SITE TESTING RESEARCH OF RE-FRACTURING TECHNOLOGY IN THE E31 RESERVOIR FOR QlNGHAI YUE-DONG

The E31 reservoir of Qinghai Yuedong Oilfield belongs to the formation of super low permeability,porosity and anormal high temperature-high pressure,and most of the wells in the reservoir can achieve a stable productivity by using the stimulation technique.However,the reservoir has the characteristics of high Yong’s Modulus,water-sensitivity and acid-sensitivity;and the previous fracturing techniques have many disadvantages such as the small scale,low proppant concentration,and short effective stimulation producing period etc.According to the reservoir characteristics and the problems existed in the previous fracturing techniques,the research of re-fracturing site testing has been developed,and the testing has been carried out for 6 times of wells,with success percentage of 100%.The maximum proppant volume has reached 30.5 m3,and the concentration is as high as 46%,improving the fracturing technique in this reservoir and achieving the obvious stimulation effect.Take example,the effective stimulation period of YD1 well has exceeded the 500d,the accumulated oil increase has reached 3259t;and the effective stimulation period of YD3 well has exceeded the 600d,the accumulated oil increase has reached 3648t.