浅海陆棚相沉积特征及其沉积差异性分析

珠江口盆地文昌A/B/C油田珠江组一段上部储层发育于浅海陆棚沉积环境,主要砂体为滨外浅滩、滨外砂坝复合体,相对而言滨外砂坝微相因水流的搬运、清洗作用强、泥质含量相对低、砂岩相对纯净而表现为相对优质的储层,但在平面及纵向上滨外砂坝微相变化较快,砂体的叠置关系不清,因此分析滨外浅滩、滨外砂坝沉积微相的特征,并确定储层砂体的展布规律对优质储层预测具有重要意义。研究通过3个油田的沉积差异性分析认为,构造走向控制砂体展布方向,距物源区远近和水体深浅决定储层砂体物性特征,文昌B油田近物源、水体较浅,其构造高部位的滨外砂坝砂体为优质储层分布区；文昌A油田距离物源较远、水体较深,储层物性最差；文昌C油田储层物性中等。

The Analysis of Sedimentary Characteristics and Sedimentary Differences In Neritic Shelf---- A case of Wenchang A/B/C District in Pearl River Mouth basin

The upper section of the First Group in Zhujiang Formation of Wenchang A/B/C Oil Field in Pearl River Mouth basin is developed in a neritic shelf sedimentary environment, whose main sand body of is a combination of offshore shallow and offshore bar, the latter microfacies manifests as relatively high-quality reservoir which owes to the potamic transport, highly sand-cleaning effect, relatively low mud contend and relatively pure sandstone. However, the current situation that offshore bar microfacies changes rapidly in the plane and in vertical, making the superimposed relationship among sand body unsharp accordingly. It is necessary and significant to analyze the sedimentary feature of offshore shallow and offshore bar microfacies, as well as confirm the rule of sandstones distribution to predict advantageous reservoir.By analyzing the sedimentary differences among three oil fields, the results indicate that the distributed direction of sand body is controlled by structural trend, the porosity and permeability of sand body is up to the distance towards provenance region and the depth of water. Wenchang B Oil Field, which is close to the provenance region and belongs to shallow-water area, has an advantageous reservoir distribution with its offshore bar located in the higher position of structure; Wenchang A Oil Field, which is far from the provenance region and belongs to deep-water area, has the worst physical properties; Wenchang C Oil Field has medium physical properties.