Fracturing with carbon dioxide: Application status and development trend

Stimulation principles, construction techniques, equipment requirements and technical features of liquid carbon dioxide fracturing were summarized, and the existing problems and development trend of this technology were discussed. Compared with the conventional hydraulic fracturing technology, it has several advantages including high flowback, small damage in reservoir, outstanding stimulation effect and so on. There are five main problems existing in this technology: friction of liquid carbon dioxide is very high; liquid carbon dioxide has an extremely low viscosity, poor proppant carrying ability and a large amount of fluid loss, thus behaves poorly in fracturing; the phase behavior of carbon dioxide is very complex in the process of fracturing, it is hard to realize accurate prediction and control for phase transition of carbon dioxide; fracturing equipments, especially blenders have obvious defects and should be improved further; computational methods for operation parameters in liquid carbon dioxide fracturing is still lacking. Supercritical carbon dioxide fracturing technology succeeds almost all the advantages of traditional liquid carbon dioxide fracturing technology, and has a better stimulation effect, smaller pump pressure and fewer requirements for blenders, thus is the trend in carbon dioxide fracturing.