陈373块薄层稠油油藏N2和CO2补充地层能量可行性研究

为探索N2、CO2对稠油物性参数的影响规律,采用室内实验与数值模拟相结合的方法。实验测定注入N2、CO2后地层条件下稠油体积膨胀系数、黏度、溶解系数等物性参数,并利用CMG油藏数值模拟软件进行CO2、N2补充地层能量的数值模拟研究。研究结果表明,在一定的温度和所测压力范围内,CO2和N2在陈373块稠油中的溶解度、体积膨胀系数均随压力的升高而升高,且CO2的溶解性能、膨胀幅度均优于N2;随压力的增大,溶解气体后原油黏度呈下降趋势,且CO2的降黏效果优于N2;在油藏压力12 MPa下,N2的溶解可使原油的黏度下降23.58%,CO2溶解可使原油黏度下降74.96%。注CO2吞吐、N2吞吐和蒸汽吞吐的平均周期产油量由高到低依次为788.5 t、419.9 t和266.7 t,因此CO2吞吐的周期产油效果最高;从保持地层能量来看,在同一井筒范围(20 m)CO2的吞吐的油藏压力降幅最小,对补充地层能量的效果最好;从经济效益来看,N2吞吐的经济效果最高、CO2吞吐次之,蒸汽吞吐已无经济效益。

Study of the feasibility by injecting nitrogen and carbon dioxide for energy complement in the thin heavy oil reservoir of Chen 373

The study combined laboratory test with numerical simulation to understand ?the effects of nitrogen and carbon dioxide on heavy oil. The coefficient of cubical expansion,viscosity of heavy oil and solubility were systematically researched by laboratory experiments. The results show that under certain pressure and certain temperature conditions, the coefficient of cubical expansion and solubility of oil which dissolve nitrogen and carbon dioxide increases with the increase of pressure. On the contrary, viscosity reduces with the increase of pressure. At 12 MPa, dissolution of N2 enables the viscosity of crude oil reduces by 23.58%, while CO2 reduces by 74.96%. The average cycle oil production are (from high to low):CO2 soaking(788.5t),N2 soaking(419.9t),steam huff and puff(266.7t), it is easy to see that CO2 soaking gets excellent results. The pressure of CO2 soaking drops least in the same shaft range(20m), as a result it can get the best result for energy complement. N2 soaking can get the maximum revenue, while steam huff and puff has no economic benefits.