超稠油HDCS高效开采技术研究

MECHANISM RESEARCH ON HDCS HIGH EFFICIENCY EXPLOITATION TECHNOLOGY FOR ULTRA-HEAVY OIL RESERVOIR

HDCS高效开采技术是一种采用油溶性复合降粘剂及CO2辅助水平井蒸汽吞吐的超稠油开采技术,它由水平井、油溶性复合降黏剂、CO2和蒸汽四个关键部分构成。研究表明超稠油HDCS高效开采技术针对超稠油油藏有诸多优势:数值模拟研究表明水平井能增强注汽能力,增大油汽比,对于薄油层能够相当大程度上减少蒸汽的热损失;实验研究表明通过注入高效油溶性降黏剂和CO2能减小油水界面张力,破碎沥青质的层状结构,降低原油粘度,降低剩余油饱和度,增强地层弹性能量,减缓油藏压力衰竭。矿场统计和分析表明该技术可有效地提高蒸汽利用率,降低注汽压力,提高油汽比,增加产量和生产周期。该技术的应用使黏度大于300000mPa.s(50℃)、埋深大于1300m、油层平均厚度小于8m的超稠油藏实现了动用,目前已在胜利油田建成4×104t的产能。

HDCS high efficiency exploitation technology is an exploitation technology for ultra-heavy oil.Oil-soluble viscosity reducer and CO2 are adopted in the technology to assist steam huff and puff in horizontal wells.It is composed of four critical parts which are horizontal well,dissolver,CO2 and steam huff and puff.The research indicated that the HDCS technology aimed at ultra-heavy oil reservoir has many advantages.The numerical simulation research indicated that horizontal well can enhance steam injection,augment oil-steam ratio and reduce heat loss for oil sheet in a considerable degree.The experimental study showed that the injection of high efficient oil-soluble viscosity reducer and CO2 can reduce oil-water interfacial tension and break the laminar structure of bitumen,reduce viscosity of crude oil and remaining oil saturation,enhance elastic energy of formation and slow down pressure exhaust of reservoir.Field counting and analysis indicated that the technology can advance steam efficiency,reduce injection pressure of steam,boost oil/steam ratio,increase output and production circle.The ultra-heavy oil reservoir whose viscosity of crude oil is above 300 000mPa·s(50℃),depth is more than 1300m and average thickness is less than 8m,has been produced by using this technology.The productivity has reached 40 000t in Shengli Oilfield.