CO_2 fracturing technique applied in Xingnan test area

Compared with conventional fracturing technique,CO2 fracturing technique has several advantages including low filtration,high flowback,small damage in reservoir,increasing production with a great degree and longer effective period.The technique has unique increasing-production mechanism when CO2 is acted as medium to develop fracture,which makes CO2 fast gasify,dissolve in crude oil,largely decline oil viscosity and increase capacity of solution gas drive.In addition,geologic condition,fracturing selected well principles and procedure for fracturing operation are described in this paper.Its application effects show that,this technique is not only adapted to thick oil layer and repeated fracturing for oil wells but also achieves better results for out-surface reservoir and thin and poor layers with the effective thickness of less than 0.5m.Lowest increasing oil model in effective period is used to calculate profits by using this technique,showing that more than RMB $5.8×104-13.8 ×104 are obtained.CO2 fracturing technique is a better increasing production and reworked measures in low pressure and low permeable reservoirs.It enlarges the area for fracturing selected wells and layers and improves fracturing effects and has wide future in Xingnan development area.