Rheological properties and friction resistance properties of CO2-emulsified viscoelastic surfactant fracturing fluid were investigated on the large-scale test loop of foam fracturing fluid. When the velocity is below 2.8 m·s-1, the friction pressure drop gradient gradually decreases with the increase of foam quality, however, when the velocity is above 2.8 m·s-1, the friction pressure drop gradient of VES-CO2with higher foam quality is higher than lower foam quality. In addition, frictional pressure drop gradient of the pure CO2is higher than the VES-CO2fracturing fluid system when the velocity is more than 1.6 m·s-1. And frictional resistance coefficient decreases with the increase of foam quality and increases slightly with the increase of temperature. Experimental correlation between frictional resistance coefficient and Reynolds number is obtained and has high precision.

Rheological properties of slick water mixed with CO2 system are studied,through the large foam fracturing fluid of high temperature and high pressure experiment system,in detail in this paper, based on the principle of tube type rheometer. The influence laws temperature, foam quality, shear rate and pressure have on the rheological characteristics are studied. The fracturing fluid rheological parameters calculation correlations are also obtained, and the foam quality influence on rheological index and rheological coefficient of the slick water mixed with CO2 system are analyzed.

Supersonic swirling separator has been developed for natural gas dehydration in recent years. Compared to Twister-I supersonic swirling separator, Twister-II type overcomes the disadvantage of uncontrolled shock and the steady swirling flow field contributes to high efficiency of gas-liquid separation. The design method is discussed. For the Laval nozzle, the contraction section is designed by double cubic curve method, while the method for expansion section is tapered tube method the same as the divergent tube, throat is smooth circular arc; the length of straight swirling pipe section for separation is 3-8 times of the diameter. The paper simulates the applicability of the supersonic swirling separator by Fluent. Studies have shown that the lower environmental temperature, the lower the outlet temperature, the easier water to cool, and the higher the separation efficiency. If the volume flow rate rises, the inlet velocity and the mass flow rate can be effectively improved. We can control the shock location by adjusting the pressure at the outlet of divergent pipe. The shock appears at the inlet in the working condition designed. When the outlet pressure is lower, the shock occurs in divergent tube; on the opposite, it moves forward. Beyond a certain degree, shock occurs at the Laval nozzle, the device fails to work.

Foam has been used for several decades to decrease the mobility of drive gas or steam, thereby increasing the reservoir sweep efficiency and enhancing the oil recovery. The optimization of the operations requires a thorough understanding of the physical aspects involved in foam flow through porous media. The present paper aims mainly at reviewing experimental and modeling studies on foam flow in porous media particularly during the last decade, to stress the new achievements and highlight the areas that are less understood. X-ray computed tomography (CT) is a useful tool to study in-situ foam behaviors in porous media and new findings were obtained through this technology. The population-balance model was improved in different forms by researchers.

Faced with two problems of energy shortage and environmental pollution, people focus on the development of renewable energy resources. Geothermal energy is the most realistic and competitive one among the renewable energy resources. Besides its reserves is abundant. Geothermal energy is widely used in many fields. Geothermal power generation technologies are introduced and whether dry stream power generation method, ORC or KC method is elected depends on the temperature of geothermal water. Geothermal heating is the simplest, most economic and most effective utilization of low temperature geothermal energy. There are also various applications in industry for geothermal energy. Geothermal water is more and more popular in health care. In addition, geothermal energy is used in planting and breeding. Cascade utilization is the most promising way for geothermal energy because the energy efficiency is the highest. Two comprehensive utilization projects are discussed in this paper. Then ground source heat pump is introduced.