柴北缘南八仙—马海地区油气成因及成藏模式研究

【作者】 胡雄；

【导师】 付晓文； 李延钧；

【作者基本信息】 西南石油大学 ， 地球化学， 2006， 硕士

【摘要】 本文引入油气分段捕获理论，采用油气藏全烃地球化学方法，对柴达木盆地北缘南八仙-马海地区侏罗系-第三系的油气的来源、成藏模式及其勘探前景进行了综合研究。 通过对烃源岩的评价、天然气组成分析、碳同位素组成分析、储层沥青生物标志化合物的对比研究，对柴北缘油气的成因类型、运移、聚集成藏进行了探讨，提供了有力的地球化学证据。研究结果表明马海地区存在三大成藏期：①其中E₃²沉积期（早期）为赛什滕凹陷J₂湖相油大规模运聚期，储层古地温35—55℃，它几乎遍布南八仙-马海地区，但保存和封盖条件不利，不同构造区残留和破坏程度不同，局部甚至存在生物降解，而马海气田因不具古圈闭，仅滞留该期油的痕迹。②第二期成藏储层古地温65—85℃，该期南八仙主要为E-N₁沉积期伊北凹陷J₁煤成油的注入，并与早期来源湖相油局部发生混合；马海气田依然因无有效圈闭而未能捕获该期油气。③第三期成藏古地温南八仙稍高于马海气田，平均古地温100℃左右，南八仙主要为N₂²沉积以后伊北凹陷J₁高演化煤成气的注入；该期是马海气田高演化天然气的主要成藏期，气源为伊北凹陷J₁煤系烃源岩。 最后指出南八仙-马海地区及其周缘存在二大油气有利勘探区，其中南八仙-马海构造带以北是赛什腾凹陷湖相油的供烃区，该区是突破南八仙-马海地区油气勘探的关键；而伊北凹陷-南八仙-马海构造带是扩大伊北凹陷煤成油气勘探成果的现实有利区。更多还原

【Abstract】 In the paper ,we introduce the mechanism of natural gas fraction entrapment and apply the whole hydrocarbon geochemistry method to studying the source, the mode of reservoir forming and exploration prospect of oil-gas in the Jurassic-Tertiary reservoir ,Mahai area , north marginal area of Qaidam basin.We discuss the genetic type of natural gas, and study the migration and accumulation of hydrocarbon in the Mahai area , by means of evaluation of petroleum source rocks, the study of comparing biological markers of reservoir bitumen. The result idcate that there are three reservoir formation stages in the Mahai area, Which are:①When stratum of lower ganchaigouzu formation deposite, migration and accumulation of lacustrine oil occur in middle Jurassic stratum of Saishiteng depression. Reservoir forming temperature is 35-55℃. Because early oil is destroyed without effective trap, there is a little irreducible oil in Mahai area. ②Reservoir paleo-tempeature of the second stage in Nanbaxian structure is 65-85℃ . The stage oil from coal come from mainly Yibei depression , and mixed part early lacustrine oil. Without effective trap, Oil-gas of the stage couldn’ be captured in Mahai gas field. ③Reservoir forming temperature of the third stage in Nanbaxian structure is higher than Mahai’s. Average paleo-tempeature is about 100℃. The high mature natural gas in Nanbaxian structure come from mainly Yibei depression.There are two beneficial exploration area in Mahai area. The north of Nanbaxian - Mahai structure is the most important exploration region . Favorable exploration prospect of oil and gas from coal is showed in Nanbaxian - Mahai structure.更多还原