Abstract

TZ-I carbonate reservoir in the Tarim Basin, Western China is deep buried (>5000m), high temperature (>130°C), low-permeability, and severely inhomogeneous, and the natural fractures, vug and huge cavity often densely distributed in it. Because the aquifer energy is poor, horizontal wells can be adopted as recovery method to expose the area of reservoir as much as possible and connect more naturally fractured formation. But the open-hole interval is too long to be effectively stimulated by un-isolated general stimulation, so the multistage isolation fracturing technique should be conducted to exert the advantage of horizontal well and maximize single-well productivity. A novel one-trip open-hole completion and stimulation system was implemented successfully to isolate the long horizontal interval with multistage packers and sliding sleeve. During the process of treatment, the characterization of opening sliding sleeve is clear, moreover, the ISIP and pressure decline after shut-in is different between every stimulation interval, which shows the system is able to effectively isolate and stimulate specified intervals. The wells productivity increased dramatically after the multistage isolation stimulation, and much higher than the vertical well or general acid fractured horizontal well in the same trap. This shows the horizontal isolating stimulation technique can enhance production and reduce rig time significantly.

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