珠江口盆地白云凹陷烃源岩热史及成熟史模拟

珠江口盆地白云凹陷文昌组和恩平组陆相烃源岩热史及成熟史研究对白云凹陷深水油气勘探具有指导意义。在恢复白云凹陷地史和热史的基础上,利用EASY%R_o模型计算了白云凹陷西凹、主凹和东凹文昌组和恩平组两套烃源岩的成熟度史,并分别对比文昌组和恩平组烃源岩在白云凹陷西凹、主凹和东凹成熟度演化特征。研究结果表明:1)自始新世早期起白云凹陷热流值持续上升,在距今约44Ma时达到最大值大约为77mW/m²,现今热流值为60mW/m²左右。2)白云凹陷西凹、主凹和东凹文昌组烃源岩开始生烃(R_o=0.5%)时间分别为距今43,44,35Ma,达到生烃高峰(R_o=1.0%)时间分别为距今30,35,17Ma,达到高成熟(R_o=1.3%)时间分别为距今25,33,13Ma;而恩平组烃源岩开始生烃时间分别为距今20,30,22Ma,达到生烃高峰时间分别为距今10,22,8Ma,达到高成熟时间分别为距今8,17,0Ma。3)白云凹陷主凹烃源岩生烃时间最早,主生油期时间短,热演化程度最高;东凹烃源岩生烃时间最晚,主生油期时间长,热演化程度最低。

SOURCE ROCK THERMAL AND MATURITY HISTORY MODELING IN THE BAIYUN SAG OF THE PEARL RIVER MOUTH BASIN

It is significant to study the source rock maturity history of the Baiyun Sag for the deep water exploration in the Baiyun Sag of the Pearl River Mouth Basin.Based on geohistory and thermal history of the Baiyun Sag,using EASY%Ro model reconstruction of the source rock maturity history in the western sag,the middle sag and the eastern sag of the Baiyun Sag.Comparing to the character of the Wenchang and Enping Formation source rocks maturity evolution in the western sag,the middle sag and the eastern sag.The studies indicate : 1)The studies of the Well B1 indicate that the character of the heat flow evolution is divided into two phase which is continuate rise in the forepart and gradually decline in the latter part in the Baiyun Sag.The heat flow reaches the maximum(76.7 mW/m2) at 44.4 Ma,the heat flow is about 60 mW/m2 at present.2)The Wenchang Formation source rock in the western sag,the middle sag and the eastern sag begins to generate hydrocarbon(Ro=0.5%)about at 43,44,35 Ma,reaches the hydrocarbon generation peak(Ro=1.0%) about at 30,35,17 Ma,reaches the high maturity(Ro=1.3%) about at 25,33,13 Ma.The Enping Formation source rock begins to generate hydrocarbon about at 20,30,22 Ma,reaches the hydrocarbon generation peak about at 10,22,8 Ma,reaches the high maturity about at 8,17,0 Ma.3)The thermal evolution of the Wenchang and Enping Formation source rocks in the middle sag of the Baiyun Sag is the highest,the time of the hydrocarbon generation is earliest and the main hydrocarbon generation phase is the shortest;the thermal evolution of the Wenchang and Enping Formation source rocks in the western sag is the lowest,the time of the hydrocarbon generation is latest and the main hydrocarbon generation phase is the longest.