| The exploitation mainly depends on injection with water in Bohai LD10-1 oilfield, produced water and well water after mixing treatment ought to be re-injected into the formation. Produced water doesn't only have high salinity, mainly containing some inorganic scaling ions, such as Ca2+,Mg2+,HCO32-,CO32-,but also' contains some dissolved gases, such as H2S,CO2,O2,and so on. Therefore, produced water would lead all kinds of pipes and equipments to a certain amount of corrosion and scaling in the sewage treatment process, and affect the normal production and re-injection. Meanwhile, a certain amount of residual polymer exists in the wastewater as a result of the injection with polymer, and some organic pharmacies would be added to the wastewater in the process of wastewater treatment. These organisms perhaps produce interaction, which perhaps bring about complex physical and chemical reactions with the products of corrosion and scaling. It has impacted water quality and seriously influenced the normal production of oil field. This article analyzed the quality of produced water and impact factors of corrosion in LD10-1 oil field through going over water treatment conditions on-site. Polymer (HPAM) on the impact of corrosion and scaling law were respectively investigated. At the same time, the inhibition mechanisms of oil amide imidazoline and scale inhibitor on-site were studied. The detailed research results are shown as follows:(1)Temperature, the amount of H2S and O2, partial pressure of CO2, bacteria, and other factors on the impact of corrosion and scaling law were analyzed. In the process of Luda 10-1 water treatment, Polymer had impact on corrosion and scaling for produced water.(2)The corrosion and scaling actuality of the wastewater with polymer was surveyed using the methods of weight loss, electrochemical corrosion, calcium carbonate deposition and hard scale test, effects of polymer molecular mass and concentration on corrosion and scaling were focused on. The results showed that HPAM played a role of mixed inhibiting corrosion, and significant Warburg impedance characteristics appeared in the impedance. What is more, the addition of polymer made the amount of the total scale and hard scale reduced significantly, while the concentration of free calcium ions in solution tended to increase.(3)Aiming at actual anticorrosion need of the oil field, this kind of corrosion inhibitor named oil amide imidazoline was synthesized by the method of solvent-dewatering. Besides, by means of modification and complexion we have developed a efficient imidazoline quaternary ammonium corrosion inhibitor which had good water-solubility. The corrosion inhibition effects of the corrosion inhibitor and its complexion were evaluated by way of weight loss and electrochemical corrosion, compared with the corrosion inhibitor on-site. In the same concentration, corrosion inhibitor after complexion had the best anti-corrosion role.(4)According to the electrochemical experiments and the structure and morphology analysis of corrosion products, the corrosion mechanisms were adsorption mechanism and formation mechanism. The fact that imidazoline inhibitor is the type of mixed adsorption and formation was confirmed, and it would produce collaborating effect with polymer in produced water, slowing down the corrosion of metal equipments.(5)Applying the scaling problem in oilfield, the method of calcium carbonate deposition was used to test the synergetic inhibition law between polymer and scale inhibitor on-site. The synergetic inhibition mechanism were proposed between polymer and scale inhibitor, according to electrochemical quartz crystal microbalance technique and the analysis of scanning electron microscopy, energy dispersive and X-ray diffraction for the debris and hard scale in water. HPAM and the scale inhibitor BHF-04 inhibit the formation of calcium scale through chelating, lattice distortion and electrostatic repulsion. |
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