Optimal Design of Stimulation Measures in Low Permeability Carbonate Reservoirs: A Case Study in Iraq H Oilfield

During the development of Iraq H oilfield, a significant decline in oil production and short duration period of fracturing measure have brought great challenge, which is mainly due to the complex and super tight formation property. By means of laboratory experiment and numerical simulation, the rock mechanics properties were firstly studied in this paper. And then the fracture propagation, closure laws and influencing factors were further investigated. At last, guided by the integration of geology, engineering, and reservoir, differentiation stimulation methods for different levels of ‘sweet spot’ areas were researched. The experimental results indicated that fracturing the reservoir hydraulically is an effective way and complex fractures could be formed. The reservoir was divided into three types of ‘sweet spot’. The area where physical and engineering sweet spots are combined (Zone I) is suitable for small-scale multi-cluster fracturing, and slickwater can be considered to maximize net present value. The area where physical and non-engineering sweet spots are combined (Zone II) is suitable for medium scale fracturing, and it is recommended to use conventional gel fracturing methods. The area where non-physical and engineering sweet spots (Zone III) are combined is suitable for large-scale intensive cutting fracturing, and careful deployment is required to strictly control economic benefits. Through optimal design of a horizontal well in H oilfield, the productivity has been greatly improved. The idea of integrated geological and engineering study, and the result of differential design will be very helpful for developing other similar reservoirs in the Middle East.