渤海湾盆地黄河口凹陷A油田火成岩发育区储层特征及三维地质建模

Reservoir characteristics and 3D geological modeling of igneous rock area in Huanghekou Sag A Oilfield,Bohai Bay Basin

渤海湾盆地A油田是与火成岩相关的大型油田,目的层碎屑岩储层与火成岩交织分布。为明确研究区火成岩的发育特征及其成因机理,综合应用岩芯、井壁取芯、测录井及三维地震等资料,通过岩矿分析、薄片观察、地震相分析等手段对火成岩类型、发育模式、分布范围以及火成岩对储层物性的影响进行研究。结果表明:(1)研究区发育爆发相、火山通道相、溢流相、次火山岩相和火山沉积相5种火山岩相,以中心式和裂隙式2种喷发模式为主;(2)受断层根部低洼区溢流相及火山通道周边侵入相影响,研究区断裂系统复杂带、火山通道发育区储层物性变差。基于上述认识,利用火山岩体精细识别追踪结果,将火山岩体嵌套进地质模型中,实现了火成岩的形态建模。该研究成果较好指导了油田开发井的实施,规避了储层风险。为油田下一步综合调整及高效开发提供指导作用。

The A Oilfield is a large-scale oilfield in Huanghekou Sag,Bohai Sea,and covered by igneous rocks.It presents the characteristics of strong volcanic activity,complex geological structure,and various types of volcanic rocks.To clarify the characteristics and formation of igneous rocks in the study area,the types,development mode,distribution of igneous rocks,and the influence of igneous rocks on reservoir physical properties were studied by means of core analysis,thin section observation,and seismic facies analysis.Results show that:(1)five volcanic lithofacies were distinguished in the study area,including explosive facies,volcanic channel facies,overflow facies,subvolcanic facies,and volcanic sedimentary facies.Two eruption modes i.e.,central and fissure eruptions,were established;(2)affected by the overflow facies in the low-lying area at the root of fault and the intrusive facies around the volcanic channel,the reservoir physical properties became worse in the areas due to strong fault activity and well-developed volcanic channels.Based on the above understanding,the volcanic rock mass was nested into the geological model by using the fine identification and tracking results of volcanic rock mass,and the shape modeling of igneous rock was realized.This study facilitated the implementation of development wells and provided guidance for the comprehensive adjustment and efficient development of the oilfield.