Acquiring and utilizing the wellbore data to recover the well performance-In the case of Yufutsu water injection well-

Japex has been operating Yufutsu Oil & Gas filed in Tomakomai, Hokkaido. The new water injection well drilled in 2009 has very good reservoir characteristics and productivity is also very good, but injectivity declines rapidly with increasing the cumulative volume of injected water.We took many wellbore data concerning pressure and temperature, and tried to consider the cause of the damage. With an analysis of the data, we considered that the damage is due to the mud cake stayed between the 5″ Slot Liner Casing and 6″ wellbore. We tried to remove the mud cake by Pulsonix cleaning and Acidizing treatment, and succeeded to recover the performance by eliminating most of the foreign object.