潜江凹陷广北油田湖底扇沉积特征分析

从区域地质背景出发,结合岩心观察、粒度分析、镜下鉴定结果及测井曲线形态等进行综合分析表明,位于蚌湖向斜南斜坡的广北油田Eq341沉积时属半深湖—深湖背景下的湖底扇相沉积,可细分为内扇、中扇和外扇三个亚相,其中中扇可细分出辫状沟道、沟道间和扇中前缘三个微相。利用钻井及地震资料描述了该扇体的空间组合及平面分布特征,并对其成因作了初步分析。结合测试资料分析,有辫状沟道的中扇为有利储油相带,并指出了该类扇体发育的有利区带,为下步岩性油藏的勘探指出了方向。

Analysis on the Sedimentary Characteristics of Sub-lacustrine Fan of Guangbei Oilfield, Qianjiang Depression

Based on integrated study on regional geologic setting, together with core observation, granulom etric analysis, microscopic identification results and types of well logging curves, it is indicated that Eq341 ofGuangbei Oilfield, which is located on the southern slope of Banghu syncline, is sub lacustrine fan faciessedimentation deposited under half deep and deep lake sedimentary environment. The sub lacustrine fanfacies sedimentation can be divided into three sub facies, including internal fan, middle fan and outer fan.The middle fan can be further divided into three microfacies, including braided channel, inter channel andfront edge of middle fan. The spatial combination and areal distribution characteristics have been studied anddescribed with well drilling and seismic data,and a preliminary analysis on its origin has been conducted. Together with analysis of production testing data, it is indicated that the middle fan with braided channel isfavorable oil saturated facies. Through this study, the exploration targets for lithologic oil reservoirs have been pointed out.