Water cut and sand control techniques applied in high water cut stage of unconsolidated sand reservoir

With many years of water flooding development in unconsolidated sand reservoirs, water cut in oil wells increased dramatically, resulting in highly increasing of sand production, pipe string corrosion, oil lifting and separation expenses. Therefore, water cut control has become a key technique for high water cut stage in unconsolidated sand reservoirs. Development affecting factors during high water cut stage in unconsolidated sand reservoirs and major hazard of high water cut oil wells were analyzed in this paper. Based on the mechanism analyzing of water cut control and sand control, a new sand material has been developed which can be used both for water cut control and sand control, and indoor experimental evaluation was set in term of water/oil resistance ratio, contact angle and conductivity. The evaluation result shows that the highest water/oil resistance ratio could reach at 5.3, contact angle at 152°, and keeping high conductivity at the same time. The application test in 4 wells in site showed that water cut could be averagely reduced 15.5%, achieved favorable results in water cut and sand control. The water cut and sand control techniques set well foundation for developing high water cut unconsolidated sand reservoirs effectively and economically, and will become an importantly popularized and applied technique in developing high water cut reservoirs.