Research on Lowering Actuating Pressure of Injection Wells of Ultra-Low Permeable Reservoirs

With the improving skills of oil exploration and exploitation, the proportion of the production of ultra-low permeable reservoirs is increasing. But the developing process has encountered many problems, such as poor reservoir properties, high injection actuating pressure, etc. Aimed at lowering the injection actuating pressure of ultra-low permeable oilfield, author has finished the indoor gradient test of actuating pressure, selected and evaluated a system of surface acting agent which later applied in the X oilfield as well. The results show that the gradient actuating pressure of Z reservoir in X oilfield ranges between 0.0308 MPa/cm to 0.2215 MPa/cm. And because the SAA system could largely reduce the surface tension between fluid and rock, the injection actuating pressure then can be reduced by 40%-50%. And its application efficiency was 75%. As a result, it is feasible to use SAA to lower the injection actuating pressure of ultra-low permeable reservoirs.