大庆油田致密油储层压裂增能影响因素分析

Analysis of factors influencing fracturing energization in tight oil reservoirs in Daqing Oilfield

为了明确不同因素对压裂增能效果的影响,对致密油藏压裂液注入、焖井、采出全过程进行了模拟。选取大庆外围致密油储层天然岩心开展实验研究,通过对采出程度、孔隙压力和含水率的监测,分析了岩心渗透率、润湿性、裂缝条数、注入量、焖井时间和泥质含量对致密油藏压裂增能动态响应特征的影响。研究结果表明,致密油储层压裂增能工艺可以有效改善致密油储层的采收率;储层物性越好、水湿性越强,压裂增能效果越好,渗透率1.68×10^(-3)μm^(2)岩心比渗透率0.39×10^(-3)μm^(2)岩心的采出程度高10.8%,强水湿岩心与弱水湿岩心的采出程度相差2.86%。此外,通过提高压裂液注入量、增加裂缝数量、优化焖井时间和加入防膨剂都能够显著提高致密油藏的采收率,为油田提供技术参考。

In order to clarify the influence of different factors on fracturing energization effect,the whole process of fracturing fluid including injection,well soaking and production in tight oil reservoirs was simulated.The natural cores from the tight oil reservoirs in the periphery of Daqing Oilfield were selected for experimental research.By monitoring the recovery degree,pore pressure and water content,the influence of factors,such as core permeability,wettability,fracture numbers,injection volume,soaking period,and shale content,on dynamic response characteristics of fracturing energization in tight oil reservoirs were analyzed.The results show that the fracturing energization technology can effectively improve the recovery rate in tight oil reservoirs,and that the better the physical properties of the reservoir and the stronger the water wettability,the better the fracturing energization effect.The recovery degree of the core with a permeability of 1.68×10^(-3)μm^(2) is 10.8%higher than that of the core with a permeability of 0.39×10^(-3)μm^(2),and the recovery degree of the core with a strong hydrophilia is 2.86%higher than that of the core with a weak hydrophilia.Furthermore,many other measures such as increasing the injection amount of fracturing fluid,increasing the number of fractures,optimizing the soaking period,and adding anti-swelling agent can all can significantly improve the recovery rate in tight oil reservoirs,which may provide technical references for oilfields.