胜利油田注空气提高采收率数模研究

Numerical simulation study on enhanced oil recovery by air injection process in Shengli Oilfield

根据胜利油田轻质油样的室内氧化实验,通过拟合动态氧化实验产出的O2与CO2含量,建立其低温氧化(LTO)动力学模型,并结合组分模型、PVT模型及相渗模型,研究低渗透油藏注空气低温氧化工艺的数值模拟方法;以胜利渤南油田罗36块为例,初步评价了油藏参数、开发参数及工艺参数等因素对注空气驱油效果的影响,同时分析了注空气提高采收率机理,并对比注空气与氮气工艺的驱油效果及经济可行性,对注空气开发矿场试验具有一定指导作用。结果表明,实验模拟与实际气体含量拟合较好,从而确定动力学参数;油藏初始温度、初始含油饱和度等是影响注空气效果的重要参数,而油藏倾角、网格大小、射孔位置等对采收率也有影响;注空气相对于氮气而言成本低,驱油效果好。

Air injection LTO （low temperature oxidation） process is a new technique economically for enhanced oil recovery （EOR） from light or medium oil and low permeability reservoirs. This paper aims at studying the oxidation kinetics of light oils and building up the reservoir simulation models for the LTO process. Oxidation experiments at reservoir temperatures have been conducted for light oil samples of the Shengli Oilfield （China） , and the data were used for deriving the kinetics model of LTO reactions, by matching the contents of oxygen and carbon dioxide in the oil displacement experiment. Conceptual reservoir simulation models have been developed for studying the EOR mechanisms and the affecting factors of the air injection LTO process, using the reservoir parameters of Luo36 Block. Moreover, air injection process was compared with nitrogen injection in terms of oil displacement efficiency and economics. The simulation results suggest that there is a good match with experimental results. Besides, reservoir temperature, air injection rate and residual oil saturation （ before air injection） are important parameters that can greatly affect the consumption of oxygen and incremental oil recovery, while reservoir dip angle, layer perforations can also affect the process. Compared with nitrogen gas injection, the advantages of air injection are the low cost in gas source and high oil displacement efficiency due to thermal effect of the LTO reactions.