电成像测井在珠江口盆地西部低阻油层研究中的应用

An application of electric imaging logging to researching low-resistivity oil intervals in the western Pearl River Mouth basin

基于丰富的电成像测井资料及其优势,结合岩心和常规测井资料,对珠江口盆地西部珠江组一段上部低阻油层段的岩性相进行了分析,划分出了6种岩性相,即薄互层砂泥岩、似层状砂泥岩、混杂状砂泥岩、平行纹层粉砂岩、块状泥质粉砂岩和粒序粉砂岩。在此基础上,开展了低阻油层段储层物性评价、沉积层序划分和宏观地质成因分析,认为3类储层中Ⅰ、Ⅱ类质量较好而具有开发价值,原始沉积环境的水体较深、能量较低导致储层岩性细、泥质含量高并多呈现砂泥岩薄互层以及和现今所处的低幅度构造背景的相互叠加影响是形成低阻油层的根本原因。

Based on abundant data of electrical imaging logging and combined with core and conventional log,the low-resistivity oil intervals in the upper part of Member 1,Zhujiang Formation,were analyzed in the western Pearl River Mouth basin,and their six lithofacies were identified,including thin-interbedded sand-mudstone,weak-bedded sand-mudstone,hybrid sand-mudstone,concordant-laminated siltstone,massive muddy siltstone and graded siltstone.According to the lithofacies identification,the reservoir petrophysics evaluation,sedimentary sequence division and macro analysis of geologic origin were conducted for these low-resistivity oil intervals.Then it can be considered that for the three types of reservoir there,TypeⅠand Ⅱ are better in qulity and worthy to be developed,and that the fundamental causes to form these low-resistivity oil intervals are the fine-grained lithologies,higher clay content and frequent thin-interbeded sand-mudstones resulted from their deeper sedimentary environment with lower energy,and the mutual superposition of these factors with the present low-amplitude structures.