论文部分内容阅读
今后几十年,对高含硫天然气油田的开发会越来越多。例如,估计世界上剩余天然气储量的40%含有2%以上的CO2和/或100ppm(100mg/L)以上的H2S。因此,对开发这些油田进行技术研究极其重要。由于存在腐蚀性气体,因此需要特别注重固井材料(套管、水泥材料)的设计。文献已证实,含盐水的酸性气体对钢材具有腐蚀性,即使含量较低,湿CO2或湿H2S也会使水泥石发生腐蚀老化。对于胶结材料,已有大量文献阐述了在含CO2条件下水泥浆性能变坏的解决办法。但在关于含H2S条件下水泥浆材料老化机理方面的资料较少。本文介绍了不同H2S含量下油井水泥稳定性问题的解决办法。不同的时间周期可以确定油井寿命:生产期(约20~40年),报废后(永久性报废井的头几十年),报废期(几个世纪)。在每一时期,固井材料(主要是水泥浆、水泥塞)都要与不同流体相接触。因此,要正确地评价油井水泥的特性,必须完成水泥浆在这些不同时期内有代表性的地层流体中的老化试验。本文介绍了在高温高压条件下的含H2S流体中完成水泥材料老化试验的方法,并获得了水泥材料的试验结果。用不同技术研究了H2S使水泥材料发生老化的主要物理-化学机理,认为这取决于与胶结材料相接触的流体的性质,发生严重老化会造成水泥石宏观性质急剧恶化。
In the coming decades, more and more fields will be developed for high-sulfur natural gas fields. For example, it is estimated that 40% of the world’s remaining natural gas reserves contain more than 2% CO2 and / or H2S above 100ppm (100mg / L). Therefore, it is extremely important to conduct technical research on these fields. Due to the presence of corrosive gases, special attention needs to be given to the design of cementing materials (casing, cementitious materials). The literature has confirmed that salty acid gas is corrosive to steel, even if the content is low, wet CO2 or wet H2S will cause corrosion of cement stone aging. For cementitious materials, a large number of literature have been elaborated on the solution to the deterioration of grout performance under CO2 containing conditions. However, there is less information on the aging mechanism of cement slurry materials containing H2S. This article describes the solution to the problem of stability of oil well cement under different H2S contents. Different time intervals determine well life: production (about 20-40 years), after scrap (the first decades of a permanent scrap well), and end of life (a few centuries). In each period, the cementing material (mainly grout, cement plug) should be in contact with different fluids. Therefore, to correctly evaluate the properties of well cement, it is necessary to complete the aging test in the representative formation fluid of the cement slurry during these different periods. This paper introduces the method of aging test of cement material in H2S containing fluid under high temperature and high pressure, and obtains the test result of cement material. The main physical-chemical mechanism of H2S cement material aging has been studied by different technologies. It is considered that this depends on the properties of the fluid in contact with the cementitious material. Severe aging will lead to the sharp deterioration of the macroscopic properties of the cement stone.