蠡县斜坡中南部沙一下亚段油藏成藏特征及富集高产控制因素

Hydrocarbon Accumulation Conditions and Control Factors of Lower Part of the First Member of Shahejie Formation in South Central of Lixian Slope

为进一步明确蠡县斜坡中南部沙一下亚段油藏成藏特征及富集高产控制因素,利用大量井震、分析化验、生产动态等基础地质资料,开展油藏特征、烃源岩特征、储盖特征及富集高产控制因素研究。研究表明:蠡县斜坡中南部沙一下亚段油藏主要为未熟—低熟型油藏,主要发育构造和岩性两大类油藏;沙一下亚段油藏油源主要为沙一亚段烃源岩,其次为沙三段烃源岩,具有“双源供烃、两期成藏”特征;沙一下亚段储盖条件优越,在低孔低渗背景下发育2条优质储层发育带,区域性和局部性盖层发育。油藏富集受3种因素控制,继承性鼻状构造提供油气运移优势通道,控制油藏富集程度;反向正断层为油气聚集提供封堵条件,控制油藏富集部位;流体势提供油气运移动力,控制油藏分布范围。油藏高产受砂体物性和圈闭幅度控制,砂体物性越好,圈闭幅度越大,含油性越高,越容易成为高产油藏。

In order to further understand the characteristics of hydrocarbon accumulation and the main controlling factors of hydrocarbon enrichment and high production in the lower part of the first member of the Shahejie formation in the south-central of Lixian slope,the characteristics of the reservoir,source rock,reservoir-cap and the main controlling factors of hydrocarbon enrichment and high production were studied based on a large number of basis geophysical data such as logging-seismic,analysis and test and dynamic production data.The results show that the reservoir in the lower part of the first member of the Shahejie Formation in the south-central Lixian slope is immature and low-mature oil reservoir,and there are mainly two types of oil reservoirs:structural and lithologic reservoirs.The oil source of the reservoir in the lower part of the first member of the Shahejie formation is mainly the source rock of the first member of the Shahejie formation,followed by the source rock of the third member of the Shahejie formation.The reservoir has the characteristics of"double source hydrocarbon supply and two-stage accumulation".The reservoir has good reservoir-cap assemblage conditions,two high-quality reservoir zones are developed under the background of low porosity and low permeability,and regional and local cap rocks are developed.Hydrocarbon enrichment is controlled by three factors:the inherited nose structure provides the dominant channel for hydrocarbon migration and controls the accumulation degree of the hydrocarbon;the reverse normal fault provides plugging conditions for hydrocarbon accumulation and controls the accumulation position of the hydrocarbon;the fluid potential increases the power of hydrocarbon migration and controls the distribution range of the hydrocarbon.High production of the reservoir is controlled by the physical property of sand body and trap amplitude.The better the physical property of sand body is,the larger the trap amplitude is and the higher the oil-bearing property of the reservoir is,the easier it is to become a high-yield reservoir.