Experimental study on physical properties after flooding under high temperature and high pressure condition: taking reservoir T_Ⅰ of Tarim Lunnan Oil Field as an example

The T_Ⅰ reservoir of the Lunnan Oil Field in the Tarim Basin has over 20 years' development history.In recent years,the application situation of water flooding was researched,but was not in formation condition.In this paper,in order to figure out oil and water seepage law,and to study the reservoir alternations of micro-pore structure and wettability after long-term water flooding,we conducted a water flooding modeling experiment under high temperature and high pressure using fluid and core from this oil field.The experimental results showed that the reduction extent of porosity and permeability of cores increased as water flooding increased,and throats' sorting became weaker.Wettability also increased as water flooding increased.The irreducible water saturation and irreducible oil saturation values on core relative permeability curve rose while the water relative permeability under irreducible oil saturation dropped.Oil displacement efficiency decreased.High-capacity channels were not formed after water flooding.The main reasons for early water breakthrough might be plane and longitudinal heterogeneity.