油气勘探“源-汇-聚”评价体系及其应用——以珠江口盆地珠一坳陷为例

“ Source-migration-accumulation”evaluation system and its application in hydrocarbon exploration: a case study of Zhu I depression in Pearl River Mouth basin

基于珠江口盆地珠一坳陷独特的地质特征和油气分布规律,综合国内外油气成藏理论及勘探评价体系,消化吸收国内外油气评价的思路和方法,提出并建立了油气勘探"源-汇-聚"评价体系。该评价体系分"烃源"、"运汇"、"聚集"三级评价单元,其中烃源单元评价可从凹陷、半地堑、洼陷3个层次定量评价不同地区烃源岩的宏观分布及资源量大小;运汇单元评价可从运汇方向及强度评价不同汇油范围内的资源潜力;而聚集单元(二级构造带和局部构造)评价有助于确定勘探方向和优选上钻目标,从而实现高效勘探。陆丰凹陷的勘探实践表明,该评价系统符合海上油气勘探的实际情况,充分体现了"源-汇-聚"评价体系在现阶段珠江口盆地油气勘探中的实用性,对勘探程度尚低、油气分布贫富不均的珠江口盆地新领域(新区、新层系、新类型)油气勘探具有重要的指导作用,也对其他海域的勘探具有很好的借鉴意义。

Based on the unique geology characteristics and hydrocarbon distribution of Zhu I depression in Pearl River Mouth basin, an evaluation system termed as ＂source-migration- accumulation＂ was established by syn- thesizing domestic and international hydrocarbon accumulation theories and exploration evaluation systems and digesting and absorbing their ideas and methods. The ＂source-migration-accumulation,, evaluation system in- eludes such three evaluation units as source unit, migration unit and accumulation unit. Source unit evaluation can quantitatively evaluate the source rock distribution and resource scale in different areas from such three lev- els as sag, half-graben or subsag. Migration unit evaluation can evaluate resource potential of different oil ac- cumulating zones by migration direction and intensity. Accumulation unit evaluation including secondary struc- tural belts and local structures contributes to determining exploration direction and drilling target. The explo- ration practice in Lufeng sag indicates that the evaluation system coincides with the actual situation in offshore hydrocarbon exploration, reflecting the applicability of the evaluation system for current hydrocarbon explora- tion in Pearl River Mouth basin. The evaluation system provides an important guidance for frontier exploration including new areas, new layers and new types in Pearl River Mouth basin with less exploration and unbalanced hydrocarbon distribution, and it is also applicable to the exploration in other sea areas.