Optimization of Carbon Dioxide Foam Fracturing Technology for Shale Gas Reservoir

Abstract

Major shale gas exploration and development fields are located in the Sichuan basin. It requires huge water sources for shale gas fracking, but the well sites are mostly in the hills, which limits the industrialization of shale gas development. CO2 foam fluids can meet the requirements of fracking fluids and relieve water stress. It analyzed the feasibility of CO2 foaming fracturing for shale gas formation fracturing, proposed a design philosophy for CO2 foaming fracturing, and optimized fracturing parameters such as foam mass, proppant concentration, friction, and discharge rate. The flowchart of CO2 foam fracturing was established in, where the fracture morphology and propagation behavior of CO2 foam fracturing were obtained from numerical simulations comparable to the hydraulic fracture generated by conventional hydraulic fracturing. The CO2 foaming fracturing technique can provide a discharge rate of 6.0 m3/min and fluid volume and captures the volume effect of the current stimulated reservoir, which needs to be improved. It can be considered an initial survey of CO2 foam fracturing available in the Sichuan Basin shale formation, which may provide new methods and clues for stimulation.

Experimental and Numerical Simulation Research on Controllable Shock Wave-Induced Shale Fracturing under Repeated Action

“…This pressure can be either static or dynamic. , For instance, hydraulic fracturing, as a representative of static methods, applies high-pressure water flow to the reservoir to create large fractures along the maximum principal stress direction, − gathering oil and gas within a hundred-meter range . Hydraulic fracturing creates large and singular fractures, which can enhance the permeability of the reservoir, − yet it remains unfavorable for extensive permeation of gas. , Additionally, hydraulic fracturing is associated with long construction periods, high resource consumption, and environmental pollution. , For a long time, measures such as high-energy gas fracturing and deep hole presplitting blasting have been taken to increase reservoir permeability through dynamic shock wave methods, − which can promote the generation of more small fractures and are more conducive to the large-scale migration of reservoir fluids. However, these methods have been applied in fields such as coalbed methane extraction ,,, and uranium mine permeability enhancement, yet they involve intense shock fracturing, which can easily cause wellbore breakage and collapse and are difficult to implement repeatedly.…”

“… 37 , 38 Additionally, hydraulic fracturing is associated with long construction periods, high resource consumption, and environmental pollution. 39 , 40 For a long time, measures such as high-energy gas fracturing and deep hole presplitting blasting have been taken to increase reservoir permeability through dynamic shock wave methods, 41 − 43 which can promote the generation of more small fractures and are more conducive to the large-scale migration of reservoir fluids. However, these methods have been applied in fields such as coalbed methane extraction 17 , 44 , 17 , 44 and uranium mine permeability enhancement, 45 yet they involve intense shock fracturing, which can easily cause wellbore breakage and collapse 46 and are difficult to implement repeatedly.…”

Research and performance optimization of carbon dioxide foam fracturing fluid suitable for shale reservoir

“…The versatility and uniqueness of foam can be attributed to its significantly higher viscosity compared to its base fluids, and the efficiency of foam fracturing is determined by its complex non-Newtonian behavior (Arezoo et al, 1858;Ahmed et al, 2017a;Jing et al, 2017;Verma et al, 2018;Wang et al, 2018;Ahmed Abdelaal et al, 2021). Numerous authors agree that foam rheology highly influences the design and overall performance of fracturing treatments (Luo X. et al, 2014;Edrisi and Kam, 2014;Gu and Mohanty, 2015;Ahmed et al, 2017b;Fei et al, 2017;Li et al, 2017;Verma et al, 2017;Kartini et al, 2021;Cong et al, 2022;Li et al, 2022;Wang et al, 2022;Gao et al, 2023). Currently, foam fracturing technology has reached a relatively mature stage in terms of indoor research, design, construction, and effectiveness assessment.…”