Temporary Sealing of Fractured Reservoirs Using Scaling Agents

Loss of drilling fluid in fractured reservoirs impedes drilling operation and may cause great damage to reservoirs. A new technique has been developed for temporary scaling (sediment forming) sealing protection of fractured reservoirs that combines the advantages of chemical, bridge, and shield sealing methods. Laboratory results indicate that (1) the plugging effect of the scaling agent is excellent with an average scaling rate of 96.14%, (2) bridging fiber materials exhibit high capacity for absorption of the scaling products, which facilitates aggregation of scaling products, (3) the plugging zone can withstand up to 6 MPa pressure, and (4) the sealing product erosion rate is great, averaging 95.48%, which can reduce the damaging effect of plug removing agents on reservoirs.