渤海湾盆地南堡凹陷全油气系统3类油气资源联合评价

Joint evaluation of three types of oil-gas resources in whole petroleum system of Nanpu sag,Bohai Bay Basin

在近几年的勘探实践中,渤海湾盆地南堡凹陷的非常规油气资源展现出一定的勘探前景,但常规与非常规油气的资源评价彼此分离,评价结果没有制约关系,不能反映实际情况。应用全油气系统成藏理论模式实现了南堡凹陷常规与非常规油气资源的联合定量评价,有望指导未来油气勘探。研究结果显示:南堡凹陷以浮力成藏下限为界,位于自由油气动力场内的常规油气原始烃量为18.07×10~8t,位于局限油气动力场内的致密油气原始烃量为38.72×10~8t,而位于油气成藏底限之下束缚油气动力场内的页岩油气原始烃量为107.46×10~8t。3类资源的联合评价结果显示:南堡凹陷的页岩油气资源量为7 577.37×10~4t,高于致密油气和常规油气的资源量;常规油气资源量为7 074.37×10~4t,在凹陷中居第二位;致密油气资源量最小,为4 985.89×10~4t。3类资源的联合评价结果指导了南堡凹陷页岩油的发现,发现了沙河街组三段Ⅳ—Ⅴ油组的致密油藏,为中—浅层常规油气的目标优选提供了技术支撑。

In the exploration practice during recent years,the unconventional oil-gas resources of Nanpu sag in Bohai Bay Basin have demonstrated some exploration prospects.However,the evaluations on conventional and unconventional oil-gas resources are mutually separated and the evaluation results are not restrictive,which cannot reflect the actual condition.The joint quantitative evaluation of conventional and unconventional oil-gas resources is realized using the theoretical pattern of reservoir accumulation in whole petroleum system,which is expected to guide the future oil-gas exploration.The results show that Nanpu sag is bounded by lower limit of buoyance-driven hydrocarbon accumulation depth(BHAD),where the original hydrocarbon quantity of conventional oil-gas in a free hydrocarbon dynamic field(F-HDF) is 18.07×10~8t,that of tight oil-gas in a confined hydrocarbon dynamic field(C-HDF) is 38.72×10~8t,and that of shale oil-gas in a bound hydrocarbon dynamic field(B-HDF) under the bottom limit of oil-gas accumulation is 107.46×10~8t.The joint evaluation results of three types of oil-gas resources show that the amount of shale oil-gas resources in Nanpu sag is 7 577.37×10~4t,higher than that of tight and conventional oil-gas resources;the amount of conventional oil-gas resources is 7 074.37×10~8t,ranking second in Nanpu sag;the amount of tight oil-gas resources is the lowest,namely 4 985.89×10~8t.The joint evaluation results of these resources provide a guide for the discovery of shale oil in Nanpu sag,based on which tight reservoirs are discovered in Ⅳ and Ⅴ oil formations of the Member 3 of Shahejie Formation,thus providing technical support for the target optimization of conventional oil-gas in middle-shallow sequences.