北一区断东二类油层三元复合驱室内实验研究
发布时间：2018-08-08 19:09
【摘要】：大庆油田从二十世纪八十年代至今,着重对三元复合驱以及驱油效果开展了大量的研究工作,已完成4个主力油层强碱三元复合驱矿场试验,随着三元复合驱驱油技术在二类油层的开展,驱替对象的渗透率更低、层间差异更大,由于存在着层间矛盾大、层段多和储层结构复杂等的问题,需要通过注入能力测试和三元复合驱段塞的优选以及色谱分离动滞留实验进行确定。以大庆油田二三类油层为依托,通过开展了聚合物分子量、浓度和岩心渗透率匹配关系的室内实验研究,计算三元体系的阻力系数、残余阻力系数等参数。通过物理模拟实验对三元复合驱主、副段塞大小及段塞中各化学剂浓度进行优选,以确定最佳主、副段塞大小及段塞浓度。通过应使用足够长的天然岩心岩在尽量接近油藏条件下进行物理模拟驱替实验观察色谱现象,确定三元组分的无因次等浓聚等参数。结果表明,三元体系的黏度降解程度影响最高注入压力,渗透率相同时,降解程度越大,最高注入压力越低;渗透率影响三元体系的最高注入压力,在三元体系的黏度降解程度相同时,渗透率越低,注入压力越高;在等黏条件下,低分子量聚合物用量较多,且在岩心中降低水相渗透率的能力较弱,而过高的聚合物分子量会导致岩心堵塞,故考虑二类油层渗透率的具体情况,建议采用1600万分子量聚合物三元体系进行注入,黏度采用剪切前50m Pa·s三元复合体系;运用制备的与实际储层孔渗特点等对应的岩心进行段塞大小与浓度优选驱油实验,确定最佳注入段塞为主段塞浓度为[1.2wt%碳酸钠+0.3wt%表面活性剂+2200mg/L聚合物溶液]0.35PV,副段塞浓度为[1.0wt%碳酸钠+0.1wt%表面活性剂+2200mg/L聚合物溶液]0.15PV;通过天然浇筑岩心三元体系动滞留实验,确定碱的滞留量为0.31mg/g,表面活性剂的滞留量为0.1 mg/g,聚合物的滞留量为0.051 mg/g,碱的滞留量最大,结合测量结果得到了三元体系各组分的无因次等浓聚,得出弱碱三元复合体系在注入时有色谱分离现象;三元复合体系在流经模型时,聚合物与碱以及表面活性剂之间都发生了色谱分离,聚合物最先突破,碱和表面活性剂随后一起突破。二类油层复杂的孔隙结构可能加剧了色谱分离的程度。
[Abstract]:From the 1980s to the present, Daqing Oilfield has carried out a lot of research work on ASP flooding and its effect, and has completed the field tests of 4 main reservoirs with strong alkali ASP flooding. With the development of ASP flooding technology in the second class reservoir, the permeability of displacement object is lower and the difference between layers is greater. It needs to be determined by injection capability test, optimization of ASP flooding slug and chromatographic separation and retention test. Based on the second and third types of oil layers in Daqing Oilfield, the parameters of resistance coefficient and residual resistance coefficient of ternary system are calculated by laboratory experimental study on the matching relationship among polymer molecular weight, concentration and core permeability. Through the physical simulation experiment, the size of ASP flooding, the size of secondary slug and the concentration of each chemical agent in the slug are selected to determine the optimum size of main and secondary slug and the concentration of slug. The chromatographic phenomena of natural core rock with long enough length should be observed by physical simulation and displacement experiments under the condition of being as close to the reservoir as possible, and the parameters such as dimensionless secondary concentration accumulation of ternary components are determined. The results show that the maximum injection pressure is affected by the viscosity degradation degree of the ternary system, the maximum injection pressure is lower with the same permeability, and the maximum injection pressure is affected by the permeability of the ternary system. When the viscosity degradation degree of the ternary system is the same, the lower the permeability is, the higher the injection pressure is, and the lower the amount of low molecular weight polymer is, the lower the permeability of water phase is in the core of rock. However, too high molecular weight of polymer will lead to core blockage, so considering the specific situation of permeability of the second class reservoir, it is suggested that 16 million molecular weight polymer ternary system be used for injection, and the viscosity is 50 MPA s ternary composite system before shear. By using the prepared core corresponding to the pore and permeability characteristics of the actual reservoir, the slug size and concentration are optimized for oil displacement experiments. The optimum concentration of main slug for injection slug is [1.2wt% sodium carbonate 0.3wt% surfactant 2200mg/L polymer solution] 0.35PV.The secondary slug concentration is [1.0wt% sodium carbonate 0.1wt% surfactant 2200mg/L polymer solution] 0.15PV.The dynamic retention experiment of natural core ternary system is carried out. It is determined that the retention of base is 0.31 mg / g, that of surfactant is 0.1 mg / g, that of polymer is 0.051 mg / g, and that of alkali is the largest. It is concluded that the weak base ternary system has chromatographic separation phenomenon at the time of injection. When the ASP system passes through the model, the chromatographic separation occurs between polymer, alkali and surfactant, and the polymer breaks through first. The base and surfactant then broke through. The complex pore structure of the second class reservoir may aggravate the degree of chromatographic separation.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357.46
，
本文编号：2172752
[Abstract]:From the 1980s to the present, Daqing Oilfield has carried out a lot of research work on ASP flooding and its effect, and has completed the field tests of 4 main reservoirs with strong alkali ASP flooding. With the development of ASP flooding technology in the second class reservoir, the permeability of displacement object is lower and the difference between layers is greater. It needs to be determined by injection capability test, optimization of ASP flooding slug and chromatographic separation and retention test. Based on the second and third types of oil layers in Daqing Oilfield, the parameters of resistance coefficient and residual resistance coefficient of ternary system are calculated by laboratory experimental study on the matching relationship among polymer molecular weight, concentration and core permeability. Through the physical simulation experiment, the size of ASP flooding, the size of secondary slug and the concentration of each chemical agent in the slug are selected to determine the optimum size of main and secondary slug and the concentration of slug. The chromatographic phenomena of natural core rock with long enough length should be observed by physical simulation and displacement experiments under the condition of being as close to the reservoir as possible, and the parameters such as dimensionless secondary concentration accumulation of ternary components are determined. The results show that the maximum injection pressure is affected by the viscosity degradation degree of the ternary system, the maximum injection pressure is lower with the same permeability, and the maximum injection pressure is affected by the permeability of the ternary system. When the viscosity degradation degree of the ternary system is the same, the lower the permeability is, the higher the injection pressure is, and the lower the amount of low molecular weight polymer is, the lower the permeability of water phase is in the core of rock. However, too high molecular weight of polymer will lead to core blockage, so considering the specific situation of permeability of the second class reservoir, it is suggested that 16 million molecular weight polymer ternary system be used for injection, and the viscosity is 50 MPA s ternary composite system before shear. By using the prepared core corresponding to the pore and permeability characteristics of the actual reservoir, the slug size and concentration are optimized for oil displacement experiments. The optimum concentration of main slug for injection slug is [1.2wt% sodium carbonate 0.3wt% surfactant 2200mg/L polymer solution] 0.35PV.The secondary slug concentration is [1.0wt% sodium carbonate 0.1wt% surfactant 2200mg/L polymer solution] 0.15PV.The dynamic retention experiment of natural core ternary system is carried out. It is determined that the retention of base is 0.31 mg / g, that of surfactant is 0.1 mg / g, that of polymer is 0.051 mg / g, and that of alkali is the largest. It is concluded that the weak base ternary system has chromatographic separation phenomenon at the time of injection. When the ASP system passes through the model, the chromatographic separation occurs between polymer, alkali and surfactant, and the polymer breaks through first. The base and surfactant then broke through. The complex pore structure of the second class reservoir may aggravate the degree of chromatographic separation.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357.46
，
本文编号：2172752
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