低渗透油藏CO_2吞吐选井条件探讨
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摘要
苏北盆地低渗透油藏分布广,普遍存在天然能量不足且构造破碎,难以形成有效注采井网等问题,因此,水驱效果差。CO_2吞吐能有效解决这一问题,并且投入少、工艺简单、见效快。选择合适的油井实施是该项工艺成败的关键。通过对苏北盆地低渗透油藏近年实施的CO_2吞吐情况进行对比分析,结合室内物理模拟实验及数值模拟成果,认为埋深为中—深层,裂缝发育的封闭油藏较适合实施CO_2吞吐,裂缝对吞吐效果影响较大,地层压力存在一个适宜区间,并非越大越好,是否能达到混相对吞吐效果并无决定性影响。位于构造较低部位,初产高,含水在30%～70%的油井比较有利于吞吐,水平井实施吞吐效果优于直井。
Low permeability reservoirs are widely distributed in Subei(northern Jiangsu province)Basin. There are some problems such as insufficient natural energy and fragmented structures, which make it difficult to form an effective injection-production well pattern. Therefore, the effect of water injection is poor. The CO_2 huff and puff technology can effectively solve these problems with less investment, simple process and rapid results. Choosing the proper wells to execute is the key to the success of this technology.Based on the comparative analysis of CO_2 huff and puff in low permeability reservoirs in Subei Basin in recent years, combined with indoor physical simulation experiments and numerical simulation results, it is considered that closed reservoirs with medium-deep burial depth and fracture development are more suitable for CO_2 huff and puff. Fractures have a greater impact on huff and puff effect. There is an appropriate interval for formation pressure, not the bigger the better, whether miscibility can be achieved or not. It has no decisive effect on the throughput effect. Oil wells with high initial production and water cut of 30 %～70 % in lower structure are more conducive to huff and puff, and the huff and puff effect of horizontal wells is better than that of vertical wells.
Low permeability reservoirs are widely distributed in Subei(northern Jiangsu province)Basin. There are some problems such as insufficient natural energy and fragmented structures, which make it difficult to form an effective injection-production well pattern. Therefore, the effect of water injection is poor. The CO_2 huff and puff technology can effectively solve these problems with less investment, simple process and rapid results. Choosing the proper wells to execute is the key to the success of this technology.Based on the comparative analysis of CO_2 huff and puff in low permeability reservoirs in Subei Basin in recent years, combined with indoor physical simulation experiments and numerical simulation results, it is considered that closed reservoirs with medium-deep burial depth and fracture development are more suitable for CO_2 huff and puff. Fractures have a greater impact on huff and puff effect. There is an appropriate interval for formation pressure, not the bigger the better, whether miscibility can be achieved or not. It has no decisive effect on the throughput effect. Oil wells with high initial production and water cut of 30 %～70 % in lower structure are more conducive to huff and puff, and the huff and puff effect of horizontal wells is better than that of vertical wells.
引文
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[2]陈民锋,姜汉桥,吴应川.CO2吞吐井位优选模糊综合评判方法研究[J].油气田地面工程,2008,27(10):1-4.
[3]鞠斌山,栾志安,郝永卯,等.CO2吞吐效果的影响因素分析[J].中国石油大学学报(自然科学版),2002,26(1):43-48.
[4]黄琴.裂缝岩心系统CO2吞吐驱油室内实验研究[J].国外油田工程,2008,24(4):9-12.
[5]钱卫明,程诗胜,葛永涛.低渗透油藏单井CO2吞吐参数实践与认识[J].断块油气田,2004,11(5):40-42.
[6]赵军胜,钱卫明,朗春燕.苏北低渗透油藏CO2吞吐矿场试验[J].断块油气田,2003,10(1):73-76.
[7]张国强,孙雷,孙良田,等.小断块油藏CO2单井吞吐强化采油可行性研究[J].西南石油学院学报,2006,28(3):61-66.
[8]王志兴,赵凤兰,侯吉瑞,等.断块油藏水平井组CO2协同吞吐效果评价及注气部位优化实验研究[J].石油科学通报,2018,3(2):183-194.