含油气盆地中深层碎屑岩储层异常高孔带研究进展

Research Progress on Anomalously High Porosity Zones in Deeply Buried Clastic Reservoirs in Petroliferous Basin

异常高孔带是指由于经历异常地质作用而形成的孔隙度高于正常压实条件下最大孔隙度的异常高孔隙度储层相对集中发育带,是含油气盆地中深层油气勘探的甜点。国内外学者对其开展了大量有益的研究,总结其研究成果对于指导深部油气藏勘探有着重要的意义。首先总结了近些年全球范围内异常高孔带的研究现状,主要包括异常高孔带概念、划分方案、类型、储集空间、成因机制及预测等。研究表明,异常高孔带的分布通常利用孔隙度正常压实趋势线(或相当的趋势线)进行确定。根据孔隙类型及含量,异常高孔带具有原生孔隙型异常高孔带和次生孔隙型异常高孔带2种类型,原生孔隙型异常高孔带储集空间以原生孔隙为主,保孔型地质因素是其形成的主控因素;次生孔隙型异常高孔带储集空间以次生孔隙为主,溶蚀增孔作用是其形成的主控因素。然后对中国含油气盆地深层异常高孔带的特征和成因机制进行了系统总结,认为其分布广泛,类型多样;其分布具有地层深度范围大、时代跨越尺度大、盆地类型多样和沉积相类型丰富等特点;其类型兼具原生孔隙型和次生孔隙型。最后指出了目前研究中存在的一些问题和今后的研究趋势。

Anomalously high porosity zone refers to a zone where reservoirs with anomalously high porosity concentrate,and the porosities are higher than the maximum porosity of reservoirs experienced normal compaction.Anomalously high porosity zones are desserts for oil and gas exploration in deep layers in sedimentary basins.Significant studies have been conducted by worldwide scholars,and the research results are important for the oil and gas exploration in deep layers.From aspects of concepts,classification scheme,types,reservoir pores,origin and prediction of anomalously high porosity zones,this paper summarized the current research progress.Studies show that the distribution of the anomalously high porosity zones can be determined by the porosity compaction curve or some other equivalent curves.The anomalously high porosity zones can be subdivided into primary pore anomalously high porosity zone and secondary pore anomalously high porosity zone.Primary pores dominant in the former type and geological processes beneficial to porosity preservation are the controlling factors.Secondary pores dominate in the other type and geological processes beneficial to dissolution are the controlling factors.Then the features and genetic mechanisms of anomalously high porosity zones in the petroliferous basins of China were summarized.These zones have the features of wide development and various types.The zones developed in layers of a big depth range and wide geological age,and the zones developed in different sedimentary facies in various basins,and both the primary and secondary types developed.And finally,the existing problems and research trend on anomalously high porosity zone were proposed.