Experimental Study On Seepage Flow Patterns Of Thin And Poor Reservoir In Xing Ten Area

The exploitation degree of main oil reservoirs in Daqing oilfield is gradually increasing,therefore the raising difficulty is also increasing.The thin and poor reservoir has complex sedimentary type,strong heterogeneity,unstable oil layer distribution,but considerable reserves.Though it has not been effectively used,thin and poor reservoir will be the main resource for increasing the production of Daqing oil field.The subdivision and adjustment measures of conventional water injection wells have limited effect on thin and poor reservoirs with poor water absorption capacity,and the conventional fracturing measures are influenced by compression layer and interslit interference with small scale.Therefore,it is necessary to clarify the seepage flow pattern of thin and poor reservoirs and the effect of fine controlled fracturing on the seepage flow pattern of thin and poor reservoirs,and provide a theoretical basis for the development of thin and poor reservoirs.In this paper,the similarity theory of physical simulation is used,combining the heterogeneity characteristics of reservoir and fluid.Artificial core plate models are prepared to carry out the study on the flow characteristics of five-spot patterns or injection-production units,considering the effects of different development factors and reservoir properties.The high permeability strip is laid on the plate model to simulate the fracture,which is prepared to carry out the study on the flow characteristics of the thin and poor reservoirs after the fine controlled fracturing.The results of experiment show that the zone near well has high water saturation and high pressure consumption in the thin and poor reservoirs.With the volume of injected water increase,the non flow zone decreases first and then becomes stable.The higher the permeability of the extraction end is,the lower the pressure gradient is.The injection end is affected by the heterogeneity enhancement,the pressure gradient increases.After the fine controlled fracturing measures,the water saturation near the crack is high,the pressure consumption is large,the fracture formed by the fine controlled fracturing approximately enlarges the radius of the wellbore,and the area of the non flow area is reduced by more than 70%.The effect of horizontal cracks on the distribution of fluid and pressure in thin reservoir is greater than that of physical and non homogeneous.In a word,the effect of the fine controlled fracturing can reduce the negative effect of reservoir heterogeneity on pressure propagation.