Huoshiling formation. Based on the study of the remaining basin characteristics and the geological background and data of this region as well as taking into account the applicable scopes of various methods and influencing factors, the vitrinite reflectance method and the profile trend method are selected to calculate the denudation quantity of Huoshiling formation in the light of different wells and areas. Restoration of the basin prototype of that period in the research area indicated that it was obviously a half-graben and horst structure, clarifying the location and scale of the depression during the basin prototype period. Based on analysis of the geological conditions for accumulations, it is pointed out that the stratigraphic onlap zone of Huoshiling formation on the western slope and the high position （volcanic rock body） of structure in the remaining dustpan-like sag of the western and southern fault zone are the favorable targets for oil and gas exploration in this region.