东营凹陷草桥潜山岩溶储层胶结物特征及其储层成因

鉴于碳酸盐岩岩溶储层成因及分布规律的复杂性及其对油气勘探的重要性,以东营凹陷草桥潜山为研究对象,以钻井岩心资料、薄片资料、测录井资料、生产数据等为基础,结合区内地层结构特征、方解石胶结物的阴极发光特征及成分差异,明确研究区碳酸盐岩潜山储集特征、成因及分布规律。结果表明草桥地区下古生界碳酸盐岩为次生孔洞和裂缝主导的储层;燕山期—喜山期抬升剥蚀及晚期淋滤作用控制了区内优质岩溶储层的形成与分布,优质储层主要分布在上古生界缺失的强烈剥蚀区,纵向上多分布在不整合面之下150 m范围内;胶结物的阴极发光和成分特征良好地记录了地质历史时期的构造及成岩流体演化,可作为判断岩溶储层成因和分布规律的重要依据。

Characteristics of cements and origin of karsted reservoirs in Caoqiao buried hill in Dongying Sag

In view of the complexity of both the origin and distribution of the karsted carbonate reservoirs and the importance to hydrocarbon exploration,the characters,origin and distribution of the lower Paleozoic carbonate reservoirs of Caoqiao buried hill in Dongying Sag were studied based on plenty of drilling cores,thin sections and production data as well as a combination of stratigraphic architecture,cathodoluminescence feature and chemical component of the calcite cements in the study area.Our results show that the reservoirs are dominated by secondary pores,caves and fissures.Uplifting and denudation between Yanshan and Himalayan periods as well as the late-stage karstification controlled the origin and distribution of the relative-high quality karsted carbonate reservoirs in Caoqiao area.The relative-high quality reservoirs mainly develop in intensively eroded areas where the upper Paleozoic is absent.And their vertical distributions are within 150 m distance from the upper unconformity.The cathodoluminescence feature and composition of the cements,which recorded the tectonic and diagenetic fluid evolution in geologic history,can serve as an important evidence for judging the origin and distribution of the karsted reservoirs.