Simulation Study on Penetrating Fracturing of Low Permeability Thin Interbedded Reservoir with Bottom Water in Bohai Oilfield

The low permeability thin interbed reservoir in Bohai Oilfield is characterized by the development of bottom water, serious sand-mud interbedding and poor lateral connectivity. The stimulation of thin interbed reservoir requires increasing the fracturing scale and conducting penetrating fracturing, but the development of bottom water requires reducing the fracturing scale and controlling the fracture height. The contradiction between the two has not been solved. In this paper, the effects of geological factors, construction factors and fracturing methods on fracture penetration are analyzed by establishing the thin interlayer fracturing model, and the research results are applied to in-situ fracturing design. And the boundary and rule of thin interlayer fractures are defined. The results show that when the reservoir thickness is greater than 5 m, the stress difference of the reservoir is greater than 3 MPa, which can completely block the propagation of the fracture through the mud layer. The upward extension of the fracture in formation thickness less than 1 m is very short, so it is not recommended to fracture the reservoir thickness is less than 1 m. For the fracture that can pass through the layer, only the thicker layer is perforated to increase the fracture length and prevent the fracture height from extending ineffectively in the mudstone layer to break through the bottom water. The results of this study have been applied to in-situ fracturing design, and the stimulation effect is remarkable, which achieves the purpose of accurately controlling the fracturing scale, ensuring the stimulation effect without communicating the water layer. The research conclusions can provide theoretical basis for hydraulic fracturing construction design of offshore thin interreservoir near bottom water, and have important guiding significance for efficient development of thin interreservoir in Bohai Oilfield.