白云岩储层成因研究进展及发展趋势

Research progress and development trend of the genesis of dolomite reservoirs

白云岩储层占全球油气储层近1/4,因深埋条件下更易保持孔隙而成为石油地质学家关注重点。白云岩储层有效孔隙可源于前驱灰岩、封闭体系白云岩化作用和成岩溶蚀改造;白云岩化作用可以增加、保持、减少孔隙,并非一定形成储层,却能提高岩石渗透率;早期白云岩化作用和适度重结晶作用有利于形成储层。白云岩抗压性、脆性更优,且易于发育裂缝,深埋条件更易保存孔隙;白云岩成因模式反映白云岩化作用方式与水文条件,有助于预测储层分布规律。稀土元素、Mg同位素成为示踪白云岩化流体新技术,碳酸盐岩U-Pb定年技术、二元同位素测温技术使储层成因认识更精准,实验与数值模拟推动储层表征向动态化发展,地质大数据有助于揭示白云岩储层成因更多规律性认识。

Dolomite reservoirs account for nearly a quarter of the global oil and gas reservoirs,and they have become the focus of petroleum geologists because of their pores in depth.The effective pores of dolomite reservoirs can originate from precursor limestone,dolomitization in the closed system,and diagenetic dissolution reformation.Dolomitization can increase,maintain,and reduce pores,but does not necessarily form a reservoir.Dolomitization can increase the permeability of the rock,enhance the compressive performance of the rock,and easily form cracks.Early dolomitization and moderate recrystallization are conducive to the formation of reservoirs.The dolomite genetic model reflects the method of dolomitization and hydrological conditions,and the genetic model of dolomite is helpful to predict the distribution of reservoirs.Rare earth elements and Mg isotopes have become new technologies for tracing dolomitization fluids.In-situ U-Pb dating technology of carbonate and cluster isotope technology have promoted more accurate genetic research,and experiments and numerical simulations have promoted dynamic reservoir characterization.Geological big data will reveal more laws of reservoir development.