Development And Experimental Investigation Of Freezing Core Sample Of Gas Hydrates-FCS-108

With gradually decreasing of oil and gas resource, its price is keeping on high level; human being has met with enormous energy problem. Because of large population, oil and gas resource depletion and the rapid development of economic, energy shortage has become a very serious problem in China. Thus, developing the new energy become more and more urgent to satisfy the need of economic development, and achieve economic and society sustainable development for China. The gas hydrate that is a kind of new energy has been a exploiting forcus for the more and more country in the past 20 years.It is estimated that the carbon volume of gas hydrates is double to the volumes of carbon in coal, oil and natural gas of the globe. So the gas hydrate has become a key factor in energy balanced development for the entire globe.The gas hydrate is regarded as the important substituting energy by the scientist in the all countries in the coming century.Exploiting gas hydrate is based on evaluate gas hydrate, and sample drilling is the most directly method to evaluate gas hydrates. The physics condition of Gas hydrates forming is 0～10℃of temperature and more tham 10MPa of pressure, It is very strict for sample drilling. At present, the pressure-tight core barrel is the main truth-preserving core sampling, and its operating principle is that maintaining pressure inhibits the gas hydrates dissociating by mechanical operating mechanism. It demands high intensity for core barrel, especially, the higher intensity and tightness for ball valve.If the tightness of ball valve has a small drop; the core will not preserve its primitive pressure, and lead to sample failure. When the design pressure of sampling device arrives at a high value, it is very difficult to raise the tight pressure for designing core barrel, and it must greatly improve the leak tightness and intensity of material..In order to inspect the function of the sample tool, the freezing sample experiment is done, and the freezing loess sample is achieved. According to the conclusion of above indoor simulate freezing experiment, the dry ice is used as coolant, the alcohol as positive freezing catalyst and cooling medium, design the prototype of gas hydrates freezing sample tool. The tool is making up of single action mechanism, control mechanism and freezing mechanism. Single action mechanism can make the inner and outer pipe assembly independent rotary to avoid disturbancing core.First of all, Development of freezing core sample of gas hydrates—FCS-108. the dry ice is used as coolant, the alcohol as positive freezing catalyst and cooling medium, design the prototype of gas hydrates freezing sample tool. The tool is making up of single-action agencies, control bodies, frozen bodies, institutions pressure the composition of the five institutions.Second, Experimental investigation of freezing core sample of gas hydrates—FCS-108. through the 200 meters experiment proves that the sample tool holds same reliable in the process of drilling. It is easy to freeze core sample in the bottom of hole, and a real freezing loess core is achieved.Finally, Security test and simulation analysis of the freezing core sample of gas hydrates—FCS-108 insulation effect . By changing the freezing core sample of gas hydrates—FCS-108 refrigeration and insulation methods .and further improve the cold source insulation effect .and comparative analysis of test results and simulation results .Insulation effect is good by zhe test results and simulation resultsconsistentent.The research puts forward the idea of freezing method for sampling gas hydrates, and a prototype of gas hydrate freezing sample tool was developed. The truth-presering core sampling is very difficulty due to the special feature of gas hydrates existing. In the future, there are so many futher researches to be done.