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旅大10-1油田含聚采出水腐蚀与结垢行为研究
【作者】 袁瑞瑞；
【作者基本信息】 西南石油大学 ， 应用化学， 2011， 硕士
【摘要】 渤海旅大10-1油田采用注水开采方式,开采过程中产生的污水与水源井水混合处理后回注进入储层。采出水具有较高的矿化度,主要含有Ca2+、Mg2+、HCO32-、CO32-等成垢无机离子,同时还含有H2S、CO2、O2等溶解性气体。因此采出水会对污水处理流程中各种管线设备造成一定的腐蚀和结垢,影响正常生产和回注效果。同时,注聚开采使得采出水中含有一定量的残余聚合物,地面处理工艺流程中也会加入一些化学药剂,这些有机物相互作用及其与腐蚀结垢产物之间的作用都会影响水质,进而影响油田的正常生产。本文结合LD10-1现场水处理工艺状况,对油田采出水水质和腐蚀的影响因素进行分析,研究了聚合物(HPAM)对油田采出水腐蚀和结垢的影响规律,分别探究了合成的油酰胺咪唑啉缓蚀剂和现场用阻垢剂的缓蚀和阻垢机理。取得的主要研究成果如下：(1)分析了温度、H2S含量、C02分压、微生物、02、聚合物浓度和分子量等各种因素对采出水腐蚀及结垢的影响。结果发现,在旅大10-1水处理流程中,聚合物的存在对腐蚀和结垢存在一定的影响。(2)通过模拟油田采出水腐蚀和结垢状况,分别采用失重法、电化学方法、碳酸钙沉积法和软硬垢测试研究了产出聚合物分子量和浓度对采出水腐蚀和结垢的影响规律。结果发现,HPAM对金属的腐蚀起到混合抑制缓蚀的作用,并在阻抗图中出现了明显的Warburg阻抗特征；此外,聚合物的加入使得总垢和硬垢生成量明显减少,同时溶液中游离钙离子浓度总体呈增加趋势。(3)针对油田防腐实际需要,采用溶剂法合成了油酰胺咪唑啉型缓蚀剂,并对其进行改性和复配,研发出一种适用于油田含聚采出水的水溶性油酰胺咪唑啉季铵盐缓蚀剂。采用失重法、电化学方法等评价了该缓蚀剂及其复配物的缓蚀性能,并将其与现场缓蚀剂BHH-08进行对比,结果发现,三者在相同加药浓度下,复配缓蚀剂的缓蚀效果最好。(4)通过电化学测试和对腐蚀产物膜的结构成分及形貌分析,提出了咪唑啉类缓蚀剂在含聚污水中的缓蚀机理：吸附机理和成膜机理。证实了该咪唑啉类缓蚀剂属于混合吸附成膜型缓蚀剂,与采出水中聚合物产生一定的协同作用,减缓了金属设备的腐蚀。(5)针对油田结垢问题,运用碳酸钙沉积法研究了聚合物与现场阻垢剂的协同作用规律。并通过电化学石英微晶天平测试技术、水体中软垢和硬垢的电镜扫描、能谱和X射线衍射分析,进一步研究了聚合物与阻垢剂之间的协同作用机理。HPAM和阻垢剂BHF-04分别通过螫合增溶、晶格畸变以及静电斥力作用抑制了钙垢的生成。
【Abstract】 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.