Distribution law of dominant seepage channels in collaborative development of layered sandstone reservoirs: a case study of the Y Formation of P Oilfield in M Basin of Africa.

Based on the data of core, well logging, laboratory analysis, water injection profile and production performance, combined with geological and reservoir engineering identification methods, the dominant seepage channels of Y Oil Group, the main of layer of P Oilfield in M Basin of African inland rift basin, were identified and quantitatively evaluated, and the distribution law and distribution mode of dominant seepage channels in the coordinated development of layered sandstone reservoir in this area were clarified. The results show that the dominant seepage channel is preferentially developed at the bottom of the positive rhythm sand body in the Y VI sand group dominated by braided river sedimentary faces. The thick dense mudstone interlayer will promote the development of the dominant seepage channel and limit its longitudinal extension. The dominant seepage channels are mostly parallel to the source and along the river direction or intersect at a small angle; it is developed in the high permeability sandstone layer of the sand group with high interlayer permeability breakthrough coefficient (> 1.25), high interlayer permeability coefficient of variation (>0.40) and large interlayer permeability difference (>4.36). The dominant seepage channels in the synergistic development of layered sandstone reservoir can be divided into three distribution modes: water control between sand groups, interlayer control within sand groups, and rhythmic control within sandstone layers. The results provide a geological reference for controlling the dominant seepage channel of layered sandstone reservoir, improving the recovery of remaining oil and realizing stable oil and water control. [ABSTRACT FROM AUTHOR]