A new bottom water shut-off method is proposed. It provides for automatic injection of the solution of paraffin in diesel fuel into excess water production zone as water cut increases. This results in the formation of a water barrier (or elimination of water breakthrough problems in the existing barrier) and thus reduction of water cut. This method involves providing wells with dual-channel wellhead assembly with two tubing strings run through it. One string is run down the hole to reach the aquifer interval; the other is placed in the oil-bearing zone and equipped with an ins ert pump and a beam unit. Oil and water zones are separated by a packer. Available water shut-off technologies, which imply injection of water shut-off materials directly into formation, do not provide sufficient efficiency in terms of duration of technological effect. As the formed water barrier is not large and water from the water-bearing zone flows quickly around it, water cut increases again. Creation of extended water barrier requires significant costs, so water shut-off treatments become uneconomic.
In summary, application of the proposed method will help increase water shut-off treatments efficiency, and in case of water production thorough the existing water barrier, water breakthrough pathways will be automatically ‘healed’ by injection of paraffin in diesel fuel in to the water production zone without shutting down the well for remedial operations.
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