塔里木盆地海相油气成藏研究进展

近年来塔里木盆地超深层海相油气勘探取得了丰硕成果，顺北奥陶系、塔中寒武系、塔河深层等油气新发现，为塔里木盆地海相油气成藏研究提供了丰富的基础资料。塔里木盆地海相油气主要分布于台盆区，油气藏类型多样，原油物性变化大，显示出成藏的复杂性。通过对大量的实际样品分析和模拟实验及大量的地质、地球化学综合分析，结合构造演化、层序地层学、沉积相与沉积环境等研究成果，在烃源岩分布及其演化、油气地球化学特征、海相油气藏分布特征等方面取得了显著进展。一是明确了塔里木台盆区海相油气主要来源于强还原环境下形成的下寒武统-中下奥陶统烃源岩，特别是台盆区下寒武统玉尔吐斯组，并明确了超深层海相油藏后生改造主要有TSR、热裂解2种类型，提出了相应的判识指标；二是在建立玉尔吐斯组缓坡型优质烃源岩沉积发育模式的基础上，通过井震标定、正演模拟和区域测线地震相解释、三维区属性分析与地震反演，预测了玉尔吐斯组烃源岩的展布，并明确其演化特征:燕山期以来长期低地温背景下的"高压生烃演化抑制模式"延缓了顺托果勒低隆寒武系烃源岩热演化，顺托果勒地区仍具晚期高成熟液态烃形成条件；三是通过台盆区油气成藏特征对比，明确了奥陶系油气分布特征，进一步明确在台盆区寻找以下寒武统玉尔吐斯组原地烃源岩与燕山期以来晚期活动走滑断裂相匹配的、以晚期供烃为主的轻质油藏-天然气藏，是塔里木台盆区超深层碳酸盐岩领域油气勘探的重要方向。 

Research progress on marine oil and gas accumulation in Tarim Basin

In recent years,great achievements have been made in the exploration of ultra-deep marine oil and gas in the Tarim Basin.New oil and gas discoveries have been achieved in the Shunbei Ordovician,Tazhong Cambrian and Tahe deep strata,which provide abundant basic data for studying the marine oil and gas accumulation in the Tarim Basin.The marine oil and gas in the Tarim Basin are mainly distributed in the platform-basin area.There are various types of reservoirs,and the physical properties of crude oil vary greatly,showing the complexity of hydrocarbon accumulation.Through the analysis of a large number of samples,simulation experiments and extensive geology and geochemistry analysis,combined with the research results of tectonic evolution,sequence stratigraphy,sedimentary facies and sedimentary environments,some significant progress has been achieved such as the distribution and evolution of source rocks,oil and gas geochemistry characteristics,and the distribution characteristics of marine oil and gas reservoirs.The following achievements have been made:1)clarification that the marine oil and gas in the Tarim platform-basin area mainly come from the Lower Cambrian-Middle/Lower Ordovician source rocks formed under strongly reducing environments,especially the Lower Cambrian Yuertusi Formation in the platform-basin.Two alterations types of ultra-deep marine reservoirs,namely,TSR and thermal cracking are defined,and the corresponding identification indicators are proposed.2)by establishing the sedimentary development mode of the gentle slope-type high-quality Yuertusi source rocks,through well-seismic calibration,forward modeling,regional survey line interpretation of seismic facies,3 D area attribute analysis and seismic inversion,the distribution of source rocks in the Yuertusi Formation may be predicted,and their evolution characteristics clarified:the"high-pressure hydrocarbon generation evolution inhibition mode"under the long-term low geothermal background since the Yanshan period has delayed the thermal evolution of Shuntuoguole low uplift Cambriansource rocks,and the Shuntuoguole area still has the formation conditions of late high-maturity liquid hydrocarbon.3)by comparing the hydrocarbon accumulation characteristics of the platform-basin area,the Ordovician oil and gas distribution characteristics have been clarified,further delineating the Cambrian Yuertusi in situ source rocks there,and identification of the light oil-gas reservoirs matching with the active strike-slip faults in the late Yanshan period and charged by the late hydrocarbon supply,which provide an key direction for oil and gas exploration in the ultra-deep carbonate rocks of the Tarim platform-basin area.