Affecting analysis of the rheological characteristic and reservoir damage of CO2 fracturing fluid in low permeability shale reservoir

Li, Qiang; Wang, Fuling; Forson, Kobina; Zhang, Jinyan; Zhang, Chenglin; Chen, Juan; Xu, Ning; Wang, Yanling

Affecting analysis of the rheological characteristic and reservoir damage of CO2 fracturing fluid in low permeability shale reservoir

2022

The fracturing property of liquid CO₂ fracturing fluid varies greatly due to the rheology of fracturing fluid during fracturing process. The main objective of this investigation is to study the rheology property of thickened liquid CO₂ by measuring the viscosity of thickened liquid CO₂ in different physical parameters of this prepared thickener and explain the causes of rheological changes. The results show that thickener content, branching content, and molecular weight of a thickener for all could significantly improve the rheology of liquid CO₂; the consistency coefficient K increased as they rose, but the rheological index n presented a decreased trend. Meanwhile, the mesh structure is proposed as a model to explain the rheological changes, and the large wetting angle means an excellent backflow, low reservoir damage, and low adsorption property. These results herein provide a basic reference to improve the CO₂ fracturing technology and molecular design of CO₂ thickener.

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