The irregular wellbore trajectory of openhole horizontal wells poses significant challenges to tool accessibility, especially for efficient and low-cost multistage stimulation. The authors share their experience with tool-free fishbone-like fracture acidizing stimulation and detailing the methodology and performance in unlocking the potential of a reservoir with reduced capital expenditure. The authors write that this strategy delivers the industry’s first tool-free fishbone fracture stimulation technology by sand jetting and acidizing in openhole wells, providing a technical solution for the low-permeability and complex lithology carbonate reservoirs in the Middle East.
Petrophysical Characteristics
The low-permeability carbonate reservoir is in central Iraq. Its first well was drilled in 1975, with 17 wells drilled before the current operator took over. Four layers of the carbonate reservoir were confirmed: Hartha, Sa’adi, Tanuma, and Khasib.
