| In production of crude oil with high paraffin content, paraffin deposit in pit shaft brings great difficulty to regular production of an oilfield. It could cause stuck pump、 stuck pumping rod、stuck pipeline and so drilling troubles, which gives rise to production halt. In these cases, they not only cause underproduction, but increase spending of borehole operation and waste energy. When a small number of paraffin enters into crude collecting line, it deposits in heavy traffic and hypothermal tubulation, and plugs gas transmission pipeline, eg:elbow、lowly areas、hot spots and so on. Therefore, source work of paraffin removing and inhibition need to be done in order to prevent these problems.To Solve the wellbore paraffin deposit problem, the most common and widely way is to use paraffin knife and inject hot-water or vapor, thus ensure regular production of oil-well with high paraffin content. Using paraffin knife and injecting hot-water or vapor are complicated and lead to long-playing production halt, which affects regular production and bring about definite economic loss. Using paraffin remover and inhibitor is a simple、practical and economical measure. Meanwhile, paraffin remover and inhibitor could be put in oil-well with intermittent mode or continuity method in line with the spot situation.At present, there are a variety of paraffin removers and inhibitors, but their effect and cost are different. CX series of paraffin removers and inhibitors are the main paraffin removers and inhibitors in Heshui oil region of Changqing Oil field. The solution rate and removal rate of CX series are quicker, and they have definite inhibiting effect. Their versatility makes them extremely useful for oil-well with high paraffin content and solving the wellbore paraffin deposit problem, so they have oilfield application value.In this paper, according to special cases of HeShui oil region, combining with the mechanism of paraffin plugging damage in HeShui oil region, the adaptation study of CX series of paraffin removers and inhibitors was carried out basing fully understanding and absorbing domestic and foreign removal technologies of paraffin removers which are in widespread using. The composition of paraffin samples which include carbon number distribution and contents of asphaltene and colloid were researched by using chemical analytical method and gas chromatography analysis method. The solubility and removal adaptability effect of CX series of paraffin removers and inhibitors was evaluated by using static solving paraffin method and static removing paraffin method. Meanwhile, high-efficiency paraffin remover was produced. The main content of this article is as follows:(1) Composition analysis and carbon number distribution of typical paraffin sample from Heshui oil regionThe composition analysis of paraffin sample was evaluated according to the standard RIPP7-9. The results are as follows:The paraffin quantity of most paraffin samples is higher, their paraffin quantity is close to or more than50%; The paraffin quantity of few paraffin samples is lower, they could be pure fuel samples or pure scale samples, or their moisture contents are higher. Therefore, in different production conditions, the composition and quality of paraffin samples from the same oilfield are different. In the production of oilfield with higher paraffin content, the corresponding paraffin removing and inhibition measures and work are needed to do in order to ensure the normal production of oilfield.The carbon number distribution of paraffin sample was studied according to the standard SH/T0653-1998. The results are as follows:The carbon number distribution of most paraffin samples is that paraffin content with low carbon number is lower, their carbon number are mainly concentrated at these three ranges:C26-C30、C31-C35、C36-C40, there are obvious peaks in the middle of chromatogram map; the carbon number of few paraffin samples are mainly concentrated after C36,and obvious peaks appear in the rear of chromatogram map. On the whole, the content of paraffin samples with low carbon number is lower, different paraffin samples have different carbon number distributions. So, in paraffin removaling scene, according to different paraffin samples, different paraffin removers are selected to achieve the best effect.(2) The solubility and removal adaptability evaluation of CX series of paraffin removers and inhibitors to paraffin samples from Heshui oil regionThe solubility and removal adaptability effect of CX series of paraffin removers and inhibitors was evaluated according to the standard SY/T6300-97(Solving paraffin test) and Static removing paraffin method. The results are as follows:①The solubility effects of the same paraffin remover are different to different paraffin samples. There is not obvious corresponding relationship between paraffin content and solubility effect; ②The removal effects of the same paraffin remover are different to different paraffin samples. There is not obvious corresponding relationship between paraffin content and removal effect;③In ordinary Circumstances, the solubility and removal adaptability effect of the same paraffin remover are complementary. For the experimental paraffin samples, the solubility and removal adaptability effects of CX-1and CX-2are better than CX-3, so they are more appropriate for paraffin samples from Heshui oil region.The inhibited adaptability effect of CX series of paraffin removers and inhibitors was evaluated according to the standard SY/T6300-97(Inhibiting paraffin test). The results are as follows:the inhibited adaptability effect of CX-3is better than CX-1and CX-2, and it has simultaneously removal effect and inhibiting effect. Thus, in paraffin removaling scene, according to different paraffin samples, different paraffin inhibitors and paraffin removers are selected to inhibit paraffin and remove paraffin.(3) The development of high-efficiency paraffin removerThrough a mass of solving paraffin and removing paraffin experiments, an oil-base and high-efficiency paraffin remover CQL-1has been developed. Its composition is RA+3%HA. For paraffin samples from Heshui oil region, the solution rate and removal rate of paraffin remover CQL-1that has been developed on the whole are more quickly than CX-1、CX-2and CX-3. The cost of CQL-1is8500Y/t, however, the cost of CX-1is9150Y/t, the cost of CX-2is7970Y/t, the cost of CX-3is12050Y/t, CQL-1has definite price advantage.The composition of emulsion paraffin remover CQL-2that has been developed is36%RA+24%kerosene+40%water+1.00%HF+0.50%HK+1.00%n-pentanol. The solubility and removal effects of paraffin remover CQL-2on the whole are better than CX-3, but less than CX-1and CX-2. The cost of CQL-2is just3725Y/t, by contrast, has a higher price. Meanwhile, CQL-2is oil-in-water paraffin remover, and has a higher safety factor that brings transportation convenience. Therefore, it also has a good application prospect. |
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