Viscosity estimation of mixed oil using RBF-ANN approach

Diluting the bitumen and heavy oil with a liquid solvent such as tetradecane is one way to decrease the viscosity. The accurate estimation for the viscosity of the aforesaid mixture is serious due to the sensitivity of enhanced oil recovery method. The main aim of this study was to propose an impressive relation between the viscosity of heavy n-alkane and Athabasca bitumen mixtures based on pressure, temperature, and the weight percentage of n-tetradecane using radial basis function artificial neural network (RBF-ANN). Also, this model has been compared with previous equations and its major accuracy was evidenced to estimate the viscosity. The amounts of mean relative error (MRE %) and R-squared received 0.32 and 1.00, respectively. The endeavors confirmed amazing forecasting skill of RBF-ANN for the approximation of the viscosity as a function of temperature, pressure, and the weight percentage of n-tetradecane.     

Improved empirical relations for estimating original oil in place recovered during microbial enhanced oil recovery under varied salinity conditions

During microbial enhanced oil recovery (MEOR) processes, the interaction between injection water (IW) and formation water (FW) salinity causes in-situ salinity variation which affects the final oil recovery. The present study explicitly quantifies the Original Oil in Place (OOIP) recovered for different IW and FW salinity conditions through numerical simulation. Based on simulation results, user-friendly empirical correlations were deduced to quickly estimate the OOIP. The results suggest that the OOIP increases drastically in all reservoirs with any initial FW salinity as the adopted salinity of IW is lowered. The study would serve as a tool for making reservoir management decisions.     

Comparison of in-situ and ex-situ microbial enhanced oil recovery by strain Pseudomonas aeruginosa WJ-1 in laboratory sand-pack columns

Microbial enhanced oil recovery (MEOR) applies biotechnology to improve residual crude oil production from substratum reservoir. MEOR includes in-situ MEOR and ex-situ MEOR. The former utilizes microbial growth and metabolism in the reservoir, and the latter directly injects desired active products produced by microbes on the surface. Taking biosurfactant-producing strain Pseudomonas aeruginosa WJ-1 for research objects, in-situ enhanced oil recovery and ex-situ enhanced oil recovery by biosurfactant-producing strain WJ-1 were comparatively investigated in sand-pack columns.The results showed that P.aeruginosa WJ-1 really proliferated in sand-pack columns, produced 2.66 g/L of biosurfactant, altered wettability, reduced oil-water interfacial tension (IFT) and emulsified crude oil under simulated in-situ process. Results also showed that higher biosurfactant concentration, lower IFT, smaller average diameters of emulsified crude oil were obtained in in-situ enhanced oil recovery experiment than those in ex-situ enhance oil recovery experiment. Similar wettability alteration was observed in both in-situ and ex-situ enhanced oil recovery experiment. The flooding experiments in sand-pack columns revealed that the recovery of in-situ was 7.46%/7.32% OOIP (original oil in place), and the recovery of the ex-situ was 4.64%/4.49% OOIP. Therefore, in-situ approach showed greater potential in enhancing oil recovery in contrast with ex-situ approach. It is recommended that the stimulation of indigenous microorganisms rather than injection of microbial produced active products should be applied when MEOR technologies were employed.     

水包油乳液型复合泥饼清除剂的室内研究

针对裂缝性致密砂岩储层存在的高密度油基钻井液固相颗粒侵入以及泥饼难以清除等问题,开发出一种高效率、抗高温、低成本的水包油型复合泥饼清除剂。复合泥饼清除剂由混合酸、抗高温渗透剂、清洗剂、乳化剂等组成。通过对复合泥饼清除剂——水包油型乳液体系以及新型泥饼清除剂——纳米乳液体系的对比研究分析表明,在洗油方面以及溶蚀泥饼结构方面,复合泥饼清除剂效果优于纳米乳液。该复合泥饼清除剂的稳定性能强,抗温可达120℃;在静态条件下泥饼清除率可以达到90%以上,在动态条件下清除后岩心渗透率恢复值可以达到89%,最佳作业时间为8 h。在目前求降本增效的形势下,该复合泥饼清除剂剂配方简单,性能优良,解堵时间较短,能够有效改善和提高岩心渗透率恢复值。      

Some observations from interrupted lifetest of GaInAsP/InP inverted-rib laser diodes

Conventionally, lifetests of semiconductor laser diodes usually involved operating the devices continuously at either constant power output or drive current, with periodic recording of their characteristics. In this paper, some effects arising from interrupted lifetest of 1.3 m GaInAsP-InP inverted-rib laser diodes are reported. This unconventional lifetest method involves constant power biasing at 4 mW/facet and 8 mW/facet respectively at 50°C, followed by a period during which the lifetest is interrupted and the devices left unbiased at room temperature. Subsequently, the devices were put back on constant power biasing at 50°C. Among a number of parameters, pronounced reduction in the threshold current, current for 4 mW/facet and 8 mW/facet were observed, indicating strong recovery effects commencing from the time when the life-test was interrupted. Redistribution of mobile defects in the cladding layer is postulated to be the cause of the degradation recovery, and the data supports the occurrence of an aging-current dependent defect annihilation mechanism. Such recovery effects have so far been observed to occur only in the GaInAsP-InP inverted-rib devices.     

光纤定时恢复器用声表面波低损耗滤波器

介绍了定时恢复器对声表面波滤波器的基本要求及实现低损耗的方法，并给出了实验结果。     

氧化吸收工艺再生SO2返回天然气净化厂二级Claus工艺的模拟研究

针对氧化吸收工艺应用于天然气净化厂Claus尾气减排的情况,利用VMGSim软件模拟了该工艺脱除Claus尾气中SO_2并返回二级Claus工艺的过程,阐明了不同的SO_2返回位置对硫回收率及主燃烧炉温度的影响,并提出了应对措施,可为氧化吸收工艺在天然气净化厂的应用提供重要参考。     

中贵线乙烷回收工程模拟计算研究

在国内大型凝析气田中,发现原料气中含有丰富的乙烷,为加强乙烷资源的有效利用,实现天然气产业效益最大化,开展了中贵线乙烷回收工程可行性研究。该项目采用ASPEN HYSYS模拟软件,对膨胀机制冷+尾气再循环脱甲烷塔双回流工艺进行研究,并对该工艺的流程特性进行分析考察了膨胀后压力、低温分离器温度、膨胀气流比例、原料气组成中CO_2与C_2H_6含量及原料气压力等因素的变化,以及对装置性能包括收率、动力消耗、天然气消耗以及年收益的影响。