Feasibility analysis on coiled tubing jet fracturing with supercritical CO2

Abstract

Hydraulic fracturing plays an important role in the development of unconventional oil and gas reservoirs but it also faces many challenges from the aspects of formation damage control and environment protection. Coiled tubing jet fracturing with supercritical CO 2 (SC-CO 2 ) will hopefully resolve challenges that such hydraulic fracturing is facing. In order to analyze the feasibility of coiled tubing jet fracturing with SC-CO 2 , the physical properties of SC-CO 2 fluid were used, the rock fracturing capability and pressure boosting effect of SC-CO 2 jets were analyzed and the reservoir stimulation effects of SC-CO 2 fluid were explained. The results demonstrated that SC-CO 2 jet fracturing operations can be carried out with lower pressure than water jet fracturing; the infiltration capability of SC-CO 2 is so strong that it can easily infiltrate into the micro-pores and micro-fractures in formation rocks and generate networks of interconnecting fractures; when SC-CO 2 is utilized as the fracturing fluid, formation damage, such as clay swelling and pore blocking, can be avoided and the reservoir stimulation effect can also be improved with its unique properties. Based on these results, the procedures and advantages of coiled tubing jet fracturing with SC-CO 2 were put forward in this paper. In conclusion, coiled tubing jet fracturing with SC-CO 2 combines the advantage of SC-CO 2 jet and coiled tubing fracturing, and is expected to become an efficient, safe and environmentally friendly stimulation method of developing unconventional oil and gas resources.

A waterless fracturing treatment: liquid nitrogen fracturing and its application prospect

“…Various fluids have been attempted by petroleum engineers in order to use little and even no water during fracturing [7,8]. With the advance of petroleum technique, a fracturing treatment with liquid nitrogen was successfully realized at the end of 20th century [9,10].…”