Abstract

Many oilfields in China have stepped into the high and ultra-high water-cut recovery stage, with the comprehensive water cut (the ratio of the monthly water production to the monthly liquid production) approaching 90%. The injection-production relationship is seen with increasing complexity. Moreover, the commingled production is often adopted in the production well, and the liquid producing structure for the individual well is unclear, which results in the difficulty of the fine matching and adjustment between the injection and production. This paper proposes a cable-controlled real-time monitoring and controlling technology for zonal production. The technique is able to implement continuous monitoring of parameters such as the zonal flow rate, pressure, water cut and temperature through the whole production, and automatically adjust the zonal liquid production rate. The key to this technology is an integrated production regulator. The pressure test range of the regulator is 0–45 MPa and flow rate test range for a single layer lies between 5 m3/d and 100 m3/d. The field testing of the proposed technology has been successfully carried out in Daqing oilfield. There were totally three payzones, and the setting depth of the regulator is of 1050–1105 m. A tracking test for one month, including the downhole flow rate and pressure monitoring, the formation pressure buildup monitoring and the water cut monitoring at the wellhead, was conducted following the construction. The testing result indicates that this technology can accurately capture the downhole production status and effectively control the high-water-cut payzone. With the oil production of the individual well unchanged, the liquid production dropped by 5%–15%. The field practice demonstrates that this technology can effectively improve the waterflooding efficiency, suppress the ineffective water circulation and fulfill the refined development requirement of the oilfield.

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