珠江口盆地荔湾3-1气田珠江组深水扇沉积相分析

根据已钻井取芯段岩相分析,从荔湾3-1气田珠江组深水扇沉积体系中划分出巨厚层和厚层块状砂岩相、厚层正粒序砂岩相、厚层逆粒序砂岩相、平行—板状斜层理砂岩相、滑塌变形砂岩相、薄层砂岩夹层相、薄层（粉）砂岩与泥岩互层相、厚层粉砂岩相、厚层泥岩相和层状深水灰岩相等10种岩相类型和识别出砂岩相组合、泥岩相组合、（粉）砂岩与泥岩互...

Facies and Depositional Model of A Deepwater Fan in the Zhujiang Formation,Liwan 3-1 Gasfield,Baiyun Sag,Pearl River Mouth Basin

Based on detailed analysis of cores, logs, and seismic data, ten lithofacies were indentified, including mega thick and thick massive sandstones, thick normal graded sandstones, thick inverse graded sandstones, parallel and tabular cross stratified sandstones, slumped and deformed sandstones, thin sandstone interlayers, thin mudstone sandstone interbeds, thick siltstones, thick mudstones, and deep water limestones. They can be organized into five lithofacies associations. These are sandstone dominated, mudstone dominated, mudstone sandstone interbed, siltstone and deep water limestone associations. Based on the analyses of lithofacies and their associations, the depositional system of the reservoir in the Zhujiang Formation, Liwan 3 1 field is identified as submarine fan. Four microfacies are further recognized within the fan based on detailed analysis, including channels (including main channels in the inner fan and distributary channels in the middle fan), inter channel, levee overbank, outer fan and basin microfacies. Facies analysis allows to reconstruct the depositional model of the deepwater fan. During relative sea level fall, a basin floor fan formed as sediments from rivers or shelf margin deltas were further transported down slope and into the basin under gravity flows. During the ensuing relative sea level rise, a slope fan was deposited as the system stepped back. The lower part of the Zhujiang Formation, mainly sandstone dominated associations, is inner fan and middle outer fan deposits of the basin floor and the slope fan respectively. The upper part, mainly mudstone dominated associations, siltstone associations, and deepwater associations are outer fan deposits of the slope fan and basin deposits. Along with the transgression, submarine fan was finally replaced by pelagic deposits.