Research and application of water free sand fracturing technology based on carbon dioxide characteristics

Jilin oilfield has great potential of tight oil resources and the reservoir physical property is poor. The conventional hydraulic fracturing technology was easy to cause reservoir pollution, and delayed the energy supplement, so the oil well production declined rapidly. Carbon dioxide water free fracturing technology has the advantages of increasing formation energy, reducing reservoir damage and mixing crude oil. Based on the study of viscosity, sand carrying capacity and filtration characteristics of liquid carbon dioxide fracturing fluid system, sand adding test of carbon dioxide anhydrous fracturing technology is carried out in this paper. Through optimizing thickener type II fracturing fluid to enhance the viscosity of carbon dioxide, adopting the sand adding method combining slug with continuous sand adding, optimizing the proportion of pre-fluid, perfecting the sand adding process, and increasing the sand adding scale, the viscosity of fracturing fluid system is increased by 15-45 times, and the effect is obviously better than that of thickener type I. By using carbon dioxide water free sand fracturing technology, the daily oil production of 10 wells is more than twice of the conventional heavy pressure, and the water resources of a single well can be saved by 1 512 m³.