【作者】 马海佳；

【导师】 刘义坤；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2008， 博士

【摘要】 大庆油田实践表明,聚合物驱可在水驱基础上提高采收率10个百分点以上。2008年大庆油田聚驱年产量达到1110万吨,占总产量的1/4,已连续七年超过1000万吨,为大庆油田高产、稳产发挥了重要作用。大庆油田受沉积环境影响,油层非均质性严重,高、低渗透层差异较大。在笼统注入聚合物驱方式下,存在着高渗透层无效循环严重、低渗透层动用程度低的矛盾。为了改善开发效果,提高资源利用率,必须实现分层注入,即通过限制高渗透层注入量、提高低渗透层注入量,保证注入流体以活塞方式均匀推进。但对于聚合物溶液这种粘弹性非牛顿流体,如果采用常规水驱分层注入技术(即通过减小过流面积来形成节流压差、控制注入量)进行分层注入,存在着粘度损失率高(40～70%)、影响驱替效果的问题。在深入调研基础上,开展了对聚合物驱分层注入技术的研究。针对不同油层的特点,形成了两项核心技术,即聚合物驱同心分注技术和聚合物驱分质注入技术。聚合物驱同心分注技术,适合于单层注入量大的一类油层,可实现2～3层聚合物分注。聚合物驱分质注入技术,适合于层间矛盾更大的二、三类油层,可实现多层聚合物分质注入。通过实现分层分子量的调节,可缓解由于低渗透油层对中、高分子量聚合物的适应性差而造成的低渗透油层堵塞问题。1、聚合物驱同心分注技术。研制了流线形环型降压槽的同心配注器,实现对注入压力的控制,满足(20～150)m3/d注入量要求,最大节流压差达到3.0MPa,对聚合物溶液最大粘损率小于4.0%。到2008年底,应用757口井,连通油井平均单井日增油2吨,含水下降1.4个百分点,累计增油96万吨。2、聚合物驱分质注入技术。实现分层分子量及分层注入量的双重控制,使聚合物分子量与油层渗透率的匹配关系趋于合理。分子量调节器采用机械降解方式实现聚合物分子量的调节,在50m3/d流量范围内,可将聚合物分子量降低(20～50)%,最大节流压差1.5Mpa。通过驱油实验确定了不同分子量聚合物与油层渗透率的匹配关系,并创立了聚合物溶液在分子量调节元件中流动的节流压差和粘损计算模型。压力调节器控制压差达到3.5MPa,单层控制流量70m3/d以内,粘度降解率小于8%。到2008年底,应用114口井。分质注入后,与正常分层注聚井对比,厚度动用比例由85.9%提高到94.9%,分质井组含水下降幅度比全区见效井高7.1个百分点。与笼统注聚井组对比,连通油井含水下降14.5个百分点,平均单井日增油3.5吨,累计增油26万吨。更多还原

【Abstract】 It is indicated that polymer flooding can enhance oil recovery above 10% on the basis of water flooding in Daqing Oil Field. The annual yield of polymer flooding has measured up to 11.10 million ton in 2008 at Daqing Oil Field,occupy 1/4 of total yield,continuously exceed 10 million ton for seven years,played an important part in high production and stable yields for Daqing Oil Field.Affected by depositional environment of Daqing Oil Field,inhomogeneity of oil layer is serious,the difference between high and low permeability zone is large. Under vague injection,the contradiction of invalid cycle seriously in high permeability zone and usage level lowly in low permeability zone is existence. In order to enhance resource utilization ratio,improve develop effect,we should achieve separate zone injection.It is to say that we should ensure the injected fluid drive uniformevenly in the method of piston by confine injection of high permeability zone and enhance injection of low permeability zone. But polymer solution is viscoelasticity and non-Newtonian fluid,routine water drive separate injection technology is about forming orifice pressure difference and controlling influx through decreasing open area,so the problem of high viscosity loss factor(40～70%)and the affection on displacement effectiveness is existence.At the basic of in-depth research,the technological research of separate zone injection in polymer flooding is launched. At the moment,two core technologies are formed aiming at the feature of different oil zone,which are the technology of concentric separate zone injection in polymer flooding and the technology of dual injection in polymer flooding. The technology of concentric separate zone injection in polymer flooding is fit forⅠoil zone whose single zone injection amount is large,can achieve 2~3 layers separate injection of polymer. The technology of dual injection in polymer flooding is fit forⅡ、Ⅲoil zone whose interlamination contradictory is more larger,can achieve multilayer dual injection of polymer. Through achieving the adjustment of layering molecular weight, the problem of low permeability zone blocking up which is caused by the poor adaptability of the low permeability zone to the middle,high molecular weight polymer is alleviated.The technology of concentric separate zone injection in polymer flooding: In order to control the injection pressure, the concentric injection distribution device use the streamline ring step-down groove, which satisfied 20-150m3 /d diurnal injection, the maximum choke pressure difference can reached to 3.0MPa, the maximum visco-loss rate to the polymer solution less than 4.0%.The technology has used in 757 wells by the end of 2008,the daily crude output increased 2t/d, water content decreased 1.4%of a single well in Connected oil well, oil production accumulativel increased 9.6×10~5 tons.The technology of dual injection in polymer flooding: The dual control of layered molecular weight and layered injection volume, so that the matching relations of the polymer molecular weight and the reservoir permeability become rational. Molecular weight regulator use the mechanical degradation to control the polymer molecular weight. Under the the scope of 50m3/d, polymer molecular weight can be reduced by 20% -50%.,the maximum choke pressure difference can reach to 1.5MPa. Identified the matching relations of the polymer molecular weight and the reservoir permeability by oil flooding experiments, and found the calculation model of the choke pressure difference and the visco-loss. Pressure regulator to control pressure reached 3.5MPa, single-layer flow control less than 70m3/d, viscosity degradation rate less than 8%.The technology has used in 114 wells by the end of 2008. After dual injection, compared with the normal separated polymer injection well, The use ratio of thickness increased from 85.9% to 94.9%. The decrease range of water content in dual injection well is 7% higher than response well in all region. Compared with general polymer injection well, water content decreased 14.5%, the daily crude output increased 3.5t, oil production accumulativel increased 2.6×10~5 tons.更多还原