松辽盆地北东区扶杨油层孔隙流体地球化学与砂岩成岩相研究

Pore Fluid Geochemistry and Diagenetic Facies of Sandstones of the Fuyang Reservoirs, Songliao Basin, China

不同孔隙水成因的局部水动力单元是决定扶杨油层砂岩成岩相类型的重要因素之一。研究区可以划分出与局部水动力单元直接相关的四个成岩相:大气水淋滤成岩相、混合水成岩相、埋藏压实水成岩相和古蒸发浓缩水成岩相、各成岩相的成岩特征、自生矿物组合、孔隙成因与孔隙组合都有明显差别。

The Fuyang reservoirs in the Songliao Basin are composed of typical unstable sandstones, with high per- centages of volcanic and feldspar fragments. Therefore, a series of physical and chemical reactions would take place between frameworks and pore water during sedimentation and burial. The geochemical properties of pore fluids are one of the important factors in determining the different diageneses in three dimensions. The origin and evolution of pore water have controlled the diagenesis and evolution of pores of the Fuyang sandstone reser-voirs. Local hydrodynamic units, with different origins and compositions of pore water, may be the main fac-tor, which would have controlled the types of diagenetic facies. The planar division lines of local hydrodynamic units agree well with those of local pore-water geochemical units and diagenetic facies. In the study area, four types of diagenetic facies can be recognized : meteoric water infiltration diagenetic facies, burial water diagenetic facies, mixture water diagenetic facies and paleo-evaporation water diagenetic facies, all of which have differ-ent compositions of autogenetic minerals, pore types and compositions, and different diagenetic charachteristics.