The technical problems during the development of unconventional oil and gas reservoirs are becoming more and more difficult to handle with conventional drilling and production methods. Supercritical carbon dioxide has so many good properties such as high rock-breaking drilling efficiency, strong dissolved displacement performance and unharmful effect on the reservoir that it can be used as a drilling, completion and production medium to effectively exploit the unconventional oil and gas reservoirs. The global distribution of unconventional oil and gas resources is introduced, application status of carbon dioxide in oil and gas development is discussed, and development prospects of supercritical carbon dioxide in the unconventional oil and gas reservoirs are systematically analyzed. Using supercritical carbon dioxide as a medium in the whole development process is an important trend of unconventional oil and gas development technologies.

The technical problems existing in deep well drilling are becoming more and more predominant during the exploration and development of oil-gas field. The poor formation drillability, low drilling rate and complicated pressure system cause the underground accidents frequent, extend well construction cycle, and make the cost of the project much higher. Therefore, it is urgent to develop new technologies to improve the efficiency of the exploration and development in deep unconventional oil-gas reservoir. The particle jet technology is a new energy-saving way which has a broad application prospect. It can take the way of sucking in particles in annulus space to cycle use the particles, and promote the drilling rate. The feasibility of particle jet as a drilling medium is verified by the theoretical and experimental study, which provides the basis for the design of particle jet tool.