Water Control through Particle Huff and Puff for Horizontal Wells with Severe Fluid Loss in Fractured-Vuggy Carbonate Reservoirs

A horizontal well with severe fluid loss in a fractured-vuggy carbonate reservoir in the eastern part of the South China Sea faced challenges such as early water production and rapid water breakthrough. Owing to the bottom water communicated by the fractured-vuggy network, the traditional mechanical and chemical water control methods were unable to solve the water discharge problem in the wells in this reservoir. Therefore, a water control technology, i.e., particle huff and puff, was proposed. Taking advantage of the leakage of the fractured-vuggy network of the carbonate formation, a large number of low-density (1.05 g/cm³) particles with stable physicochemical properties, mainly resins, were“swallowed”, so as to improve the heterogeneity of the formation. After put into production, some of the particles in the network would be gradually “spit back” to the annulus of the wellbore and its adjacent wells, so as to mitigate the water channeling. The results of particle huff and puff simulation experiment demonstrated that particles can enter the experimental fracture when the flow rate is greater than 0.003 3 m/s and can “spit back” from the experimental fracture when the flow rate is greater than 0.009 0 m/s. The particle huff and puff condition is easily met in the field. The technology was applied to three new wells and one old well in a fractured-vuggy reservoir, and the water cut was reduced by 5−10 percentage points compared with the adjacent wells or the wells themselves before the measures. The cumulative oil increase for a single well was 3×10⁴ m³ to 8×10⁴ m³, indicating obvious water control and oil increase effects. The proposed particle huff and puff technology provides a new water control solution to the water discharge problem of horizontal wells with severe fluid loss in fractured-vuggy carbonate reservoirs.