Subdivision Cutting Fracturing Technology for Horizontal Shale Oil Wells in the Longdong Area of the Changqing Oilfield

The shale oil reservoirs in the Longdong area of the Changqing Oilfield are characterized by low brittleness index and undeveloped natural fractures. In this case, complex fracture networks are difficult to form. During multi-stage and multi-cluster volumetric fracturing, uniform reservoir stimulation is hard to achieve due to various effects of reservoir properties, in-situ stresses, anisotropy and inter-cluster interference of hydraulic fractures, and uneven fluid inflow within the clusters. According to the principle of maximizing fracture-controlled reserves, reservoir quality was evaluated and graded for the shale oil horizontal sections, and a heterogeneous geological model was built. On this basis, the layout of single-stage and single-cluster fractures by subdivision cutting fracturing was designed according to the spatial distribution of sweet spots and the comprehensive sweet spot index, and the fracturing parameters were optimized accordingly. As a result, a subdivision cutting fracturing technology for horizontal shale oil wells was developed. Field tests were conducted in 10 horizontal shale oil wells in the Longdong area of the Changqing Oilfield with good stimulation effect, where the daily oil production of the test wells was 35.9% higher than that of adjacent wells. With its successful application, this technology provides a new idea for the stimulation of the similar shale oil reservoirs.