Identification And Distribution Of Large Pore Paths In S266 Block Of Shuguang Oilfield

Under the action of long-term waterflooding development,the reservoir of high water cut oilfield is washed by different degrees of water flooding,which leads to a certain change of reservoir porosity and permeability.Some of the wells are badly damaged by washing and form large pores,resulting in an ineffective circulation of injected water,which leads to the increase of reservoir heterogeneity and seriously affects the potential tapping of remaining oil in the reservoir.It is of great significance to study large channel identification method and large pore distribution law for tapping the remaining oil potential in high water cut stage.In this paper the Shu 266 area Dujiatai reservoir group as an example,in the guidance of sedimentology,reservoir geology,development of physics theory,firstly study the geological characteristics of target layer in the study area,the Shu 266 area belongs to the structural lithologic reservoirs,reservoir Dujiatai reservoir group to belong to the fan delta front deposition the rock types are mainly lithic feldspar sandstone and feldspathic lithic sandstone.The content of cement is low,mainly with argillaceous cementation,and the rock is relatively loose.The identification characteristics of large holes in this block are studied.In dynamic data,water absorption percentage is far greater than the well layer,the adjacent layer increased with time indicating there are large pore water injection increasing percentage of single wells,water cut wells a sudden increase at a certain time;in the logging curve showed the potential amplitude value,sonic value increased and wells enlargement,resistivity curve appeared amplitude and amplitude decrease etc..A logging interpretation of porosity,permeability,average pore throat radius and other parameters of the model,using cluster analysis and discriminant analysis to determine the five grade classification method of big channel,from I to V,the nature of channel variation.Based on the analysis of large pore formation conditions,studied the distribution law of large pore,large pore I first appeared in the most easily thick layer of underwater distributary channel in the lower part,or non central sand core position;II and III channels are widely distributed,including sand sheet,wide central internal channel the IV,V large pore distribution in channel sand,sand sheet edge,interdistributary bay and the narrow sand sheet inside.