沉积盆地中油气充注与储集层成岩作用的响应关系

Response Relationship Between Hydrocarbon Charging and Diagenesis of Reservoirs in Sedimentary Basin

埋藏期的油气充注可引起储集层中一系列有机-无机物理和化学变化,从而改造储集层的储集空间大小和润湿性,进而影响物性和油气运移动力。油气充注对储集层的影响主要表现在4个方面:①有机质生烃增压和早期油气充注占位可使岩层增加一定的抗压实能力,让深埋条件下的储集层仍能保存较多的储集空间和渗透性;②油气充注可在一定程度上抑制自生矿物的生长,如自生石英、自生伊利石等,从而降低胶结作用的减孔效应;③有机酸伴随油气充注可对储集层中的长石碎屑、方解石胶结物等易溶矿物进行溶蚀改造,从而有效改善岩石的物性和孔隙结构;④早期油气充注可在矿物表面形成油膜,致使储集层呈现中性—弱亲油性,利于油气运移中克服分子的表面张力。综上所述,建立油气充注与储集层成岩演化时序,恢复成藏期自生矿物在空间上的组合关系,可有效预测油气优势运移路径。

Hydrocarbon charging during burial period can cause a series of organic-inorganic physical and chemical changes in the reservoir, thus reforming the size of the reservoir space and wettability of the reservoir, thereby affecting the physical properties and the migration of oil and gas. The influence of hydrocarbon charging on reservoir is mainly manifested in the following four aspects: ① Organic hydrocarbon generation and early occupancy of hydrocarbon charging can increase the compaction resistance of rock layers, so that the reservoir under deep buried conditions can still preserve more reservoir space and permeability;② hydrocarbon charging can restrain the growth of authigenic minerals to a certain extent, such as authigenic quartz, authigenic illite and so on, then reduce the pore-reducing effect caused by cementation;③ organic acid accompanied by hydrocarbon charging can dissolve and transform the soluble minerals, such as feldspar clastic and calcite cements in the reservoir, thus effectively improving the physical properties and pore structure of the rock;④ early hydrocarbon charging can form oil film on the mineral surface, which makes the reservoir appear neutral-weak lipophilic, and is beneficial to overcome the surface tension of molecules in oil and gas migration. To sum up, it is effective to predict the dominant migration path of oil and gas by establishing the diagenetic evolution sequence of hydrocarbon charging and reservoir, and restoring the spatial association of authigenic minerals in the reservoir-forming period.