歧口17-2油田注入水颗粒粒径与喉道配伍性研究

The Compatibility between Suspended Solids Partice Size and Pore Throat during Water-Flooding in Qikou 17-2 Oilfield

歧口17-2油田注入水颗粒粒径指标主要是依据行业标准制定的,在此基础上开展其与喉道的配伍性研究是极有必要的。通过对地层系数的计算统计明确了目标油田主力注水层位分布。利用主力注水层位岩心的压汞曲线数据,分析了其微观孔隙结构,获得了主流喉道中值。综合考虑,取渗透率约为2 000mD的24块岩心进行模拟注水实验。根据国标SY/T 5329—94,针对目标油田主力吸水层位渗透率,取最严格质量浓度指标上限5mg/L时,认为渗透率伤害值超过25%的粒径区间即为规避区间,现场注水时粒径需考虑规避区间的下限,目标油田为主流喉道中值的1/8。当注入水颗粒质量浓度为5mg/L,粒径增加至4μm时渗透率伤害率值增大至20%,故目标油田注入水中悬浮颗粒质量浓度应小于5mg/L,粒径应小于4μm。

The injected water suspended solids particle size index of Qikou 17-2 oilfield is mainly based on the industry standard ,it is essential to carry out the study on compatibility between suspended solids particle size and pore throat on this basis .The distribution of principle water-injection intake level for Qikou 17-2 oilfield is obtained via the statistics of the formation factor .Based on the capillary pressure curves from the main water injection reservoir ,the microscopic pore structure was analyzed and the median primary fluid throat was obtained .In order to find out the compatibility ratio of suspended particle to the median primary fluid throat during water-flooding for the target oilfield ,24 pieces of cores ,which its’ permeability are around 2 000 mD ,are used to simulate water-flooding .According to Chinese standard SY/T 5329-94 ,the upper limit of particles concentration of the most strictest index at the target permeability is 5 mg/L .Considering that when the damage extent is over 25% ,the relevant size distribution of the particles should be avoided and it’s lower limit is adopted for the working site .Experimental results show that the ratio of the lower limit to the median primary fluid throat is 1/8 .The damage extent was over 20% when the concentration of the particles was 5 mg/L and the upper limit of the size distribution was 4μm . Thus the concentration and the upper limit of the size distribution of the suspend particles should be controlled individually in 5 m g/L and 4 μm .