Prediction of asphaltene precipitation by the extended Flory–Huggins model using the modified Esmaeilzadeh–Roshanfekr equation of state

Asphaltene precipitation is caused by a number of factors, such as the variation of pressure and temperature, the change in composition and the mixing of oil with diluting solvents. The deposition of asphaltene precipitation is one of the main problems with the oil industries, appearing in the well bore, the well tubing and the refining processes. This causes an increase in the operating costs and imposes the costs of cleaning and washing well tubing as well. Therefore, it would be economically beneficial to know under what conditions and to what amount the asphaltene precipitates.In this paper, a model is presented based on the Flory–Huggins theory of polymeric solutions. Because the interaction parameter term plays a key role in the asphaltene precipitation, a correlation is proposed to account for the effect of the solvent ratio in addition to molecular weight. Several adjustable parameters in terms of the interaction parameter are determined in this work using a series of experimental precipitation data from a crude oil sample of a field located in the southwest of Iran (oil sample 1), and applying a robust optimization method (the differential evolution). Regarding the influence of the solubility parameter on the accuracy of the final results, a comparison is made between the m-ER, PR and the SRK EOSs. Finally, the obtained results from the comparison between the asphaltene precipitation amounts of various solvents and the existing experimental values for another group of data from oil sample 1, and two other oil samples verify the accuracy of the presented model.     

轻烃分析技术在海拉尔盆地储集层含水性评价中的应用

海拉尔盆地地质情况复杂、油水层解释难度大,特别是储集层是否含水难于判断。针对这一情况,从罐顶气轻烃分析角度,在分别探讨芳烃、环烷烃、烷烃的物理性质与储集层含水性关系的基础上,阐述了优选含水性评价参数的依据,通过该盆地40多口评价井储集层轻烃参数的统计分析,建立了芳烃百分含量与异构烷烃/环烷烃峰面积比值的解释评价图板。该图板在海拉尔盆地37口井的应用中取得了较好效果,总体解释符合率达到85%以上,有效地解决了该盆地油水层解释评价难的问题。     

塔河油田底水砂岩油藏水平井堵水提高采收率技术

塔河油田三叠系油藏为中孔、中—高渗底水块状断背斜型砂岩油藏,水油体积比达到100倍以上,底水能量充足。油田主要以水平井开发,由于受油藏非均质性影响,水平井在开发中表现为底水沿高渗段点状锥进水淹,导致大量剩余油无法采出。在水平段非均质特性和出水规律研究基础上,提出了提高采收率的技术思路：多次堵水,使油水界面均匀抬升到水平段,从而提高采收率。该技术在现场实践中取得较好的应用效果。     

苏北盆地中低渗油藏早期注水开发技术研究

为了提高复杂小断块低渗油藏的开发水平,在早期油藏描述和开发技术政策综合研究的基础上,采用“早期注水、合理布井、平稳注采”等方法,运用开发全过程的油气层保护措施,实现了有效的早期或同步注水;与此同时,又超前开展精细油藏描述和渗流机理等综合研究,广泛应用新工艺、新技术进行跟踪调整,巩固了早期注水成果,确保了油田高效稳产。G6、Z2、W2断块的开发实践表明,这些方法和技术开发复杂小断块低渗油藏是有效的。