Technology Research On Polymer Flooding About High Temperature And High Sanity Reservoir

Polymer flooding is an effective method to enhance oil recovery. Results from experiment and pilot test show that polymer flooding can enhance oil recovery to10% after water flooding. At present, domestic polymer flooding technology is mainly used in low temperature and low sanity reservoir, while the technology for high temperature and high sanity reservoir is very little. Therefore, in order to popularize the application of polymer flooding technology and exploit the remaining oil, it is very important to research the polymer flooding technology for the high temperature and high sanity reservoir, which can contribute a lot to relieve the current oil supply and demand antinomy. As some blocks of Jiangsu oilfield have disadvantages such as low reserves, serious heterogeneities, high temperature and high salinity, the adaptability of polymer flooding technology in these blocks needs to be judged by some experiments. Aiming at the practical needs of the high temperature and high sanity reservoir exploitation, according to the geological characteristic and fluid characteristic of the high temperature and high sanity reservoir, and using of modern physical simulation method, the author has evaluated the oil increasing effect of polymer flooding in "Zhen 15 block" of Jiangsu oilfield. Under 70℃, six kinds of polymer which were screened out at first were evaluated on their viscosity characteristic, static adsorption, resorting characteristic, rheology and viscoelastic indicators. The results show that the Daqing anti-salt's performance is superior to other polymers, and further evaluation from experiments verifies that the Daqing aunti-salt has better transmission capacity and has better gluing effect with Cr3+ cross-linker. Flooding experiments with the Daqing auti-salt and its polymer gel show that polymer dosage, concentration, slug composition, injection time, and heterogeneity condition of the reservoir all influence the oil increasing effect a lot. For those reservoirs with serious heterogeneities, when the cost of chemicals is close, the slug composition of"profile modification+ polymer flooding"or"polymer flooding + profile modification +polymer flooding increases oil better than pure polymer flooding.