摘要
揭示鄂尔多斯盆地延长组长1油层组油藏的油气富集规律对指导该盆地长1油层组的油气勘探具有重要意义。以陕北W地区为例,在地层划分对比的基础上,运用残余厚度法,并结合前人的区域古地貌研究成果,对研究区长1油层组顶部古地貌进行了恢复,同时分析了古地貌与长1油层组石油分布的关系。结合长1油层组的构造、沉积相、砂体厚度及封盖条件等控藏要素及与油气分布的关系,总结了研究区长1油层组油藏的富集规律。结果表明,研究区延长组长1油层组顶部发育有侵蚀沟谷、侵蚀斜坡和侵蚀残梁3种地貌单元,古地貌具有"一沟谷、两斜坡、两残梁"的特点,地形相对较高的残梁区对长1油层组石油分布具有重要控制作用。鼻状隆起构造脊、砂体较厚且砂地比较大的河道发育区也对长1油层组石油分布起着重要控制作用。另外,旋回性泥岩、致密砂岩层、侵蚀不整合面和水动力等多种封盖条件为长1油藏的形成起着重要遮挡作用。在上述控制因素作用下,形成以构造-岩性油藏和岩性油藏为主,岩性-水动力油藏为辅的多种油藏类型。鄂尔多斯盆地长1油层组的石油勘探重点应放在长1地形较高古地貌及沉积砂体发育的有利相带等的复合区域。
Revealing the accumulation patterns of Chang 1 oil reservoir of the Yangchang Formation in Ordos Basin is very significant for oil and gas exploration in this area .Based on stratigraphic division and correlation ,the paleogeomor-phology of Chang 1 oil reservoir is restored by using residual thickness methods combined with previous research of re-gional paleogeomorphology .On this basis ,its relationship with the distribution of hydrocarbons is analyzed .The patterns of hydrocarbon accumulation of this formation in this region are summarized through a comprehensive analysis of various controlling factors on hydrocarbon accumulation such as structures ,sedimentary facies ,sandstone thickness ,sealing condi-tions,and so on.Three geomorphic units are recognized in Chang 1 oil reservoir,namely erosion valley,erosion slope and erosion monadnock .The paleogeomorphology features in “one valley,two slopes and two monadnocks”.The erosion mo-nadnocks in relatively higher terrain ,the ridges of nose-like uplift ,channel sands with larger thickness and higher net-to-gross ratio all have significant controlling effects on distribution of hydrocarbons of this formation .Moreover ,cyclical mud-stone,tight sandstone ,erosion unconformity surfaces and hydrodynamic force all have large contributions to the sealing of the Chang 1 oil reservoir.Structural-lithologic reservoir and lithologic reservoir are the primary reservoir types ,while li-thologic-hydrodynamic reservoir is the secondary reservoir type .The overlapping regions of the main factors ,such as the＆nbsp;higher paleogeomorphology and the favorable sedimentary facies zones with larger sandstone thickness are the key explo -ration targets of this formation in Ordos Basin .
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2013年第5期619-624,共6页
Oil & Gas Geology
基金
国家自然科学基金项目(41102083)
陕西省教育厅科研计划项目(2013JK0846)
博士启动基金项目(YS29031610)
关键词
古地貌
油气富集
油藏类型
长1油层组
鄂尔多斯盆地
paleogeomorphology
hydrocarbon enrichment
reservoir type
Chang 1 oil reservior
Ordos Basin
