Successful Application Analysis of Double Water Control in Fractured Reef Reservoir in Liuhua Oilfield

Abstract Water breakthrough (WBT) in the horizontal wells often leads to water flooding in the well, especially to those heavy oil reservoirs in reef limestone carbonate. The excessive water production from the hydrocarbon producing horizontal wells can adversely affect the economic life of the well, furthermore this could result in the well permanent abandonment. Nowadays, no effective methods of water control are available for the similar reservoirs, traditional water control methods have three technology barriers: (1) can not accurately locate the WBT positions;(2) difficulty of identifying the wellbore completion, fluid, and nearby formation conditions;(3) Not being designed to control water from new water breakthrough points. This paper shows a newly developed water control technology by using continuous Packed-off double water control technology (CPI). It was successfully implemented in a well of a fractured reef limestone oil field in South China Sea. This technology completely overcome the above shortcomings of traditional water control methods. The mechanism is to pack patent particles into the wellbore and near-wellbore fractures to create a double "artificial well wall". It suppresses radial and axial turbulence effectively. The operation procedure of CPI water control method is simple. It has been proven with lower cost and longer effective duration of controlling water, which can greatly increase oil recovery. Results show that the water content in the well of CPI water control is only 10% to 33% of the adjacent wells at the same geological layers. The initial oil water ratio in the CPI well is 13, which is ten times better than the adjacent wells. After 2 months' production, the water content of CPI well is 13.3%, compared to 67%, 62%, and 89% of the adjacent wells.