致密油藏水平井分段压裂CO_2吞吐实验研究

Experiments of CO_2 Huff-n-puff Process in Staged Fracturing Horizontal Wells for Developing Tight Oil Reservoirs

目前,某油田正在进行CO_2吞吐试验,该油田属于致密油藏,分段压裂水平井CO_2吞吐效果受诸多因素制约,急需通过物理模拟方法研究复杂条件下的CO_2吞吐机理。因此,采用大型物理模拟实验系统,首次选用露头平板模型,针对致密油首次利用致密岩芯和实际原油,开展分段压裂水平井CO_2吞吐模拟实验研究。实验结果表明,CO_2吞吐能有效提高致密油藏采收率,且注入压力是CO_2吞吐效果重要的影响因素;通过对吞吐过程中模型不同位置压力、出口产量等关键参数分析,明确了CO_2吞吐地层能量补充特征。研究成果对于致密油藏有效开发具有一定指导意义。

Using large physical simulation equipment and outcrop plate model,an experimental study on CO2huff-n-puff instaged fracturing of horizontal wells was carried out.The experiment results show that CO2huff-n-puff can effectively improveoil recovery of tight oil reservoir.In addition,the injection pressure is an important factor affecting CO2huff-n-puff effect.Byanalyzing pressures at different model locations,production and other key parameters,we clearly define the stratigraphic energysupplement features of CO2huff-n-puff.The result of the research has great significance in the effective development of tightoil reservoirs.