塔里木盆地轮探1井超深层油气勘探重大发现与意义

Great discovery and its signifi cance of ultra-deep oil and gas exploration in well Luntan-1 of the Tarim Basin

2020年1月,位于塔北隆起轮南低凸起的轮探1井在8200m之下的下寒武统白云岩中获得轻质原油,塔里木古老克拉通超深层油气勘探获得重大突破。通过对轮探1井发现情况描述与超深层寒武系盐下油藏发现历程分析,旨在为其他类似地区新区、新层系、新类型的勘探提供借鉴与参考。轮探1井钻揭寒武系玉尔吐斯组一套优质烃源岩,以及阿瓦塔格组蒸发膏岩/沙依里克组—吾松格尔组白云岩储层与玉尔吐斯组泥岩/震旦系奇格布拉克组白云岩风化壳储层两套储盖组合。轮探1井产层为吾松格尔组,为正常温压系统的挥发性油藏;震旦系奇格布拉克组风化壳获得微量天然气。塔里木盆地台盆区勘探经历了从碎屑岩到碳酸盐岩、从碳酸盐岩到盐下白云岩的两次战略转移;轮探1井是第二次战略转移的重要标志,具有里程碑意义。轮探1井成藏有利条件在于具有继承性稳定古隆起与优质的生储盖组合;通过类比,分析了塔里木盆地寒武系盐下白云岩勘探前景,指出塔中—古城、塔北南斜坡、麦盖提斜坡北—柯坪等有利区为下步勘探重点区带。

In January 2020,light crude oil was obtained from Lower Cambrian dolomite with burial depth greater than 8200m in well Luntan-1,which was located in the Lunnan low bulge in the Tabei uplift,indicating a major breakthrough in ultra-deep oil and gas exploration in old craton of Tarim Basin.This paper describes the background of well Luntan-1 discovery and analyzes the exploration history of the ultra-deep Cambrian sub-salt oil reserves,aiming to provide experience and reference for the exploration of new zones,new strata and new types in other similar areas.According to the drilling results,well Luntan-1 penetrated a set of high-quality source rocks in Cambrian Yuertusi Formation and 2 sets of reservoir-cap assemblages,which are evaporite gypsum cap rocks in the Awatage Formation and dolomite reservoir in the Shayilike-Wusonggeer Formations,and mudstone cap in the Yuertusi Formation and dolomite weathering crust reservoir in the Sinian Qigebulake Formation.The production layer in well Luntan-1 is the Wusonggeer Formation with volatile oil at normal temperature and pressure systems.In addition,trace natural gas was obtained from the weathering crust of the Sinian Qigebulake Formation.The exploration of platform-basin area in the Tarim Basin has experienced 2 strategic shifts from clastic rocks to carbonate rocks,and then to sub-salt dolostones.Well Luntan-1 is an important sign of the second strategic shift,which is of milestone significance.The favorable oil accumulation conditions of well Luntan-1 are the successive development of stable paleo-uplift and the high-quality source-reservoir-cap assemblages.By analogy,this paper analyzes the exploration prospect of the Cambrian sub-salt dolostones in Tarim Basin,and points out that the Tazhong-Gucheng area,the south slope of Tabei area and the northern Maigaiti slope-Keping area are the favorable and key zones for further exploration.