薄层超稠油油藏烟道气SAGP室内实验评价

Indoor Experimental Evaluation of Flue Gas SAGP in Thin Ultra-Heavy Oil Reservoirs

针对薄层超稠油油藏蒸汽驱采收率较低的问题,以准噶尔盆地北缘哈山地区浅层稠油为研究对象,对发育隔层的超稠油油藏进行烟道气SAGP室内二维物理模拟实验研究,研究蒸汽腔发育及气体分布特征,分析油、气、水在烟道气SAGP过程中的变化规律,进而评价薄层超稠油油藏烟道气SAGP提高采收率的潜力,优化注烟道气时机和注气量。研究表明:薄层超稠油烟道气SAGP阶段采出程度可达到56%,累计油汽比为0.21,具有较大的提高采收率潜力;采用蒸汽与烟道气同注的方式,烟道气位于蒸汽腔前缘,没有在油层顶部和盖层底部附近形成低温隔热带;烟道气聚集在蒸汽腔的前缘,阻碍了蒸汽腔的横向扩展,减缓了蒸汽超覆现象;当蒸汽腔扩展到油层底部时,注入0.08~0.10倍孔隙体积的烟道气,采收率为54%~56%。该研究成果可为薄层超稠油藏提高采收率提供重要参考。

To address the problem of low recovery rate by steam flooding in thin ultra-heavy oil reservoirs,an indoor two-dimensional physical simulation experiment of flue gas SAGP was conducted on ultra-heavy oil reservoirs with developed interlayers by taking shallow heavy oil in the Hashan area on the northern edge of the Junggar Basin as the study object to study the characteristics of steam chamber development and gas distribution,and to analyze the change law of oil,gas and water in the process of flue gas SAGP,so as to evaluate the potential of flue gas SAGP in thin ultra-heavy oil reservoirs to enhance recovery and optimize the timing and volume of flue gas injection.The study shows that the recovery degree of the thin ultra-heavy oil in the flue gas SAGP stage can reach 56%,and the cumulative oil-to-steam ratio is 0.21,so there is a large potential for recovery enhancement;the steam is injected together with the flue gas,the flue gas is located at the front edge of the steam chamber,and no low-temperature insulation zone is formed near the top of the oil layer and the bottom of the cap layer;the flue gas gathers at the front edge of the steam chamber,which hinders the lateral expansion of the steam chamber and slows down the steam overlap;when the steam chamber is extended to the bottom of the oil layer,the recovery rate is 54%to 56%by injecting 0.08 to 0.10 times the pore volume of flue gas.The research results can provide an important reference for recovery enhancement of thin ultra-heavy oil reservoirs.