陆丰A油田恩平组是珠江口盆地陆丰凹陷的主要产层,其砂体非均质性较强.采用层次分析的思路,应用地震沉积学研究方法,通过岩心、三维地震、测井及生产动态资料综合分析,对陆丰A油田恩平组开展了海上稀井网区砂体构型精细刻画,明确了储集砂体结构.研究表明:①陆丰A油田恩平组发育浅水辫状河三角洲前缘沉积,主要包括水下分流河道、河口坝、分流间湾,②研究区辫状河三角洲前缘的水下分流河道主要为多级分叉的似网状河道,剖面上砂体呈侧向切叠型、侧向拼接型和孤立型叠置样式,③三角洲前缘末端发育小规模水下分流河道和朵状河口坝,剖面上砂体呈侧向拼接型、孤立型及砂坝与河道切叠复合型叠置样式,④研究区辫状河三角洲由不同成因类型的砂体拼接叠置而成,沿物源方向,单河道砂体组合样式由多期切叠式逐渐向侧向切叠和侧向拼接式转变,最终过渡为孤立式,单河道发育规模逐渐减小,数量逐渐增加,砂体之间的连通性逐渐降低.

The Pearl River Mouth Basin is one of the important petroliferous basins in China. At first, the main intervals of oil and gas exploration and development in the basin were concentrated in Neogene, but with the advancement of rolling development, Paleogene has gradually become the focus and hotspot of oil and gas development. Lufeng A Oilfield is the earliest oilfield to develop Paleogene in the Pearl River Mouth Basin, and the development layer system is Enping Formation of Paleogene. Due to the strong heterogeneity of sand body in the study area, with the deepening of development process, the oilfield has exposed many problems, such as unclear interpretation of oil-water interface, unclear corresponding relationship of sand body and so on. In order to solve these problems and meet the needs of oil and gas development, it is urgent to clarify the sand body configuration. In this paper, using the idea of analytic hierarchy process and the research method of seismic sedimentology, through the comprehensive analysis of core, three-dimensional seismic, logging and production performance data, the sand body configuration in Enping Formation of Lufeng A Oilfield is finely characterized. The results show that: (1) Shallow braided river delta front deposits are developed in Enping Formation of Lufeng A Oilfield, mainly including underwater distributary channel, mouth bar and inter-distributary. (2) The underwater distributary channel in the front of braided river delta in the study area is mainly multi-level braided network-like channel, and on the profile shows lateral shear superposition, lateral splicing and isolated superposition styles, (3) Small scale underwater distributary channel and lobed mouth bar are developed at the end of the delta front, and lateral splicing, isolated and bar-channel composite sand body superposition styles are developed in the section, (4) The braided river delta in the study area is formed by the splicing and superposition of sand bodies of different types. Along the provenance direction, the combination style of single channel sand bodies is transformed from multi-stage cutting-stacking style to lateral cutting-stacking and lateral splicing style, finally to isolation style. At the same time, the development scale of single channel is gradually reduced, the development number of single channel is gradually increased, and the connectivity between sand bodies is gradually reduced.