东营凹陷古近系沙四上亚段滩坝砂体固体—流体相互作用定量恢复及次生孔隙成因预测

东营凹陷古近系沙四上亚段地层大规模发育典型的湖相滩坝砂体,并获得大量油气发现。作者从固体与流体相互作用的产物——胶结物和次生孔隙入手,结合盆地的演化和断层的演化阶段,来定量半定量地恢复储集层中流体性质的变化以及对储集层物性的影响。根据流体来源和持续时间,可以把固体—流体作用过程划分为5个阶段: 初始流体作用阶段、围岩流体作用阶段、外来流体作用阶段、排烃流体作用阶段和排烃后流体作用阶段。根据滩坝砂体的分带性和次生孔隙形成机理,总体可分为砾质滩坝酸性流体主控次生孔隙发育带、近岸滩坝酸碱流体共同作用次生孔隙发育带和远岸滩坝—中央共振带滩坝碱性流体主控次生孔隙发育带,并进行了平面上次生孔隙成因的推测。

Quantitative recovery of solid-fluid interaction and prediction of cause of secondary pores in beach and bar reservoirs in the upper part of Member 4 of Shahejie Formation of Paleogene,Dongying sag

There are large scale of typical lacustrine beach and bar sandbodies of the upper part of the Member 4 of Shahejie Formation of Paleogene in Dongying sag and a great amount of oil and gas has been found in this area. Based on the analysis of cements and secondary pores,which are the products of the solid-fluid interaction,we can quantitatively or semi-quantitatively recover the process of the liquid changing and its effects on the porosity of reservoirs combing with the evolution of the basin and the structure development stages. Finally,in accordance with the fluid sources and time of duration, the whole evolution process can be divided into five stages,which are the reaction stage of initial liquid,the reaction stage of liquid from surrounding rocks,the reaction stage of liquid from outer sources,the reaction stage of liquid with hydrocarbon migration and the reaction stage after hydrocarbon accumulation. According to the formation mechanism of secondary pores and the zoning character of beach and bar sand bodies,we can indentify the secondary pore zones as the zone dominated by the acid fluids in gravelly beach and bar along the shore line,the zone effected commonly by the acid and alkaline fluids in the near shore bar sand bodies,and the zone dominated by the alkaline fluids in the bar far from shore and in the central resonance belt,and the speculation of secondary pores in the plane also been done in this article.