珠二坳陷白云凹陷海相烃源岩及其成藏贡献  

Contribution of Marine Source Rock to Hydrocarbon Accumulation,ZhuⅡ Sag

作　　者：郭玉峰[1] 杜秀琴[1] 傅宁 

机构地区：[1]中国石油长庆油田分公司勘探开发研究院,陕西西安710018 [2]中海油研究总院,北京100027

出　　处：《天然气地球科学》2014年第12期1975-1982,共8页Natural Gas Geoscience

基　　金：国家重点基础研究发展规划("973")项目"南海深水区盆地热演化与生烃作用研究"(编号:29CB219402)资助

摘　　要：珠二坳陷白云凹陷海相烃源岩主要指的是海陆过渡相沉积背景下形成的海相烃源岩（恩平组和珠海组烃源岩）,该类烃源岩具有陆源生烃母质和海相生烃母质双源输入的混合特征,其生成的油气亦有双源成因的特征,烃源岩TOC平均值为1.2%,干酪根类型主要为Ⅱ2型,具有油气兼生的能力。油源对比和混合比例估算表明,珠二坳陷白云凹陷目前所发现的轻质（凝析油）油可分为3类不同成因油：煤成油、海相油和混合油。白云凹陷北坡PY34-1-B、PY30-1-C、PY34-1-A等气田为煤成烃,恩平组煤系烃源岩的贡献量均大于70%;LH19-5-A、LH19-5-2D、PY30-1-B、PY35-2-A和PY35-2-E等气田主要为海相成因油气,恩平组海相烃源岩的贡献量高达60%~87%;白云凹陷深水区（荔湾地区）LW3-1-B、LW3-1-D、LH34-2-A、LH29-1-A和LH16-2-A等油气田主要为混合成因,但仍以恩平组海相烃源岩为主要贡献,贡献量在60%左右。煤系烃源岩主要分布在白云凹陷的北部陆坡区,而海相烃源岩则主要分布在白云凹陷深水区,海相烃源岩可能是深水区的主力烃源岩。Marine source rocks within Zhu ⅡSag were defined as the source rocks deposited under the marine-terrestrial transitional facies（Enping Formation and Zhuhai Formation）.This kind of source rock,with average TOCof 1.2% andⅡ2type kerogen,contains mixed organic matters of terrestrial and marine origin,so it has the ability to yield oil and gas.Comprehensive oil-source correlation indicated that light（condensate）oils can be classified to three types：coal-derived oil,marine-soured oil and mixed oil.Mixture contribution of two end members of coal and marine source rock was calculated with mathematic method.It shows that the oil from PY34-1-2,PY30-1-3,PY34-1-1gas fields in the north slope of Baiyun Sag are predominate from coal measure with its contribution more than 70%;while the oil from LH19-5-1,LH19-5-2D,PY30-1-2,PY35-2-1and PY35-2-5gas fields are originated mainly from marine source rocks with its contribution up to 60%-87%;and the oil,from LW3-1-2,LW3-1-4,LH34-2-1,LH29-1-1and LH16-2-1wells in deep water zone,Baiyun Sag（Liwan area）,are mixture origin but with about 60%from marine source rock.The result indicates that coal measure source rocks are restricted within northern slope area,while marine source rocks distributed in deep water zone of Baiyun Sag are the main contributor within this area.

关 键 词：海相烃源岩 原油成因分类 油源对比 混合比例计算 白云凹陷 珠江口盆地 

分 类 号：TE121.2[石油与天然气工程—油气勘探]