MICROCOSMIC EXPERIMENT MODELING ON WATER-DRIVEN-OIL MECHANISM IN FRACTURED-VUGGY RESERVOIRS

Fractured-vuggy carbonate reservoir on behalf of the Tahe Oilfield in Tarim Basin is one of special reservoir types,where eroded holes and large cavities are main store space for oil and gas,and structure fracture and eroded fracture is the main flow path for fluid.By means of light-eroded microcosmic glass plane model,water-driven-oil mechanics in the type of reservoirs is studied.The experimental results show that water-oil mutual phase or "piston-driven pattern" for plane drive can exist in the process of water-driven-oil in medium or smaller-scale cavities,and only "piston-driven pattern" for vertical drive can exist in large-scale cavities,and there are many styles of movement in fractures including front-skipping,block-breaking,subsection-moving and dominant path flow.Residual oil distribution styles are divided into continuous phase type and separate phase type.Continuous phase types include "cecum style" residual oil in vugs or remaining oil in orthodoxy fractures with main flow paths.Separate phase types include segment shape,film shape,drop shape,horn shape.Based on the above,the unsteady phenomenon on the well production is analyzed by microcosmic flow mechanism,and countermeasures are provided for water-flooding in the type of reservoirs.