成岩相的形成、分类与定量评价方法

根据成岩作用和成岩相对储集层发育的控制作用及与储集层分布的关系,探讨成岩相的形成机理、划分方案与评价方法及其在油气勘探中的应用和意义。针对碎屑岩、碳酸盐岩和火山岩等扩容性成岩相,提出了有机酸性水溶解作用、白云石化等8种主要成岩作用机理。划分出9类扩容性成岩相和7类致密化成岩相,提出了反映岩性、成岩作用和孔渗性3个层次内容的“孔渗级别＋岩石类型＋成岩作用类型”的成岩相命名方案。在成岩相勘探评价中,强调根据沉积相、测井相、地震相和岩心薄片等综合定量预测,提出了“四个步骤”、“三图叠合”的评价方法和成图方式,根据不同成岩相类型的分布预测有利储集体、“甜点”、成岩圈闭及油气成藏。指出了成岩相的发展方向及成岩学的设想和思考。图16表6参31

Genesis, classification and evaluation method of diagenetic facies

Based on the controlling of diagenesis and diagenetic facies on reservoir development, this paper discusses the formation, classification and evaluation of diagenetic facies and its application and significance in petroleum exploration. For constructive diagenetic facies such as clastic rock, carbonate rock, and igneous rock, eight kinds of genetic mechanisms are developed, including dissolution of organic acid, dolomitization and so on. Nine constructive diagenetic facies and seven destructive diagenetic facies are classified. A naming scheme for diagenetic facies is proposed reflecting lithology, diagenesis, porosity and permeability, that is, "porosity and permeability level + rock type + diagenesis type". Diagenetic facies are evaluated synthetically and quantitatively on the basis of sedimentary facies, log facies, seismic facies, rock cores, and thin sections. And "four steps" and "superposition of three charts" are put forward as the methods of evaluation and mapping. Favored reservoirs, "sweet spots" and lithostratigraphic traps could be predicted according to the distribution of different types of diagenetic facies. The development of the study on diagenetic facies is also discussed in the paper.