Research and Application of Liquid Carbon Dioxide Composite Fracturing in W Oilfield

In response to the problems of unsatisfactory measures and formation damage caused by blockage during the transformation of tight reservoirs in W oilfield using fracture network fracturing technology, on-site tests of liquid CO2 composite fracturing were conducted. The use of liquid CO2 to create branch fracture networks, increase energy efficiency, and hydraulic fracturing to create main fractures, improve the conductivity of the fracture network, and alternate slug injection of the two to achieve an increase in the transformation volume and effective utilization of tight oil. By utilizing the unique physicochemical properties of liquid CO2 and drawing on the ideas of W oilfield fracture network fracturing design, targeted improvements have been made in the fracturing fluid system, construction displacement, proppant, and other aspects, optimizing the scheme design. The experimental results were analyzed from phase changes, swept volume, and fracture stimulation effect, and the applicability of liquid CO2 composite fracturing in W oilfield was evaluated. After fracturing well A, initial daily oil increase reached 7.7 t, and final cumulative oil increase reached 2500 tons, achieving good stimulation effect and economic benefits. It provides a new idea for the effective production of tight reservoir in W oilfield, and has a certain reference value for the development of tight oil in onshore oilfield.