ABSTRACT
Tight oil is widely distributed around the world, and industrialized exploitation has been developed and applied in North America, greatly alleviating the contradiction between supply and demand of energy. The main storage space of tight oil reservoirs is micro-nano pores, and a reliable method for studying the occurrence of tight oil in micro-nano pores has not been studied. In this paper, the microscopic occurrence of tight oils in the Songliao Basin, Ordos Basin, and Tarim Basin in China are studied in combination with nuclear magnetic resonance (NMR) and field emission scanning electron microscopy (FE-SEM) scanning techniques. A method for characterizing the storage space, occurrence state, and influencing factors of tight oil based on SEM and NMR was proposed. The results show that the storage space of tight oil reservoirs is nanoscale cracks and pores. Mainly, these are distributed on the scale of less than 1 µm and more than 10 µm, the volume of porecracks is less than 1 µm, which account for more than 80% of the total volume. This indicates that the tight oil mainly exists in the nanoscale pore throat. The scattered distribution of crude oil in the black shape of oil spot is mainly in the micro-nano pores, and the crude oil content in the micro-cracks is small, indicating that nanoscale cracks are the main space for the occurrence of tight oil. However, some micro-cracks can penetrate oil spots or oil stains, and can connect the oil spots with scattered distribution, which will greatly improve the mobility of crude oil. In addition, oil spot accumulation areas often develop illite and illite/smectite mixed-layer, and clay minerals have developed nanoscale pores. The crude oil and clay minerals have certain associated characteristics. This study is of great significance for understanding the law of the occurrence and migration of tight oil and the basic theoretical research and technological innovation of the development of tight oil reservoir.
ABSTRACT
OBJECTIVE: To purify hVEGF_(121)/EGFP fusion protein using transfected BMSCs as culture media, in addition, to detect the function of hVEGF_(121)/EGFP fusion protein in vitro.METHODS: The pEGFP-N_2-hVEGF_(121) recombinant plasmid, which was constructed in the preliminary work of our study group,was used to extract the plasmid DNA. BMSCs were transfected with pEGFP-N2-hVEGF_(121) by positive ionic liposome transfection method. Under a fluorescent microscopy, the expression of hVEGF_(121)/EGFP fusion protein was detected. The hVEGF_(121)/EGFP fusion protein was purified with Am icon ultrafiltration centrifuge tube and the expression of fusion protein was detected by Western-Blotting method.RESULTS: The BMSCs, which transfected with pEGFP-N2-hVEGF_(121), was observed under the fluorescent microscope. Western blotting confirmed that pEGFP-N_2-hVEGF_(121) fusion protein expressed in the culture media of transfected BMCS. MTT results showed the number of human umbilical vein endothelial cells in the fusion protein team was significantly greater than that in the control group (P < 0.05), and Miles test confirmed that pEGFP-N_2-hVEGF_(121) fusion protein increased the permeability of the blood vessel wall.CONCLUSION: ①This study successfully confirmed the pEGFP-N_2-hVEGF_(121) recombinant plasmid, which carrying VEGF_(121)/EGFP fusion protein, can be expressed in BMSCs.②The VEGF_(121)/EGFP fusion protein have the function of wild-type VEGF in vitro.
