Most main oilfields in China have already entered a "double high" development stage (high water cut, high recovery degree). To further enhance oil recovery in reservoirs after polymer flooding (RAPFs), an efficient activator formulation for promoting metabolism of endogenous microorganism was studied by aerogenic experiments, physical simulation experiments, electron microscopy scanning and pyrophosphate sequencing. Results show that the activator could activate the endogenous microorganisms in the injected water and make the pressurized gas reach 2 MPa after 60 d static culture of the activator in a high pressure vessel. The oil recovery efficiency of natural core physical simulation flooding can be improved by more than 3.0% (OOIP) in RAPFs when injected 0.35 PV activator with 1.8% mass concentration, and a lot of growth and reproduction of activated endogenous microorganism in the core was observed by electron microscopy scanning. Field trial with 1 injector and 4 producers was carried out in the east of south II block of Sa Nan in December 2011. By monitoring four effective production wells, changes of carbon isotope δ13C (PDB) content of methane and carbon dioxide were -45 per thousand to -54 per thousand and 7 per thousand to 12 per thousand. Compared with east II of Sa Nan block, the oil amount increased by 35.9%, water cut stabled at 94%. The incremental oil was 5 957 t during the three and a half years, which provides an alternative approach for further improving oil recovery in similar reservoirs.
Carbon Dioxide ; chemistry ; Carbon Isotopes ; analysis ; China ; Diphosphates ; chemistry ; Methane ; chemistry ; Oil and Gas Fields ; microbiology ; Polymers ; Water ; Water Microbiology

Objective To study the effect of vibration training with adjusted frequency on changes in explosive force of lower limbs, balance and muscle function around ankle joints of patients with functional ankle instability (FAI), so as to provide an empirical basis for rehabilitation training of FAI patients in clinic. Methods Twenty-six FAI patients were randomly divided into the experimental group (n=14) and the control group (n=12). The experimental group received 8-week rehabilitation training with vibration intervention, while the control group only received 8-week rehabilitation training. Changes in maximum power, average power, maximum speed and average speed of the injured limb during vertical jump with single leg, changes in distances during long jump, changes in time during one-leg standing with eyes open and closed，changes in contract time (tc), relax time (tr) and displacement (Dm) of medial gastrocnemius (GM), lateral gastrocnemius (GL) and tibialis anterior (TA) muscles before and after training were measured and compared. Results In the experimental group, the maximum power and maximum speed of the injured limb during vertical jump with single leg, the distance during long jump with single leg and the time during one-leg standing with open and closed eyes were significantly improved, and the increase was higher than that of the control group. The increase of tc of all muscles in the experimental group was smaller than that of the control group, but tr and Dm did not show any regularity. Conclusions Vibration training with adjusted frequency can effectively improve the explosive force and balance ability of lower limbs of FAI patients, and promote the tc shortening of GL, GM and TA muscles, but whether vibration training with adjusted frequency can reduce muscle tension and promote muscle relaxation is still not clear.