莺歌海盆地流体垂向输导体系及其对天然气成藏控制作用

垂向输导体系主控下的热流体活动是莺歌海盆地重要的地质特征之一, 决定了盆内独特的油气成藏过程.依据地震剖面综合解释、三维地震属性提取和岩石薄片观察, 分析了流体垂向输导体系的构成要素, 并利用PetroMod v11进行2D盆地数值模拟, 定量化计算了自源超压和传导超压的大小, 获得以下主要认识: (1)底辟伴生断裂和水力破裂是东方区最主要的2种垂向输导要素, 且在垂向上存在分异性, 深部流体输导以水力破裂为主, 浅层输导以底辟伴生断裂为主; (2)流体的垂向输导刺穿了超压封存箱并导致自源超压面在盆地中央抬升近2 000 m, 现今盆地东方区3 000 m左右黄流组油气藏中剩余压力的90%来自传导型超压; (3)盆内存在2个有利天然气聚集带: 箱顶传导常压带和箱内自源-传导超压带, 其中后者天然气藏受水力破裂输导控制, 具有流体输导高效且距离烃源灶近的优势, 是盆地内最有勘探潜力的天然气聚集带. 

Vertical Migration System and Its Control on Natural Gas Accumulation in Yinggehai Basin

Thermal fluid activity controlled by vertical migration system is one of major geological characteristics in the Yinggehai Basin, which contributes to special hydrocarbon accumulation processes. Combined with a comprehensive interpretation of seismic section, 3D property parameter extractions and thin section observation, The elements of the vertical migration system are analyzed and the diffused and migration overpressure are quantitatively calculated by PetroMod v11 2D software in the paper. It is concluded that. diapir-associated fractures and hydraulic fractures are two main elements of vertical migration system in the basin. The processes vary vertically, with deep migration mainly controlled by hydraulic fractures while the shallow one mainly controlled by diapir-associated fractures in Dongfang area. Fluid activity pierces through the overpressure compartment vertically leading to the diffused overpressure surface being uplifted about 2 000 m in the center of the Yinggehai Basin. 90% of the reservoir remaining pressure comes from migration overpressure at about 3 000 m of the Huangliu Group at present. (3) There are two potential nature gas accumulation zones in the basin, including a top-compartment conductive pressure zone and in-compartment diffused-conductive overpressure zone. As the nature gas reservoir is controlled by hydraulic fracture migration system and has the advantage of being close to the hydrocarbon source kitchen and effective migration, the in-compartment diffused-conductive overpressure zone is the most potential nature gas accumulation zone in the basin.