涠西南A洼现今地温场恢复及有利勘探方向  

Current geothermal field restoration and favorable exploration direction in the A Sag of the Weixinan Depression

作　　者：胡晨晖 HU Chenhui(Zhanjiang Branch of CNOOC Ltd.,Zhanjiang 524057,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《复杂油气藏》2023年第2期154-160,共7页Complex Hydrocarbon Reservoirs

基　　金：中海石油(中国)有限公司科技项目“中海油‘十三五’油气资源评价”(YXKY-2018-KT-01)。

摘　　要：北部湾盆地涠西南A洼与B洼为已证实的富生烃洼陷,烃源岩的热史及地温场研究程度差异明显。B洼钻井工作量大,测温数据多,热史研究程度高。A洼勘探程度低,可靠的测温数据少。地温场的分布特征及烃源岩热演化的认识不清,制约了目前的勘探。通过对涠西南A洼的钻井温度数据进行拟合,建立涠西南A洼已钻井的BHT温度的校正经验公式,重建了涠西南A洼的现今地温场,恢复不同区带烃源岩热演化史。结果表明,A洼地温梯度分布在28.1~40.2℃/km,呈现北低南高,中段高东西段较低的特征;近源及中源构造范围内烃源岩为有效烃源岩;涠洲11-X构造位于油气运移路径上,是A洼下步重点勘探方向。The A Sag and B Sag are proven hydrocarbon-rich depressions in the Weixinan of the Beibu Gulf Basin,and there are obvious differences in the degree of research on the thermal history and geothermal field of the hydrocarbon source rocks.The B Sag has a large drilling workload,a large number of temperature measurement data,and a high degree of thermal history research.The A Sag has a low degree of exploration and few reliable temperature measurement data.The distribution characteristics of the geothermal field and the thermal evolution of hydrocarbon source rocks are not well understood,which restricts the current exploration.By fitting the drilling temperature data in the A Sag of the Weixinan Depression,it was established an empirical formula for correcting the BHT temperature of wells drilled.The present geothermal field in the A Sag of the Weixinan Depression was reconstructed,and the thermal evolution history of source rocks in different zones was recovered.The results show that,the geothermal gradient distribution in A Sag ranges from 28.1 to 40.2℃/km,showing a characteristic of low in the north and high in the south,with high in the middle section and low in the east-west section;the hydrocarbon source rocks within the near-source and middle-source structures are effective hydrocarbon source rocks;the Weizhou 11-X structure is located on the hydrocarbon transport path,which is the next key exploration direction in the A Sag.

关 键 词：BHT温度 地温梯度 烃源岩 涠西南凹陷 

分 类 号：TE132[石油与天然气工程—油气勘探]