超深稠油注天然气气举降掺稀先导试验

塔河油田稠油埋藏深(5 500～6 700 m)、黏度高(10~2~10~3Pa·s)、胶质沥青质含量高,开采难度大。针对常规稠油掺稀工艺存在稀油供应压力大、经济效益差的问题,提出了稠油注天然气气举降掺稀的方法。通过油气混溶室内实验和现场先导试验相结合开展了稠油注天然气气举降掺稀工艺技术研究。结果表明,对于井筒举升难度大的稠油,利用天然气的混溶降黏和气举双重功效,能够有效地提升稠油井筒流动性,降低掺稀量,提高稠油开发效率。开展先导试验的XD1井在试验期间稀稠质量比由试验前1. 27下降至0. 63,平均节约稀油50. 4%,累计节约稀油421. 7 t,累计增油205. 4 t,取得了较好降黏增油效果。

Pilot test of the viscosity reduction by the natural gas injection and lift for the extra-deep heavy oil

Because of the deep buried depth (5 500-6 700 m), high viscosity (10^2-10^3 Pa·s) and high content of the asphaltene, it is difficult to develop for the heavy oil in Tahe Oilfield. In light of the problems of the big pressure of thin oil supply and poor economic benefit for the conventional heavy-oil viscosity reducing technology, the viscosity-reducing method of the heavy oil by the natural gas injection and lift was proposed. Through the combination of oil and gas miscible indoor experiment and field pilot test, the technical research on the viscosity reducing technology by heavy-oil natural gas injecting and lifting was conducted. The results show that for the difficulty of the heavy oil wellbore lift, with the help of the dual effects of the natural gas mixed solution-viscosity reduction and gas lift, the wellbore liquidity of the heavy oil can be effectively improved, the amount of the dilution can be reduced and the efficiency of the heavy oil development can be improved. During the pilot test, the ratio of the thin oil to heavy oil of Well XD1 decreased from 1.27 to 0.63, the average saved oil rate was 50.4%, the accumulative total of the saved oil was up to 421.7 t and cumulative incremental oil production reached 205.4 t, so the effects of decreasing viscosity and increasing oil have achieved.