环县地区富县组古地貌特征及其对油藏的控制

Characteristics of palaeogeomorphology and its control on oil reservoirs of Fuxian Formation in Huanxian area

余威,弓俐,王峰,常鹏,范毅君,田景春

成都理工大学沉积地质研究院，四川 成都 610059 油气藏地质及开发工程国家重点实验室，四川 成都 610059 中国石油长庆油田分公司第五采气厂，陕西 西安 710018 中国石油长庆油田分公司风险勘探项目组，宁夏 银川 750006

Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu 610059, China No. 5 Gas Production Plant, Changqing Oilfeild Company, PetroChina, Xi′an 710018, China Risk Exploration Project Team, Changqing Oilfield Company, PetroChina, Yinchuan 750006, China

通过对研究区岩心、钻井、测井及地震数据的分析，运用井震结合法和地层厚度印模法对研究区侏罗系富县组古地貌进行了精细描绘，研究了古地貌对富县期沉积相、储集砂体、油气运移，油气成藏的影响。结果表明：环县地区侏罗系富县组古地貌类型有5种，分别是侵蚀河谷、河间丘、斜坡带、残梁（丘）、高地；研究区侏罗系古地貌控制富县期粗粒辫状河河道沉积发育分布，深切河谷使富县组地层与下伏地层形成角度不整合接触关系，同时差异压实形成鼻隆构造，为油气运移和储集提供了较好的基础和条件；古地貌的存在为后期形成披盖压实构造创造了有利条件，对环县地区侏罗系的油气成藏和分布具有重要的意义。

Based on the analysis of core, drilling, logging, and seismic data in the study area, the paleogeomorphology of Fuxian Formation of Jurassic in the study area is described by well-seismic combination method and formation thickness impression method, and the influence of paleogeomorphology on sedimentary facies, reservoir sand body, oil and gas migration and hydrocarbon accumulation in Fuxian period of Jurassic is analyzed. The results show that there are five types of paleogeomorphology in Fuxian Formation of Jurassic in Huanxian area, which are eroded valley, inter river hill, slope belt, residual beam ( hill ), and highland; The Jurassic paleogeomorphology controls the development and distribution of coarse-grained braided river channel sediments in Fuxian period. Deep valley makes the Fuxian formation and the underlying strata form an angular unconformity contact relationship, at the same time, differential compaction forms nose-shaped uplift, which forms a good foundation and condition for oil and gas migration and accumulation; The existence of paleogeomorphology has created favorable conditions for the formation of mantle compaction structure in the later stage, which is of great significance to the hydrocarbon accumulation and distribution of Jurassic in Huanxian area.

doi:10.6056/dkyqt202105011