Experimental Study on New Method for Pressurized Lost Circulation

Some fractured reservoirs might be penetrated during well drilling, resulting in lost circulation. If serious lost circulation occurs, complex conditions and accidents such as borehole collapse, pipe sticking and well blowout might occur, not only influencing the well drilling efficiency, but also causing great economic tosses. Therefore, it is essential to plug the fractured lost channel with pressurized lost circulation method. By using new method, namely adding the gangue (KZ) in the anti-high temperature sulphoantion drilling fluid, and raising in the activator processing fluid, the new drilling fluid system can be developed, which can improve the compressive strength of the formation. The experimental results have demonstrated that adding KZ can enhance the drilling fluid performance effectively, and improve the compressive strength of the formation, but also had proven feasibility of the activator can activates the KZ activeness. Regarding anti-high temperature sulphoantion drilling fluid, when the KZ is 30% and the activator is 30%, compressive strength of the formation achieves in a big way. This method can be very good to deal with the pressurized lost circulation of fractured reservoirs.