Application of plugging-while-drilling technology in long open-hole interval of the Well Yueman-3-3

Yueman Block is a key development target in Tarim Oilfield in the past few years. Although the open-hole second spud-in interval is up to 5 500 m, and the well penetrates multiple layers, the safe density window is only 0.01~0.02 g/cm3. During drilling operation, lost circulation and stability of sidewalls are frequent problems. Using conventional polysulfonate drilling fluid, daily consumption of the drilling fluid may up to 100 m3, which significantly limits the application of polysulfonate drilling fluid in the area. To eliminate these problems, plugging-while-drilling agents, ultra-fine calcium carbonate, nanometer plugging agents and other plugging materials with desirable properties have been used in accordance with specific formation conditions in the Yueman Block. Assessment on HTHP filtration loss, HTHP water loss through filtration, HTHP sand-bed filtration, HTHP sand-bed water loss through filtration and core displacement capacities in both directions provides competent plugging formula suitable for specific geologic conditions in the Block. These drilling fluids have been deployed in combination with existing drilling fluid system in Well Yueman-3-3. Compared with adjacent wells, this well is suitable for the drilling fluid having a density higher by 0.02~0.04 g/cm3, but with no outstanding lost circulation. The innovative technology may provide satisfactory solution to filtration loss, sidewall instability and some other technical problems in the Yueman Block.