六盘山盆地烃源岩的地球化学特征及油气勘探潜力

依据六盘山盆地露头和钻测井资料,应用有机地球化学的多种分析方法,对六盘山盆地乃家河—马东山烃源岩进行分析评价,分析表明:乃家河组烃源岩有机含量为0.43％～3.18％,平均值为1.76％,有机质类型以偏腐泥为主,镜质体反射率Ro值为0.52％～0.67％,平均值为0.60％,马东山烃源岩有机质含量为0.73％～3.65％平均值为1.69％,有机质类型以偏腐植型为主,晶质体反射率Ro为0.64％～0.75％,平均值为0.69％.对比可知,马东山组烃源岩的有机质丰富,热演化程度好于乃家河组,但同质类型没有乃家河组好.六盘山具有两套生储组合,白垩系李洼峡组发现不同级别油气显示,有较好的油气成藏条件,油气资源丰富,勘探潜力较好.

On Geochemical Characteristics and Oil--Gas Exploration Potential of Source Rock in Liupanshan Basin

In the light of outcrops and drilling and logging information of Liupanshan Basin, a variety of organic geochemistry analytical methods are,used to analyze and evaluate source rock of Naijiahe--Madongshan. The result presents that in Naijiahe formation, organic content of source rock is 0. 43% -3. 18%, an average value of 1.76%, organic matter type is predominantly sapropelic and vitrinite reflectance Ro is 0.52%-0. 67%, an average value of 0. 60%; and that in Madongshan formation, organic content is 0. 73%- 3.65%, an average value of 1.69%, organic matter type is predominantly humic and crystalline reflectance Ro is 0. 64%-0. 75%, an average value of 0. 69%. It is concluded by contrast that source rock in Madongshan formation contains rich organic matter and has higher thermal evolution degree than in Naijiahe formation, but its homogeneous type is not so good as in the latter. There are two source--reservoir combinations in Liupanshan Basin. Different levels of oil and gas shows have been discovered in cretaceous Liwaxia formation where reservoir forming condition is good, Oil and gas resources are abundant and exploration potential is great.