Archaeal communities in water flooding oil reservoirs of China

In this study, oil reservoir samples were sampled total 50 water samples (10 injection wells and 40 production wells) before field test before June of 2010. These sampling sites XJLZ (T), XJQZ (Q), HBMGL (M), DQNE (N), DGYEZ (D), HBB19 (B), SLZ3 (Z) and LHA12 (A) blocks from Xinjiang, Huabei, Daqing, Dagang, Shengli and Liaohe oilfields. Meanwhile, 110 of injection and production water samples were also sampled in XJLZ (T), DQNE (N) and SLZ3 (Z) after field test. The conduct in situ with displacement recovery in XJLZ (T) was injecting nutrients (22 days) and gas (22 days) in turn from August of 2010, and the nutrients were composed of molasses 1.4%, NH4Cl 0.3%, NaNO3 0.7%, Na3PO4 0.12% and indigenous bacteria 2%. In DQNE (N), N2-2-P140 and N2-D3-P40 of production wells not only adopted displacement recovery, but also huff and puff in a single well. Another two production wells, N2-2-P141 and N2-D2-P40, were only conducted displacement recovery. N2-2-P139 was the control production well far away from the field area. SLZ3 (Z) block only was conducted huff and puff in Z3-26 and Z3-X24 of production wells, and the nutrient was reagent mixture with corn steep powder.