Application of Liquid CO2 Fracturing in Tight Oil Reservoir

Wang, Feng (PetroChina Jilin Oilfield Company) | Wang, Yucai (PetroChina Jilin Oilfield Company) | Zhu, Yongzhi (Oil and Gas Engineering Research Institute, PetroChina Jilin Oilfield Company) | Duan, Yongwei (Oil and Gas Engineering Research Institute, PetroChina Jilin Oilfield Company) | Chen, Shi (Oil and Gas Engineering Research Institute, PetroChina Jilin Oilfield Company) | Wang, Cuicui (Oil and Gas Engineering Research Institute, PetroChina Jilin Oilfield Company) | Zhao, Wei (Oil and Gas Engineering Research Institute, PetroChina Jilin Oilfield Company)

OnePetro 

Abstract

The low control reserve of a single well and the difficult on energy supplement in the reservoir are two key problems in tight oil reservoir development. It is testified that non-liquid CO2 fracturing not only efficiently increases the reservoir energy but also intensifies the reservoir transformation through the field test in Jinlin oil field.

The transformation volume of non-liquid CO2 fracturing is confirmed, through micro-seismic data monitor in the borehole during fracturing, that it is 2.5 times of that of normal hydraulic fracturing with the same liquid volume usage, which can remarkably increase the complexity of the fracture. Through the laboratory experiments and the oil sampling analysis after fracturing, CO2 is verified that it can reduce the oil viscosity efficiently, therefore, it can make oil miscible and enhance the flooding efficiency by non-liquid fracturing implementation. The results of reservoir static pressure test after fracturing prove that reservoir pressure remarkably increases compared with that before fracturing and has the effects of advanced energy storage.

Five tight oil wells fracturing have been successful in Jilin oil field until now. Oil production after fracturing increases obviously compared with that before fracturing. The average oil production increase per well is 2.31 ton. According to the research, the stimulation effects of non-liquid CO2 fracturing are seriously underestimated and there is wide prospect in the application of the technique during the tight oil reservoir development.