华北油田京11区块弱碱复合驱结垢规律及防治技术研究

发布时间：2018-01-17 00:32

  本文关键词：华北油田京11区块弱碱复合驱结垢规律及防治技术研究　出处：《中国石油大学(华东)》2015年硕士论文　论文类型：学位论文

  更多相关文章： 结垢 预测 结垢机理 阻垢剂 阻垢机理 分子动力学模拟

【摘要】：油田注水开采过程中地层和设备结垢是开发过程中遇到的主要问题之一,而对于采用弱碱复合驱技术的华北油田京11区块这一问题尤为突出。本论文结合理论预测、静态实验以及计算机分子模拟方法针对京11区块的结垢问题及防治技术进行了系统研究。首先根据京11区块的水质分析结果,采用饱和指数法和稳定指数法预测了地层水和注入水的结垢趋势,结果表明两种水样都具有严重的碳酸钙垢结垢趋势,并且结垢趋势随着温度和碳酸钠含量的增加而增大,两种水样都没有硫酸钙垢结垢趋势。为了验证理论预测的正确性,明确结垢规律和结垢机理,本文采用静态结垢实验方法,研究了水样结垢规律及其影响因素。实验结果表明,温度升高、pH值增大、钙离子浓度增大、碳酸钠含量增加都会使水样结垢率增加,XRD分析结果表明垢的主要成分为碳酸钙,水样的结垢机理为温度等热力学参数变化引起溶液中盐类溶解度变化而结垢。在明确了所结垢为碳酸钙垢之后,针对碳酸钙垢进行了阻垢剂筛选评价研究。采用静态防垢实验,研究了聚天冬氨酸(PASP)、聚丙烯酸(PAA)、二乙烯三胺五甲叉膦酸(DTPMP)、羟基乙叉二膦酸(HEDP)四种阻垢剂在实际工况条件下的阻垢率。研究发现阻垢率:HEDPDTPMPPAAPASP。HEDP在浓度超过2mg/L之后阻垢率超过95%,当温度升高到90℃后,阻垢性能急剧下降,另外,钙离子和碳酸钠浓度增大都会使HEDP阻垢率降低,为了满足弱碱复合驱防垢要求,实验得出,HEDP阻垢剂在浓度超过20mg/L时阻垢率可以满足碳酸钠浓度20g/L时条件下的防垢要求。为了解释阻垢剂的阻垢机理,本论文采用分子动力学方法研究了阻垢剂分子与垢晶体表面的相互作用。计算了静态实验所用四种阻垢剂分子与碳酸钙晶体(104)面和(11_0)面的结合能、阻垢剂分子形变能以及阻垢剂分子中氧原子和碳酸钙表面钙离子的径向分布函数。研究发现结合能大小顺序为:HEDPDTPMPPAAPASP,与实验所得阻垢率大小顺序一致,说明相互作用越强,阻垢性能越好,并且四种阻垢剂的形变能都小于其对应结合能,因此阻垢剂分子会在垢表面的吸附作用下发生形变,紧密附着在垢表面,径向分布函数研究结果表明,HEDP和DTPMP阻垢机理为羟基氧原子与钙离子的螯合作用为主,PAA和PASP阻垢机理羰基氧原子与垢表面钙离子静电相互作用。
[Abstract]:Formation and equipment scaling is one of the main problems in oilfield water injection production. However, the problem of Jing11 block in Huabei Oilfield based on weak alkali composite flooding technology is particularly prominent. The static experiment and computer molecular simulation are used to study the scaling problem and prevention technology of Jing11 block systematically. Firstly, according to the water quality analysis results of Jing11 block. The saturation index method and stability index method are used to predict the scaling tendency of formation water and injected water. The results show that both water samples have serious scaling tendency of calcium carbonate. And the scaling trend increases with the increase of temperature and sodium carbonate content, the two kinds of water samples have no scaling trend. In order to verify the correctness of theoretical prediction, the scaling law and scaling mechanism are clear. In this paper, the scaling law of water sample and its influencing factors are studied by using static scaling experiment method. The results show that the pH value increases and the calcium ion concentration increases with the increase of temperature. The increase of sodium carbonate content will increase the scaling rate of water samples. XRD results show that the main component of scale is calcium carbonate. The scaling mechanism of the water sample is that the change of the solubility of salt in the solution caused by the change of thermodynamic parameters such as temperature. The selection and evaluation of scale inhibitor for calcium carbonate scale were studied. The static scale inhibition experiment was used to study the polyaspartic acid (PASPN) and polyacrylic acid (PAA). Diethylenetriamine pentamethylphosphonic acid (DTPMP). Hydroxy ethylenediphosphonic acid (HEDP). The scale inhibition rate of four kinds of scale inhibitors under actual operating conditions. It was found that the scale inhibition rate was over 95% after the concentration of 2 mg / L was more than 2 mg / L in the scale inhibition ratio: HEDPDTPMPPA ASP. Net HEDP. When the temperature rises to 90 鈩，

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